Since Donald J. Trump’s victory in the presidential election, Tesla’s shares had been on a remarkable upswing. Investors were optimistic that the company would reap rewards from the over $250 million spent by CEO Elon Musk to support Trump’s campaign.

However, an 8% drop in Tesla’s stock on Tuesday almost completely erased gains from that rally. Investors who initially believed that Trump could help facilitate regulatory approval for Tesla’s autonomous driving technology are becoming increasingly anxious that Musk is focusing too much on political affairs in Washington, while sales of Tesla vehicles continue to decline.

Concerns are also mounting that Musk’s deep involvement in right-wing politics, notably his endorsement of a far-right party in recent German elections, may be alienating a substantial portion of potential customers. In the U.S., even some Republicans are expressing alarm over Musk’s aggressive cost-cutting measures as head of the so-called Department of Government Efficiency.

The decline in shares, which has pushed Tesla’s market capitalization below $1 trillion, poses a threat to Musk’s position as the world’s richest individual, given that a significant portion of his wealth is tied to Tesla stock. Additionally, these stock decreases are likely to escalate unrest among investors and employees who are frustrated that Musk has yet to outline a strategy to reverse the steady loss of market share in the U.S., Europe, and China.

Shares closed at $302.80 on Tuesday, marking the lowest point since November 7, just two days after the election. This represents a 37% decrease from the peak of $479.86 on December 17.

The losses on Tuesday were partly driven by a staggering drop in Tesla’s European sales, which plummeted by 50% in January compared to the previous year, according to new car registration data from the European Automobile Manufacturers’ Association. Despite the overall electric vehicle market growing by 34%, Tesla’s sales in the region saw a significant decline, as reported by the association on Tuesday.