NEW YORK: US stocks ended mixed on Tuesday in choppy trade as investors worried about the weak global economy and a poor start to the corporate earnings season.

The Dow Jones Industrial Average fell 25.41 points (0.30 percent) to close at 8,448.56, extending a losing streak to a fifth session.

The tech-dominated Nasdaq composite climbed 7.67 points (0.50 percent) to 1,546.46 and the broad-market Standard & Poor's 500 index advanced 1.53 points (0.18 percent) to finish at 871.79.

The blue-chip Dow floated in and out of positive territory without gaining upward momentum.

Traders remained worried a day after US aluminium giant Alcoa kicked off the earnings season with a wider than expected net quarterly loss of 1.19 billion dollars.

"Alcoa's fourth-quarter loss, falling substantially below analysts' lowered estimates, has set the tone for a tough earnings reporting season," said Fred Dickson, chief market strategist at DA Davidson & Co.

"This was definitely not a surprise, but the reality of how tough operating conditions have become for most companies in the face of the growing global recession now appears to be unsettling investors."

Alcoa, a Dow component, tumbled 5.07 percent to 9.55 dollars on Tuesday.

Two other Dow blue chips fell more than five percent. Bank of America plummeted 6.82 percent to 10.65 and General Electric dropped 5.62 percent to 14.94 after a Barclays analyst lowered its earnings forecast on the conglomerate.

Investors appeared to shrug off Federal Reserve chairman Ben Bernanke's speech at the London School of Economics, in which he pledged to expand aggressive efforts to stem the financial crisis, citing the bank's "powerful tools."

Among stocks in focus, troubled banking giant Citigroup reversed losses to end with a hefty 5.36 percent gain at 5.90 dollars.

Citi announced it was "in discussions" with Morgan Stanley on a potential tie-up of the brokerage operations of the two firms.

During afternoon trade, The Wall Street Journal reported online that Citi was preparing a "major reorganisation" that would further dismantle the financial conglomerate, citing people familiar with the matter.

Citigroup shares lost 17 percent Monday amid mounting fears over the viability of Citigroup, despite 45 billion dollars in capital injections from the US Treasury to shore up its finances.

Morgan Stanley also rebounded to a slight 0.37 percent gain at 18.86 dollars.

JPMorgan Chase, which brought forward its earnings by a week, to Thursday, surged 5.78 percent to 26.35.

The tech sector bounced higher, lifted by better than expected earnings results from India's technology service provider Infosys Technologies, up 5.87 percent at 27.40.

Microsoft climbed 1.80 percent to 19.82.

Bonds also ended mixed. The yield on the 10-year Treasury bond fell to 2.297 percent from 2.309 percent on Monday, while that on the 30-year bond rose to 3.017 percent from 2.990 percent. Bond yields and prices move in opposite directions. - AFP/de