Tesla’s profit from sales of electric cars slumped in the last three months of last year because of price cuts intended to thwart increasingly intense competition, the company said on Wednesday as it warned of a tough year ahead.

Profit in the fourth quarter nearly doubled to $7.9 billion, up from $3.7 billion a year earlier. But $5.9 billion of that profit came from a tax benefit. Without that one-time accounting effect, profit would have fallen.

Tesla has slashed prices for the two cars that make up the bulk of its sales — the Model 3 sedan and the Model Y sport utility vehicle — as automakers like BYD, in China, and General Motors, Hyundai, Ford Motor and Volkswagen, in the United States and Europe, have begun selling more electric vehicles.

The price cuts have helped Tesla sell more cars and forced other carmakers to respond, helping to make electric vehicles more affordable. But the cuts have weighed on Tesla’s profit. In 2022, Tesla was one of the most profitable carmakers in the world, but its margins from vehicle sales have fallen by almost one-third in the last year and are now comparable to those of other large rivals.

Because of the price cuts, sales revenue from cars last quarter rose just 1 percent from a year earlier, to $21.6 billion — even though Tesla sold 1.8 million cars in 2023, a 35 percent increase from 2022. Tesla made up some of the difference by reducing manufacturing costs.

Tesla shares slumped about 6 percent in after-hours trading after the company said it expected sales growth to be “notably slower” in 2024 as it developed a budget-priced vehicle. Elon Musk, Tesla’s chief executive, said during a conference call Wednesday that the vehicle, whose design is still a secret, might be available by late 2025.

“That will be a challenge,” he cautioned, because of new technology being developed to manufacture the car at a lower cost.

At Wednesday’s close, Tesla stock was 17 percent below where it started the year and down more than 25 percent from its 12-month high in July.

The carmaker faces an array of challenges this year, including economic uncertainty in all of its major markets and questions about the future role of Mr. Musk. He surprised investors this month when he said on X, the social media site he owns, that he wanted the Tesla board to raise his stake in the company to 25 percent, from 13 percent, effectively giving him shares worth more than $80 billion.

If he doesn’t get his wish, Mr. Musk said, he will develop new artificial intelligence products “outside of Tesla.” Tesla’s board has not responded publicly.

Mr. Musk said Wednesday that he needed 25 percent to protect him from being ousted “by some sort of random shareholder advisory firm.” He added, “There’s a lot of activists that basically infiltrate those organizations and have, you know, strange ideas about what should be done.”

Mr. Musk did not clarify how Tesla’s board could grant him a stake worth $80 billion without diluting the value of Tesla shares.

The automaker commands more than half the electric vehicle market in the United States, and it has more models than any other manufacturer that qualify for $7,500 tax credits under rules that took effect Jan. 1. Plummeting prices for lithium, cobalt and other materials essential to battery production should help lower manufacturing costs.

Tesla has begun selling the Cybertruck, a pickup that is the company’s first new model since the Model Y in 2020. But Tesla remains dependent on the Model 3 and Model Y for sales. BYD and Volkswagen, along with its Audi, Porsche and Skoda brands, offer larger selections of vehicles.

Tesla said Wednesday that the cost of ramping up production of the Cybertruck had weighed on profit, and that it would take longer than usual to produce the vehicle in large volumes because of a complex manufacturing process. The truck’s body is made of stainless steel, which resists rust and is more durable than the steel used in most cars, but is also harder to shape and weld.

Slowing sales growth for electric vehicles is another challenge. Surveys show that many people are interested in electric vehicles but hesitant to buy because of high prices and concern about finding enough places to charge the cars.

In a setback, Hertz said this month that it would sell some of its fleet of Teslas because they were less profitable than expected, and because some customers struggled with the unfamiliar technology.

Election-year politics add another element of uncertainty for all electric vehicle makers. Former President Donald J. Trump, the front-runner for the Republican nomination, has called electric vehicles a hoax, and his supporters have vowed to roll back Biden administration policies intended to promote the cars and encourage domestic manufacturing.

Senator John Barrasso, a Republican from Wyoming who has endorsed Mr. Trump, recently portrayed electric vehicles as a subsidy for rich liberals at the expense of “hardworking families in my home state.”