I never knew it, till now. According to my J.K. Lasser, the short answer is the option is not taxed when received or exercised, only when the stock is sold. So on this count the transfer of income does imply a revenue drain since capital gains rates are much lower than rates on ordinary income or corporate income. One exception is if the holding period is short -- then the 'ordinary' income rates apply. A second is that the spread is subject to the AMT (which also has lower marginal rates). The basis is the price gross of the spread -- the purchase price of the stock. But it can get much more complicated, naturally.
So on the whole the transfer is indeed tax bounty for the rich.
mbs