At 1400 GMT the Dow Jones Industrial Average of 30 blue-chip stocks had added 65.55 points (0.53 percent) at 12,344.56.

The broad-based S&P 500 index rose 7.55 points (0.57 percent) to 1,326.99, while the tech-heavy Nasdaq Composite gained 14.09 points (0.51 percent) at 2,770.98.

Corporate news driving the surge included a buoyant earnings report and forecast from discount retailer Family Dollar Stores, whose shares added 0.4 percent in early trade.

The market also got a charge from Valeant Pharmaceuticals's unsolicited $5.7 billion bid for biotech firm Cephalon.

Cephalon's shares jumped 28.1 percent, while Valeant added 11.3 percent.

Shares in private-equity group Apollo Global Management fell 3.0 percent on the first day of trading after an initial public offering Tuesday priced at $19.

The market appeared content with the ADP payrolls firm's report that US companies added 201,000 jobs in March, a sign of steady, if not stellar, economic growth.

Coming on two previous months of over-200,000 figures, ADP said the data "removes any remaining doubt that private nonfarm payroll employment accelerated heading into 2011."

The bond market was slightly higher. The yield on the 10-year Treasury fell to 3.48 from 3.49 percent late Tuesday, while that for the 30-year slipped to 4.54 percent from 4.55 percent.

Bond prices and yields move in opposite directions.