Goldman Sachs Group Inc. will raise at least $7.5 billion from Warren Buffett’s Berkshire Hathaway Inc. and public investors in a bid to quell concerns that pushed up the Wall Street firm’s borrowing costs and hurt its stock.

Berkshire is buying $5 billion of perpetual preferred shares, New York-based Goldman said yesterday in a statement. Goldman, which this week transformed itself from the biggest American securities firm to the fourth-largest bank by assets, also plans to raise at least $2.5 billion by selling common stock in a public offering.

The chief executive officer of Goldman, Lloyd Blankfein, is turning to Mr. Buffett, the billionaire investor and second-wealthiest American, to boost market confidence even though Goldman hasn’t reported a quarterly loss since it went public in 1999. The bankruptcy of Lehman Brothers Holdings Inc. and emergency sale of Merrill Lynch & Co. to Bank of America Corp. on September 15 have fueled fears about firms that rely on bond markets for funding.

“At this point you’re better safe than sorry, I think that’s the moral of Lehman,” , an analyst at CreditSights Inc. in New York, David Hendler, said. “Everything’s different because of the extraordinarily weak market conditions, as vividly described by our Treasury Secretary and Fed Chairman” in congressional testimony yesterday, Mr. Hendler said.

Goldman stock surged in trading after the close of the New York Stock Exchange. The shares, which closed at $125.05 in composite trading, jumped as high as $138.88, an 11% increase.

“The investment will further bolster our strong capitalization and liquidity position,” Mr. Blankfein, 54, said in yesterday’s statement. Berkshire’s investment “is a strong validation of our client franchise and future prospects.”