Dear guys:

I have one problem when calculate the call option price under binomial tree model (1) (Derivaties: option pricing model). I understand the concept under this method, but have confused when remember the method in Fix income, valuation the callable bond (2) (also using binomial tree method and using call rule). I think that, the call option price we find from (1), must be the same as the straight bond minus the callable bond in (2). But, actually, it’s not. Would you guys please give me an explanation ? Thanks in advance.