
Around the formula...
In a now famous article, Fisher Black and Myron Scholes (1972) presented a model for pricing Europeanstyle options that is now very widely used
. For a call option, the Black & Scholes formula is as follows :
with :

where :
V = current price of the underlying asset
N(d) is a cumulative standard normal distribution (average 0, standard deviation 1)
K = option's strike price
e = exponential function = 2,71828
r_{F} = continual annual riskfree rate
s = instantaneous standard deviation of the return on the underlying asset
t = time remaining until maturity (in years)
and ln = Naperian logarithm

