DETROIT—General Motors Co. on Tuesday reaffirmed its full-year profit outlook on an expected surge in demand and said it was curbing spending and hiring ahead of a potential economic slowdown, but a 40 percent drop in its quarterly net income disappointed, sending shares lower in premarket trading.

The Detroit automaker’s net income fell 40 percent in the second quarter from a year earlier due to supply-chain snarls, including a global semiconductor chip shortage, sending its shares down 2.2 percent in premarket trading.

Chief Executive Mary Barra said the company was “already taking proactive steps to manage costs and cash flows” ahead of a possible slowdown in the economy.

“In addition, we have modeled several downturn scenarios, and we are prepared to take more deliberate action when and if necessary,” she added on a conference call with analysts.

The company, a bellwether for U.S. manufacturing and global automaking, has taken steps to offset a surge in inflation and other challenges, Chief Financial Officer Paul Jacobson said.

“We’ve slowed down some hiring [and] we have put off some costs and expenses we were going to make going into this year to try to balance that out with the pressure we’ve seen from both inflation as well as some of the other supply-chain challenges,” Jacobson told reporters on a conference call, adding that GM was not contemplating layoffs.

Nevertheless, Jacobson said GM sees a lot of pent-up demand for its vehicles, in marked contrast with U.S. retail giant Walmart Inc.’s warning on Monday that consumers were cutting discretionary purchases as it slashed its profit forecast.

The automaker reaffirmed its forecast of full-year net income of $9.6 billion to $11.2 billion, and adjusted earnings before interest and taxes (EBIT) of $13 billion to $15 billion, while expecting global deliveries to be up sharply in the second half of the year.

Second-quarter net income was $1.7 billion, or $1.14 a share, down 40 percent from $2.8 billion, or $1.90 a share, a year earlier. Analysts had expected $1.20 a share, according to Refinitiv data. Revenue rose nearly 5 percent to $35.8 billion.

GM said net operating cash in the quarter dropped to $3.1 billion, from $7.2 billion a year earlier, while net income margin fell to 4.7percent, from 8.3 percent in last year’s quarter.

GM said average transaction prices jumped $6,600 per vehicle in the quarter, and noted that U.S. dealer inventories remain historically low, at 10 to 15 days’ supply.

But the company also said it had more than 90,000 unfinished vehicles, mostly high-margin trucks and SUVs, waiting for chips and other parts. Morgan Stanley analyst Adam Jonas estimated their value at $4.5 billion in revenue and $1.5 billion in EBIT.

CFO Jacobson said GM expects to finish and deliver all those vehicles by year-end.

“Its time to walk the walk and not just talk the talk for GM, as patience is wearing thin on the Street around the name,” Wedbush Securities analyst Daniel Ives said in a research note.

GM’s China operations lost $100 million in the quarter due to COVID-19 restrictions there.

GM’s quarterly revenue in China, a key market, fell to $6.1 billion, from $9 billion in the first three months and $9 billion in the year-earlier period. Deliveries to dealers fell to 473,000, from 602,000 in the first quarter and 620,000 a year ago.

By Ben Klayman and Paul Lienert