Unable to shake their worries about Europe, investors drove stocks to a four-month low Thursday and piled into bonds, sending the yield on the 10-year Treasury note close to an all-time low.

The Dow Jones industrial average posted its 11th loss in 12 days after a pair of discouraging economic reports further unnerved traders already concerned about a possible exit from the euro by Greece.

The Dow lost 156.06 points, most of it toward the end of the trading day, to close at 12,442.49. It is down almost 6 percent for May, and what had been a strong year for stocks has been reduced to a slender 1.8 percent gain.

The Standard & Poor's 500 stock index closed at its lowest point since Jan. 17.

The yield on the benchmark 10-year note hit 1.69 percent. That is lower than any 3 p.m. reading since at least 1953, according to records kept by the Federal Reserve.

According to other financial data providers, including Dow Jones and Bloomberg, the yield on the 10-year dipped slightly lower, to 1.67 percent, at other points in the trading day last September.