Opção de precificação e volatilidade avançadas estratégias e técnicas de negociação
Opção Volatilidade & amp; Preços: Estratégias e Técnicas Avançadas de Negociação.
Um dos livros mais lidos entre os operadores de opções ativas em todo o mundo, o Option Volatility & Pricing foi completamente atualizado para refletir os mais recentes desenvolvimentos e tendências em produtos de opção e estratégias de negociação.
Modelos de precificação Considerações sobre volatilidade Estratégias básicas e avançadas de negociação Técnicas de gerenciamento de risco E muito mais!
Escrito de forma clara e fácil de entender, Opção Volatilidade e Preços aponta os principais conceitos essenciais para o sucesso comercial. Com base em sua experiência como trader profissional, o autor Sheldon Natenberg examina a teoria e a realidade da negociação de opções. Ele apresenta os fundamentos da teoria da opção, explicando como essa teoria pode ser usada para identificar e explorar oportunidades de negociação. A Opção Volatilidade e Preços ensina você a usar uma ampla variedade de estratégias de negociação e mostra como selecionar a estratégia que melhor se adapta à sua visão das condições do mercado e da tolerância a riscos individuais.
Novas seções incluem:
Cobertura ampliada da opção de ações Estratégias para futuros e opções sobre índices de ações Uma discussão mais ampla e mais aprofundada sobre a volatilidade Análise de distorções de volatilidade Distribuição de inter-mercado com opções.
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Revisão do LibraryThing.
Este livro fornece introdução aos modelos matemáticos de opções. Em um lado positivo, dá a melhor explicação que já vi da análise de opções. No lado negativo, o valor prático deste livro - em. Итать весь отзыв.
Tudo o que você precisa saber sobre opções. Sinta-se mais voltado para os criadores de mercado. Ainda muito muito útil cargas de informação. Итать весь отзыв.
Opção Volatilidade e Preços: Advanced Trading Strategies and Technues, 2ª Edição.
Clique nas categorias de assunto deste livro para ver os títulos relacionados:
O QUE CADA OPERADOR DE OPÇÕES PRECISA SABER. O livro que todos os operadores devem ter.
O best-seller Opção Volatilidade e Preços fez Sheldon Natenberg uma autoridade amplamente reconhecida na indústria de opções. Em empresas em todo o mundo, o texto é muitas vezes o primeiro livro que novos comerciantes profissionais recebem para aprender as estratégias de negociação e técnicas de gerenciamento de risco necessárias para o sucesso nos mercados de opções.
Agora, nesta segunda edição revisada, atualizada e expandida, este profissional comercial de trinta anos apresenta o guia mais abrangente sobre estratégias e técnicas avançadas de negociação agora em impressão. Cobrindo uma ampla gama de tópicos tão diversificados e excitantes quanto o próprio mercado, este texto permite que traders novos e experientes aprofundem os muitos aspectos dos mercados de opções, incluindo: As bases da teoria de opções Cobertura dinâmica Volatilidade e estratégias de negociação direcional Risco análise Gestão de posições Futuros e opções do índice de ações Contratos de volatilidade.
Clara, concisa e abrangente, a segunda edição do Option Volatility & Pricing certamente será um acréscimo importante à biblioteca de traders de todos os opcionais - tão valiosa quanto os aclamados seminários da Natenberg nas maiores bolsas de valores e empresas de comércio do mundo.
Você aprenderá como os operadores de opções profissionais se aproximam do mercado, incluindo as estratégias de negociação e técnicas de gerenciamento de risco necessárias para o sucesso. Você obterá uma compreensão mais completa de como os modelos de precificação teóricos funcionam. E, o melhor de tudo, você aprenderá a aplicar os princípios da avaliação de opções para criar estratégias que, dada a avaliação das condições e tendências do mercado, tenham maiores chances de sucesso.
A negociação de opções é uma ciência e uma arte. Este livro mostra como aplicar ambos ao efeito máximo.
Revisões do livro do cliente.
Por David em 11 de janeiro de 2015.
a bíblia da negociação de opções.
Por Felicia em 30 de dezembro de 2014.
Ótimo estado, item como esperado.
Por Kevin Rodrigue em 12 de novembro de 2014.
Isso é realmente tudo que você precisa PERÍODO. Bem, talvez Tastytrade. :)
Uma obrigação para qualquer um que considera as opções de negociação.
Por Apage em 24 de fevereiro de 2015.
Este livro é considerado o & # 34; bíblico & # 34; nas opções implicava volatilidade. Natenburg foi pioneiro neste estudo décadas atrás, e seu trabalho ainda é relevante hoje em dia. Qualquer um que esteja pensando em opções de negociação deve adicionar este livro à sua biblioteca. Este livro cobre tudo, desde os gregos, o modelo Black-Scholes, as opções binomiais, a cobertura com opções e muito mais. . . Recomendo a leitura deste livro com lápis e papel quadriculado em mãos para trabalhar com alguns dos conceitos, para ter certeza de que você entende o que está lendo; o estilo de escrita é claro (se um tanto seco) e o autor não tem problema em comunicar seu conhecimento e ensinar ao leitor os conceitos, mas este livro se constrói rapidamente e se você não tem certeza de algum conceito desde o início, e não corrige você provavelmente ficará perdido em seções posteriores. Embora este livro cubra os fundamentos de opções e distribuições normais / desvios padrão; ajudaria muito conhecer os fundamentos dos conceitos acima mencionados antes de ler este livro para compreender completamente as informações apresentadas.
Por Paul M. Witt em 04 de agosto de 2015.
Principal base teórica para precificação e negociação de opções.
Por Guangchao Zheng em 18 de junho de 2015.
Compre a 1ª edição! A segunda edição está arruinada com erros básicos.
Por Jon Smith em 18 de abril de 2015.
Em termos de conteúdo, este livro foi excelente. Ele forneceu ótimos exemplos para as opções de aprendizado para iniciantes pela primeira vez. Eu fiz alguns cursos antes e suas estratégias, tecnologias e terminologias foram úteis. Eles eram um pouco iniciantes, mas como um profissional de risco de mercado, não o farei como ele descreveu o livro como o primeiro livro que os novos traders profissionais recebem para aprender as estratégias de negociação e técnicas de gerenciamento de risco necessárias para sucesso nos mercados de opções. & # 34; Dado que foi excelente. Agora as razões para a classificação 1: Simplificando, o livro é preenchido com 101 erros básicos: 1) Erros matemáticos simples, como multiplicação versus adição ocorrem ao longo do exemplo do livro 2) Parece que ele substituiu exemplos (do livro anterior?) Com novos números, mas ele apenas atualizou parcialmente o exemplo às vezes. Por exemplo: ele terá 3 posições com um preço de exercício de: 70, 75 e 80 e fora de agora, onde ele acaba usando 70, 75 e 65 para seus três golpes. 3) Ele tem vários erros de digitação nos quais ele afirma uma coisa duas vezes e depois o oposto direto um segundo depois (geralmente o exemplo está errado). 4) A quantidade de erros é surreal como faz você questionar a integridade do livro como um todo. 5) Eu não diria que é & # 34; estratégias e técnicas avançadas & # 34; mas iniciante a intermediar estratégias e técnicas. Embora eu ache este livro um bom recurso (já que coloquei ênfase nas idéias e termos, não nos exemplos), eu não o recomendaria como seu primeiro livro (que ele descreveu como). Com base nos comentários da 1 ª edição, eu diria comprar esse livro, pois pode ser o melhor livro para as opções. Se ele passou o tempo e forneceu bons exemplos, eu daria a este livro 5 estrelas e diria que era uma coleção indispensável para sempre. Mas os erros ocorrem com muita frequência e se dividem em um nível básico. Para um livro básico que é fortemente falho, eu vi que só deveria ser classificado como 1. Se eu não tivesse experiência anterior em opções (cursos acadêmicos e experiência profissional), eu ficaria confuso. Felizmente, a maioria dos erros que ele comete são bastante óbvios e você deve ser capaz de corrigi-los sozinho, mesmo que esteja aprendendo pela primeira vez. No geral, eu digo comprar a primeira edição e evitar este livro como uma praga. No geral, se ele tivesse lido o livro, ele deveria ter sido capaz de facilmente entender seus erros. É uma pena que ele não tenha tido tempo de rever o livro para se certificar de que estava escrito corretamente. Eu fiquei muito desapontado com Sheldon Natenberg, pois sua primeira edição foi considerar a Bíblia das opções (ainda é). 2 ª edição foi um fracasso completo.
Por Drax em 25 de setembro de 2015.
A versão atualizada tem mais detalhes e exemplos do mundo real. Ótima introdução às opções.
Por Igor Sushko em 24 de novembro de 2015.
Eu amo isso. Livro muito profundo e abrangente.
Livro mais importante sobre valores em negociação de opções.
Por D. Gordon em 11 de setembro de 2015.
Este é o livro para ler sobre o assunto, porque é tão bem apresentado. Detalhes sutis e conseqüências são explicados em um estilo muito bem escrito que é fácil de compreender.
em profundidade sobre Volatilidade.
Por Swampfish1 em 22 de agosto de 2015.
Uma explicação detalhada e detalhada da volatilidade e seu impacto nos preços e nas probabilidades. Uma leitura séria requer estudo.
Por Sammywig em 29 de fevereiro de 2016.
o padrão da indústria para pessoas novas na negociação de opções.
Forte na teoria, mas fraco na realidade, mais alguns erros descuidados.
Por Chris G. Pflum em 27 de novembro de 2016.
Este é o melhor livro que li sobre o modelo teórico de precificação. Está bem escrito, as figuras e tabelas reforçam o texto, e a matemática é tão simples quanto possível, considerando a complexidade do modelo Black, Sholes, Merton (modelo). No entanto, dei ao livro apenas três estrelas porque ele não confirma ou compara seus valores teóricos com dados de mercado. Além disso, o livro contém erros descuidados que não devem existir depois de duas edições. Embora meus comentários se concentrem nas falhas do livro, ainda o recomendo veementemente para os operadores sérios que desejam avançar no entendimento das opções. O livro falha em conectar a teoria com a realidade. Todos os exemplos de negociações, figuras e tabelas são hipotéticos. Os preços das opções e a volatilidade que eles implicam (IV) são derivados do modelo. O livro não parece usar dados de mercado. Meus comentários específicos apontam discrepâncias entre as descobertas hipotéticas / teóricas do livro e minhas observações sobre condições reais de mercado. Cerca de um terço do livro contém informações supérfluas que podem não interessar aos comerciantes de varejo. Este material inclui longas discussões de arbitragem, formadores de mercado, conversões sintéticas e os efeitos das taxas de juros e dividendos sobre os preços das opções. Eu li e estudei este material, mas isso não influenciou minha negociação. Página 228, considerações de risco - capítulo 13 introduz e define o conceito de "borda teórica" que é repetida ao longo do livro. A definição vaga deve ser simplificada e expressa em termos mais concretos. Afirma, “vantagem teórica - o lucro médio resultante de uma estratégia, assumindo que a avaliação das condições de mercado do corretor está correta.” Com base nos dados usados para construir os spreads neste capítulo, a vantagem teórica parece ser nada mais do que a diferença entre o preço teórico e de mercado de uma opção. Página 260, Usando Sintética em uma Estratégia de Propagação - Em vez de comprar um longo straddle: 1 de junho de 100 em call e 1 de junho de 100 put, poder-se-ia negociar o equivalente sintético: 2 de junho 100 calls e short 100 shares do subjacente. Aqui e em outros lugares, o texto não oferece vantagens práticas (por exemplo, risco versus recompensa) de usar um versus o outro. Páginas 265 - 292, Arbitragem de Opções - Capítulo 15 alega que “conversões e reversões são estratégias comuns” (página 276), mas no final do capítulo (página 288) Natenberg admite que apenas um operador de arbitragem que tem baixos custos de transação e imediato É provável que o acesso aos mercados lucre com conversões e reversões. Como o livro parece inconsistente, fiz negociações simuladas de conversões e reversões do S & P 500 ETF (SPY) e as mantive até a expiração. Embora os riscos fossem extremamente baixos, os lucros nem cobririam as comissões. Por exemplo, em 12 de outubro de 2016, o SPY estava sendo negociado a US $ 213,82 e a conversão de 1 contrato custaria US $ 21.396,00 (1 de outubro de 214 de Put @ 1,82, -1 de outubro de 214 de ligação @ 1,68 e de 100 de SPY @ 213,82). No vencimento, a conversão perdeu US $ 2,50 (lucro de US $ 2,50 - comissões de US $ 5,00). Os rendimentos de outros equivalentes sintéticos (caixas e rolos) não foram melhores. Embora os operadores profissionais possam lucrar com a arbitragem de opções, os operadores de varejo que têm fundos limitados e devem pagar comissões devem evitá-los. Páginas 293 - 321, Exercício antecipado das opções americanas - De acordo com o Capítulo 16, a decisão de manter ou exercer uma opção depende principalmente de dividendos e taxas de juros. Os negócios hipotéticos assumem que a ação paga um dividendo antes que a opção expire e as taxas de juros sejam de 6%. Presumivelmente, se uma ação não pagar um dividendo e as taxas de juros estiverem próximas de 0, nada disso se aplica. Presume-se que o preço das ações caia pelo valor do dividendo na mesma data em que o dividendo é pago. Na prática, o preço de uma ação pode cair na data de dividendo X e, em seguida, recuperar ou cair ainda mais quando o dividendo é pago. Eu pessoalmente vi isso acontecer com a Verizon (VZ) e AT & T (T). A menos que as ações estejam pagando um dividendo especial e não-programado, acredito que o mercado irá precificar o dividendo para a ação, fazendo com que os ajustes descritos neste capítulo sejam desnecessários. Página 358, Máximo Gama, Theta e Vega - A Figura 18-10 ilustra que “Aumentar a taxa de juros pode fazer com que a vega de uma opção de ações diminua conforme o tempo aumenta.” Os valores de vega são plotados em três curvas correspondentes a taxas de juros assumido para ficar fixo em 0%, 10% e 20% por até 4 anos. No início, o vega aumenta para todas as taxas de juros e, após 10 meses, a taxa de juros cai, mas apenas se as taxas de juros estiverem em 20%. Este número, como outros, faz suposições extremas sobre as taxas de juros apenas para ilustrar um ponto. Nos últimos 10 anos, as taxas de juros dos EUA variaram de cerca de 0% a 5,25%. A maioria dos exemplos teóricos deste livro pressupõe que a taxa de juros varie de 6% a 20%. Estas taxas são altas mesmo quando comparadas com a taxa de 3% em 1994, quando a primeira edição deste livro foi publicada. Parece estranho que Natenberg dedique tanto seu livro aos efeitos das taxas de juros, quando eles têm muito pouco efeito sobre as opções de curto prazo que são ativamente negociadas. Ele admite o mesmo no final de seu livro quando afirma: “Como as opções mais negociadas tendem a ser de curto prazo, com vencimentos inferiores a um ano, as taxas de juros teriam que mudar drasticamente para ter impacto em opções profundamente dentro do dinheiro. ”(página 467, terceiro parágrafo). Página 359, Binomial Option Pricing - O modelo de Cox - Ross - Rubinstein foi desenvolvido no final da década de 1970 como um "método de explicar a teoria básica de precificação de opções para estudantes sem usar matemática avançada". Embora esse modelo (como a régua de cálculo) possa ter sido útil há 40 ou 50 anos, não tem valor prático hoje. A maioria das plataformas de negociação pode calcular instantaneamente o valor teórico de uma opção. Página 381, Volatilidade revisitada - A maioria dos números no Capítulo 20 mostra que as volatilidades implícitas (IV) tendem de alta para baixa, indo de opções de curto prazo para opções de longo prazo (por exemplo, Figuras 20-12, 20-13, 20- 14, 20-18, 20-20 e 20-21). Por outro lado, observei que a IV muitas vezes funciona na direção oposta (ou seja, as opções de curto prazo têm um IV menor do que as opções de longo prazo). Eventos como ganhos, aquisições, fusões, recompras de ações, eleições e eventos mundiais podem desencadear um surto de IV em qualquer mês de vencimento que se seguir imediatamente ao evento. A volatilidade implícita eventualmente reverte para um valor médio, mas pode permanecer abaixo da média por meses e, de repente, saltar acima da média e voltar em alguns dias. Na minha opinião, IV não tem tendência, mas se move aleatoriamente acima e abaixo de sua média móvel. Surpreendentemente, Natenberg não discute se análises técnicas poderiam ser aplicadas a IV. Para distinguir opções caras (com IV alto) das mais baratas (com um IV baixo), eu uso um “Oscilador Estocástico de Volatilidade Implícita” que plota o atual nível de volatilidade implícito como uma porcentagem de sua faixa de 52 semanas. Página 412, Análise de Posição - Para simplificar uma dispersão complicada de puts, calls e o estoque subjacente, Natenberg converte as puts em seus equivalentes sintéticos. Por exemplo, 19 de março, 65 opções de compra são convertidas em 19 de março de 65 chamadas e abreviadas 1900 ações subjacentes. Esse tipo de conversão é válido apenas para puts e chamadas com um delta de 0,50. As puts que estão sendo convertidas, no entanto, possuem diferentes strikes e diferentes deltas. Página 432, Algumas reflexões sobre a criação de mercado - O texto avalia os riscos de uma coleção mista de opções que um criador de mercado pode acumular ao longo do tempo; "Vamos também assumir que a volatilidade implícita para junho muda a 75 por cento da taxa de variação em abril e a volatilidade implícita para agosto muda em 50 por cento da taxa de variação em abril." Posteriormente na página 501 parágrafo) ao discutir a mudança da volatilidade, o texto declara: “… quando o preço subjacente sobe, a volatilidade implícita tende a cair; quando o preço subjacente cai, a volatilidade implícita tende a subir. ”Na minha opinião, as flutuações diárias no IV são aleatórias e freqüentemente não estão em conformidade com projeções baseadas em um modelo teórico. Embora a IV reverta para uma média, essa reversão só se torna aparente em gráficos semanais ou mensais. Durante um período de dias, a IV permanece maioritariamente abaixo da sua média e faz breves picos acima da sua média. Meu ponto aqui é que IV é imprevisível ao longo de um período de tempo de 3 a 4 meses. Na minha opinião, os dados de mercado não confirmam essas suposições sobre a taxa de mudança e as afirmações de que a IV aumenta quando o preço da ação cai ou a IV cai quando o preço da ação sobe. O Gráfico 1 (anexo a estes comentários) apresenta o preço diário e o IV do Dow Jones Industrials (DIA) de março a outubro de 2016. Observe que preço e IV não se correlacionam: • tendências de preços em alta, enquanto IV não segue tendência; • o preço fica dentro de um desvio padrão de sua regressão linear, enquanto IV freqüentemente move mais de um desvio padrão acima e abaixo de sua regressão linear; • o preço permanece predominantemente acima da média móvel de 120 dias, enquanto o IV permanece predominantemente abaixo da média móvel de 120 dias. Meu ponto aqui é que, além de distinguir opções baratas de dispendiosas, o modelo teórico não projeta as variações e tendências mês a mês em IV. Página 471, Volatilidade é Constante ao Longo da Vida da Opção - Figuras 23.3, 23.4 e 23.5 e o texto declara que as opções no dinheiro diminuem de valor quando a volatilidade cai e aumentam de valor quando a volatilidade aumenta. Essa relação pode ser válida para o valor teórico da opção, mas não para o preço de mercado. O preço de mercado de uma opção implica uma volatilidade (IV) que não se correlaciona com a volatilidade histórica (V) do ativo subjacente. O gráfico 2 (anexado a estes comentários) representa a IV e a V diárias da Eli Lily Corporation (LLY) de abril a 21 de novembro de 2016. O gráfico superior mostra que a IV subiu de agosto a novembro enquanto V permaneceu na faixa. O gráfico mais baixo mostra que de maio a novembro os valores IV foram de 1,2 X a 3 X acima de V. Como as opções caras têm IV alto e as opções baratas têm IV baixo, esses gráficos sugerem que as opções de LLY se tornaram cada vez mais caras de maio a novembro embora a volatilidade do estoque de LLY permanecesse estável. Página 507, Implied Distributions - Esta seção alega que um número infinito de spreads borboleta teria o mesmo valor máximo de apenas um spread. Ele afirma: “Na expiração, a borboleta 95/100/105 (ou seja, comprar uma chamada 95, vender duas chamadas 100, comprar uma chamada 105) terá um… valor máximo de 5,00.” Um número infinito de propagações de borboleta em cinco pontos os intervalos também teriam "um valor de exatamente 5,00". Mais tarde (página 508), Natenberg convida o leitor a "confirmar que todos os valores de borboleta realmente somam 5,00 ...". Os gráficos 3 e 4 (anexados a estes comentários) descrevem os spreads borboleta do índice Nasdaq (QQQ) em 118.37. O Gráfico 3 apresenta 2 spreads de borboleta em intervalos de expiração de 0,50 e o Gráfico 4 representa 4 distribuições de borboleta nos mesmos intervalos de expiração. Usando valores de mercado, minha plataforma Tradestation calculou que o spread de 2 borboletas teria um valor máximo de US $ 260,00, enquanto o spread de 4 borboletas teria um valor máximo de US $ 190,00. Talvez se eu tivesse usado os valores teóricos da opção, como Natenberg supostamente fez, minhas borboletas teriam confirmado “que todos os valores de borboleta realmente somam [o mesmo valor].” No entanto, eu acho que Natenberg teria melhor servido seus leitores se ele apontou a diferença significativa entre os spreads construídos a partir dos valores teóricos versus valores de mercado das opções. Erros descuidados Página 172, O texto incorretamente mostra que um estrangulamento longo e curto tem um gamma positivo, teta negativo e vega positivo. O strangle curto deve ter gama negativa, teta positiva e vega negativa. Página 189, Figuras 11-22 e 11.23, Os números afirmam incorretamente que para um spread longo e curto do calendário, o comerciante compraria um longo prazo e venderia uma opção de curto prazo. Para o spread curto do calendário, o trader venderia a opção de longo prazo e compraria a opção de curto prazo. Página 206, Figura 11-33, em curto e longo transmite o mesmo número de puts e chamadas são vendidos ou comprados. Dois dos seis straddles nesta figura vendem mais calls que puts, e um straddle compra mais puts do que calls. Página 260, 5º parágrafo, O exemplo de um touro colocado spread incorretamente compra e vende o mesmo número de contratos da mesma opção. Em outras palavras, o spread não existe. Page 329, parágrafo 1º, O texto declara: “Ao comparar a volatilidade implícita com a volatilidade esperada ao longo da vida da opção, o hedger deve ser capaz de fazer uma determinação sensata sobre se deseja comprar ou vender opções”. "Volatilidade esperada"? O termo não está definido no glossário nem aparece no índice. Página 343, Figura 18.7, O número de ocorrências usadas para calcular o valor médio do estoque deve ser 60 e não 153., Preço de Opção Binomial, O segundo parágrafo afirma que uma das vantagens do preço da opção binomial é que você pode não são considerações de juros ou dividendos ”. Juros e dividendos são considerados nas fórmulas e números apresentados ao longo deste capítulo. Página 412, A tabela no meio da página mostra que 38 (19 + 19) Março 65 puts foram sinteticamente convertidos para 0 de março 65 chamadas e 0 estoque subjacente. Isso não é possível. Página 447, parágrafo 2, O valor do índice ponderado pelo preço que inicialmente era 100 deveria ser 150. Páginas 469 e 470, Figuras 23-3 e 23-4. Esses números supostamente ilustram como as mudanças no preço afetam a volatilidade; no entanto, os eixos não são rotulados e não é aparente o que os gráficos estão traçando. Último parágrafo e Figura 23-5 - O texto declara: “Quando o preço do subjacente remanescente geralmente está entre 95 e 105, as opções com preços de exercício de 95, 100 e 105 valem mais do que o valor de Black-Scholes em um mercado de alta volatilidade e menos do que o valor da Black-Sholes em um mercado de baixa volatilidade. “Todos os valores das opções na Figura 23-5 e talvez o livro inteiro foram calculados a partir da fórmula de Black-Sholes. Nesse caso, não está claro como os valores das opções calculados com a fórmula Black-Sholes poderiam “valer mais do que a fórmula Black-Sholes”. Página 502, Figura 24.14, O texto nesta figura deve indicar: declínio inclinado - não "investimento" distorcido e aumento de inclinação - não "demanda" distorção. Gráfico 1, Média Industrial Dow Jones (DIA), Gráfico de Volatilidade Implícita vs Cotação Implícita 2, Eli Lilly Corporation (LLY), Volatilidade Implícita Diária (IV) vs Volatilidade Histórica (Desvio Padrão da Volatilidade VSD) Gráfico 3, Índice Nasdaq (QQQ), Lucro Máximo de 2 Spreads Borboleta em .50 Intervalos de Expiração Gráfico 4, Índice Nasdaq (QQQ), Lucro Máximo de 4 Spreads Borboleta em .50 Intervalos de Expiração.
Se você tem um extenso conhecimento em matemática, você achará este livro bastante fácil. Eu tenho uma licenciatura em matemática e sabia.
Por Matt Elgazar em 03 de março de 2015.
Este livro é para os comerciantes de opções graves. Se você é apenas um cara em casa que quer aprender um pouco sobre opções e não tem pelo menos um pouco de experiência em matemática, então este livro não é para você. No entanto, se você tiver um extenso conhecimento em matemática, você achará este livro bastante fácil. Eu tenho uma licenciatura em matemática e não sabia nada sobre as opções antes deste livro, por isso foi confuso no início. Depois de aprender o básico de outros recursos e recorrer a isso eu acho que há muita informação aqui. Eu não acredito que este livro esteja completamente desatualizado. As teorias de precificação e as estratégias de distribuição estão atualizadas e ele diz claramente (várias vezes) que o comerciante médio terá dificuldades em criar ou criar oportunidades de arbitragem. Isso não significa que esteja desatualizado, apenas significa que você não deve tentar negociar como um operador de arbitragem. Simples. BTW - para os comentários de uma estrela que dizem que eles não precisam usar os gregos para serem opções de negociação bem-sucedidas, você pode muito bem trocar o subjacente porque a opção dos gregos tem muito a oferecer. Se você está negociando opções sem prestar atenção à volatilidade implícita ou aos gregos, você está negociando cego. Se você é rentável desta forma, então você provavelmente estará fazendo seu dinheiro direcionalmente, caso em que você está muito melhor negociando o subjacente. Você pode ter tido muita sorte se for uma opção de negociação lucrativa sem prestar atenção ao IV ou aos gregos. Ou se você é muito bom em prever a direção do mercado, então IV pode ter comido alguns dos seus lucros. Eu recomendo altamente este livro.
A Bíblia de negociação de opções.
Por Steve Burns em 09 de novembro de 2013.
Repetidamente os comerciantes que mais respeito recomendam este livro como o melhor livro de opções para os interessados em opções de negociação. Embora eu concorde, este é um excelente livro didático para aprender as complexidades dos contratos de opções, juntamente com a maioria, se não todas as possíveis estratégias de negociação. O que eu consideraria é que este livro lê basicamente como um livro escolar e é uma leitura difícil, levou-me um bom tempo para passar por isso devido à densidade do estilo de escrita. Para os novos traders e aqueles que são novos para as opções, eu sugeriria livros mais básicos que fossem mais fáceis de começar e trabalhassem até chegar a este, à medida que você progride em sua compreensão das opções Gregas e como seus preços são criados. Eu salvaria este como seu quinto ou sexto livro de opções depois que você já tiver um controle sobre todas as opções básicas. Este é um dos livros mais informativos e completos sobre as opções apenas estar pronto para ser capaz de compreendê-lo quando você lê-lo, isso não é leitura casual, é para o comerciante opção séria.
Opção Volatilidade e Preços: Estratégias e Técnicas Avançadas de Negociação.
Sheldon Natenberg (1994)
Por que ler isso?
Um dos livros mais lidos entre os operadores de opções ativas em todo o mundo.
Embora voltado principalmente para profissionais e comerciantes, também será útil para amadores interessados em como negociar opções.
Aponta os principais conceitos essenciais para o sucesso da negociação, incluindo o preço das opções e as estratégias de treinamento até o nível desejado.
Começando.
A opção Volatility and Pricing apresenta os fundamentos da teoria das opções e mostra como ela pode ser usada para identificar e explorar oportunidades de negociação. Ele funciona através de muitas das estratégias clássicas de negociação, de modo que o trader pode selecionar a melhor estratégia para si mesmo em termos de condições de mercado e tolerância ao risco pessoal. Considera os aspectos técnicos de como as opções negociadas funcionam sem serem muito matemáticas.
Sheldon Natenberg, um destinatário do Traders & rsquo; Hall of Fame Lifetime Achievement, iniciou sua carreira comercial em 1982 no Chicago Board Options Exchange. Desde 1985, ele tem negociado opções de commodities na Chicago Board of Trade e conduzido seminários em muitas das bolsas do mundo.
Discute os desenvolvimentos e tendências mais atuais em produtos de opção e estratégias de negociação, como modelos de precificação, considerações de volatilidade, estratégias de negociação básicas e avançadas e técnicas de gerenciamento de risco.
Explica os fundamentos subjacentes de uma maneira compreensível.
Analisa as estratégias de opções e definições de diferentes modelos de precificação populares, bem como o desenvolvimento de um modelo teórico de precificação de opções.
Descreve como determinar se uma opção foi superada ou subvalorizada.
Examinando a teoria e a realidade da negociação de opções, ela mostra que a precificação e modelagem de opções não podem ser uma ciência exata devido à volatilidade.
Explica o essencial da volatilidade em grande detalhe e como aplicá-la a diferentes posições de opção.
Revela a mecânica de como precificar uma opção.
Discute a distribuição Normal e como ela se relaciona com a volatilidade e o investimento em opções.
Citações
& ldquo; A direção em que o mercado subjacente se movimenta pode ter um efeito significativo na lucratividade de uma estratégia de opções. & rdquo;
& ldquo; Cada comerciante que entra no mercado deve equilibrar duas considerações opostas, recompensa e risco. & rdquo;
& ldquo; Apenas um operador que compreenda perfeitamente o que um modelo pode e não pode ser capaz de tornar o modelo seu servo em vez de seu mestre. & rdquo;
Opção Volatilidade & amp; Preços: Estratégias e Técnicas Avançadas de Negociação.
por Sheldon Natenberg.
Um dos livros mais lidos entre os operadores de opções ativas em todo o mundo, Option Volatility & amp; O preço foi completamente atualizado para refletir os mais recentes desenvolvimentos e tendências em produtos de opção e estratégias de negociação.
Um dos livros mais lidos entre os operadores de opções ativas em todo o mundo, Option Volatility & amp; O preço foi completamente atualizado para refletir os mais recentes desenvolvimentos e tendências em produtos de opção e estratégias de negociação.
Escrito de forma clara e fácil de entender, Option Volatility & amp; Preços aponta os principais conceitos essenciais para o sucesso comercial. Com base em sua experiência como trader profissional, o autor Sheldon Natenberg examina a teoria e a realidade da negociação de opções. Ele apresenta os fundamentos da teoria da opção, explicando como essa teoria pode ser usada para identificar e explorar oportunidades de negociação. Opção Volatilidade & amp; O preço ensina você a usar uma ampla variedade de estratégias de negociação e mostra como selecionar a estratégia que melhor se adapta à sua visão das condições de mercado e da tolerância a riscos individuais.
Opção Volatilidade e Precificação: Estratégias e Técnicas Avançadas de Negociação: Estratégias e Técnicas Avançadas de Negociação.
Entrega gratuita em todo o mundo.
Acessível. Despachado do Reino Unido em 2 dias úteis.
Descrição.
dado para aprender as estratégias de negociação e técnicas de gestão de risco necessárias para o sucesso nos mercados de opções.
em si, este texto permite novos e experientes.
comerciantes para aprofundar em muitos aspectos dos mercados de opções, incluindo:
maiores bolsas de derivativos e firmas comerciais.
compreensão mais completa de como os modelos teóricos de preços funcionam. E, o melhor de tudo, você aprenderá como aplicar os princípios da avaliação de opções para criar estratégias que, dada a avaliação de condições e tendências de mercado, tenham maiores chances de sucesso.
Opção Volatilidade & amp; Preços: Estratégias e Técnicas Avançadas de Negociação.
Um dos livros mais lidos entre os operadores de opções ativas em todo o mundo, o Option Volatility & Pricing foi completamente atualizado para refletir os mais recentes desenvolvimentos e tendências em produtos de opção e estratégias de negociação.
Modelos de precificação Considerações sobre volatilidade Estratégias básicas e avançadas de negociação Técnicas de gerenciamento de risco E muito mais!
Escrito de forma clara e fácil de entender, Opção Volatilidade e Preços aponta os principais conceitos essenciais para o sucesso comercial. Com base em sua experiência como trader profissional, o autor Sheldon Natenberg examina a teoria e a realidade da negociação de opções. Ele apresenta os fundamentos da teoria da opção, explicando como essa teoria pode ser usada para identificar e explorar oportunidades de negociação. A Opção Volatilidade e Preços ensina você a usar uma ampla variedade de estratégias de negociação e mostra como selecionar a estratégia que melhor se adapta à sua visão das condições do mercado e da tolerância a riscos individuais.
Novas seções incluem:
Cobertura ampliada da opção de ações Estratégias para futuros e opções sobre índices de ações Uma discussão mais ampla e mais aprofundada sobre a volatilidade Análise de distorções de volatilidade Distribuição de inter-mercado com opções.
Revisão do LibraryThing.
Este livro fornece introdução aos modelos matemáticos de opções. Em um lado positivo, dá a melhor explicação que já vi da análise de opções. No lado negativo, o valor prático deste livro - em.
Tudo o que você precisa saber sobre opções. Sinta-se mais voltado para os criadores de mercado. Ainda muito muito útil cargas de informação.
Opção Volatilidade & amp; Preços, Estratégias e Técnicas Avançadas de Negociação.
Índice.
A linguagem das opções
Especificações do contrato.
Opção de compra: o direito de comprar ou adquirir uma posição longa em um determinado ativo a um preço fixo em ou antes de um dado especificado. Opção de venda: o direito de vender ou assumir uma posição vendida em um determinado ativo.
A diferença entre uma opção e um contrato de futuros:
Um contrato de futuros requer entrega a um preço fixo. O vendedor deve fazer a entrega e o comprador deve receber o ativo. O comprador de uma opção pode optar por receber (uma chamada) ou fazer a entrega (uma opção).
O preço de exercício, ou preço de exercício, é o preço pelo qual o subjacente será entregue, caso o titular de uma opção opte por exercer o seu direito de comprar ou vender.
data de vencimento: A data após a qual a opção não poderá mais ser exercida é a data de vencimento.
O prêmio pago por uma opção pode ser separado em dois componentes, o valor intrínseco e o valor do tempo.
A quantia adicional de prêmio além do valor intrínseco que os negociantes estão dispostos a pagar por uma opção é o valor do tempo, às vezes também chamado de prêmio de tempo da opção ou valor extrínseco.
O prêmio de uma opção é sempre composto precisamente por seu valor intrínseco e seu valor de tempo. Se uma chamada de ouro de US $ 400 for negociada a US $ 50 com ouro a US $ 435 por onça, o valor de tempo da chamada deve ser de US $ 15, já que o valor intrínseco é de US $ 35. Os dois componentes devem totalizar o prêmio total da opção de US $ 50.
Se a opção não tiver valor de tempo, seu preço consistirá apenas em valor intrínseco. A opção está sendo negociada em paridade.
Qualquer opção que tenha um valor intrínseco positivo é considerada in-the-money pela quantidade do valor intrínseco. Uma opção que não tem valor intrínseco é considerada fora do dinheiro.
Uma opção cujo preço de exercício é idêntico ao preço atual do contrato subjacente é considerado no dinheiro, tal opção também está fora do dinheiro, uma vez que não tem valor intrínseco.
A distinção entre uma opção no dinheiro e uma opção fora do dinheiro, porque uma opção no dinheiro tem a maior quantidade de prêmio de tempo e geralmente é negociada de forma muito ativa.
REQUISITOS DE MARGEM.
Quando um comerciante faz uma operação de abertura em uma bolsa, a bolsa pode exigir que o comerciante deposite alguma quantia de margem ou capital de boa fé.
Estratégias Elementares.
COMPRA SIMPLES E VENDA ESTRATÉGIAS.
longo e curto um contrato subjacente.
longa uma chamada.
CARACTERÍSTICAS DE RECOMPENSA DE RISCO.
posições longas em 95, 100 e 105 chamadas.
o lucro e a perda de uma posição curta nas chamadas 95, 100 e 105.
posições longas em 95, 100 e 105 puts.
as posições de venda curtas em 95, 100 e 105 puts.
ESTRATÉGIAS DE COMBINAÇÃO.
o lucro e a perda no vencimento da compra combinada de uma chamada de 100 para 2,70 e uma de 100 para 3,70.
Curta-os.
vender um 95 colocado para 1,55 e um 105 para 1,15.
vender a chamada de 90 e comprar a chamada de 100.
compre um 105 put por 7,10 e venda um 100 put por 3,70, para um débito total de 3,40.
CONSTRUIR UM GRÁFICO DE EXPLOSÃO.
Se o gráfico se inclinar, isso será feito a um preço de exercício. Portanto, podemos calcular o proflt ou 10ss a cada preço de exercício envolvido e simplesmente conectar esses pontos com linhas retas. Se a posição for 10 ng e números equa1 curtos de cal1s (puts), o potencial risco (upside) de downside ou recompensa será igual ao total de débito ou crédito requerido para estabelecer a posição. Se o preço de exercício for mais alto, todas as chamadas entrarão em ação, de modo que a posição inteira funcionará como uma posição subjacente que é um contrato subjacente longo ou curto igual ao número de chamadas longas ou curtas líquidas. Abaixo do preço de exercício mais baixo, todas as colocações entrarão no dinheiro, de modo que a posição inteira funcionará como uma posição subjacente que é contratos subjacentes longos ou curtos igual ao número de posições longas ou curtas líquidas.
longa uma 95 chamada a 5,50 curto três 105 chamadas a 1,15.
short um 90 cdll em 9.35 long two 100 calls em 2.70 short four 95 puts em 1.55 long two 100 puts em 3.70.
long one 100 call a 2.70 short one 100 put em 3.70.
long one 90 put em .45 short one 100 call em 2.70 long um contrato subjacente em 99.00.
Introdução aos modelos de preços teóricos.
Se ele compra opções, não só ele deve estar certo sobre a direção do mercado, ele também deve estar certo sobre a velocidade do mercado.
Os fatores mínimos que você deve considerar:
O preço do contrato subjacente. O preço de exercício A quantidade de tempo restante até a expiração. A direção na qual ele espera que o mercado subjacente se mova. A velocidade na qual ele espera que o mercado subjacente se mova.
VALOR TEÓRICO.
As duas considerações mais comuns em um investimento financeiro são o retorno esperado e os custos de manutenção. E, de fato, os dividendos são uma consideração adicional na avaliação de opções em estoque.
O objetivo da avaliação de opções é determinar, através do uso de modelos teóricos de precificação, o valor teórico de uma opção. O comerciante pode, então, tomar uma decisão inteligente sobre se a opção é superfaturada ou subvalorizada no mercado, e se a avaliação teórica é suficiente para justificar a entrada no mercado e a realização de uma negociação.
UMA ABORDAGEM SIMPLES.
Podemos agora resumir os passos necessários no desenvolvimento de um modelo:
Proponha uma série de preços possíveis no vencimento do contrato subjacente. Atribuir uma probabilidade apropriada a cada preço possível. Manter um mercado subjacente livre de arbitragem. A partir dos preços e probabilidades nos passos 1, 2 e 3, calcule o retorno esperado para a opção. A partir do retorno esperado da opção, deduzir o custo de carregamento.
Em sua forma original, o Modelo Black-Scholes pretendia avaliar as opções européias (sem exercício antecipado permitido) sobre ações pagas sem dividendos. Pouco depois de sua introdução, percebendo que as ações mais vantajosas pagam dividendos, Black e Scholes acrescentaram uma quantia de dividendos. Em 1976, Fischer Black realizou pequenas modificações no modelo para permitir a avaliação de opções sobre contratos futuros. E em 1983, Mark Garman e Steven Kohlhagen fizeram várias outras modificações para permitir a avaliação de opções em moedas estrangeiras. A versão de futuros e a versão em moeda estrangeira são conhecidas oficialmente como o Modelo Negro e o Modelo Garman-Kohlhagen, respectivamente. Mas o método de avaliação em cada versão, seja o modelo Black-Scholes original para opções de ações, o modelo Black para opções de futuros ou o modelo Garman-Kohlhagen para opções em moeda estrangeira, é tão semelhante que todos passaram a ser conhecidos como simplesmente o modelo Black-Scholes. As várias formas do modelo diferem principalmente em como eles calculam o preço a termo do contrato subordinado, e um operador de opções simplesmente escolherá a forma apropriada para o instrumento subjacente.
Para calcular o valor teórico de uma opção usando o modelo de Black-Scholes, precisamos conhecer no mínimo cinco características da opção e seu contrato subjacente. Tem:
O preço de exercício da opção. The amount of time remaining to expiration. The current price of the underlying contract. The risk-free interest rate over the life of the option. The volatility of the underlying contract.
Black and Scholes also incorporated into their model the concept of the riskless hedge . To take advantage of a theoretically mispriced option,it is necessary to establish a hedge by offsetting the option position with this theoretically equivalent underlying position. That is, whatever option position we take, we must take an opposing market position in the underlying contract. The correct proportion of underlying contracts needed to establish this riskless hedge is known as the hedge ratlo .
Volatilidade.
RANDOM WALKS AND NORMAL DISTRIBUTIONS.
Thís leads to an important distínction between evaluation of an underlying contract and evaluation of an option. If we assume at prices are distributed along a normal distribution curve, the value of an underlying contract depends on where the peak of the curve is located, while the value of an option depends on how fast le curve spreads out.
LOGNORMAL DISTRIBUTIONS.
A continuously compounded rate of return of +12% yields a profit of $127.50 after one year, while a continuously compounded rate of return of -12% yields a loss of only $113.08.
When price changes are assumed to be normally distributed, the continuous compounding of these price changes wiU cause the prices at maturity to be lognormally distributed .
The Black-Scholes Model is a contínuous time model. It assumes at the volatility of an underlying instrument is constant over the life of the option, but that this volatility is continuously compounded. These two assumptions mean that the possible prices of the underlying instrument at expiration ofthe option are lognormally distributed.
It also explains why options with higher exercise prices caηy more value than options with lower exercise prices, where both exercise prices appear to be an identical amount away from the price of the underlying instrument.
Summarize the most irnportant assurnptions governing price movement int the Black-Scholes Model:
Changes in the price of an underlying instrurnent are randorn and cannot be artificially manipulated, nor is it possible to predict beforehand direction in which prices will move. The percent changes in the price of an underlying instrurnent are norrnally distributed. Because the percent changes in the price of the underlying instrurnent are assumed to be continuously cornpounded, the prices of the underlying instrument at expiration will be lognormally distributed. The mean of the lognormal distribution will be located at the forward price of the underlying contract.
TYPES OF VOLATILITIES.
Future Volatility: Future volatility is what every trader would like to know, the volatility at best describes the future distribution of prices for an underlying contract. Historical Volatility Forecast Volatility Implied Volatility: It is volatility being implied to the underlying contract through the pricing of the option in the marketplace. Even though the term premium real1y refers to an option's price, it is common among traders to refer to the implied volati1ity as the premium or premium level. If the current implied volatility is high by historical standards, or high relative to the recent historical volatility of the underlying contract, a trader might say that premium levels are high; if implied volatility is unusuallylow, he might say that premium levels are low.
He might then look at the difference between each option's theoretical value and its price in marke lace selling any options which were overpriced relative to the theoretical value, and buying any options which were underpriced.
Using an Option's Theoretical Value.
The purchase or sale of a theoretically mispriced option requires us to establish a hedge by taking an opposing positlon in the underlying contract. When this is done correctly, for small changes in the price of the underlying, the increase (decrease) in the value of the optlon position will exactly offset the decrease (increase) in the value of the opposing position in the underlying contract. Such a hedge is unbiased, or neutral , as to the direction of the underlying contract.
The number which enables us to establish a neutral hedge under current market conditions is a by-product of theoretical pricing model and is known as the hedge ratio or, more commonly, the delta .
The delta of a call option is always somewhere between 0 and 1.00. The delta of an option can change as market conditions change. An underlying contract always has a delta of 1.00.
The steps we have thus far taken illustrate the correct procedure in using an option theoretical value:
Purchase (sell) undervalued (overvalued) options. Establish a delta neutraI hedge against the underlying contract. Adjust the hedge at regular intervals to remain delta neutral.
At that time we plan to close out the position by:
Letting any out-of-the-money options expire worthless. Selling any in-the-money options at parity (intrinsic value) or, equiva1ently, exercising them and offsetting them against the underlying futures contract. Luidating any outstanding futures contracts at the market price.
1n a frictionless market we assume that:
Traders can freely buy or sell the underlying contract without restriction AlI traders can borrow and lend money at the same rate. Transaction costs are zero. There are no tax considerations.
Option Values and Changing Market Conditions.
three interpretations of delta:
the hedge ratio Rate of Change in the theoretical value: The de1ta is a measure of how an optio 's value changes with respect to a change in the price of the underlying contract. Theoretical or Equivalent Underlying Position.
The gamma sometimes referred to as the curvature of an option, is the rate at which an option's delta changes as the price of the underlying changes.
If an option has a gamrna of 5for each point rise (fal1) in the price of the und. erlying, the option will gain (lose) 5 de1tas.
Every option trader learns to look carefully not only at current directional risk (the delta), but also at how that directional risk will change if the underlying market begins ωmove (the gamma).
The theta(θ) ,or tíme decay factor, is the rate at which an option loses value as time passes.
THE VEGA OR KAPPA.
The vega of an option is usually given in point change ín theoretical value for each one percentage point change in volatility.
Since vega is not a Greek letter, a common alternative in academic literature, where Greek letters are preferred, is kappa (K).
A sensibilidade do valor teórico de uma opção a uma mudança nas taxas de juros é dada pelo seu rho (P).
Delta: Deltas range from zero for far out-of. the-money calls to 100 for deeply in-the-money calls, and from zero for far out-of-the-money puts to -100 for deeply in-the-money puts.
At-the-money calls have deltas of approximately 50, and at-the-money puts approximately -50.
As time passes, or as we decrease our volatility assumption, call deltas move away om 50,and puts deltas away from -50. As we increase our volatility assumption, cal1 deltas move towards 50, and put deltas towards -50.
As we increase our volati1ity assumptíon, the gamma of an in.
money option rises, while gamma of an at le.
money option falls. As we decrease our volatility assumption, or as time to expiration grows shorter, the gamma of an in.
the money option falls, while the gamma of an at.
the-money option rises, sometimes dramatically.
money options have greater etas than either in.
ofthe-money options with otherwise identical contract specifications.
The theta of an at-the-money option increases as expiration approaches. A short-term, at-the-money option will a1 ways decay more quickly than a long-term, at-the-money option.
As we increase (decrease) our volatility assumption, the theta of an option will rise (fall). Higher volatility means there is greater time value associated with the option, so at each day's decay wil1 also be greater when no movement occurs.
Out-of-the-money options have the greatest vega as apercent of theoretical value.
The various positions and their respective signs are given in Figure 6-26. The sign of the delta, gamma, theta, or vega, toge er with the magnitude of the numbers, tel1 the trader which changes in market conditions will either help or hurt his position, and to what degree. The positive or negative effect of changing market conditions is summarized in Figure 6-27.
An option's elasticity , sometimes denoted with the Greek letter omega(or less commonly the Greek letter lambda), is the relative percent change in an option's value for a given percent change in the price of the underlying contract.
The elasticity is sometimes referred to as the option's leverage value . The greater an option's elasticity, the more highly leverage the option.
An easy method of calculating:
elasticity = (underlying price) / (theoretical value) * delta.
Introduction to Spreading.
Spreading is simply a way of enabling an optlon trader to take advantage of theoretlcally mispriced options, while at the same time reducing the effects of short-term changes in market conditions so that he can safely hold an optlon positlon to maturity.
WHY SPREAD?
At some point the intelligent trader will have to consider not only the potential profit, but also the risk associated with a strategy.
No trader will survive very long if his livelihood depends on estimating each input with 100% accuracy. Even when he incorrectly estimates the inputs, the experienced trader can survive if he has constructed intelligent spread strategies which allow for a wide margin of error.
Volatility Spreads.
Regardless ofwhich method we choose, each spread will have certain features in common:
Eachspread will be approximately delta neutral. Cada spread será sensível a alterações no preço do instrumento subjacente. Each spread will be sensitive to changes in implied volatility. Each spread wil1 be sensitive to the passage of time.
BACKSPREAD.
A backspread is a delta neutral spread which consists of more long (purchased) options than short (sold) options where all options expire at the same time.
A call backspread consists of long calls at a higher exercise price and short calls at a lower exercise price. A put backspread consists of long puts at a lower exercise price and short puts at a higher exercise price.
If no movement occurs, a backspread is likely to be a losing strategy.
A trader will tend ωchoose the type ofbackspread which reflects his opinion about market direction. If he foresees a market with great upside potential, he will tend to choose a call backspread; if he foresees a market with great downside potential he will tend to choose a put backspread. He will avoid backspreads in quiet markets since the underlying contract is unlikely to move very far in either direction.
RATIO VERTICAL SPREAD.
A trader who takes the opposite side of a backspread also has a delta neutral spread, but he is short more contracts than long, with all options expiring at the same time. Such a spread is sometimes referred to as a ratio spread or a vertical spread.
Designe o oposto de um backspread como um spread vertical de proporção.
A straddle consists of either a long call and a long put, or a short call and a short put, where both options have the same exercise price and expire at the same time.
If both the call and put are purchased, the trader is said to be long the straddle; if both options are sold, the trader is said to be short the straddle.
Like a straddle, a strangle consists of a long call and a long put, or a short call and a short put, where both options expire at the same time. In a strangle, however, the options have different exercise prices. If both options are purchased, the trader is long the strangle if both options are sold, the trader is short the strangle.
To avoid confusion a strangle is commonly assumed to consist of out-the-money options. If the underlying market is current1y at 100 and a trader wants to purchase the June 95/105 strangle, it is assumed that he wants to purchase a June 95 put and a June 105 call. When both options are in-the-money, the position is sometimes referred to as a guts .
A butterfly consists of options at three equally spaced exercise prices, where all options are of the same type (either all calls or all puts) and expire at the same time.
In a long butterfly the outside exercise prices are purchased and the insíde exercise price is s01d, and vice versa for a short butterfly.
It is always 1 x 2 x 1, with two of each inside exercise price traded for each one of the outside exercíse prices. If the ratio is other than 1 x 2 x 1, the spread is no longer a butterfly.
a long butterfly tends to act like a ratio vertica1 spread and a short butterfly tends to act like a backspread.
TIME SPREAD (calendar spread or horizontal spread)
Time spreads, sometimes referred to as calendar spreads or horizontal spreads, consist of opposing positions whlch expire in different months. The most common type of time spread consists o.
The most common type of time spread consists of opposing positions in two options of the same type (either both calls or both puts) where both options have the same exercise price. When the long-term option is purchased and the short-term option is sold, a trader is long the time spread; when the short-term option is purchased and the long-term option is sold, the trader is short the time spread.
If we assume that the options making up a time spread are approxjmately at-the-money, time spreads have two important characteristics:
A long time spread always wants the underlying market sit still. Since a short-term at-the-money option always decays more quickly than a longterm at-the-money option, regardless of whether the options are calls or puts, both a long call time spread and a long put time spread want the underlying market to sit sti1l. Ideally, both spreads would like the short-term option to expire right at-the-money so that the long-term option will retain as much time value as possible while the short-term option expires worthless.
A long time spread always benefits jrom an increase in implied volatility. As time to expiration increases, the vega of an option increases. This means that a long-term option is always more sensitive in total points to a change in volatility than a short-term option with the same exercise price.
These two opposing forces, the decay in an option's value due to the passage of time and the change in an option's value due to changes in volatility, give time spreads their unue characteristics. When a trader buys or sel1s a time spread, he is not only attempting to forecast movement in the underlying market. He is剖sotrying to forecast changes in imp1ied volatility.
THE EFFECT OF CHANGING INTEREST RATES AND DIVIDENDS.
If we are considering stock options with different expiration dates, we mut consider two different forward prices. Andthese two forward prices may not be equaly sensitive to a change in interest rates.
If interest rates increase,the time spread will widen because the June forward price will rise more quickly than the March forward price. Therefore, a long (short) call time spread in the stock option market must have a positive (negative) rho.
if interest rates increase, the put time spread will narrow. Therefore, a long (short) put time spread in the stock option market must have a negative (positive) rho.
An increase (decrease) in dividends lowers (raises) the forward price of stock.
In a time spread, if a dividend payment is expected between expiration of the short-term and long-term option, the long-term option will be affected by the lowered forward price of the stock. Hence, an increase in dividends, if at least one dividend payment is expected between the expiration dates, will cause call time spreads to narrow and put time spreads to widen. A decrease in dividends will have the opposite effect, with call time spreads widening and put time spreads narrowing. The effect of changing interest rates and dividends on stock option time spreads is shown below:
DIAGONAL SPREADS.
A diagonal spread Is similar to a time spread, except that the options have different exercise prices.
OTHER VARIATIONS.
A Christmas tree (also referred to as a ladd is a term which can be applied to a variety of spreads. The spread usually consists of three different exercise prices where all options are of the same type and expire at the same time. In a long (short) call Christmas tree, one call is purchased (sold) at the lowest exercise price, and one call is sold (purchased) at each of the higher exercise prices. In a long (short) put Christmas tree, one put is purchased (sold) at the highest exercise price, and one put is sold (purchased) at each of the lower exercise prices.
Long Christmas trees , when done delta neutral, can be thought of as particular types of ratio vertical spreads. Such spreads therefore increase in value if the underlying market either sits still or moves very slowly. Short Christmas trees can be thought of as particular types of backspreads, and therefore increase in value with big moves in the underlying market.
It is possible to construct a spread which has the same characteristics as a butterfly by purchasing a straddle (strangle) and selling a strangle (straddle) where the straddle is executed at an exercise price midway between the strangle's exercise prices. All options must expire at the same time. Because the position wants the same outcome as a butterfly, it is known as an iron butterfly .
Another variation on a butterfly, known as a condor , can be constructed by splitting the inside exercise prices. Now the position consists of four options at consecutive exercise prices where the two outside options are purchased and the two inside options sold (a long condor), or the two inside options are purchased and the two outside options sold (a short condor). Como com uma borboleta, todas as opções devem ser do mesmo tipo (todas as chamadas ou todas as opções) e expirar ao mesmo tempo.
SPREAD SENSITIVITIES.
CHOOSING AN APPROPRlATE STRATEGY.
With so many spreads avai1 able, how do we know which type of spread is best?
Ideally, we would like ωconstruct a spread by purchasing options which are underpriced and se1li ng options which are overpriced.
If options general/y appear underprtced (low implied volatility), look for spreads with a positive vega. This includes strategies in backspread or long time spread category.!f options generally appear overpriced (high implied volatility),look for spreads wtth a negative vega. This includes strategies in the ratio vertical or short time spread category.
Long time spreads are likely to be profitable when implied volatility is low but is expected to rise; short time spreads are likely to be profttable when implied volatility is high but is expected to fail.
ADJUSTMENTS.
O uso otimizado de um modelo teórico de precificação requer que um negociante mantenha continuamente uma posição neutra durante a vida útil do spread.
Adjust at regular intervals – In theory, the adjustment process is assumed to be continuous because volatility is assumed to be a continuous measure of the speed of the market. Adjust when the positlon becomes a predetermlned number 01 deltas or short. Adjust by feel.
ENTERING A SPREAD ORDER.
The following contingency orders, all ofwhich are defined in Appendix A, are often used in option markets:
Immediate Or Cancel.
Market If Touched.
Market On Close.
One Cancels The Other.
Stop Umit Order.
Ordem de Stop Loss.
Risk Considerations.
CHOOSING THE BEST SPREAD.
We can summarize these risks as follows:
Delta (DirectionaI) Risk-The risk that the underlying market will move in one direction rather than another. When we create a position which is delta neutral, we are trying to ensure that initially the position has no particular preference as to the direction in which the underlying instrument will move. A delta neutral position does not necessarily eliminate all directional risk, but it usually leaves us immune to directional risks within a limited range. Gamma (Curvature) Risk - The risk of a large move in the underlying contract, regardless of direction. The gamma position is a measure of how sensitive a position is to such large moves. A positive gamma position does not really have gamma risk since such a position will, in theory, increase in value with movement in the underlying contract. A negative gamma position, however, can quickly lose its theoretical edge with a large move in the underlying contract. The consequences of such a move must always be a consideration when analyzing the relative merits of different positions. Theta (Time Decay) Risk一Therisk that time will pass with no movement in the underlying contract. This is the opposite side of gamma risk. Positions with positive gamma become more valuable With large moves in the underlying. But if movement helps, the passage of time hurts. A positive gamma always goes hand in hand with a negative theta. A trader with a negative theta will always have to consider the risk in terms of how much time can pass before the spread's theoretical edge disappears. The position wants movement, but if the movement fails to occur within the next day, or next week, or next month, will be spread, in theory, still be profitable? Vega (Volatility) Risk — The risk that the volatility which we input into the theoretical pricing model will be incorrect. If we input an incorrect volatility, we will be assuming an incorrect distribution of underlying prices over time. Since some positions have a positive vega and are hurt by declining volatility, and some positions have a negative vega and are hurt by rising volatility, the vega represents a risk to every position. A trader must always consider how much the volatility can move againsthim before thepotential profit from a position disappears. Rho (Interest Rate) Risk-The risk that interest rates will change over the life of the option. A position with a positive rho will be helped (hurt) by an increase (decline) in interest rates, while a position with a negative rho wil1 show just the opposite characteristics. Generally, the interest rate is the least important of the inputs into a theoretical pricing model, and it is unlikely, except for special situations, that a trader will give extensive thought to rho risk associated with a position.
PRACTICAL CONSIDERATIONS.
While there is no substitute for experience, most traders quickly learn an important rule: straddles and strangles are the riskiest of all spreads.
HOW MUCH MARGIN FOR ERROR?
Perhaps a better way to approach the question is to ask not what is a reasonable margin for error, but rather to ask what is the correct size in which to do a spread given a known margin for error.
DIVIDENDS AND INTEREST.
WHAT IS A GOOD SPREAD?
It is impossible ωtake into consideration everypossible risk. A spread which passed every risk test would probably have so little theoretical edge that it wouldn't be worth doing. But the trader who allows himself a reasonable margin for error will find that even his losses will not lead to financial ruin. A good spread is not necessarily the one that shows the greatest proflt when things go well; it may be the one which shows the least loss when things go badly. Winning trades always take care of themselves. Losing trades, which don't glve back al1 the profits from the winning ones, are just as important.
ADJUSTMENTS.
An adjustment to trader's delta position may reduce his directional risk, but if he simultaneously increases his gamma, theta, or vega risk, he may inadvertently be exchanging one type of risk for another.
A delta adjustment made with the underlying contract is essentially a risk neutral adjustment. An adjustment made with options may reduce the delta risk, but will also change the other nsk characteristfcs assocíated wtth the position.
A disciplined trader knows that sometimes, because of risk considerations, the best course ls to reduce the size of the spread, even if it means gi. ving up some theoretical edge. This may be hard on the trader's ego, particular1y 1f he must personally go back into the market and either buy back options which he originally sold at a lower price, or sell out options whîch he originally purchased at a higher price. However, if a trader is unwilling to swallow his pride from time to time, and admit that he made a mistake, his trading career is certain to be a short one.
If a trader finds that any de1ta adjustment in the option market that reduces his risk will also reduce his theoretical edge,and he is unwil1ing to give up any theoretical edge, his only recourse is to make h1s adjustments in the underlying market. An underlying contract has no gamma, theta, or vega, so the risks of the position will remain essentially the same.
A QUESTION OF STYLE.
In practice, however, many option traders begin theîr trading careers by taking positions in the underlying market, where direction is the primary consideration. Many traders therefore deve10p a style of trading based on presumed directional moves in the underlying market. A trader might,for examp1e, be a trend follower, adhering to the philosophy that "the trend is your friend." Or he might be a contrarian. preferring to "buy weakness, sell strength."
An important consideration in deciding whether to enter into a trade is often the ease with which the trader can reverse the trade. Luid option markets, where there are many buyers and sellers, are much less risky than illuid markets, where there are few buyers and sellers. In the same way, a spread which consists of very luid options is much less risky出ana spread which consists of one or more illuid options.
Bull and Bear Spreads.
NAKED POSITIONS.
If all options are overpríced (high implied volatility), we might sell puts to create a bullish position, or sel1 calls to create a bearish position. If al1 options are underpriced (low implied volatility), we might buy calls ωcreate a bullish position, or buy puts to create a bearish position.
The problem with this approach is that,as with all non-hedged positions, there is very llttle margin error.
BULL AND BEAR RATIO SPREADS.
If a trader believes that implied volatility is too hlgh, one sensible strategy is a ratio vertical spread.
Even though the trader was correct ín his bullish sentiment, the position was primarily a volatility spread, so that the volatility characteristics of the position eventually outweighed any considerations of market direction.
Since this spread is a volatility spread, the primary consideration, as before, is the volatility of the market. Only secondarily are we concerned with the direction of movement. If the trader overestimates volatility, and the market moves more slowly than expected, the spread which was initially de1ta positive can instead become delta negative.
BULL AND BEAR BUTTERFLIES AND TlME SPREADS.
If the underlying market is currently at 100, he might choose to buy the June 105/110/115 call butterfly. Since this position wants the underlying market at 110 at expiration, and it is currently at 100, the position is a bull butterfly. This will be reflected in the position having a positive delta.
Unfortunately, if the underlying market moves too swift1y, say to 120, the butterfly can invert from a positive to a negative delta position.
Conversely, if the trader is bearish, he can always choose to buy a butterfly where the inside exercise price is below the current price of the underlying market. But again, if the market moves down too quickly and goes through the inside exercise price, the position will invert from a negative to a positive delta.
In a simi1ar manner, a trader can choose time spreads 由atare either bul1ish or bearish. A long time spread always wants the near-term contract to expire exactly at-the-money. A long time spread will be initial1y bullish if the exercise price of the time spread is above the current price of the underly1ng market.
SPREADS VERTICAIS.
Vertical spreads are not on1y initially bullish or bearish, but they remain bullish or bearish no matter how market conditions change. A vertical spread always consists of one long (purchased) option and one short (sold) option, where both options are of the same type (either both calls or both puts) and expire at the same time. The options are distinguished only by their different exercise prices. Typical vertical spreads might be:
buy 1 June 100 call.
sell 1 June 105 cal1.
buy 1 March 105 put.
sell 1 March 95 put.
If a trader wants to do a vertical spread, he has essentially four choices. If he is bullish he can choose a bull vertical call spread or a bull vertical put spread; if he is bearish he can choose a bear vertical call spread or a bear vertical put spread. Por exemplo:
bull call spread: buy a June 100 call.
bull put spread: buy a June 100 put.
bear call spread: sell a June 100 call.
bear put spread: sell a June 100 put.
Two factors determine the total directional characteristlcs of a vertlcal spread:
The delta of the specific vertical spread The size in which the spread is executed.
The greater the distance between exercise prices, the greater the delta value associated with the spread. A 95/110 bull spread wil1 be more bullish than a 100/110 bull spread, which will, ín turn, be more bullish than a 100/105 bull spread.
Once a trader decides on an expiratlon month in which to take his directlonal position, he must decide which specific spread is best. Ou seja, ele deve decidir quais preços de exercício usar. A common approach is focus on the at-the-money optlons. If a trader does this, he will have the fol1owing choices:
The reason becomes clear if we recall one of the characteristics of option evaluation introduced in Chapter 6: If we consider three options, an in-the-money, at-the-money, and out-of-the-money option which are identical except for their exercise prices, the at-the-money option is always the most sensitive in total points to a change in volatility.
This characteristic leads to a very simple rule for choosing bull and bear vertical spreads:
If implied volatility is too low, vertical spreads should focus on purchasing the at-the-money optlon. If implied volatility is too high, vertical spreads should focus on selling the at-the-money options.
A trader is not required to execute any vertical spread by first buying or selling the at-the-money option. Such spreads always involve two options, and a trader can choose to either execute the complete spread in one transaction, or leg into the spread by trading one option at a time. Regardless of how the spread is executed, the trader should focus on the at-the-money option, either buying it when implied volatility is too low, or selling it when implied volatility is too high.
The choice of the at-the-money option is slightly different when we move to stock options. If we define the at-the-money option as the one whose de1ta is closest to 50, then we may find at the at-the-money option is not always the one whose exercise price is closest current price of the underlying contract. This ís because the option with a delta closest 50 will be the one whose exercise price ís closest to forward price of underlying contract. In stock options, the forward price is the current price of stock, plus carrying costs on the stock, less expected dividends.
Why míght a trader with a directional opinion prefer a vertical spread to an outright long or short posítíon in the underlying instrument? For one thing, a vertical spread is much less risky than an outright posítion. Atrader who wants to take a position which is 500 deltas long can either buy fíve underlying contracts or buy 25 vertical calI spreads with a delta of 20 each. The 25 vertical spreads may sound riskier than five underlying contracts, until we remember at a vertical spread has limited risk whíle the position in underlying has open-ended risk. Of course, greater risk also means greater reward. A trader with a long or short position in the underlyíng market can reap huge rewards if the market makes a large move in his favor. By contrast, the vertical spreader's profits are limited, but he will also be much less bloodied if the market makes an unexpected move in the wrong direction.
Option Arbitrage.
SYNTHETIC POSITIONS.
synthetic long underlying = long call + short put synthetic short underlying = short call + long put.
where all options expire at the same time and have the same exercise price.
Rearranging the components of a synthetic underling position, we can create four other synthetic relationships:
synthetic long call = long an underlylng contract + long put synthetic short call = short an underlying contract + short put synthetic long put = short an underlying contract + long call synthetic short put = long an underlying contract + short call.
The difference between the call and put price ís often referred to as the synthettc market. In the absence of any interest or dividend considerations, the value of the synthetic market can be expressed as:
call price - put price = underlying price - exercise price.
If this equality holds, there ís no difference between taking a position in the underlying market, or taking an equivalent synthetic position in the option market.
The three-sided relationship between a call, a put, and its underlying contract means that we can always express the value of any one of these contracts in terms of the other two:
underlying price = call prîce - put prîce + exercíse price call prîce = underlying price + put príce - exercíse price put price = call prîce - underlying prîce + exercise price.
This three-sided relationship is sometimes referred put-call parity .
CONVERSIONS AND REVERSALS.
When a trader identifies two contracts which are essentially the same but which are trading at different prices, the natural course ís to execute an arbitrage by purchasing the cheaper contract and selling the more expensive.
No matter what happens in the underlying market, the underlying position will do exactly .25 better than the synthetìc position. The entire position wíll therefore show a profit of .25, regardless of movement in the underlying market.
The foregoing position, where the purchase of an underlying contract is offset by the sale of a synthetic position, is known as a conversion . The opposíte position, where the sale of an underlying contract is offset by the purchase of a synthetic position, is known as a reverse conversion or, more commonly, a reversal .
conversion = long underlying + synthetlc short underlying = long underlying + short call + long put reversal = short underlying + synthetic long underlying = short underlying + long call + short put.
As before, we assume that the call and the put have the same exercise price and expiration date.
Typically, an arbitrageur will attempt to simultaneously buy and sell the same items in different markets to take advantage of price discrepancies between the two markets.
Synthetic positions are often used to execute conversions and reversals, so traders sometimes refer to the synthetic market (the difference between the call price and put price) as the converston/reversal market.
All experienced traders are familiar with the price relationship between a synthetic position and its underlying contract, so that any imbalance in the conversion/reversal market is 1ikely to be short-lived. If the synthetic is overpriced, all traders will want to execute a conversion (buy the underlying, sell the call, buy the put). If the synthetic is underpriced, all traders will want to execute a reversal (sell the underlying, buy the call, sell the put). Such activity, where everyone is attempting to do the same thing, will quickly force the synthetic market back to equilibrium. De fato, os desequilíbrios no mercado de conversão / reversão são geralmente pequenos e raramente duram mais do que alguns segundos.
Futures Option Markets.
If the cash flow resulting from an option trade and a trade in the underlying instrument is identical, the synthetic relationship is simply:
call price - put price = underlying price - exercise price.
This will be true if interest rates are zero, or in futures markets where both the underlying contract and options on that contract are subject to futures-type settlement.
Assuming that all options are European (no early exercise permitted), we can now express the synthetic relationship in futures markets where the options are settle in cash as follows:
cal1 price - put price = futures price - exercise price - carrying costs.
where the carrying costs are calculated on either the difference between the futures price and the exercise price, or the difference between the call price and put price, both of which will be approximately the same.
Taking into consideration the interest rate component, we can express the synthetic relationship as:
call price - put price = stock price - exercise price + carrying costs.
where the carrying costs are calculated on the exercise price.
call price - put price = stock price - exercise price + carrying costs - dividends.
where the carrying costs are calculated on the exercise price and the dividends are those expected prior to expiration.
ARBITRAGE RISK.
Risco da taxa de juros.
Anytime a strategy is executed one leg at a time, there is always the risk of an adverse change in prices before the strategy can be completed.
The practical solution is to avoid carrying conversions and reversals to expiration when there is a real possibility of expiration right at the exercise price.
If al1 contracts are subject to futures-type settlement, any credit or debit resulting from changes in the price of the underlying futures contract wil1 be offset by an equal but opposite cash flow from changes in prices of the option contracts.
The risk arises because a synthetic position in options and an actual position in the underlying contract can have different characteristics, either in terms of settlement procedure, as in the futures option market, or in terms of the dividend payout, as in the stock option market.
How might we eliminate this risk?
short a call long a put long an underlying contract.
replace the long underlyingpositlon with a deeply in-the-money call Now our position is:
short a call long a put long a deeply in-the-money call.
instead of replacing the underlying position with a deeply in-the-money call, we can sell a deeply in-the-money put:
short a cal1 long a put short a deeply in-the-money put.
This type of position, where the underlying instrument in a conversion or reversal is replaced with a deeply in-the-money option, is known as a three-way .
Suppose we also execute a reversal at 90:
long a June 90 call short a June 90 put short an underlying contract.
short a June 100 call long a June 100 put long an underlying contract.
The long and short underlying contracts cancel out, leaving:
long a June 90 call short a June 90 put.
short a June 100 call long a June 100 put.
This position, known as a box, is similar to a conversion or reversal, except that any risk associated with holding a position in the underlyíng contract has been eliminated because the underlying position has been replaced with a synthetic underlying position at a different exercise price.
Since a box eliminates the risk associated with carrying a position in the underlying contract, boxes are even less risky than conversions and reversals, which are themselves low-risk strategies.
JELLY ROLLS.
Another method of eliminating a position in the underlying contract is to take a synthetic position in a different expiration month, rather than at a different exercise price as with a box.
For example, suppose we have executed the following reversal:
long a June 100 call short a June 100 put short an underlying contract.
short a September 100 call long a September 100 put long an underlyíng contract.
If the underlyíng contract for bothJune and Septernber is identical, theywil1 cancel out, leaving us with:
long a June 100 cal1 short a June 100 put.
short a September 100 cal1 long a September 100 put.
These combined long and short synthetic positions taken at the same exercise prices but in different expiration months is known as a jelly roll or simplya roll.
The value of the roll is the cost of holding the stock for the three-month period from June to September.
jelly roll = long-term synthetic - short-term synthetic = (long-term call-long-term put) - (short-term call-short-term put) = (long-term call-short-term call) - (long-term put - short-term put) = caηying costs - expected dividends.
USING SYNTHETICS IN VOLATILITY SPREADS.
the synthetic relationship:
synthetic short cal1 = short put + short underlying.
TRADING WITHOUT THEORETICAL VALUES.
Regardless of the exact theoretical value, there ought to be a uniform progression of both individual option prices and spread prices in the marketplace. If this uniform progression is violated, a trader can take advantage of the situation by purchasing the option or spread which is relatively cheap and selling the option or spread which is relatively expensive.
The trader can start with conversions and reversals, then look at vertical spreads and butterflies, and finally consider straddles and time spreads.
Early Exercise of American Options.
Given the opportunìty, under what cìrcumstances might a trader consìder exercising an American option prior to expiration? How much more should a trader be wi1ling to pay for an American option over an equivalent European option?
FUTURES OPTIONS.
option value = ìntrinsic value + volati1ìty value - interest rate value.
A trader who exercises a futures option early does so to capture the interest on the option's intrinsic value. This intrinsic value will be credited to his account only if the option is subject to stock-type settlement.
OPÇÕES DE AÇÕES.
Early Exercise of Calls for the Dividends.
call value = intrînsic value + interest rate value + volatility value - dividend value.
Since the only reason a trader would ever consider exercising a stock option call early is to receive the dividend, if a stock pays no dividend there is no reason to exercise a call early. If the stock does paya dividend, the only time a trader ought to consider early exercise is the day before the stock goes ex-dividend. At no other time in its life is a stock option call an early exercise candidate.
put value = intrinsic value - interest rate value + volatility value + dividend value.
Whereas a stock option call can only be an early exercise candidate on the day prior to the stock's ex-dividend date, a stock option put can become an early exercise candidate anytime the interest which can be earned through the sale of the stock at the exercise price is sufficiently large.
infer two conditions which are necessary before a trader considers exercising option early to capture is additional profit:
The option must be trading at parity. The option must have a delta close to 100.
The importance of early exercise is greatest when the underlying contract is a stock or physical commodity. In such a case there is a significant difference between the carrying cost on an option and the caπyi cost on underlying position. This difference will especially affect the difference between European and Am erican put values, since early exercise wil1 allow the trader to earn interest on the proceeds from the sale at the exercise price. An option trader in either the stock or physical commodity market will find that the additional accuracy offered by an American model, such as the Cox-Ross-Rubenstein or Whaley models, will indeed be worthwhile.
THE EFFECT OF EARLY EXERCISE ON TRADING STRATEGIES.
Cobertura com Opções.
PROTECTIVE CALLS AND PUTS.
The simplest wayωhedge an underlying position using optìons is to purchase either a call to protect a short position, or a put to protect a long position.
Since each strategy combines an underlying position with an option position, it follows from Chapter 11 that the resulting protected position is a synthetic option:
short underlying + long call = long put long underlying + long put = long call.
COVERED WRITES.
The value of typical covered writes, also known as overwrites, are covered call and covered put.
As with the purchase of a protective optlon, a covered write consists of a position in the under ng and an option. It can therefore be expressed as a synthetic position:
long underlying + short call = short put short underlying + short put =short call.
A popular strategy, known as a fence, is to simultaneously combine the purchase of a protective option with the sale ofa covered option. For example, with an underlying contract at 50, a hedger with a long position might choose to simultaneously sell a 55 call and purchase a 45 put.
Fences are popular hedging tools because they offer known protection at alow cost, or even a credit. At the same time ,they still allow a hedger to participate, at least partially, in favorable market movement. Fences go by a variety of names: range forwards, tunnels, cylinders; among floor traders they are sometimes known as split price conversions and reversals.
COMPLEX HEDGING STRATEGIES.
As a first step in choosing a strategy, a hedger might consider the following:
Does the hedge need to offer protection against a I'worst case" scenario? How much of the current directional risk should the hedge eliminate? What additional risks is the hedger willing to accept?
ll otnel ctors being equal, in a high implied volatility market a hedger should buy as few options as possible and sell as many options as possible. Conversely, in a low implied volatility market a hedger should buy as many options as possible and sell as few options as possible.
A hedger who constructs a position with unlimited risk in either direction is presumably taking a volatility position. There is nothing wrong with this, since volatility trading can be highly profitable. But a true hedger ought not lose sight of what his ultimate goal is: to protect an existing position, and to keep the cost of this protection as low as possible.
PORTFOLIO INSURANCE.
if he wants to replicate the combination of the underlying asset and the 100 put, he must sell off 43% of his holdings in the asset. When he does that, he will have a position theoretically equivalent to owning a 100 call.
This process ofcontinuously rehedging an underlying position to replicate an option position is often referred to as portfolio insurance.
If the mix of securities in a portfolio approximates an index, and futures contracts are available on that index, the manager can approximate the results of portfolio insurance by purchaslng or selling futures contracts to increase or decrease the holdings in his portfolio.
Even if options are available on an underlying asset, a hedger may still choose to effect a portfolio insurance strategy himself rather then purchasing the option in the marketplace. For one thing, he may consider the option too expensive. If he believes the option is theoretically overpriced, in the long run it will be cheaper to continuously rehedge the portfo1io. Or he may find insufficient luidity in the option market to absorb the number of option contracts he needs to hedge his position. Finally, the expiration of options which are available may not exactly correspond to the period over which he wants to protect his position. If an option is available, but expires earlier than desired, the hedger might still choose to purchase options in marketplace, and then pursue a portfolio insurance strategy over the period following the option's expiration.
Volatility Revisited.
SOME VOLATILITY CHARACTERISTICS.
we might surmise at an underlying contract is likely to have a typicallong-term average, or mean volatility. Moreover, the volatility of the underlying contract appears to be mean reverting. When volatility rises above the mean, one can be fairly certain that it will eventually fall back to its mean; when volatility fal1 s below the mean, one can be fairly certain that it will eventual1y rise to its mean.
VOLATILITY FORECASTING.
In addition ωthe mean reverting characteristic, volatility also tends to exhibit sen. al correlatton. The volatility over any given period is likely ωdepend on, or correlate with, the volatility over the previous period, assuming that both periods cover the same amount of time. If the volatilityofa contract over the last fourweeks was 15% , the volatility over the next four weeks is more likely to be close to 15% an far away from 15%.
A PRACTICAL APPROACH.
Rather than asking what the correct volati1ity is, a trader might instead aSk, given the current volatiUty climate, what' right strategy? Rather than trying to forecast an exact volatility, a trader will try to pick a strategy that best fits the volatility conditions in the marketplace. To do this, a trader will want to consider several factors:
What is long. term mean volatility of underlying contract? What has been the recent historical volatility in relation to em volatility? What is trend in recent historical volatility? Where îs imp1ied volatility and what is its trend? Are we dealing wi options of shorter or longer duration? How stable does the volati1ity tend to be?
SOME THOUGHTS ON IMPLIED VOLATILITY.
Implied versus Historical Volatility.
Market participants are making the logical assumption that what has happened in the past is a good indicator of what will happen in the future.
the fluctuations in implied volatility were usually less than the fluctuations in historical volatility. When the historical volatility declined, the implied volatility rarely dec1ined by an equal amount. And when historical volatility increased, the implied volatility rarely increased byan equal amount. Because volatility tends to be mean reverting, when historical volati1ity is above its mean there is a greater likelihood that it will dec1ine, and when historical volatility is below its mean there is a greater likelihood that it will increase.
Stock Index Futures and Options.
professional arbitrageurs find at in spite of the highly luid and usually efficient index markets, pricing disparities occur often enough to warrant close monitoring of these markets. When a disparity does exist, a trader can execute an arbitrage by hedging the mispriced index against either other stock indices or against a basket of stocks. Such arbitrage strategies are commonly refeηed to as index arbitrage .
CALCULATING AN INDEX.
There are several different methods of calculating stock index values, but the most common methods entail weighting the stocks either by price or by capitalization.
REPLICATING AN INDEX.
the number of shares of each stock required to replicate an index.
for a price weighted index: point value / index divisor.
for a capitalization weighted index: outstanding shares x point value / index divisor.
FUTUROS DO ÍNDICE DE AÇÕES.
The purchase of a futures contract offers one important advantage over the purchase of the component stocks: no cash outlay ís required to purchase a futures contract. Consequently, there is an interest rate savings equal to the cost of borrowing sufficient cash to purchase all the stocks in the index.
INDEX ARBITRAGE.
If the futures príce doesn't reflect the fair value, a trader can execute a profitable arbitrage by purchasing the undervalued asset, either the basket of stocks or the futures contract, and selling overvalued asset.
This type of trading strategy, where one buys or sells a mispriced stock index futures contract and takes an opposing position in the underlying stocks, is one type of index arbitrage. Since computers can often be programmed to calculate the fair value of a futures contract, and to execute the arbitrage when the futures contract is mispriced, such astrategy is also commonly referred to as program trading. A buy prograrn consists of buying the stocks and selling the futures contract, and a sell program consists of selling the stocks and buying the futures contract.
INDEX OPTIONS.
There are real1y two types of stock index options, those where the underlying is a stock index futures contract, and those where the underlying is the index itself.
Options on Stock Index Futures.
Although the ultirnate decision about the underlying price is trader's, in a stock index futures option rnarket a trader should be very careful about using an underlying futures price different from the quoted price. As we have already seen ,出 theoretical value of astock index futures contract depends information which rnay ot be readily available to the trader. If he 1s wrong about the price at which the index is actually trading because the individual stock prices do not reflect the true rnarket, his theoretical evaluation of the futures contract wil1 be incorrect.
It may seem odd, but in fact it doesn't matter whether the index opens the next morning at a higher price, lower price, or unchanged. What matters is that the marketplace believes that the market will change, and that all contracts are priced accordingly. In such a case, the trader rnust exercise those options which, given the perceived change in the underlying price, now have a value less than parity, and replace them with other contracts which are not limited by parity constraints.
Because it can be difficult to trade a complete and correctly proportioned basket of stocks, and because there is the additional risk of early exercise after an index arbitrage has been executed, mispriced synthetic relationships are not as easy to exploit ín index option markets as in other option markets.
Opção Volatilidade & amp; Pricing, Advanced Trading Strategies and Technues.
Índice.
The language of options.
Especificações do contrato.
Call option: the right to buy or take a long position in a given asset at a fixed price on or before a specified data. Put option: the right to sell or take a short position in a given asset.
The difference between an option and a futures contract:
A futures contract requires delivery at a fixed price. The seller must make delivery and the buyer must take delivery of the asset. The buyer of an option can choose to take delivery(a call) or make delivery(a put).
The exercise price , or strike price is the price at which the underlying will be delivered should the holder of an option choose to exercise his right to buy or sell.
expiration date : The date after which the option may no longer be exercised is the expiration date.
The premium paid for an option can be separated into two components, the intrinsic value and the time value .
The additional amount ofpremium beyond the intrinsic value which traders are willing to pay for an option is the time value, sometimes also referred to as the option's time premium or extrinsic value.
An option's premium is always composed of precisely its intrinsic value and its time value. If a $400 gold call is trading at $50 with gold at $435 per ounce, the time value of the call must be $15 , since the intrinsic value is $35. Os dois componentes devem totalizar o prêmio total da opção de US $ 50.
If the option has no time value, its price will consist solely of intrinsic value. The option is trading at parity .
Any option which has a positive intrinsic value is said to be in-the-money by the amount of the intrinsic value. An option which has no intrinsic value is said to be out-of-the-money .
An option whose exercise price is identical to the current price of the underlying contract is said to be at-the-money , such an option is also out-of-the-money since it has no intrinsic value.
The distinction between an at-the-money and out-of-the-money option because an at-the-money option has the greatest amount of time premium and is usually traded very actively.
REQUISITOS DE MARGEM.
When a trader makes an opening trade on an exchange, the exchange may require the trader to deposit some amount of margin , or good faith capital.
Elementary Strategies.
SIMPLE BUY AND SELL STRATEGIES.
long and short an underlying contract.
long a call.
RISK REWARD CHARACTERISTICS.
long positions in 95, 100,and 105 calls.
the profit and loss from a short position in the 95, 100, and 105 calls.
long positions in 95, 100,and 105 puts.
the short put positions in 95, 100,and 105 puts.
COMBINATION STRATEGIES.
the profit and loss at expiration from the combined purchase of a 100 call for 2.70, and a 100 put for 3.70.
short them.
sell a 95 put for 1.55 and a 105 call for 1.15.
sell the 90 call and purchase the 100 call.
buy a 105 put for 7.10 and sell a 100 put for 3.70, for a total debit of 3.40.
CONSTRUCT AN EXPlRATION GRAPH.
If the graph bends, it wìll do so at an exercise price. Therefore, we can calculate the proflt or 10ss at each exercise price involved and simply connect these points with straight lines. If the position is 10ng and short equa1 numbers of cal1s (puts), the potential downside (upside) risk or reward wi11be equal ωthe total debit or credit required to establish the position. Ab ove highest exercise price all calls will go into-the-money, so the entire position will act like an underlying position which is either long or short underlying contracts equal to the number of net long or short calls. Below the lowest exercise price all puts will go into-the-money, so the entire position will act like an underlying position which is either long or short underlying contracts equal to the number of net long or short puts.
long one 95 call at 5.50 short three 105 calls at 1.15.
short one 90 cdll at 9.35 long two 100 calls at 2.70 short four 95 puts at 1.55 long two 100 puts at 3.70.
long one 100 call at 2.70 short one 100 put at 3.70.
long one 90 put at .45 short one 100 call at 2.70 long one underlying contract at 99.00.
Introduction to Theoretical Pricing Models.
If he purchases options, not only must he be right about market direction, he must also be right about market speed .
The minimum factors you must consider:
The price of the underlying contract. The exercise price. The amount of time remaining to expiration. The direction in which he expects the underlying market move. The speed at which he expects the underlying market to move.
THEORETICAL VALUE.
The two most common considerations in a financial investment are the expected return and carrying costs. And, in fact, dividends are an additional consideration in evaluating options on stock.
The goal of option evaluation is to determine, through the use of theoretical pricing models, the theoretical value of an option. The trader can then make an intelligent decision whether the option is overpriced or underpriced in the marketplace, and whether the theoretical edage is sufficient to justify going into the marketplace and making a trade.
A SIMPLE APPROACH.
We can now summarize the necessary steps in developing a model:
Propose a series of possible prices at expiration for the underlying contract. Assign an appropriate probability to each possible price. Maintain an arbitrage-free underlying market. From the prices and probabi1ities in steps 1, 2, and 3, calculate the expected return for the option. From the option's expected return, deduct the carrying cost.
In its original form, the Black-Scholes Model was intended to evaluate European options (no early exercise permitted) on non-dividend paying stocks. Shortly after its introduction, realizing that rnost stocks do pay dividends, Black and Scholes added a dividend cornponent. In 1976, Fischer Black rnade slight rnodifications to the rnodel to allow for the evaluation of options on futures contracts. And in 1983, Mark Garman and Steven Kohlhagen made several other modifications to allow for the evaluation of options on foreign currencies. The futures version and the foreign currencyversion are known officially as the Black Model and the Garman-Kohlhagen Model, respectively. But the evaluation rnethod in each version, whether the original Black-Scholes Model for stock options, the Black Model for futures options, or the Garman-Kohlhagen Model for foreign currency options, is so similar that they have all come to be known as simply the Black-Scholes Model. The various forrns of the model differ primarily in how they calculate the forward price of由eunderlying contract, and an option trader will simply choose the form appropriate to the underlying instrument.
In order to calculate an option's theoretical value using the Black-Scholes Model, we need to know at a minimum five characteristics of the option and its underlying contract. Tem:
The option's exercise price. The amount of time remaining to expiration. The current price of the underlying contract. The risk-free interest rate over the life of the option. The volatility of the underlying contract.
Black and Scholes also incorporated into their model the concept of the riskless hedge . To take advantage of a theoretically mispriced option,it is necessary to establish a hedge by offsetting the option position with this theoretically equivalent underlying position. That is, whatever option position we take, we must take an opposing market position in the underlying contract. The correct proportion of underlying contracts needed to establish this riskless hedge is known as the hedge ratlo .
Volatilidade.
RANDOM WALKS AND NORMAL DISTRIBUTIONS.
Thís leads to an important distínction between evaluation of an underlying contract and evaluation of an option. If we assume at prices are distributed along a normal distribution curve, the value of an underlying contract depends on where the peak of the curve is located, while the value of an option depends on how fast le curve spreads out.
LOGNORMAL DISTRIBUTIONS.
A continuously compounded rate of return of +12% yields a profit of $127.50 after one year, while a continuously compounded rate of return of -12% yields a loss of only $113.08.
When price changes are assumed to be normally distributed, the continuous compounding of these price changes wiU cause the prices at maturity to be lognormally distributed .
The Black-Scholes Model is a contínuous time model. It assumes at the volatility of an underlying instrument is constant over the life of the option, but that this volatility is continuously compounded. These two assumptions mean that the possible prices of the underlying instrument at expiration ofthe option are lognormally distributed.
It also explains why options with higher exercise prices caηy more value than options with lower exercise prices, where both exercise prices appear to be an identical amount away from the price of the underlying instrument.
Summarize the most irnportant assurnptions governing price movement int the Black-Scholes Model:
Changes in the price of an underlying instrurnent are randorn and cannot be artificially manipulated, nor is it possible to predict beforehand direction in which prices will move. The percent changes in the price of an underlying instrurnent are norrnally distributed. Because the percent changes in the price of the underlying instrurnent are assumed to be continuously cornpounded, the prices of the underlying instrument at expiration will be lognormally distributed. The mean of the lognormal distribution will be located at the forward price of the underlying contract.
TYPES OF VOLATILITIES.
Future Volatility: Future volatility is what every trader would like to know, the volatility at best describes the future distribution of prices for an underlying contract. Historical Volatility Forecast Volatility Implied Volatility: It is volatility being implied to the underlying contract through the pricing of the option in the marketplace. Even though the term premium real1y refers to an option's price, it is common among traders to refer to the implied volati1ity as the premium or premium level. If the current implied volatility is high by historical standards, or high relative to the recent historical volatility of the underlying contract, a trader might say that premium levels are high; if implied volatility is unusuallylow, he might say that premium levels are low.
He might then look at the difference between each option's theoretical value and its price in marke lace selling any options which were overpriced relative to the theoretical value, and buying any options which were underpriced.
Using an Option's Theoretical Value.
The purchase or sale of a theoretically mispriced option requires us to establish a hedge by taking an opposing positlon in the underlying contract. When this is done correctly, for small changes in the price of the underlying, the increase (decrease) in the value of the optlon position will exactly offset the decrease (increase) in the value of the opposing position in the underlying contract. Such a hedge is unbiased, or neutral , as to the direction of the underlying contract.
The number which enables us to establish a neutral hedge under current market conditions is a by-product of theoretical pricing model and is known as the hedge ratio or, more commonly, the delta .
The delta of a call option is always somewhere between 0 and 1.00. The delta of an option can change as market conditions change. An underlying contract always has a delta of 1.00.
The steps we have thus far taken illustrate the correct procedure in using an option theoretical value:
Purchase (sell) undervalued (overvalued) options. Establish a delta neutraI hedge against the underlying contract. Adjust the hedge at regular intervals to remain delta neutral.
At that time we plan to close out the position by:
Letting any out-of-the-money options expire worthless. Selling any in-the-money options at parity (intrinsic value) or, equiva1ently, exercising them and offsetting them against the underlying futures contract. Luidating any outstanding futures contracts at the market price.
1n a frictionless market we assume that:
Traders can freely buy or sell the underlying contract without restriction AlI traders can borrow and lend money at the same rate. Transaction costs are zero. There are no tax considerations.
Option Values and Changing Market Conditions.
three interpretations of delta:
the hedge ratio Rate of Change in the theoretical value: The de1ta is a measure of how an optio 's value changes with respect to a change in the price of the underlying contract. Theoretical or Equivalent Underlying Position.
The gamma sometimes referred to as the curvature of an option, is the rate at which an option's delta changes as the price of the underlying changes.
If an option has a gamrna of 5for each point rise (fal1) in the price of the und. erlying, the option will gain (lose) 5 de1tas.
Every option trader learns to look carefully not only at current directional risk (the delta), but also at how that directional risk will change if the underlying market begins ωmove (the gamma).
The theta(θ) ,or tíme decay factor, is the rate at which an option loses value as time passes.
THE VEGA OR KAPPA.
The vega of an option is usually given in point change ín theoretical value for each one percentage point change in volatility.
Since vega is not a Greek letter, a common alternative in academic literature, where Greek letters are preferred, is kappa (K).
A sensibilidade do valor teórico de uma opção a uma mudança nas taxas de juros é dada pelo seu rho (P).
Delta: Deltas range from zero for far out-of. the-money calls to 100 for deeply in-the-money calls, and from zero for far out-of-the-money puts to -100 for deeply in-the-money puts.
At-the-money calls have deltas of approximately 50, and at-the-money puts approximately -50.
As time passes, or as we decrease our volatility assumption, call deltas move away om 50,and puts deltas away from -50. As we increase our volatility assumption, cal1 deltas move towards 50, and put deltas towards -50.
As we increase our volati1ity assumptíon, the gamma of an in.
money option rises, while gamma of an at le.
money option falls. As we decrease our volatility assumption, or as time to expiration grows shorter, the gamma of an in.
the money option falls, while the gamma of an at.
the-money option rises, sometimes dramatically.
money options have greater etas than either in.
ofthe-money options with otherwise identical contract specifications.
The theta of an at-the-money option increases as expiration approaches. A short-term, at-the-money option will a1 ways decay more quickly than a long-term, at-the-money option.
As we increase (decrease) our volatility assumption, the theta of an option will rise (fall). Higher volatility means there is greater time value associated with the option, so at each day's decay wil1 also be greater when no movement occurs.
Out-of-the-money options have the greatest vega as apercent of theoretical value.
The various positions and their respective signs are given in Figure 6-26. The sign of the delta, gamma, theta, or vega, toge er with the magnitude of the numbers, tel1 the trader which changes in market conditions will either help or hurt his position, and to what degree. The positive or negative effect of changing market conditions is summarized in Figure 6-27.
An option's elasticity , sometimes denoted with the Greek letter omega(or less commonly the Greek letter lambda), is the relative percent change in an option's value for a given percent change in the price of the underlying contract.
The elasticity is sometimes referred to as the option's leverage value . The greater an option's elasticity, the more highly leverage the option.
An easy method of calculating:
elasticity = (underlying price) / (theoretical value) * delta.
Introduction to Spreading.
Spreading is simply a way of enabling an optlon trader to take advantage of theoretlcally mispriced options, while at the same time reducing the effects of short-term changes in market conditions so that he can safely hold an optlon positlon to maturity.
WHY SPREAD?
At some point the intelligent trader will have to consider not only the potential profit, but also the risk associated with a strategy.
No trader will survive very long if his livelihood depends on estimating each input with 100% accuracy. Even when he incorrectly estimates the inputs, the experienced trader can survive if he has constructed intelligent spread strategies which allow for a wide margin of error.
Volatility Spreads.
Regardless ofwhich method we choose, each spread will have certain features in common:
Eachspread will be approximately delta neutral. Cada spread será sensível a alterações no preço do instrumento subjacente. Each spread will be sensitive to changes in implied volatility. Each spread wil1 be sensitive to the passage of time.
BACKSPREAD.
A backspread is a delta neutral spread which consists of more long (purchased) options than short (sold) options where all options expire at the same time.
A call backspread consists of long calls at a higher exercise price and short calls at a lower exercise price. A put backspread consists of long puts at a lower exercise price and short puts at a higher exercise price.
If no movement occurs, a backspread is likely to be a losing strategy.
A trader will tend ωchoose the type ofbackspread which reflects his opinion about market direction. If he foresees a market with great upside potential, he will tend to choose a call backspread; if he foresees a market with great downside potential he will tend to choose a put backspread. He will avoid backspreads in quiet markets since the underlying contract is unlikely to move very far in either direction.
RATIO VERTICAL SPREAD.
A trader who takes the opposite side of a backspread also has a delta neutral spread, but he is short more contracts than long, with all options expiring at the same time. Such a spread is sometimes referred to as a ratio spread or a vertical spread.
Designe o oposto de um backspread como um spread vertical de proporção.
A straddle consists of either a long call and a long put, or a short call and a short put, where both options have the same exercise price and expire at the same time.
If both the call and put are purchased, the trader is said to be long the straddle; if both options are sold, the trader is said to be short the straddle.
Like a straddle, a strangle consists of a long call and a long put, or a short call and a short put, where both options expire at the same time. In a strangle, however, the options have different exercise prices. If both options are purchased, the trader is long the strangle if both options are sold, the trader is short the strangle.
To avoid confusion a strangle is commonly assumed to consist of out-the-money options. If the underlying market is current1y at 100 and a trader wants to purchase the June 95/105 strangle, it is assumed that he wants to purchase a June 95 put and a June 105 call. When both options are in-the-money, the position is sometimes referred to as a guts .
A butterfly consists of options at three equally spaced exercise prices, where all options are of the same type (either all calls or all puts) and expire at the same time.
In a long butterfly the outside exercise prices are purchased and the insíde exercise price is s01d, and vice versa for a short butterfly.
It is always 1 x 2 x 1, with two of each inside exercise price traded for each one of the outside exercíse prices. If the ratio is other than 1 x 2 x 1, the spread is no longer a butterfly.
a long butterfly tends to act like a ratio vertica1 spread and a short butterfly tends to act like a backspread.
TIME SPREAD (calendar spread or horizontal spread)
Time spreads, sometimes referred to as calendar spreads or horizontal spreads, consist of opposing positions whlch expire in different months. The most common type of time spread consists o.
The most common type of time spread consists of opposing positions in two options of the same type (either both calls or both puts) where both options have the same exercise price. When the long-term option is purchased and the short-term option is sold, a trader is long the time spread; when the short-term option is purchased and the long-term option is sold, the trader is short the time spread.
If we assume that the options making up a time spread are approxjmately at-the-money, time spreads have two important characteristics:
A long time spread always wants the underlying market sit still. Since a short-term at-the-money option always decays more quickly than a longterm at-the-money option, regardless of whether the options are calls or puts, both a long call time spread and a long put time spread want the underlying market to sit sti1l. Ideally, both spreads would like the short-term option to expire right at-the-money so that the long-term option will retain as much time value as possible while the short-term option expires worthless.
A long time spread always benefits jrom an increase in implied volatility. As time to expiration increases, the vega of an option increases. This means that a long-term option is always more sensitive in total points to a change in volatility than a short-term option with the same exercise price.
These two opposing forces, the decay in an option's value due to the passage of time and the change in an option's value due to changes in volatility, give time spreads their unue characteristics. When a trader buys or sel1s a time spread, he is not only attempting to forecast movement in the underlying market. He is剖sotrying to forecast changes in imp1ied volatility.
THE EFFECT OF CHANGING INTEREST RATES AND DIVIDENDS.
If we are considering stock options with different expiration dates, we mut consider two different forward prices. Andthese two forward prices may not be equaly sensitive to a change in interest rates.
If interest rates increase,the time spread will widen because the June forward price will rise more quickly than the March forward price. Therefore, a long (short) call time spread in the stock option market must have a positive (negative) rho.
if interest rates increase, the put time spread will narrow. Therefore, a long (short) put time spread in the stock option market must have a negative (positive) rho.
An increase (decrease) in dividends lowers (raises) the forward price of stock.
In a time spread, if a dividend payment is expected between expiration of the short-term and long-term option, the long-term option will be affected by the lowered forward price of the stock. Hence, an increase in dividends, if at least one dividend payment is expected between the expiration dates, will cause call time spreads to narrow and put time spreads to widen. A decrease in dividends will have the opposite effect, with call time spreads widening and put time spreads narrowing. The effect of changing interest rates and dividends on stock option time spreads is shown below:
DIAGONAL SPREADS.
A diagonal spread Is similar to a time spread, except that the options have different exercise prices.
OTHER VARIATIONS.
A Christmas tree (also referred to as a ladd is a term which can be applied to a variety of spreads. The spread usually consists of three different exercise prices where all options are of the same type and expire at the same time. In a long (short) call Christmas tree, one call is purchased (sold) at the lowest exercise price, and one call is sold (purchased) at each of the higher exercise prices. In a long (short) put Christmas tree, one put is purchased (sold) at the highest exercise price, and one put is sold (purchased) at each of the lower exercise prices.
Long Christmas trees , when done delta neutral, can be thought of as particular types of ratio vertical spreads. Such spreads therefore increase in value if the underlying market either sits still or moves very slowly. Short Christmas trees can be thought of as particular types of backspreads, and therefore increase in value with big moves in the underlying market.
It is possible to construct a spread which has the same characteristics as a butterfly by purchasing a straddle (strangle) and selling a strangle (straddle) where the straddle is executed at an exercise price midway between the strangle's exercise prices. All options must expire at the same time. Because the position wants the same outcome as a butterfly, it is known as an iron butterfly .
Another variation on a butterfly, known as a condor , can be constructed by splitting the inside exercise prices. Now the position consists of four options at consecutive exercise prices where the two outside options are purchased and the two inside options sold (a long condor), or the two inside options are purchased and the two outside options sold (a short condor). Como com uma borboleta, todas as opções devem ser do mesmo tipo (todas as chamadas ou todas as opções) e expirar ao mesmo tempo.
SPREAD SENSITIVITIES.
CHOOSING AN APPROPRlATE STRATEGY.
With so many spreads avai1 able, how do we know which type of spread is best?
Ideally, we would like ωconstruct a spread by purchasing options which are underpriced and se1li ng options which are overpriced.
If options general/y appear underprtced (low implied volatility), look for spreads with a positive vega. This includes strategies in backspread or long time spread category.!f options generally appear overpriced (high implied volatility),look for spreads wtth a negative vega. This includes strategies in the ratio vertical or short time spread category.
Long time spreads are likely to be profitable when implied volatility is low but is expected to rise; short time spreads are likely to be profttable when implied volatility is high but is expected to fail.
ADJUSTMENTS.
O uso otimizado de um modelo teórico de precificação requer que um negociante mantenha continuamente uma posição neutra durante a vida útil do spread.
Adjust at regular intervals – In theory, the adjustment process is assumed to be continuous because volatility is assumed to be a continuous measure of the speed of the market. Adjust when the positlon becomes a predetermlned number 01 deltas or short. Adjust by feel.
ENTERING A SPREAD ORDER.
The following contingency orders, all ofwhich are defined in Appendix A, are often used in option markets:
Immediate Or Cancel.
Market If Touched.
Market On Close.
One Cancels The Other.
Stop Umit Order.
Ordem de Stop Loss.
Risk Considerations.
CHOOSING THE BEST SPREAD.
We can summarize these risks as follows:
Delta (DirectionaI) Risk-The risk that the underlying market will move in one direction rather than another. When we create a position which is delta neutral, we are trying to ensure that initially the position has no particular preference as to the direction in which the underlying instrument will move. A delta neutral position does not necessarily eliminate all directional risk, but it usually leaves us immune to directional risks within a limited range. Gamma (Curvature) Risk - The risk of a large move in the underlying contract, regardless of direction. The gamma position is a measure of how sensitive a position is to such large moves. A positive gamma position does not really have gamma risk since such a position will, in theory, increase in value with movement in the underlying contract. A negative gamma position, however, can quickly lose its theoretical edge with a large move in the underlying contract. The consequences of such a move must always be a consideration when analyzing the relative merits of different positions. Theta (Time Decay) Risk一Therisk that time will pass with no movement in the underlying contract. This is the opposite side of gamma risk. Positions with positive gamma become more valuable With large moves in the underlying. But if movement helps, the passage of time hurts. A positive gamma always goes hand in hand with a negative theta. A trader with a negative theta will always have to consider the risk in terms of how much time can pass before the spread's theoretical edge disappears. The position wants movement, but if the movement fails to occur within the next day, or next week, or next month, will be spread, in theory, still be profitable? Vega (Volatility) Risk — The risk that the volatility which we input into the theoretical pricing model will be incorrect. If we input an incorrect volatility, we will be assuming an incorrect distribution of underlying prices over time. Since some positions have a positive vega and are hurt by declining volatility, and some positions have a negative vega and are hurt by rising volatility, the vega represents a risk to every position. A trader must always consider how much the volatility can move againsthim before thepotential profit from a position disappears. Rho (Interest Rate) Risk-The risk that interest rates will change over the life of the option. A position with a positive rho will be helped (hurt) by an increase (decline) in interest rates, while a position with a negative rho wil1 show just the opposite characteristics. Generally, the interest rate is the least important of the inputs into a theoretical pricing model, and it is unlikely, except for special situations, that a trader will give extensive thought to rho risk associated with a position.
PRACTICAL CONSIDERATIONS.
While there is no substitute for experience, most traders quickly learn an important rule: straddles and strangles are the riskiest of all spreads.
HOW MUCH MARGIN FOR ERROR?
Perhaps a better way to approach the question is to ask not what is a reasonable margin for error, but rather to ask what is the correct size in which to do a spread given a known margin for error.
DIVIDENDS AND INTEREST.
WHAT IS A GOOD SPREAD?
It is impossible ωtake into consideration everypossible risk. A spread which passed every risk test would probably have so little theoretical edge that it wouldn't be worth doing. But the trader who allows himself a reasonable margin for error will find that even his losses will not lead to financial ruin. A good spread is not necessarily the one that shows the greatest proflt when things go well; it may be the one which shows the least loss when things go badly. Winning trades always take care of themselves. Losing trades, which don't glve back al1 the profits from the winning ones, are just as important.
ADJUSTMENTS.
An adjustment to trader's delta position may reduce his directional risk, but if he simultaneously increases his gamma, theta, or vega risk, he may inadvertently be exchanging one type of risk for another.
A delta adjustment made with the underlying contract is essentially a risk neutral adjustment. An adjustment made with options may reduce the delta risk, but will also change the other nsk characteristfcs assocíated wtth the position.
A disciplined trader knows that sometimes, because of risk considerations, the best course ls to reduce the size of the spread, even if it means gi. ving up some theoretical edge. This may be hard on the trader's ego, particular1y 1f he must personally go back into the market and either buy back options which he originally sold at a lower price, or sell out options whîch he originally purchased at a higher price. However, if a trader is unwilling to swallow his pride from time to time, and admit that he made a mistake, his trading career is certain to be a short one.
If a trader finds that any de1ta adjustment in the option market that reduces his risk will also reduce his theoretical edge,and he is unwil1ing to give up any theoretical edge, his only recourse is to make h1s adjustments in the underlying market. An underlying contract has no gamma, theta, or vega, so the risks of the position will remain essentially the same.
A QUESTION OF STYLE.
In practice, however, many option traders begin theîr trading careers by taking positions in the underlying market, where direction is the primary consideration. Many traders therefore deve10p a style of trading based on presumed directional moves in the underlying market. A trader might,for examp1e, be a trend follower, adhering to the philosophy that "the trend is your friend." Or he might be a contrarian. preferring to "buy weakness, sell strength."
An important consideration in deciding whether to enter into a trade is often the ease with which the trader can reverse the trade. Luid option markets, where there are many buyers and sellers, are much less risky than illuid markets, where there are few buyers and sellers. In the same way, a spread which consists of very luid options is much less risky出ana spread which consists of one or more illuid options.
Bull and Bear Spreads.
NAKED POSITIONS.
If all options are overpríced (high implied volatility), we might sell puts to create a bullish position, or sel1 calls to create a bearish position. If al1 options are underpriced (low implied volatility), we might buy calls ωcreate a bullish position, or buy puts to create a bearish position.
The problem with this approach is that,as with all non-hedged positions, there is very llttle margin error.
BULL AND BEAR RATIO SPREADS.
If a trader believes that implied volatility is too hlgh, one sensible strategy is a ratio vertical spread.
Even though the trader was correct ín his bullish sentiment, the position was primarily a volatility spread, so that the volatility characteristics of the position eventually outweighed any considerations of market direction.
Since this spread is a volatility spread, the primary consideration, as before, is the volatility of the market. Only secondarily are we concerned with the direction of movement. If the trader overestimates volatility, and the market moves more slowly than expected, the spread which was initially de1ta positive can instead become delta negative.
BULL AND BEAR BUTTERFLIES AND TlME SPREADS.
If the underlying market is currently at 100, he might choose to buy the June 105/110/115 call butterfly. Since this position wants the underlying market at 110 at expiration, and it is currently at 100, the position is a bull butterfly. This will be reflected in the position having a positive delta.
Unfortunately, if the underlying market moves too swift1y, say to 120, the butterfly can invert from a positive to a negative delta position.
Conversely, if the trader is bearish, he can always choose to buy a butterfly where the inside exercise price is below the current price of the underlying market. But again, if the market moves down too quickly and goes through the inside exercise price, the position will invert from a negative to a positive delta.
In a simi1ar manner, a trader can choose time spreads 由atare either bul1ish or bearish. A long time spread always wants the near-term contract to expire exactly at-the-money. A long time spread will be initial1y bullish if the exercise price of the time spread is above the current price of the underly1ng market.
SPREADS VERTICAIS.
Vertical spreads are not on1y initially bullish or bearish, but they remain bullish or bearish no matter how market conditions change. A vertical spread always consists of one long (purchased) option and one short (sold) option, where both options are of the same type (either both calls or both puts) and expire at the same time. The options are distinguished only by their different exercise prices. Typical vertical spreads might be:
buy 1 June 100 call.
sell 1 June 105 cal1.
buy 1 March 105 put.
sell 1 March 95 put.
If a trader wants to do a vertical spread, he has essentially four choices. If he is bullish he can choose a bull vertical call spread or a bull vertical put spread; if he is bearish he can choose a bear vertical call spread or a bear vertical put spread. Por exemplo:
bull call spread: buy a June 100 call.
bull put spread: buy a June 100 put.
bear call spread: sell a June 100 call.
bear put spread: sell a June 100 put.
Two factors determine the total directional characteristlcs of a vertlcal spread:
The delta of the specific vertical spread The size in which the spread is executed.
The greater the distance between exercise prices, the greater the delta value associated with the spread. A 95/110 bull spread wil1 be more bullish than a 100/110 bull spread, which will, ín turn, be more bullish than a 100/105 bull spread.
Once a trader decides on an expiratlon month in which to take his directlonal position, he must decide which specific spread is best. Ou seja, ele deve decidir quais preços de exercício usar. A common approach is focus on the at-the-money optlons. If a trader does this, he will have the fol1owing choices:
The reason becomes clear if we recall one of the characteristics of option evaluation introduced in Chapter 6: If we consider three options, an in-the-money, at-the-money, and out-of-the-money option which are identical except for their exercise prices, the at-the-money option is always the most sensitive in total points to a change in volatility.
This characteristic leads to a very simple rule for choosing bull and bear vertical spreads:
If implied volatility is too low, vertical spreads should focus on purchasing the at-the-money optlon. If implied volatility is too high, vertical spreads should focus on selling the at-the-money options.
A trader is not required to execute any vertical spread by first buying or selling the at-the-money option. Such spreads always involve two options, and a trader can choose to either execute the complete spread in one transaction, or leg into the spread by trading one option at a time. Regardless of how the spread is executed, the trader should focus on the at-the-money option, either buying it when implied volatility is too low, or selling it when implied volatility is too high.
The choice of the at-the-money option is slightly different when we move to stock options. If we define the at-the-money option as the one whose de1ta is closest to 50, then we may find at the at-the-money option is not always the one whose exercise price is closest current price of the underlying contract. This ís because the option with a delta closest 50 will be the one whose exercise price ís closest to forward price of underlying contract. In stock options, the forward price is the current price of stock, plus carrying costs on the stock, less expected dividends.
Why míght a trader with a directional opinion prefer a vertical spread to an outright long or short posítíon in the underlying instrument? For one thing, a vertical spread is much less risky than an outright posítion. Atrader who wants to take a position which is 500 deltas long can either buy fíve underlying contracts or buy 25 vertical calI spreads with a delta of 20 each. The 25 vertical spreads may sound riskier than five underlying contracts, until we remember at a vertical spread has limited risk whíle the position in underlying has open-ended risk. Of course, greater risk also means greater reward. A trader with a long or short position in the underlyíng market can reap huge rewards if the market makes a large move in his favor. By contrast, the vertical spreader's profits are limited, but he will also be much less bloodied if the market makes an unexpected move in the wrong direction.
Option Arbitrage.
SYNTHETIC POSITIONS.
synthetic long underlying = long call + short put synthetic short underlying = short call + long put.
where all options expire at the same time and have the same exercise price.
Rearranging the components of a synthetic underling position, we can create four other synthetic relationships:
synthetic long call = long an underlylng contract + long put synthetic short call = short an underlying contract + short put synthetic long put = short an underlying contract + long call synthetic short put = long an underlying contract + short call.
The difference between the call and put price ís often referred to as the synthettc market. In the absence of any interest or dividend considerations, the value of the synthetic market can be expressed as:
call price - put price = underlying price - exercise price.
If this equality holds, there ís no difference between taking a position in the underlying market, or taking an equivalent synthetic position in the option market.
The three-sided relationship between a call, a put, and its underlying contract means that we can always express the value of any one of these contracts in terms of the other two:
underlying price = call prîce - put prîce + exercíse price call prîce = underlying price + put príce - exercíse price put price = call prîce - underlying prîce + exercise price.
This three-sided relationship is sometimes referred put-call parity .
CONVERSIONS AND REVERSALS.
When a trader identifies two contracts which are essentially the same but which are trading at different prices, the natural course ís to execute an arbitrage by purchasing the cheaper contract and selling the more expensive.
No matter what happens in the underlying market, the underlying position will do exactly .25 better than the synthetìc position. The entire position wíll therefore show a profit of .25, regardless of movement in the underlying market.
The foregoing position, where the purchase of an underlying contract is offset by the sale of a synthetic position, is known as a conversion . The opposíte position, where the sale of an underlying contract is offset by the purchase of a synthetic position, is known as a reverse conversion or, more commonly, a reversal .
conversion = long underlying + synthetlc short underlying = long underlying + short call + long put reversal = short underlying + synthetic long underlying = short underlying + long call + short put.
As before, we assume that the call and the put have the same exercise price and expiration date.
Typically, an arbitrageur will attempt to simultaneously buy and sell the same items in different markets to take advantage of price discrepancies between the two markets.
Synthetic positions are often used to execute conversions and reversals, so traders sometimes refer to the synthetic market (the difference between the call price and put price) as the converston/reversal market.
All experienced traders are familiar with the price relationship between a synthetic position and its underlying contract, so that any imbalance in the conversion/reversal market is 1ikely to be short-lived. If the synthetic is overpriced, all traders will want to execute a conversion (buy the underlying, sell the call, buy the put). If the synthetic is underpriced, all traders will want to execute a reversal (sell the underlying, buy the call, sell the put). Such activity, where everyone is attempting to do the same thing, will quickly force the synthetic market back to equilibrium. De fato, os desequilíbrios no mercado de conversão / reversão são geralmente pequenos e raramente duram mais do que alguns segundos.
Futures Option Markets.
If the cash flow resulting from an option trade and a trade in the underlying instrument is identical, the synthetic relationship is simply:
call price - put price = underlying price - exercise price.
This will be true if interest rates are zero, or in futures markets where both the underlying contract and options on that contract are subject to futures-type settlement.
Assuming that all options are European (no early exercise permitted), we can now express the synthetic relationship in futures markets where the options are settle in cash as follows:
cal1 price - put price = futures price - exercise price - carrying costs.
where the carrying costs are calculated on either the difference between the futures price and the exercise price, or the difference between the call price and put price, both of which will be approximately the same.
Taking into consideration the interest rate component, we can express the synthetic relationship as:
call price - put price = stock price - exercise price + carrying costs.
where the carrying costs are calculated on the exercise price.
call price - put price = stock price - exercise price + carrying costs - dividends.
where the carrying costs are calculated on the exercise price and the dividends are those expected prior to expiration.
ARBITRAGE RISK.
Risco da taxa de juros.
Anytime a strategy is executed one leg at a time, there is always the risk of an adverse change in prices before the strategy can be completed.
The practical solution is to avoid carrying conversions and reversals to expiration when there is a real possibility of expiration right at the exercise price.
If al1 contracts are subject to futures-type settlement, any credit or debit resulting from changes in the price of the underlying futures contract wil1 be offset by an equal but opposite cash flow from changes in prices of the option contracts.
The risk arises because a synthetic position in options and an actual position in the underlying contract can have different characteristics, either in terms of settlement procedure, as in the futures option market, or in terms of the dividend payout, as in the stock option market.
How might we eliminate this risk?
short a call long a put long an underlying contract.
replace the long underlyingpositlon with a deeply in-the-money call Now our position is:
short a call long a put long a deeply in-the-money call.
instead of replacing the underlying position with a deeply in-the-money call, we can sell a deeply in-the-money put:
short a cal1 long a put short a deeply in-the-money put.
This type of position, where the underlying instrument in a conversion or reversal is replaced with a deeply in-the-money option, is known as a three-way .
Suppose we also execute a reversal at 90:
long a June 90 call short a June 90 put short an underlying contract.
short a June 100 call long a June 100 put long an underlying contract.
The long and short underlying contracts cancel out, leaving:
long a June 90 call short a June 90 put.
short a June 100 call long a June 100 put.
This position, known as a box, is similar to a conversion or reversal, except that any risk associated with holding a position in the underlyíng contract has been eliminated because the underlying position has been replaced with a synthetic underlying position at a different exercise price.
Since a box eliminates the risk associated with carrying a position in the underlying contract, boxes are even less risky than conversions and reversals, which are themselves low-risk strategies.
JELLY ROLLS.
Another method of eliminating a position in the underlying contract is to take a synthetic position in a different expiration month, rather than at a different exercise price as with a box.
For example, suppose we have executed the following reversal:
long a June 100 call short a June 100 put short an underlying contract.
short a September 100 call long a September 100 put long an underlyíng contract.
If the underlyíng contract for bothJune and Septernber is identical, theywil1 cancel out, leaving us with:
long a June 100 cal1 short a June 100 put.
short a September 100 cal1 long a September 100 put.
These combined long and short synthetic positions taken at the same exercise prices but in different expiration months is known as a jelly roll or simplya roll.
The value of the roll is the cost of holding the stock for the three-month period from June to September.
jelly roll = long-term synthetic - short-term synthetic = (long-term call-long-term put) - (short-term call-short-term put) = (long-term call-short-term call) - (long-term put - short-term put) = caηying costs - expected dividends.
USING SYNTHETICS IN VOLATILITY SPREADS.
the synthetic relationship:
synthetic short cal1 = short put + short underlying.
TRADING WITHOUT THEORETICAL VALUES.
Regardless of the exact theoretical value, there ought to be a uniform progression of both individual option prices and spread prices in the marketplace. If this uniform progression is violated, a trader can take advantage of the situation by purchasing the option or spread which is relatively cheap and selling the option or spread which is relatively expensive.
The trader can start with conversions and reversals, then look at vertical spreads and butterflies, and finally consider straddles and time spreads.
Early Exercise of American Options.
Given the opportunìty, under what cìrcumstances might a trader consìder exercising an American option prior to expiration? How much more should a trader be wi1ling to pay for an American option over an equivalent European option?
FUTURES OPTIONS.
option value = ìntrinsic value + volati1ìty value - interest rate value.
A trader who exercises a futures option early does so to capture the interest on the option's intrinsic value. This intrinsic value will be credited to his account only if the option is subject to stock-type settlement.
OPÇÕES DE AÇÕES.
Early Exercise of Calls for the Dividends.
call value = intrînsic value + interest rate value + volatility value - dividend value.
Since the only reason a trader would ever consider exercising a stock option call early is to receive the dividend, if a stock pays no dividend there is no reason to exercise a call early. If the stock does paya dividend, the only time a trader ought to consider early exercise is the day before the stock goes ex-dividend. At no other time in its life is a stock option call an early exercise candidate.
put value = intrinsic value - interest rate value + volatility value + dividend value.
Whereas a stock option call can only be an early exercise candidate on the day prior to the stock's ex-dividend date, a stock option put can become an early exercise candidate anytime the interest which can be earned through the sale of the stock at the exercise price is sufficiently large.
infer two conditions which are necessary before a trader considers exercising option early to capture is additional profit:
The option must be trading at parity. The option must have a delta close to 100.
The importance of early exercise is greatest when the underlying contract is a stock or physical commodity. In such a case there is a significant difference between the carrying cost on an option and the caπyi cost on underlying position. This difference will especially affect the difference between European and Am erican put values, since early exercise wil1 allow the trader to earn interest on the proceeds from the sale at the exercise price. An option trader in either the stock or physical commodity market will find that the additional accuracy offered by an American model, such as the Cox-Ross-Rubenstein or Whaley models, will indeed be worthwhile.
THE EFFECT OF EARLY EXERCISE ON TRADING STRATEGIES.
Cobertura com Opções.
PROTECTIVE CALLS AND PUTS.
The simplest wayωhedge an underlying position using optìons is to purchase either a call to protect a short position, or a put to protect a long position.
Since each strategy combines an underlying position with an option position, it follows from Chapter 11 that the resulting protected position is a synthetic option:
short underlying + long call = long put long underlying + long put = long call.
COVERED WRITES.
The value of typical covered writes, also known as overwrites, are covered call and covered put.
As with the purchase of a protective optlon, a covered write consists of a position in the under ng and an option. It can therefore be expressed as a synthetic position:
long underlying + short call = short put short underlying + short put =short call.
A popular strategy, known as a fence, is to simultaneously combine the purchase of a protective option with the sale ofa covered option. For example, with an underlying contract at 50, a hedger with a long position might choose to simultaneously sell a 55 call and purchase a 45 put.
Fences are popular hedging tools because they offer known protection at alow cost, or even a credit. At the same time ,they still allow a hedger to participate, at least partially, in favorable market movement. Fences go by a variety of names: range forwards, tunnels, cylinders; among floor traders they are sometimes known as split price conversions and reversals.
COMPLEX HEDGING STRATEGIES.
As a first step in choosing a strategy, a hedger might consider the following:
Does the hedge need to offer protection against a I'worst case" scenario? How much of the current directional risk should the hedge eliminate? What additional risks is the hedger willing to accept?
ll otnel ctors being equal, in a high implied volatility market a hedger should buy as few options as possible and sell as many options as possible. Conversely, in a low implied volatility market a hedger should buy as many options as possible and sell as few options as possible.
A hedger who constructs a position with unlimited risk in either direction is presumably taking a volatility position. There is nothing wrong with this, since volatility trading can be highly profitable. But a true hedger ought not lose sight of what his ultimate goal is: to protect an existing position, and to keep the cost of this protection as low as possible.
PORTFOLIO INSURANCE.
if he wants to replicate the combination of the underlying asset and the 100 put, he must sell off 43% of his holdings in the asset. When he does that, he will have a position theoretically equivalent to owning a 100 call.
This process ofcontinuously rehedging an underlying position to replicate an option position is often referred to as portfolio insurance.
If the mix of securities in a portfolio approximates an index, and futures contracts are available on that index, the manager can approximate the results of portfolio insurance by purchaslng or selling futures contracts to increase or decrease the holdings in his portfolio.
Even if options are available on an underlying asset, a hedger may still choose to effect a portfolio insurance strategy himself rather then purchasing the option in the marketplace. For one thing, he may consider the option too expensive. If he believes the option is theoretically overpriced, in the long run it will be cheaper to continuously rehedge the portfo1io. Or he may find insufficient luidity in the option market to absorb the number of option contracts he needs to hedge his position. Finally, the expiration of options which are available may not exactly correspond to the period over which he wants to protect his position. If an option is available, but expires earlier than desired, the hedger might still choose to purchase options in marketplace, and then pursue a portfolio insurance strategy over the period following the option's expiration.
Volatility Revisited.
SOME VOLATILITY CHARACTERISTICS.
we might surmise at an underlying contract is likely to have a typicallong-term average, or mean volatility. Moreover, the volatility of the underlying contract appears to be mean reverting. When volatility rises above the mean, one can be fairly certain that it will eventually fall back to its mean; when volatility fal1 s below the mean, one can be fairly certain that it will eventual1y rise to its mean.
VOLATILITY FORECASTING.
In addition ωthe mean reverting characteristic, volatility also tends to exhibit sen. al correlatton. The volatility over any given period is likely ωdepend on, or correlate with, the volatility over the previous period, assuming that both periods cover the same amount of time. If the volatilityofa contract over the last fourweeks was 15% , the volatility over the next four weeks is more likely to be close to 15% an far away from 15%.
A PRACTICAL APPROACH.
Rather than asking what the correct volati1ity is, a trader might instead aSk, given the current volatiUty climate, what' right strategy? Rather than trying to forecast an exact volatility, a trader will try to pick a strategy that best fits the volatility conditions in the marketplace. To do this, a trader will want to consider several factors:
What is long. term mean volatility of underlying contract? What has been the recent historical volatility in relation to em volatility? What is trend in recent historical volatility? Where îs imp1ied volatility and what is its trend? Are we dealing wi options of shorter or longer duration? How stable does the volati1ity tend to be?
SOME THOUGHTS ON IMPLIED VOLATILITY.
Implied versus Historical Volatility.
Market participants are making the logical assumption that what has happened in the past is a good indicator of what will happen in the future.
the fluctuations in implied volatility were usually less than the fluctuations in historical volatility. When the historical volatility declined, the implied volatility rarely dec1ined by an equal amount. And when historical volatility increased, the implied volatility rarely increased byan equal amount. Because volatility tends to be mean reverting, when historical volati1ity is above its mean there is a greater likelihood that it will dec1ine, and when historical volatility is below its mean there is a greater likelihood that it will increase.
Stock Index Futures and Options.
professional arbitrageurs find at in spite of the highly luid and usually efficient index markets, pricing disparities occur often enough to warrant close monitoring of these markets. When a disparity does exist, a trader can execute an arbitrage by hedging the mispriced index against either other stock indices or against a basket of stocks. Such arbitrage strategies are commonly refeηed to as index arbitrage .
CALCULATING AN INDEX.
There are several different methods of calculating stock index values, but the most common methods entail weighting the stocks either by price or by capitalization.
REPLICATING AN INDEX.
the number of shares of each stock required to replicate an index.
for a price weighted index: point value / index divisor.
for a capitalization weighted index: outstanding shares x point value / index divisor.
FUTUROS DO ÍNDICE DE AÇÕES.
The purchase of a futures contract offers one important advantage over the purchase of the component stocks: no cash outlay ís required to purchase a futures contract. Consequently, there is an interest rate savings equal to the cost of borrowing sufficient cash to purchase all the stocks in the index.
INDEX ARBITRAGE.
If the futures príce doesn't reflect the fair value, a trader can execute a profitable arbitrage by purchasing the undervalued asset, either the basket of stocks or the futures contract, and selling overvalued asset.
This type of trading strategy, where one buys or sells a mispriced stock index futures contract and takes an opposing position in the underlying stocks, is one type of index arbitrage. Since computers can often be programmed to calculate the fair value of a futures contract, and to execute the arbitrage when the futures contract is mispriced, such astrategy is also commonly referred to as program trading. A buy prograrn consists of buying the stocks and selling the futures contract, and a sell program consists of selling the stocks and buying the futures contract.
INDEX OPTIONS.
There are real1y two types of stock index options, those where the underlying is a stock index futures contract, and those where the underlying is the index itself.
Options on Stock Index Futures.
Although the ultirnate decision about the underlying price is trader's, in a stock index futures option rnarket a trader should be very careful about using an underlying futures price different from the quoted price. As we have already seen ,出 theoretical value of astock index futures contract depends information which rnay ot be readily available to the trader. If he 1s wrong about the price at which the index is actually trading because the individual stock prices do not reflect the true rnarket, his theoretical evaluation of the futures contract wil1 be incorrect.
It may seem odd, but in fact it doesn't matter whether the index opens the next morning at a higher price, lower price, or unchanged. What matters is that the marketplace believes that the market will change, and that all contracts are priced accordingly. In such a case, the trader rnust exercise those options which, given the perceived change in the underlying price, now have a value less than parity, and replace them with other contracts which are not limited by parity constraints.
Because it can be difficult to trade a complete and correctly proportioned basket of stocks, and because there is the additional risk of early exercise after an index arbitrage has been executed, mispriced synthetic relationships are not as easy to exploit ín index option markets as in other option markets.
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