NEW YORK (AP) — Oil and gas companies are pulling the U.S. stock market lower in early trading as crude oil sinks to around $50 a barrel.

The Standard and Poor's 500 index fell seven points, or 0.4 percent, to 2,092 as of 9:35 a.m. Eastern time on Thursday.

The Dow Jones industrial average dropped 100 points, or 0.5 percent, to 17,936.

In commodity markets, the price of oil fell $2.74, or 5 percent, to $50.07 a barrel in New York.

Shares in Wal-Mart slid after the world's largest retail chain turned in revenue that fell short of Wall Street's expectations. Wal-Mart also announced plans to give 500,000 of its U.S. employees a raise within six months.

Bond prices slipped. The yield on the 10-year Treasury note edged up to 2.09 percent.