Tesla on Tuesday reported a 45 percent drop in profit in the three-month period between April and June, a result of the electric car company’s sluggish sales.

The automaker said it earned $1.5 billion in the second quarter of the year on revenue of $25.5 billion. In the second quarter of 2023, Tesla made $2.7 billion and had revenue of $24.9 billion.

The company’s current operating profit margin, a measure of how much money it makes on every dollar of revenue, was 6.3 percent, compared with 9.6 percent in the same period a year ago.

The results will most likely heighten pressure on Tesla and its chief executive, Elon Musk, to show that the company can find new ways to grow and make money.

Tesla shares have jumped 40 percent since the end of the May in large part because investors are betting that Mr. Musk will successfully remake Tesla into an artificial intelligence company that operates a driverless taxi service and sells robots for manufacturing and other tasks.

The company’s bottom line was helped by sales of regulatory credits to other automakers that need them in order to meet emissions standards. Tesla sold $890 million in credits in the second quarter, up from $282 million a year earlier.

Another area of growth for the company has been sales of batteries that are primarily used to store and discharge power on electricity grids. Sales of those systems doubled in the quarter, to $3 billion, from a year earlier.

Even taking those gains into account, the company’s second quarter profit was lower than what Wall Street analysts had expected, and Tesla’s stock fell about 6 percent in extended trading on Tuesday after its earnings report.

It is unclear whether the company’s new taxi and robot businesses will come up to speed fast enough to make up for Tesla’s weakening car sales. Several companies, including Google’s parent Alphabet, have been developing driverless taxis for many years but are only offering rides in a few cities.

“Perhaps more than ever in the company’s recent history, Tesla’s investors need results,” Thomas Monteiro, a senior analyst at Investing.com, said in an email on the company’s results. “Those will have to come fast — both for the humanoid robot and for the robotaxi.”

In a conference call to discuss the earnings report, Mr. Musk said the company had delayed an event where it would reveal the design of its driverless taxi to October, from early August.

Sales of Tesla’s electric cars fell 4.8 percent in the second quarter, to 444,000 vehicles from the same period a year earlier. Production in the period declined 14 percent, to about 411,000 cars.

The second quarter’s setback comes after Tesla reported a 55 percent drop in profit and 9 percent decline in revenue in the first three months of 2024.

The company is facing increasing competition as other manufacturers have ramped up production of electric models. Tesla’s share of electric vehicle sales in the United States fell in the second quarter to below 50 percent for the first time, according to Cox Automotive, a research firm.

Mr. Musk acknowledged that the arrival of new, more affordable electric cars made by other companies “has made it more difficult for Tesla” to sell cars.

From April through June, Tesla accounted for 49.7 percent of electric vehicles sales in the United States, down from 59.3 percent a year earlier, Cox said. Ford Motor said this month that it sold nearly 24,000 E.V.s in the second quarter, far fewer than Tesla but a 61 percent increase from a year ago. General Motors’ sales of battery-powered models rose 40 percent, to nearly 22,000 vehicles.

Separately, G.M. said on Tuesday that it made $2.9 billion in the second quarter, a 14 percent increase from a year ago. Its operating profit margin, at 9.3 percent, outpaced Tesla’s, a rare accomplishment for G.M.

Mr. Musk said that Tesla, which for much of its existence did not advertise, would more aggressively market its driver-assistance system known as Full Self-Driving. It can perform certain functions like changing lanes, accelerating and braking on its own, but drivers must be prepared to intervene at any point if the program errs. Tesla owners can access the system through a $99 monthly subscription.

Tesla’s slump in sales appears to be at least partly the result of the right-wing politics of Mr. Musk. Tesla’s early customers and fans included many environmentalists and left-leaning consumers, many of them residents of California. Registrations of new Teslas in the state fell 24 percent in the second quarter, according to data published last week by the California New Car Dealers Association.

Mr. Musk said Tesla was moving cautiously on plans, announced last year, for a new factory in Mexico until after the presidential election. He said former President Donald J. Trump, the Republican candidate whom Mr. Musk recently endorsed, might impose tariffs on cars imported from that country.

“It doesn’t make sense to invest a lot in Mexico if that is the case,” he said.

With its sales slumping, Tesla has been trying to slash costs. In April, Mr. Musk said the company would lay off more than 10 percent of its staff, or about 14,000 people, worldwide. The cuts include 2,000 workers at its plant in Fremont, Calif., and nearly 2,700 at another in Austin, Texas.

It has also cut the prices of its cars, which has reduced the profit it makes on each vehicle it sells. For a time, those cuts helped to lift sales, but now the company is struggling to win over customers even with lower prices.