Tesla shares tumbled nearly 8% on Monday following CEO Elon Musk’s surprise announcement of a new U.S. political movement, the America Party, renewing investor concerns over his focus on the electric vehicle giant amid declining sales.

The move comes in the wake of a public spat between Musk and former ally, President Donald Trump, over a tax-cut and spending bill. Trump dismissed Musk’s latest political effort as “ridiculous” and threatened to slash federal subsidies for Musk-owned companies, escalating tensions that had already wiped out $150 billion from Tesla’s market value in early June.

Investor anxiety deepened after Tesla reported its second consecutive quarterly drop in vehicle deliveries last week. The company’s stock has now lost 35% of its value since peaking in December, making it the worst performer among the so-called “Magnificent Seven” tech stocks this year.

“Elon’s political distractions are not helping,” said Shawn Campbell, an adviser at Camelthorn Investments and a Tesla shareholder. “Tesla needs to focus on business, not politics.”

With pressure mounting, Tesla must sell over one million vehicles in the second half of the year to avoid a full-year sales decline—a daunting challenge given growing economic uncertainty and backlash over Musk’s political activities.

If current trends continue, Tesla is on track to shed more than $80 billion in market value, while short sellers are set to gain roughly $1.4 billion in paper profits from Monday’s stock slump.