European markets were also well up.
Women walk past an electronic stock indicator today in Tokyo as the yen's recent weakness helped boost Japan's Nikkei 225 and its heavy orientation toward exporting companies. The index in Tokyo jumped 1.6 percent to 9,171.26, a two-month high. Markets across the world were higher today.
At 10 a.m. on Wall Street, the Dow Jones industrial average was up 163 points, while the Standard & Poor's 500 index was up 20. And the Nasdaq composite index was up 40.
European markets were sharply higher as well.
Financial analysts say it's because of optimism that leaders in the United States will reach a deal to avoid the so-called fiscal cliff, a package of tax increases and government spending cuts set to take effect Jan. 1.
U.S. investors are also encouraged by corporate earnings reports. Lowe's says its third-quarter profit surged 76 percent. That's after a strong report from Home Depot last week. Tyson Foods also beat Wall Street expectations.
Existing home sales increased 2.1 percent, more than was expected, CNBC reported, and builder confidence was up, in figures released at 10 o'clock.