Assume a European chooser option where stock price is $10, strike price is $10, volatility is 20%, dividend yield is 0%, and risk-free rate is 4%. The choice can be made within the next six months (T1 = 0.5 years) and the option will expire in one year (T2 = 1.0 year). What is a synthetic (portfolio) equivalent to the chooser option?
答案是:A call option with strike price 10 and maturity 1 year and a put option with strike price 9.8 and maturity 0.5 year.
选择期权在t1选择什么应该取决于当时价格。根据F=s*e^(tr),如果当时价格小于10*e^-(0.4*0.5),会选择是put,如果大于会选择call。也就是当半年过去了,价格大于9.8,你会拥有一个call,(replication也是在价格大于9.8时,拥有一个 call,put无用)。小于9.8你会拥有一个put。(replication是这个时候你short了一个股票+long a call=一个put,可画pay off图得出)