Short-selling legend Jim Chanos had a few choice words for VinFast Auto, the wunderkind car stock from Vietnam, shortly before it tanked by more than 40% in Tuesday’s trading session.

The speculator, who famously made a fortune betting against Enron before its demise, branded the electric vehicle newcomer a “$200 billion meme stock” only hours earlier.

“Retail is buying a stock that options traders think will drop 50%…in the next three weeks,” he tweeted on Musk’s rebranded X site, citing the implied price based on put options set to expire on Sept. 15.

It’s unclear whether Chanos was signaling he himself was taking on a short position in VinFast just as he has with EV rival Tesla, but investors follow the Wall Street veteran for trading advice.

Either way, shares in VinFast plummeted thereafter.

Chanos could not be immediately reached for comment, while representatives from VinFast did not respond to a request by Fortune for comment.

The Vietnamese carmaker’s debut as a publicly traded company marked something of a fairy tale for the startup.

Eschewing a conventional and more rigorous IPO, it listed earlier this month through a special purpose acquisition company (SPAC).

In a matter of days, it had overtaken almost the entire car industry in market value.

If $VFS (Vinfast) is lucky, they will do 40K units this year. Toyota will do 40K units in the next 40 hours.

This is despite the fact that VinFast is just a six-year-old carmaker that sold only 18,700 electric vehicles to date and hails from a country that built half as many cars as Morocco last year.

Worse, what notoriety it had won came from building the worst new EV to be launched in the U.S. market this year.

Customers were so furious it quickly rushed out in June a policy to compensate owners for their troubles.

VinFast losing over $80 billion in market cap on a single Tuesday and still ranking as the world’s third most valuable carmaker, after Tesla and Toyota, highlights the company’s significant overvaluation at the beginning of the week.

High stock price based on VinFast’s thin free float

To truly grasp the astonishing scale of VinFast’s market capitalization, let’s compare it with its automotive peers.

According to Morningstar data cited by Yahoo Finance, Toyota’s market cap is less than its trailing 12-month revenue. This is a reasonable valuation for a mature industry leader. In contrast, GM and Ford face more substantial discounts from investors.

In the realm of growth stocks, electric vehicle manufacturers like Rivian, Nio, and Xpeng are valued at up to six times their respective revenue figures. Tesla, under Elon Musk’s leadership, commands an even higher premium as investors anticipate a greater share of high-margin earnings from its self-driving software, FSD.

In stark contrast, VinFast was trading at a staggering 350 times its annual sales. This raises serious questions about its market valuation.

Yet as much as it may be tempting for short-sellers to place sizable bets on the air eventually being let out of its inflated, it’s not that easy.

For Chanos or anyone else willing to place a bearish wager, simply locating a prime broker able and willing to loan out the shares could prove extremely challenging.

That’s because 99% of the stock is held by one man: chairman and founder Pham Nhat Vuong, who at one point this week was Asia’s second richest tycoon on paper thanks to VinFast.

Moreover, since the bet could quickly go south at the slightest buying pressure, the collateral requirements that come with shorting VinFast could prove prohibitively high.

For anyone willing to risk money on such a volatile stock, it may be easier to take Chanos’s indirect suggestion and simply look for opportunity in the options market.