By Kate Gibson, MarketWatch

NEW YORK (MarketWatch) -- U.S. stocks traded mostly lower Wednesday after U.S. economic growth unexpectedly shrank in the final quarter of 2012, with the economy expanding 2.2% for the full year.

The Dow Jones Industrial Average (DJI) lost 20.97 points, or 0.1%, to 13,933.45 in morning trade.

Boeing Co. (BA) was among blue-chip gainers after the aircraft maker reported quarterly earnings and revenue that beat Wall Street's estimates.

The S&P 500 index (SPX) was down 2.89 points, or 0.2%, at 1,504.95, with its financial sector the worst performer and telecommunications the best of its 10 major industry groups.

U.S.-listed shares of BlackBerry maker Research in Motion Ltd. (RIMM) rallied as the Canadian company's chief executive readied to show off the first phone with the new BlackBerry 10 system Wednesday in New York.

The Nasdaq Composite (RIXF) shed 3.07 points, or 0.1%, to 3,150.65, with the technology-laden index's losses lessened by a sharp rise in shares of Amazon.com Inc. (AMZN) a day after the online retailer reported better-than-expected fourth-quarter gross profit margins.

For every five stocks advancing nine declined on the New York Stock Exchange, where 139 million shares traded as of 10:25 a.m. Eastern.

Stock-index futures fell after the Commerce Department reported fourth-quarter gross domestic product dropped at a 0.1% annual rate, the worst performance since the second quarter of 2009, when the economy remained in recession.

"For the first half of 2013, we do not envisage a very strong acceleration in economic growth," Kathy Bostjancic, director for macroeconomic analysis at the Conference Board, said in a statement.

"However, there are reasons for hope in the second half of the year as the fiscal drag wanes and housing, which long created a drag on the economy, continues to turn from a headwind to a tailwind," she added.

A separate report from a payrolls processor said private companies added 192,000 workers in January, with the better-than-expected rise coming ahead of Friday's nonfarm payrolls report for January.

The Federal Reserve is expected to release a policy statement Wednesday afternoon after a two-day meeting of the Federal Open Market Committee.

Subscribe to WSJ: http://online.wsj.com?mod=djnwires