US banking giant Goldman Sachs on Tuesday said its second quarter net profit soared 65 percent, exceeding market expectations, thanks to robust trading operations.

The Wall Street investment bank, which has repaid a government bailout, reported net earnings of 3.44 billion dollars in the second quarter, up sharply from 1.81 billion in the first quarter.

Earnings per share were 4.93 dollars in the April-June period, markedly stronger than the 3.54 dollars expected by analysts.

Goldman Sachs said the results included its payback of government aid under the Treasury's 700-billion-dollar Troubled Asset Relief Program (TARP), a program launched last year to shore up the reeling financial sector amid a severe recession.

Excluding a one-time preferred dividend of 426 million dollars to the government related to the repurchase of the firm's TARP preferred stock, earnings per share were 5.71 dollars, it said.

Revenues amounted to 13.76 billion dollars in the second quarter, up 46 percent from a year ago and from the preceding quarter.

"While markets remain fragile and we recognize the challenges the broader economy faces, our second-quarter results reflected the combination of improving financial market conditions and a deep and diverse client franchise," Lloyd Blankfein, chairman and chief executive, said in a statement.

Trading was the key profit driver among the bank's three segments.

Trading revenues soared by 51 percent from the first quarter, to 10.78 billion dollars, and were 93 percent higher than the second quarter of 2008.

Net revenues in investment banking leapt 75 percent from the first quarter, to 1.44 billion dollars, but were still 15 percent lower than a year earlier.

Asset management and securities services amounted to 1.54 billion dollars, up 6.0 percent from the first quarter and 28 percent lower on an annual basis.

"Our role as an intermediary focused on making markets for buyers and sellers helped drive our performance," Blankfein said, adding that the bank also had been active as an underwriter of many significant debt and equity offerings for clients,"

Shares in Goldman Sachs slipped 0.16 percent to 149.20 dollars in early trade.

Scott Marcouiller at Wells Fargo Advisors said Goldman's earnings "beat expectations, but there was a muted response in the stock as it was largely discounted yesterday."

Goldman had leapt 5.34 percent Monday after it received an upgrade from influential Wall Street financial analyst Meridith Whitney.

"What is obvious here is that Goldman Sachs is living up to every bit of its expectations on how it is routinely and systematically taking money out of the markets in its trading activities. But this was already known based upon recent reports," said Jon Ogg of 24/7WallSt.com.