U.S. stocks jumped on Monday, extending gains from the previous week, on renewed risk-taking sentiment after the Group of 20 pledged to keep economic stimulus in place until a recovery was assured.

Corporate mergers and acquisitions also boosted the market, with General Electric Co gaining 3.4 percent to $15.85 after a source said GE and Comcast Corp agreed on a valuation of around $30 billion for a joint venture between NBC Universal and Comcast.

G20 finance ministers and central bankers agreed over the weekend to keep government aid flowing, boosting global stocks while pressuring the dollar as high-yielding and commodity-linked currencies benefited.

Stocks closed higher last week even as the unemployment rate in the United States rose to 10.2 percent in October. The S&P 500 is up about 61 percent from a 12-year closing low in early March.

It's basically the fact that we have free money right now, basically we're reinflating things and that is what's taking place rather than evidence of a solid recovery, said Peter Jankovskis, co-chief investment officer at OakBrook Investments in Lisle, Illinois.

The Dow Jones industrial average <.DJI> gained 155.23 points, or 1.55 percent, to 10,178.65. The Standard & Poor's 500 Index <.SPX> rose 17.18 points, or 1.61 percent, to 1,086.48. The Nasdaq Composite Index <.IXIC> added 30.57 points, or 1.45 percent, to 2,143.01.

Kraft Foods Inc formalized a proposed takeover of Britain's Cadbury Plc , but failed to improve the terms of its initial approach. Kraft was down 1.2 percent at $26.44.

Healthcare companies were in the spotlight after the U.S. House of Representatives approved a healthcare reform bill on Saturday that would include a government-run health insurance option to compete with private insurers.

The Morgan Stanley Healthcare Payor index <.HMO> was up 1.5 percent, while the NYSE Arca Pharmaceutical index <.DRG> rose 1.6 percent.

Shares of McDonald's Corp gained 1.5 percent to $62.66 after the fast-food chain posted a 3.3 percent increase in global comparable sales.

Sprint Nextel Corp is preparing to pump at least $1 billion more into wireless broadband company Clearwire Corp, the Wall Street Journal reported, citing two sources. Sprint Nextel stock added 8.9 percent to $3.10.

Oil futures jumped 3 percent, or more than $2, to above $79 a barrel, and gold hit a record high above $1,110 an ounce, as the dollar index <.DXY> slid 1 percent as investors awaited the outcome of the G20 meeting.

(Reporting by Angela Moon; Editing by Jan Paschal)