Shares of Catamaran, a pharmacy benefits manager, were up 24 percent; UnitedHealth, the nation's biggest health insurer, gained 2.2 percent.
Other mergers and acquisitions had Teva Pharmaceutical Industries (TEVA) agreeing to buy Auspex Pharmaceuticals (ASPX) for $3.2 billion in cash, and Horizon Pharma (HZNP) saying it would acquire Hyperion Therapeutics (HTPX).
The Dow industrials (DJI) advanced 264 points, or 1.5 percent, to close at 17,976. The S&P 500 (SPX) gained 25 points, or 1.2 percent, to 2,086, and the Nasdaq Composite (COMP) climbed 56 points, or 1.2 percent, to 4,947.
Wall Street also found solace in signals sent during the weekend from China's central bank chief, which said there are further steps the government can take to bolster growth in the nation's economy.
Economic reports Monday were mixed, with consumer purchases rising less than anticipated last month, and more Americans than expected signing contracts to buy previously owned homes in February.
The data also showed the U.S. savings rate climbing to 5.8 percent from 5.5 percent in January.
"That's the highest since December 2012 and helps to explain why retail sales have been so muted over the past few months," said Peter Boockvar, chief market strategist at the Lindsey Group. "Today's spending figure is another sign that we had a punk first quarter in the U.S. economy."