About $13bn (£10.3bn) was wiped off Tesla's shares after chief executive Elon Musk tweeted that the electric car company's "stock price is too high".
In a series of other tweets, Mr Musk, 48, also said he was "selling almost all physical possessions" and "will own no house".
He added his girlfriend was "mad at me".
There will be no Mars if we let them take our freedom away
— Elon Musk (@elonmusk) May 1, 2020
We'll go to Mars in 6 months, 12 months tops, depending on regulator approval.
DAMN REGULATORS