在无套利条件约束下的二项式期权定价公式

Cox-Ross-Rubinstein的二项式期权定价公式中期权的价格与股票的上涨或者下降的概率无关，本文从证券的风险和收益的关系出发，指出期权的价值与概率是一一对应的给出放宽条件下的期权公式，从而可以得出按照无套利条件所获得的市场价格是脆弱的，在资金可以最影响价格的情况下很容易地造成套利。

Binomial Option Pricing Function on the Arbitrage-Free Condition

It is interesting that in the Cox,Ross and Rubinstein context of binomial matched up-with pricing function the optional a price has no relation to the probability of the underlying stock's going up or stock's down. Based upon the relation ship between the risk and the return, we found that the optional price matched upwith the probability. Without taking the stock price as constant, we obtained the new binomial optional pricing function. Then we was ableto get such a conclusion that the equilibrium price under the no-arbitrage condition is not stable. Because the market is not large enough that the fund might affect the stock, price, there is very easy to make a chance full of arbitrage.