Tesla’s sales in the United States fell almost 9 percent in the first three months of the year even as the overall market for electric vehicles grew, according to data compiled by a research firm.

Car buyers are moving away from Teslas and toward models like General Motors’ Chevrolet Equinox electric vehicle, which starts at around $35,000 and can travel more than 300 miles on a charge, Cox Automotive, the research firm, said in a report.

Sales of all-electric vehicles in the United States rose 11 percent during the first quarter to about 300,000 cars and light trucks, Cox said, much faster than the overall auto market, which has been flat. About 8 percent of new domestic car sales were electric, Cox said, a slight increase from 2024.

“Despite many obstacles — and what you may read elsewhere — electric vehicle sales continue to grow at a healthy pace in the U.S. market,” the firm said.

Tesla, whose chief executive is Elon Musk, still sells far more electric cars in the United States than any other automaker, accounting for 44 percent of the market, according to Cox. But its share has fallen from 51 percent a year earlier.

The decline in Tesla’s U.S. sales mirror a global slump. The company said this month that deliveries during the quarter in all markets fell 13 percent to 337,000 vehicles.

Analysts attribute the decline to Tesla’s aging selection of models; poor sales of its newest one, the Cybertruck; increasing competition; and Mr. Musk’s embrace of President Trump and right-wing politics, which has led to protests at Tesla dealerships and alienated many buyers. Democrats and independents are more likely to buy electric vehicles than Republicans.

In addition, sales of the Cybertruck have not lived up to projections made by Mr. Musk. Tesla sold 6,400 Cybertruck pickups during the quarter, more than double a year earlier, when the company was still ramping up production, but just half as many as in the last three months of 2024.

Traditional carmakers were slow to offer electric vehicles that could compete with Tesla on technology and design but have been catching up. G.M. sold 10,300 Equinoxes in the quarter. The vehicle was not available a year earlier. G.M. brands, which also include Cadillac and GMC, accounted for 11 percent of the electric vehicle market during the quarter, up from 6 percent a year earlier.

The Ford Mustang Mach-E was the best-selling electric vehicle that was not a Tesla, according to the Cox figures. But sales of the electric Mustang may suffer in months to come. It is made in Mexico and is now subject to Mr. Trump’s 25 percent tariff on imported cars. That could force Ford to eventually raise the price of the car.

Mr. Trump’s trade war is expected to have a smaller effect on Tesla, because the company makes all the cars it sells in the United States in factories in California and Texas. But it will still be hurt. Tesla stopped accepting orders from Chinese customers for its Model S and Model X, luxury vehicles that the company only makes in California, after China placed large levies on U.S. imports in retaliation for Mr. Trump’s tariffs.

Claire Fu contributed reporting.