The loyalty of Tesla’s US customers to the electric vehicle brand has plunged since CEO Elon Musk endorsed Donald Trump for president last year.

That’s according to data from research firm S&P Global Mobility shared exclusively with Reuters.

The data shows Tesla customer loyalty peaked in June of 2024 when 7 percent of Tesla-owning households in the market for a new car bought another Tesla, according to an S&P analysis of vehicle-registration data in all 50 states.

That industry-leading brand loyalty rate started to nosedive in July when Musk endorsed Trump following an assassination attempt on the Republican nominee in Pennsylvania.

It bottomed out at near 50 percent last March, just below the industry average, after Musk launched Trump’s budget-slashing Department of Government Efficiency in January and started firing thousands of government workers.

But Tesla's loyalty rate has since risen to 57 percent according to the most recent data, which is from May, putting it at about the industry average.

ALSO READ: Tesla ordered by Florida jury to pay $243 million in fatal Autopilot crash

An S&P analyst called it "unprecedented" to see the runaway leader in customer loyalty fall so quickly to industry-average levels, saying quote, "I’ve never seen this rapid of a decline in such a short period of time."

Tesla remains the US electric-vehicle sales leader but has seen its dominance erode as Musk last year delved into politics and focused Tesla more on developing self-driving technology than on new affordable models for human drivers.

Those self-driving plans took a step backward last week when a Florida jury found Tesla liable to pay $243 million to victims of a fatal crash in 2019 involving an Autopilot-equipped Model S.

The verdict was a rare win for victims of accidents involving Autopilot and could encourage more legal action against Musk's EV maker.