U.S. stocks rose on Monday on strong results from Caterpillar and a flurry of merger-and-acquisition activity, though weakness in financial shares limited gains.

Caterpillar Inc , the heavy machinery maker, also raised its full-year profit forecast after reporting results, saying economic conditions are definitely improving. The stock gained 5.7 percent to $72.64 and was the top boost on the Dow.

Whirlpool Corp surged 12.8 percent to $115.22 after earnings beat estimates and it raised its full-year profit view, a bullish sign for consumer spending.

Financials fought a headwind, with Citigroup Inc down 4.3 percent to $4.64 after the U.S. Treasury said it would begin selling its huge stake in the bank. The government acquired 27 percent of the bank after $45 billion in bailouts. JPMorgan Chase & Co fell 1.2 percent to $44.43.

The Dow Jones industrial average <.DJI> was up 34.53 points, or 0.31 percent, at 11,238.81. The Standard & Poor's 500 Index <.SPX> rose 1.94 points, or 0.16 percent, at 1,219.22. The Nasdaq Composite Index <.IXIC> added 4.95 points, or 0.20 percent, at 2,535.10.

Caterpillar and Whirlpool were both very strong and suggest a continuation of the recovery, but the issue with Citigroup and continued questions about financial regulation remain a concern, said Kurt Brunner, portfolio manager at Swarthmore Group in Philadelphia.

A sweeping overhaul of financial regulations was slated for a crucial Senate test vote Monday. A Republican leader said all 41 Republican senators would likely vote against launching floor debate and try instead to negotiate changes.

Hertz Global Holdings Inc agreed to buy Dollar Thrifty Automotive Group Inc for about $1.2 billion, while Charles River Laboratories International , the U.S. clinical research company, plans to acquire WuXi PharmaTech Inc for $1.6 billion.

Stifel Financial Corp will acquire rival Thomas Weisel Partners Group Inc for about $300 million in stock.

Dollar Thrifty gained 9 percent to $42.30, while WuXi surged 20 percent to $19.87, and Thomas Weisel soared 66 percent to $7.25.

Greece remained in focus a day after a Greek official said an aid package would help avert a sovereign debt default, though signs grew the package may have to be bigger. The situation in Greece has weighed on equities in recent weeks.

The Bank of New York Mellon index of leading Greek ADRs <.BKGR> fell 3 percent.

(Editing by Jeffrey Benkoe)