option price. If we want to know the value of a call option based on our expectation, we can write the following crude expression of probability weighted cash inflows and out flows: CStimes p -fracXleft(1rright)ttimes p, where p is the probability. What happens when you re-enter those other volatility values back into.you will get a different theoretical price, right? The second part, N(d2)Ke-rt, provides the current value of paying the exercise price upon expiration (remember, the Black-Scholes model applies to European options that can be exercised only on expiration day). This is partly due to the expectation that most equities will increase in value over the long term and also because a stock price has a price floor of zero.

This will make the forward price used for the calculation the same as the base price but still use the Interest Rate to discount the premium. I've corrected the paragraph as noted. JLFebruary 8th, 2011 at 9:06am Peter, Thank you for the fast response. This is counter to what should happen, logically if I can earn a better return in a safer investment then the price of a higher risk investment should be lower. The more an asset price swings around from day to day, the more volatile the asset is said. The likely reason for the difference between your calculated prices and the actual prices is the volatility input that you use. I am not an expert by any means. TonyDecember 4th, 2010 at 11:19am I've working with both your historical volatility and Black Scholes sheets. Given a stock price S, exercise price X, annual risk-free rate r, time to maturity t and annual standard deviation of return of the underlying asset, we can determine the value of call option using the following formula: CStimes N(d_1) -Xe-rttimes N(d_2 where N(d1) and. Your work has been very helpful in trying to understand option pricing. The real question is: How do you establish the binary points and probabilities thereof for any given security? If we have current value of call premium C, stock price S, exercise price X, time to maturity t and risk-free rate r, we can work back to find out the implied volatility.

With the volatility at 30 an ATM option comes close to t OTM/ITM options are way out. How you link 'research' to an Excel model is an open question.