Investing icon Warren Buffett took his own advice Tuesday - getting "greedy when others are fearful" - when he ignored the banking-sector bonfire and slapped down a cool  $5 billion for a stake in Goldman Sachs Group Inc. (GS).

By literally putting his money where his mouth is, Buffett’s actions - and reputation as a shrewd bargain hunter - restored some of Goldman’s luster and helped bolster investor confidence in the U.S. banking system.

And the "Oracle of Omaha" isn’t done, yet.

Buffett’s Berkshire Hathaway Inc. (BRK.A, BRK.B) agreed to buy $5 billion in perpetual preferred Goldman shares that pay 10% interest.  In addition, Berkshire receives warrants giving it the right to buy $5 billion worth of Goldman’s common shares at any time over the next five years at a price of $115 per share. The shares closed Tuesday at $125.05 and  yesterday (Wednesday) at $133, up $7.95, or 6.36%, each.

"Goldman Sachs is an exceptional institution," Buffett said in a statement. "It has an unrivaled global franchise, a proven and deep management team and the intellectual and financial capital to continue its track record of outperformance."

Based on Tuesday’s closing price of $125.05, Buffett made an almost instantaneous paper profit of about $437 million on the warrants. With yesterday’s advance, that paper profit rose to $783 million.

Scott Roth, management partner at Severn River Capital Management, told Bloomberg News that by his calculations Buffett is buying the preferred stock for about $3.2 billion, after accounting for the warrants. Roth worked at Goldman more than a decade ago and is betting the stock won’t drop.

"As usual Mr. Buffett has struck an extremely attractive deal," Guy Moszkowski, an analyst at Merrill Lynch & Co. Inc. (MER), wrote in a note to clients. "He is, we believe, getting a better deal than he did in 1987 when he bought a Salomon Bros. convertible with a 9% yield, for a company that is considerably more attractive than the ‘87 Salomon."

Goldman Sachs, which has booked roughly $5 billion in losses and write-downs, and which has lost about 40% of its market value this year, is benefiting, too. In addition to Berkshire’s cash infusion, the firm gets a vote of confidence from Wall Street’s greatest legend at a time of extreme uncertainty. 

The collapse of The Bear Stearns Cos. Inc. and Lehman Bros. Holdings Inc. (OTC: LEHMQ), and the hurried sale of Merrill Lynch to Bank of America Corp. (BAC), sent shockwaves through the industry.