Tesla’s sell-off on Wall Street intensified on Monday, with shares of the electric vehicle maker plunging 15%, their worst day on the market since September 2020.

On Friday, Tesla wrapped up a seventh straight week of losses, its longest losing streak since debuting on the Nasdaq in 2010. The stock has fallen every week since CEO Elon Musk went to Washington, D.C., to take on a major role in the second Trump White House.

Since peaking at $479.86 on Dec. 17, Tesla shares have lost more than 50% of their value, wiping out upward of $800 billion in market cap. Monday marked the stock’s seventh worst day on record.

Tesla led a broader slump in U.S. equities, with the Nasdaq tumbling almost 4%, its steepest decline since 2022.

During an interview on Fox Business after hours on Monday, Musk was asked how he manages to run his businesses while fulfilling his role in the Trump White House. He said he’s doing so “with great difficulty.”

In addition to Tesla’s troubles, Musk’s social network X experienced several outages throughout the day on Monday, and his aerospace and defense company SpaceX is investigating two explosions in a row that occurred during test flights of its massive Starship rocket.

Musk also said during the interview that he expected to remain in the Trump administration for another year. After the broadcast, he posted on X that “It will be fine long-term,” referencing Tesla’s steep stock price decline.

The downdraft in Tesla’s stock on Monday was tied to uncertainty surrounding President Donald Trump’s plans on tariffs. Canada and Mexico are key markets for automotive suppliers, and increased tariffs, with the potential for a trade war, will likely affect production and lead to higher prices.

Tesla is also dealing with brand erosion due to Musk’s incendiary political rhetoric and his extensive work with the Trump administration, where he is leading up the so-called Department of Government Efficiency. Musk, the world’s wealthiest person, has become the public face of the administration’s effort to dramatically shrink the federal government’s workforce, spending and capacity.

Meanwhile, Musk has used X to level accusations against judges whose decisions he did not like and promoted false Kremlin talking points about Ukraine President Volodymyr Zelenskyy.

Activists and former Musk fans have protested at Tesla facilities across the U.S., and Tesla vehicles and facilities have been the apparent targets of vandalism and arson attempts. Repeated arson attempts and instances of vandalism occurred at a Tesla store and service center in Loveland, Colorado, most recently on March 7, police told CNBC.

Ben Kallo, an analyst at Baird, told CNBC’s “Squawk on the Street” on Monday that recent reports of vandalism could hurt demand.

“When people’s cars are in jeopardy of being keyed or set on fire out there, even people who support Musk or are indifferent Musk might think twice about buying a Tesla,” Kallo said.

Analysts at Bank of America’s wrote in a report on Monday that Tesla’s new vehicle sales plummeted about 50% in Europe in January from a year earlier, partly owing to growing distaste for the brand. The firm also noted that some prospective customers are waiting for the new version of the Model Y.

Tesla’s Model Y, which is a small SUV, remained the best-selling battery electric vehicle globally in January. It was followed by China’s Geely Geome, which surpassed the Tesla Model 3 sedan for the month.

Global sales of electric vehicles, including fully electric and plug-in hybrid models, increased 21% in January from a year ago, even as Tesla’s sales declined. The growth was driven by demand in Europe, according to Bank of America.