there are major differences between call options and warrants.
When call options are exercised, the stock provided to the option holder comes from
the secondary market, but when warrants are exercised, the stock provided to the
warrant holders is either newly issued shares or treasury stock the company has previously
purchased. This means that the exercise of warrants dilutes the value of the
original equity, which could cause the value of the original warrant to differ from
the value of a similar call option. Also, call options typically have a life of just a few
months, whereas warrants often have lives of 10 years or more. Finally, the Black-
Scholes model assumes that the underlying stock pays no dividend, which is not
unreasonable over a short period but is unreasonable for 5 or 10 years. Therefore,
investment bankers cannot use the original Black-Scholes model to determine the
value of warrants.