U.S. stocks closed slightly lower on Thursday as a trio of better-than-expected economic data wasn't enough to entice buyers to take on much risk in a market sitting on strong gains just before the new year.

The S&P 500 is up 6.5 percent so far this month, putting it on track for the best December since 1991.

Reports on the labor market, business activity and housing all showed surprising strength.

New U.S. claims for initial unemployment benefits in the latest week dropped to the lowest level since July 2008, while a report from the Institute for Supply Management-Chicago showed business activity in the U.S. Midwest rose to its highest level since July 1988. November pending home sales also rose more than anticipated.

The numbers were very strong this morning, but people are becoming more cautious since it's the end of the year, especially since we've already had a great run, said Bruce McCain, chief investment strategist at Key Private Bank in Cleveland, Ohio.

Monster Worldwide Inc , an employment agency, rose 2.1 percent to $24.12 after the jobless data. The Dow Jones U.S. business training and employment agencies index <.DJUSBE> rose 0.3 percent.

In a sign of investor anticipation of increased merger activity, Anadarko Petroleum Corp jumped 6.9 percent to $75.59 after the UK's Daily Mail reported BHP Billiton Ltd may be lining up a $90 per share offer for the company.

The Dow Jones industrial average <.DJI> was down 15.67 points, or 0.14 percent, at 11,569.71. The Standard & Poor's 500 Index <.SPX> was down 1.86 points, or 0.15 percent, at 1,257.92. The Nasdaq Composite Index <.IXIC> was down 3.95 points, or 0.15 percent, at 2,662.98.

Technical indicators such as the S&P 500's relative strength index and elevated levels of bullishness are leading some investors to call for a pullback.

Though many predict stocks will pull back in January, Peter Kenny, managing director at Knight Equity Markets in Jersey City, New Jersey, does not see that happening until February.

The common sense of the street is that we get pullback after this Santa Claus rally and a very strong run-up in the S&P since August, he said. But I don't think it will be in early January because everybody is expecting it.

The S&P is up more than 14 percent since August, contributing to a reluctance to make large bets as light volume leaves the market more susceptible to volatility.

February crude futures fell 1.9 percent to $89.35 per barrel after the latest U.S. inventory data, though the drop had little impact on energy companies.

(Editing by Leslie Adler)