DETROIT — General Motors posted a healthy $2.8 billion second-quarter profit Wednesday, but its cautious outlook for the rest of the year spooked investors.

The Detroit automaker made the strong profit despite a global shortage of computer chips that have forced it and other companies to temporarily close factories.

While GM raised its outlook for the year, it also cautioned about high commodity prices and lower production due to the chip shortage, and it warned that the highly contagious delta variant of the coronavirus could hamper its supply chain.

The cautious tone rattled investors, who pushed GM shares down more than 8% in midday trading.

Chief Financial Officer Paul Jacobson predicted that GM would produce 100,000 fewer vehicles in the second half of the year compared with the first, even as other companies forecast improvements in semiconductor production. GM said it managed the shortage well and was able to divert scarce chips to factories that make higher profit pickup trucks and large SUVs.

But Edward Jones Industrials analyst Jeff Windau said investors are building some uncertainty into GM’s stock price after the company forecast $3.5 billion to $4.5 billion worth of increased costs in the back half of the year.

“Obviously there’s some shutdowns, and there’s just concerns with how things are evolving,” Windau said. “Expectations have been rising over the last couple of months. This just kind of comes back and potentially resets the bar a little bit.”

On Tuesday, GM announced that pickup truck plants in Flint, Michigan; Silao, Mexico; and Fort Wayne, Indiana; would be closed next week due to the chip shortage. Production is to resume on Aug. 16. But factories in Tennessee and Mexico that make cars and SUVs that were down since July 19 will come back on line Monday.

Even with the caution, GM told the same story as competitors Ford, Stellantis and others reporting strong profits, saying that high prices and healthy demand for expensive pickup trucks and luxury SUVs overcame inventory shortages.

GM boosted its net income guidance for the full year to $7.7 billion and $9.2 billion, and pretax earnings to a range of $11.5 billion to $13.5 billion from $10 billion to $11 billion.

Executives said Wednesday that they expect tight inventory and high prices to continue through the year as the chip shortage lingers into 2022.