U.S. stock futures ticked lower, while prices for crude oil and natural gas extended their climb.

Futures for the S&P 500 declined 0.2% Monday, indicating that the broad market index would start the week with losses. Contracts for the tech-focused Nasdaq-100 fell 0.5% and futures for the Dow Jones Industrial Average almost 0.1% lower.

Third-quarter...

U.S. stock futures ticked lower, while prices for crude oil and natural gas extended their climb.

Futures for the S&P 500 declined 0.2% Monday, indicating that the broad market index would start the week with losses. Contracts for the tech-focused Nasdaq-100 fell 0.5% and futures for the Dow Jones Industrial Average almost 0.1% lower.

Third-quarter earnings season will kick off this week, and investors are awaiting insight into the impact of stickier-than-anticipated inflation, brought on by supply-chain disruptions, labor shortages and surging energy prices. Some are worried that higher costs for products and energy could crimp demand, while winter could lead to a resurgence in Covid-19 infections and hospitalizations. No major earnings are due Monday.

“If it wasn’t for the huge amount of savings people are sitting on from the pandemic, I’d be more worried,” said Mike Bell, global market strategist at J.P. Morgan Asset Management. “The obvious risk to that is winter. I don’t think anyone knows if that will lead to another pickup in cases and hospitalizations.”

Futures for Brent crude, the global gauge of oil prices, rose 2% to $84.04 a barrel, near their highest level in three years. Some investors are betting that a world-wide shortage of natural gas and other fuels needed to power homes and businesses will spill into the oil market.

Shares of energy companies rose in premarket trading. Occidental Petroleum shares rose 2.3% and Marathon Oil gained 2.8%.

U.S. bond markets were closed for a federal holiday. The yield on Germany’s benchmark 10-year bond ticked up to minus 0.117% from minus 0.152% Friday—its highest level since May.

Bitcoin added to recent gains, rising 1.9% from its Sunday 5 p.m. ET level to $56,486.32. Speculation has been mounting that the Securities and Exchange Commission will approve a bitcoin futures exchange-traded fund in coming weeks, which could increase the number of firms able to gain exposure to the cryptocurrency. 

Overseas, the pan-continental Stoxx Europe 600 ticked down 0.3%, with losses led by the travel and leisure sector. The U.K’s FTSE 100 edged up almost 0.4%, led by gains in energy and mining companies. 

Stocks in Asia were mixed, as Hong Kong’s Hang Seng climbed 1.9% and Japan’s Nikkei 225 index added 1.6%, whereas China’s benchmark Shanghai Composite was flat after adding 0.6% during the session.

Earnings season kicks off this week, amid concerns that rising costs could hamper profits.

Photo: brendan mcdermid/Reuters

Write to Caitlin Ostroff at caitlin.ostroff@wsj.com