February 2nd, 2012, 12:17 pm
Hi daveangel,I'm sorry but I can't understand the formula of forward price. When I mentioned the "yield" r2, I meant that this bond is risky. Because the bond has default possibility, its price is discounted by r2 from par to S on today instead of using r1 for discounting(supposing the bond is zero-coupon bond). Thus I thought the forward price of this bond should be S*exp(r2*T). And when the bond defaults, the option price is zero, thus it seems the option price is also risky and P(0,T) should be exp(-r2*T).But in risk-neutral world, it indeed consider an asset's yield is the risk-free rate r1, thus from this point, the forward price as well as the option price should have nothing to do with r2, so the Fo=S*exp(r1*T) and P(0,T)=exp(-r1*T). I think both of the above two are reasonable thus I'm quite confusing. But I really can't understand why Fo equals to S * exp((r1 - r2)*t) in this situation In my opinion, S * exp((r1 - r2)*t) happens in such situation like a stock option when the stock has dividend yield. Could you please kindly explain more?