The S&P 500 was flat at 2,040.35 in midday trading.
The Dow Jones Industrial Average rose 0.1% to 17,651.50, and the Nasdaq fell 0.38% to 4,670.53.
The yield on a 10-year Treasury bond rose 0.78% to 2.34%.
The price of gold declined 0.11% to $1,184.30.
Irvine-based Allergan Inc. was up 5.1% to $208.90 and market cap of $62.2 billion. The drug maker said it agreed to be bought for $66 billion by Actavis Plc, which has U.S. headquarters in New Jersey. Actavis was up 1.5% to a market cap of $65.6 billion. Allergan’s other suitor, Valeant Pharmaceuticals International Inc. in Canada, was up about 1% to a market cap of $45.4 billion.
Newport Beach-based William Lyon Homes was down 12% to $19.95 and a market cap of $623.3 million. It plans to offer 1 million tangible equity units valued at $100 and use proceeds to pay down debt on a $120 million line of credit. The borrowing was part of its $520 million purchase of Bellevue, Wash.-based Polygon Northwest Homes.