Expectations for solid quarterly results helped the market to an early advance, but the enthusiasm waned throughout the session, prompting some traders to lock in profits. Dow Jones industrial Alcoa Inc. — the first major U.S. company to report — sagged after releasing its results post-close.

While analysts forecast another round of double-digit profit growth from companies in the Standard & Poor's 500 index, some said strong results may have already been priced into the market and that lingering confusion about interest rates and economic growth were keeping stocks from gaining.

"The nice thing about earnings is that they're probably going to be higher," said Ed Peters, chief investment officer for PanAgora Asset Management. "Unfortunately, that's old news. Good earnings have already been discounted — people are looking at what's going to happen next."

Several acquisitions were giving stocks some support. Kraft Foods Inc. agreed to buy the Spanish and Portuguese units of United Biscuits for $1.07 billion, and Kimco Realty Corp. acquired Pan Pacific Retail Properties Inc. for $2.9 billion.

At the close of trading, the Dow added 12.88, or 0.12 percent, to 11,103.55, after gaining as much as 84 points earlier.

Broader stock indicators were mixed. The S&P 500 rose 1.86, or 0.15 percent, to 1,267.34, and the Nasdaq dropped 13.13, or 0.62 percent, to 2,116.93.

Bonds were flat after last week's rally, with the yield on the 10-year Treasury note unchanged at 5.13 percent from late Friday. The U.S. dollar was little changed against other major currencies, and gold prices tumbled to about $625 an ounce.

Wall Street's persistent concerns about the economy squelched excitement over earnings. Although companies were largely expected to show upbeat results, recent profit warnings from Advanced Micro Devices Inc., 3M Co. and EMC Inc. sparked fears that higher interest rates have contained inflation but are hurting economic growth.

"I think the key thing will be earnings," John Caldwell, chief investment strategist for McDonald Financial Group, said of whether stocks rise or fall in the coming weeks. "The numbers look good, but enough people are on edge after 3M and EMC."

Crude futures fell as energy traders took profits from the recent surge in prices, but worries about Iran and motor fuel demand were expected to support the market. A barrel of light crude lost 48 cents to $73.61 on the New York Mercantile Exchange.

A bigger-than-forecast rise in wholesale inventories last month fed hopes that easing demand will help cool the economy. While the 0.8 percent increase was greater than economists' predictions of 0.5 percent, that was sharply less than the 1.3 percent gain in April.

Aluminum producer Alcoa said soaring metal prices helped its profit swell 62 percent, but revenue still missed Wall Street expectations. Shares ended the regular session 14 cents lower at $33.41, and plunged $1.26 in after-hours trading.

Other companies reporting this week include PepsiCo Inc., which posts its results Thursday morning; earnings from Dow component General Electric Co. are due Friday morning.

Profit warnings from Kronos Inc., EMC and AMD pulled tech stocks lower. Kronos sank $5.16 to $29.46, EMC lost 77 cents to $10.41 and AMD slumped $1.05 to $22.51.

Along with the purchase of United Biscuits' Iberian businesses, Kraft is also buying the rights to Nabisco trademarks in the European Union, Eastern Europe, the Middle East and Africa. Kraft added a penny to $30.21.

Shopping center operator Kimco will also assume about $1.1 billion of debt from Pan Pacific, which owns about 140 retail properties. Kimco rose 54 cents to $37.41, and Pan Pacific slid 65 cents to $69.35.

WPS Resources Corp. said it will take over Peoples Energy Corp. for $1.52 billion in stock. WPS rose 53 cents to $48.51, and Peoples Energy gained 42 cents to $39.09.

Overseas, Japan's Nikkei stock average jumped 1.6 percent. Britain's FTSE 100 gained 0.14 percent, Germany's DAX index added 0.43 percent and France's CAC-40 was higher by 0.58 percent.

Advancing issues led decliners by about 5 to 3 on the New York Stock Exchange, where preliminary consolidated volume of 1.96 billion shares trailed the 2.12 billion shares that changed hands Friday.

The Russell 2000 index of smaller companies slipped 0.22, or 0.03 percent, to 709.08.