A fantastic January for U.S. stocks ended on a slightly sour note Thursday as concerns about the economy — sparked by a jump in jobless claims and nervousness over Friday’s monthly jobs report — hung on the major indices.

The Dow Jones Industrial Average took the worst of it, declining 0.36% to 13,860.58. The S&P 500 fell 0.26% to 1,498.11, and the Nasdaq slid marginally to 3,142.13. For the month, the Dow Jones gained 5.8%, the S&P 500 improved 5% and the Nasdaq — weighed by a poor January for Apple (NASDAQ:AAPL) — finished ahead 4%.

Earnings news ruled the majority of the day. Postal equipment maker Pitney Bowes (NYSE:PBI) reached three-month highs after gaining more than 20% on an unexpected earnings beat and the announcement of cost-cutting measurements. Meanwhile, UPS (NYSE:UPS) headed the other way, falling just more than 2% after announcing fourth-quarter earnings that fell short of forecasts and issuing weak 2013 guidance.

PulteGroup (NYSE:PHM) was unable to keep up its scorching run despite reporting a big increase in fourth-quarter earnings and a 27% improvement in new orders. However, a projected decline in community count hampered PHM shares, which lost more than 1%.

On the corporate front, Constellation Brands (NYSE:STZ) cratered by 17% after the U.S. Department of Justice challenged Anheuser-Busch InBev‘s (NYSE:BUD) bid to buy out Mexico’s Grupo Modelo (PINK:GPMCF). That deal included a provision in which Constellation would buy out the remaining half of its Crown Imports joint venture with Grupo for $1.85 billion, giving it sole distribution rights for all of Grupo’s brands in the U.S. GPMCF and BUD shares fell by roughly 7% and 6%, respectively.

Lastly, Facebook (NASDAQ:FB) shares dipped early but recovered to losses of less than 1% after reporting Street-beating Q4 earnings and sales, but slower-than-expected mobile and mobile revenue growth.

Earnings notables for Friday include energy sector giants Exxon Mobil (NYSE:XOM) and Chevron (NYSE:CVX), along with Mattel (NASDAQ:MAT) and Newell-Rubbermaid (NYSE:NWL).

Three Up

• WMS Industries (NYSE:WMS): Up 51.2% ($8.38) to $24.75.
• Fortinet (NASDAQ:FTNT): Up 21.9% ($4.24) to $23.59.
• JDS Uniphase (NASDAQ:JDSU): Up 17% ($2.11) to $14.51.

Three Down

• Elizabeth Arden (NASDAQ:RDEN): Down 16.3% ($7.46) to $38.41.
• Fusion-io (NYSE:FIO): Down 13% ($2.61) to $17.48. (Read more here)
• Time Warner Cable (NYSE:TWC): Down 11.3% ($11.36) to $89.34.

Marc Bastow is an Assistant Editor of InvestorPlace. As of this writing, he was long AAPL and XOM.