NEW YORK – Stocks slipped on Friday, pushing the market to a weekly loss, as investors assessed the latest round of company earnings.

Express Scripts, the largest U.S. pharmacy benefits manager, fell after its fourth-quarter earnings slipped, hurt by the loss of Minnetonka-based UnitedHealth, a large customer. Groupon plunged after the online deals company said it expects to post a loss this quarter and issued a weak outlook for the year.

The Standard & Poor's 500 index rose in early trading Friday and had almost wiped out its loss for the year by late morning, climbing to within two points of its record close. By late afternoon, the index started to turn lower.

The stock market has gained this month after getting a boost from decent corporate earnings for the fourth quarter and optimism that the economy will start to pull out of its slump as the weather improves.

While investors have been willing to overlook much of the weak economic data this month, they appear reluctant to push the stock market above its recent highs before they see firmer evidence that the economy is sustaining its recovery.

Investors are "giving the economic data points a bit of a free pass, but at the same time they're not fully convinced either," said Robert Pavlik, chief market strategist at Banyan Partners, a wealth management firm.

The S&P 500 index fell 3.53 points, or 0.2 percent, to 1,836.25. The index lost 2.38 points for the week and is now 12 points below its record close of 1,848.38, set Jan. 15.

The Dow Jones industrial average fell 29.93 points, or 0.2 percent, to 16,103.30. The Nasdaq composite dropped 4.13 points, or 0.1 percent, to 4,263.41.