Shares of Yahoo Inc. made the biggest advance on the Standard & Poor's 500 Index at midday Monday after investor Carl Icahn sent a letter to the Web portal's shareholders raising yet again the possibility of a merger with Microsoft Corp.
The S&P 500 rose 2.50 points to 1,265.40.
In an open letter, Icahn said he and Microsoft Chief Executive Steve Ballmer have "spoken frequently" in the past week and urged Yahoo shareholders to elect a new board. Yahoo shares added $2.55, or 11.9 percent, to $23.90.
Shares of Broadcom Corp. got a boost after Piper Jaffray's Gary W. Mobley upgraded the semiconductor company to "Buy" from "Neutral," predicting it will get a revenue boost. The stock added $1.81, or 6.9 percent, to $28.03.
Shares of RadioShack Corp. rose 83 cents, or 6.8 percent, to $13.09 after a Lehman Brothers analyst predicted the electronics retailer's quarterly results would exceed expectations, thanks in part to better sales of TV converter boxes.
Leading the decliners, First Horizon National Corp. fell 69 cents, or 9.8 percent, to $6.38. A Friedman, Billings, Ramsey analyst said the regional bank was among the most exposed to the slowdown in single-family residential construction.
Shares touched an all-time low of $6.29 earlier in the session.
Government-backed mortgage borrower Freddie Mac lost $1.93, or 13.2 percent, to $12.58 after hitting a 14-year low of $12.68 earlier in the session.
Mortgage insurer MGIC Investment Corp. fell 59 cents, or 8.4 percent, to $6.46.