NEW YORK (CNNMoney.com) - Stocks made modest gains at the start of trading Monday as enthusiasm over merger activity offset rising oil prices.

The Dow Jones industrial average (down 58.36 to 10,793.62, Charts) and the Nasdaq composite (down 18.99 to 2,262.58, Charts) were little changed while the broader Standard & Poor's 500 index (down 6.81 to 1,264.03, Charts) rose slightly.

Oil prices were higher after Iran resumed uranium enrichment and ended United Nations checks of its nuclear sites in response to action against it by the International Atomic Energy Agency Saturday.

The March light crude futures contract for NYMEX gained 56 cents to $65.92 a barrel in electronic trading.

Jason Schenker, an economist who tracks energy for Wachovia, said he believes that oil traders are pricing in some increased risk for a disruption to Iranian oil, but that he doubts that supplies from Iran will be halted by the dispute over its nuclear program.

"Across the United Nations, no one wants to see supplies restricted. And it's not in Iran's best fiscal interest to do so either," he said. "It's quite conceivable we could see prices go back to $60, high $50's if this reaches a negotiated resolution or even a stalemate."

Citadel Broadcasting (Research) was putting the finishing touches over the weekend on a $2.7 billion agreement to acquire the bulk of the radio assets of media conglomerate Walt Disney (Research), according to a published report in the Wall Street Journal. Disney also is set to report fourth-quarter results after the bell Monday, with forecasts for a slight decline in earnings per share on essentially flat revenue.

Reuters also reported that Wachovia (Research), the nation's No. 4 bank, has teamed up with private equity firm Kohlberg Kravis Roberts & Co. to bid for the controlling stake in GMAC, the finance unit of embattled automaker General Motors (Research), which is looking to sell its most profitable unit to return its debt to investment grade status.

A possible bid for GMAC could be weighed by the board of GM, which meets Monday. The board may also vote to cut its dividend. An advisor to Kirk Kerkorian, its largest individual shareholder, urged the company to cut its $2 annual dividend by half, as part of a move to also cut both management and hourly workers pay and conserve case at the embattled automaker.

Major markets in Asia closed mostly higher Monday, with Japan's Nikkei reaching a 5-1/2-year high. Major European markets also moved higher in early trading.

Treasury prices fell, lifting the yield on the benchmark 10-year note to 4.53 percent, from 4.52 percent reached late Friday. The dollar was down against the yen but up on the euro.