Midday Leaders & Laggards: S&P 500

Light, sweet crude for August delivery was up 69 cents at $136.73 a barrel on the New York Mercantile Exchange. The S&P 500 was fell 1.98 at 1,271.72 at midday after alternating between gains and losses earlier in the session.

Leading the decliners, government-backed mortgage buyer Freddie Mac lost $1.22, or 9.1 percent, to $12.23, continuing a volatile week for the stock.

Department store Dillard's Inc. lost 70 cents, or 6.4 percent, to $10.20, a day before most retailers post their sales results for June.

And The New York Times Co. declined 78 cents, or 5.2 percent, to $14.28 after a Lehman Brothers analyst cut estimates on the newspaper publisher and questioned whether the company will cut its dividend.

Leading the gainers was U.S. Steel, which advanced $19.36, or 12.9 percent, to $169.91 following a price target increase to $240 from $220 by Deutsche Bank.

Shares of QLogic Corp. gained $1.23, or 8.7 percent, to $15.19 after raising its fiscal first-quarter profit and revenue outlook.

And Nucor Corp. added $5.01, or 8 percent, to $68.17 on an upgrade to "Short Term Buy," from "Neutral," from UBS.