以下是引用juedistar在2008-7-22 10:47:00的发言:请教一下关于期权定价的问题:在B-S公式中,看涨期权的S(T)大于K(T)和看跌时S(T)小于K(T)的概率怎么算?或者说S(T)是什么分布?
另一个,有个可以在T也可以在T/2时执行的期权,S(T/2)大于a的概率和S(T)大于b的概率一样么。我原来是学别的专业的,但愿我说清楚了。。。
拜谢答复!
For the calculation of P(s(T)>K) you could refer to the book by Bijork 'Arbitrage Theory in Continuous Time'. But before that you should know the properties of Brownian Motion and Gaussian Distribution. I would like to mention that the guy who gave you some hints before was wrong about the independency of the increament of Brownian Motion. (WT/2 - W0) and (WT-WT/2) are independent because they are non overlapping Gaussian random variables.
S(T) is a random variable which is assumed to follow log-normal distribution while s(t) is a Markov process.
You could also refor to the book Stochastic Calculus and Its Financial Application, published by Springer. In chapter 1 of that book, first step analysis and random walk are introduced.
T/2 or T are not stopping times. The only thing you could say is, when stock process hit a or -b at time Tao , Tao is a stopping time.
[此贴子已经被作者于2008-7-30 1:48:18编辑过]