A bidding contest for a discount retailer and easing concerns about Ukraine helped send U.S. stock indexes higher.
At the close on Wall Street, the Standard & Poor's 500 index was up 16.7 points, or nearly 0.9 percent, to 1,971.7. The Dow Jones industrial average gained 175.8 points, or about 1.1 percent, to 16,838.7. The Nasdaq composite climbed 43.4 points, or nearly 1 percent, to 4,508.3.
Dollar General jumped nearly 12 percent, $6.68 to $64.14, after the company made a bid to buy Family Dollar. The company is hoping to beat out a rival bid from Dollar Tree.
Airline stocks rose as the price of oil fell, which could mean lower costs for jet fuel. United Continental and American Airlines each climbed nearly 4 percent.
Bond prices fell. The yield on the 10-year Treasury note rose to 2.39 percent.
Although the Russian convoy heading into rebel territory in Ukraine has stopped, it is not clear the crisis is easing. Ukraine on Monday accused pro-Russia separatists of killing dozens of civilians in an attack on a convoy fleeing a besieged rebel-held city.
In the meantime, central bankers, policy experts and academics from around the world gathered at Jackson Hole, Wyoming, for an annual talkfest later this week. Federal Reserve Chair Janet Yellen's speech Friday on the U.S. labor market is expected to "reiterate her views that slack remains substantial, and that the Fed should keep monetary policy accommodative still in order to address that," Mihuzo Bank analysts said in a commentary.