In early afternoon trade in New York on Monday, the Dow Jones Industrial Average had added 0.34 percent to 13,657.53, while the Nasdaq Composite gained 0.08 percent to 2,668.52 and the S&P 500 was 0.07 percent higher to 1,531.51.
The gains came as the earnings season was about to get underway.
Mergers and acquisitions activity was in focus with a report that Apollo Management has raised its offer for chemicals group Huntsman (NYSE: HUN) to $28 per share.
Huntsman added 20 cents to $28.20.
FedEx (NYSE: FDX) gained 4.2 percent to $115.51 after a media report that private equity could be interested in making a bid.
Meanwhile, Boeing (NYSE: BA) was 92 cents higher to $99.80 in the wake of its unveiling over the weekend of its new aircraft, the Dreamliner 787.
Reports are that the aerospace group has received enough orders for the new plane that it is sold out until 2015.
Pharmaceutical and consumer products group Johnson & Johnson (NYSE: JNJ) added $1 to $63.13 after its board approved a share buyback worth $10 billion.
Exchange operators were mixed on the expectation that shareholders in the Chicago Board of Trade (NYSE: BOT) are likely to approve a deal to merge with the Chicago Mercantile Exchange (NYSE: CME).
While the Intercontinental Exchange (NYSE: ICE), which has also bid in for CBOT, added 46 cents to $156.55, CME dropped $4.29 to $570.51 and CBOT declined $1.60 to $222.40.