Shares in Tesla fell 6.8% on Monday, wiping $79bn off the company's value, amid concerns over Elon Musk's new political party.
Tesla's market capitalization dropped to about $921bn from just over $1tn, reducing Musk's stake by nearly $15bn to below $120bn.
Investors fear that Musk's involvement in politics could distract him from Tesla's operations, leading to a negative impact on the company.
Despite being the world's richest person, Musk's political aspirations have raised concerns among investors and received criticism from former President Trump.