Serving the Quantitative Finance Community

 
User avatar
tttchen
Topic Author
Posts: 0
Joined: July 14th, 2002, 3:00 am

Probability of being in the money

January 24th, 2006, 12:28 am

I recall reading that under Black-Scholes, N(d2) can be analogized as the probability the (call) option will be in the money at expiration. The actual language, however, left me thinking that it wasn't really the probability of being in the money, but more as a conceptual framework.So, is N(d2) truly the probability that the option, at maturity, would equal or exceed the strike price? If not, what is the formula (if any)?
 
User avatar
taotaol
Posts: 0
Joined: February 18th, 2005, 8:44 pm

Probability of being in the money

January 24th, 2006, 1:22 am

yes, it is
 
User avatar
spursfan
Posts: 2
Joined: October 7th, 2001, 3:43 pm

Probability of being in the money

January 24th, 2006, 8:07 am

it's the probability in a risk-neutral world so you might want to do some more reading on martingales and change of measure
 
User avatar
ppauper
Posts: 11729
Joined: November 15th, 2001, 1:29 pm

Probability of being in the money

January 24th, 2006, 1:31 pm

it's easy to work out from scratch:price an option that pays 1 if the option expires in the money and 0 if it is out of the money.The value of that will be exp(-rt) * (probability in the money).If you have the BS formula, there are 2 terms: take the term that involves a factor of E (the exercise price or sometimes X) and divide it by E.That's the value of an the option I just mentioned