About five minutes after the opening bell, the Dow Jones Industrial Average and the broad S&P 500 index were both up 0.4 percent, while the tech-heavy Nasdaq Composite Index was up 0.3 percent.
Oil futures rose sharply last week to their highest levels in months following attacks on Saudi Arabia by the Iran-backed Houthi movement in Yemen.
On Monday, prices fell slightly, with a barrel of North Sea oil (Brent) costing $115.79 after falling 0.8 percent during the day.
Several major technology companies with strong ties to AI - such as Nvidia, Micron, Broadcom and AMD - were also rising sharply.