Stocks barely budge in light trading

Stocks slipped Monday in one of the quietest trading sessions of the year. Worries about European debt crept up again, and Apple became the most valuable company of all time.

The Dow Jones industrial average fell 3.56 points to 13,271.64. The Standard & Poor's 500 and the Nasdaq composite index were virtually unchanged at 1,418.13 and 3,076.21, respectively.

In a monthly report, the German central bank reiterated doubts about having the European Central Bank buy bonds to help struggling European economies. It stressed that such purchases could carry "substantial risks."

Earlier this month, stocks rallied after ECB President Mario Draghi said the bank might buy bonds of some European countries to lower their borrowing costs. German Chancellor Angela Merkel also seemed to soften her stance on the idea.

"We're getting mixed messages at best coming from Europe," said Jim Russell, chief equity strategist at U.S. Bank Wealth Management.

Apple, the most valuable company in the world, became the most valuable in history. It hit a market value of $624 billion, surpassing Microsoft's record from 1999. Apple is worth almost twice as much as the next most valuable company, Exxon Mobil. -- AP