pU.S stocks rebounded from early losses on Thursday (December 20) after Republican House Speaker John Boehner said he would keep working on a solution to the "fiscal cliff" while also slamming President Barack Obama's approach to budget talks.pbr pNYSE Euronext was the S&P 500's biggest gainer, surging 34 percent to $32.25 (USD) after IntercontinentalExchange Inc said it would buy the operator of the New York Stock Exchange for $8.2 billion.pbr pICE shares shot up 1.4 percent to $130.10.pbr pRepublicans in the U.S House of Representatives pushed ahead with their own plan to avoid a series of steep tax hikes and spending cuts due in early 2013, complicating negotiations with the White House. Obama has vowed to veto the plan.pbr pInvestors have hoped for an agreement soon between policymakers, but progress has been slow. Boehner said he expected to continue to work with Obama, but repeated his charge that the president and Senate Democrats were trying to "slow walk" the country over the fiscal cliff.pbr pThe Dow Jones industrial average gained 59.75 points, or 0.45 percent, to 13,311.72 at the close. The S&P 500 rose 7.88 points, or 0.55 percent, to 1,443.69. The Nasdaq Composite climbed 6.02 points, or 0.20 percent, to 3,050.39.