“The Big Short” investor Michael Burry inquired about ways to bet against bitcoin just before the world’s largest cryptocurrency hit a six-month high to breach the $60,000 level.

Burry wrote in a tweet on Wednesday that “Okay, this is something I have never done before. What’s the best way to shorten cryptocurrency?” Do you need to borrow money? Do you have a rebate for borrowers? The position can be squeezed, and the call-in made. When things are so volatile, I think it’s better not to cut, but this is my opinion.

Bitcoin topped $60,000 on Friday, notching its highest level since April 17. Analysts and investors are hopeful that the U.S. regulators will allow the creation of the first Bitcoin futures. exchange-traded fund as soon as next week. This would allow mainstream investors to access the crypto market. It also allows digital assets to be accepted on Wall Street in a greater way.

He was a prominent investor who has voiced his disapproval of cryptocurrency, pointing out their volatility and speculation trading. He once compared bitcoin with the 2007 housing boom, which he bet against but had greatly profited.

MSCI claims that there’s $7.1 trillion market capital tied to crypto stocks. MSCI says that only 79 of the 6,500 members of corporate boards are crypto experts. He said this in an now-deleted Tweet Thursday that it was a feature and not a bug.

Burry has called Shiba Inu meme token “pointless” for the last week.

Burry was among those who called and made a profit during the subprime crisis. In Michael Lewis’s book, “The Big Short”, and in the Oscar-winning movie that followed, Burry is depicted. Scion Asset Management now has Burry managing $340 million.

Scion Asset Management has not yet responded to CNBC’s request.

Burry frequently deletes or makes secret his Twitter account, @michaeljburry. In the last week, Burry reactivated and made public his Twitter account. He tweeted a variety of topics including taxes on the rich and Federal Reserve. Burry apparently deleted his account on Friday.