Investing.com -- U.S. stock futures fell early Tuesday, kicking off a shortened trading week as Wall Street monitored the U.S.-Iran conflict alongside rising trade tensions between Canada and the U.S. Futures tied to the Dow Jones Industrial Average fell 0.8% by 05:30 ET (09:30 GMT). S&P 500 futures fell 0.3% and Nasdaq-100 futures slipped 0.1%. U.S. markets were closed Monday for Labor Day.

Shares of major U.S. energy companies rose in premarket trading, tracking a jump in oil prices after Iran warned that Gulf oil and gas infrastructure could be targeted in retaliation for strikes on its own assets. Exxon Mobil gained 1.8% and Chevron rose 1.7%. ConocoPhillips added 1.6%, while Diamondback Energy and Marathon Petroleum each climbed 1.1%. Valero Energy rose 1.6%.

Meanwhile, Eaton shares gained more than 3% after UBS upgraded the stock to Buy from Neutral and raised its price target to $515 from $450. The bank cited strong sales growth and expected margin improvement in the third quarter and beyond, driven by proactive pricing actions and better execution.

Everpure shares rose 2.5% after the company was set to join the S&P 500, alongside Illumina, as part of the index’s quarterly rebalancing effective before market open on September 21. Both companies, moving up from the S&P MidCap 400, will replace Builders FirstSource and The Trade Desk.

Shake Shack shares rose about 1% after RBC Capital Markets initiated coverage with an Outperform rating and an $89 price target. RBC said the company is at an inflection point, with growing scale and improved marketing and supply chain sophistication potentially driving upside through at least 2027.

Old Dominion Freight Line shares climbed 1.3% after an interim operating update pointed to accelerating revenue growth heading into the third quarter. In an 8-K filing Wednesday, the company said revenue per day rose 12.4% compared with August 2025, driven largely by higher less-than-truckload revenue per hundredweight, a key pricing metric for the industry.