Berkshire Goldman Preferreds Yield over 17% at Initiation

Barry points out that Doug Kass thinks Berkshire's effective yield on the Goldman preferred's is ~17%. Here's the calculation to support that:

Berkshire Hathaway will receive warrants to buy $5 billion in common stock at a strike price of $115 a share, which can be used at any time in a five-year period.

Using the good old Black-Scholes model with the pre-"Buffett Bounce" $115 Stock Price, a $115 Strike, 5 Years to Expiration, and 40% Volatility (roughly the level it has been trading) we get an "option" value of $47.89 per share. Berkshire can buy $5 Billion of Goldman stock with these warrants, thus he owns 43,478,261 shares. This amounts to $2.082 Billion. Taking the $5 Billion Berkshire paid less the value of the warrants at initiation equals $2.917 Billion for the Preferreds.

Berkshire will receive $500 Million per Year, which divided by that $2.917 Billion = 17.14% Yield. If Goldman is willing to capitalize at this value, it makes me question how desperate they really are...