Midday Leaders & Laggards: S&P 500

The Standard & Poor's 500 Index drifted slightly lower at midday Tuesday, with shares of Office Depot Inc. taking the biggest hit after the office supplies retailer forecast a 10 percent drop in same-store sales.

The S&P 500 lost 0.05 points to trade at 1,252.26 just before noon EDT.

Office Depot shares plunged $3.41, nearly a third of their value, to $7 after the company said the weak economy squeezed its second-quarter sales and predicted a "difficult" environment for the rest of the year.

The stock fell to an eight-year low of $6.60 earlier in the session.

EMC Corp. tumbled $1.59, or 10.5 percent, to $13.55 after the data-management provider's subsidiary, VMware Inc., replaced its chief executive and said its revenue would fall short of prior estimates.

Nucor Corp. declined $4.08, or 6.2 percent, to $61.98. Earlier Tuesday, the steel producer said it completed a $658 million acquisition of 50 percent of the stock of a joint venture with Italy's Duferco SA.

Regional banks led the gainers after Federal Reserve Chairman Ben Bernanke said in a speech that the central bank will lay out new rules next week aimed at protecting home buyers from dubious lending practices.

Fifth Third Bancorp rose 81 cents, or 7.9 percent, to $11.12.

Huntington Bankshares Inc. added 34 cents, to 6.4 percent, to $5.66.

Insurance provider XL Capital Ltd. rose $1.26, or 6.8 percent, to $19.68.