U.S. stocks closed nearly unchanged Monday, after a day of uneven trading plagued by investors' fears about the approaching "fiscal cliff."

The Dow Jones industrial average finished down 0.31 point at 12,815.08, according to data available at 5:30 p.m. EST. It had spent the day trading gains and losses, never rising more than 46 points or falling more than 32.

The closing level of the Dow was revised several times after trading closed. The New York Stock Exchange had experienced a trading glitch during the day, forcing it to alter its normal procedure for determining the closing prices of some stocks.

The Standard & Poor's 500 index edged up 0.15 point to 1,380. The Nasdaq composite fell 0.61 to 2,904.26.

J.C. Penney Co.'s stock fell more than 13 percent on Monday -- the biggest percentage decline by far among big companies in the S&P 500 for the day. Penney stock closed at just under $18, its lowest price since March 2009 when the United States was in a recession. The drop follows Standard & Poor's move to lower Penney's credit rating deeper into junk status on Friday.

Trading was very light. The federal government and the U.S. bond market were closed for Veterans Day, and no economic reports were released.

"Nothing good is going on," said Scott Freeze, president of Street One Financial in Huntingdon Valley, Pa. "Everything forward-looking remains dreary."

The fiscal cliff refers to government spending cuts and tax increases that are scheduled to kick in at the beginning of the new year, unless a divided Congress and the White House can work out a compromise.

Economists say the cliff could cost the economy $800 billion and 3 million jobs and would plunge the United States back into recession.

Last week, after voters returned a long-deadlocked and divided government to Washington, the Dow dropped 434 points in two days and had one of its worst weeks of the year.

Fiscal cliff worries were blamed for keeping a lid on European markets and Asian markets, which closed mostly lower.