Recasts top of story, adds details of earnings estimates, changes headline, adds bullet points

By Akash Sriram

April 16 (Reuters) - Californians further soured on Tesla TSLA.O in the first quarter, pulling down the electric-vehicle maker's registrations by 15% as backlash against Elon Musk's company intensified in the state that has embraced EVs most across the United States.

The drop-off means Tesla no longer accounts for a majority of the EV market share in the state, according to the California New Car Dealers Association (CNCDA).

There have been relentless protests in many cities in California - echoing the backlash in other countries - against Musk's involvement in U.S. President Donald Trump's administration and his embrace of far-right politics in Europe, a key factor behind Tesla's 13% drop in first-quarter deliveries globally.

California's embrace of EVs makes Tesla's falloff more concerning given that overall zero-emission vehicle sales in the state rose 7.3% during the first three months of the year. While Tesla's market share fell to 43.9% from 55.5% a year earlier, brands such as Honda 7267.T, Ford F.N and GM's GM.N Chevrolet grew their footprint.

"An aging product lineup and backlash against Musk's political initiatives are likely key factors for the decline in Tesla BEV market share," the CNCDA said in a statement on Wednesday.

Tesla shares fell 5.2%; they have lost nearly half their value since peaking in mid-December.

Investors will be closely watching Tesla's earnings release on Tuesday to see whether the company will maintain its growth forecast for the year in light of the decline in sales in key markets evidenced in the first quarter. Analysts have steadily reduced their estimates for its first-quarter results to a mean of 42 cents a share, according to data compiled by LSEG, down from 69 cents three months ago.

California accounts for nearly a third of Tesla's sales in the U.S., according to Reuters calculations based on data from Cox Automotive and the CNCDA. That makes it an outsized contributor to the EV maker's success in America, as the state accounted for roughly 13% of new registrations of gasoline-powered light vehicles in 2023, according to U.S. Energy Department figures.

While Tesla's Model Y SUV remained the best-selling EV in the state, its sales plummeted about 30% in the first quarter, compared with a year earlier, the CNCDA said.

Tesla said earlier this month that retooling production lines for a refreshed Model Y resulted in several weeks of lost production.

The CNCDA also expects total new vehicle registrations in the state to fall 2.3% in 2025 from last year due to U.S. trade policies.

(Reporting by Akash Sriram in Bengaluru; Editing by Sayantani Ghosh, David Gaffen and Devika Syamnath)

((Akash.Sriram@thomsonreuters.com; On X as @HoodieOnVeshti; +91-99017-77617))