Don’t count Bill Gates as a fan of cryptocurrency or NFTs, with the tech icon calling them “100% based on greater fool theory.”

The crypto market is in the midst of a massive downturn, one that has seen billions wiped from the ledgers. While many are looking at this as a buying opportunity, Gates is not impressed with crypto or NFTs, according to CNBC. Gates referred to both, but especially NFTs, as being “based on fool theory,” meaning the value on an already overvalued asset only goes up when enough investors want them.

“I’m used to asset classes … like a farm where they have output, or like a company where they make products,” Gates said, regarding NFTs.

On the topic of crypto, Gates said: “I’m not involved in that. I’m not long or short any of those things.”

Interestingly, Gates comments come at a time when NFTs are increasingly gaining mainstream support. Salesforce recently unveiled its own NFT platform, NFT Cloud, as a way for companies to mint and sell NFTs. The company emphasized their intention of making their platform a trusted marketplace, one that would be environmentally friendly, addressing two of the biggest critiques of the burgeoning tech.

Only time will tell if the crypto market will recover, and if NFTs will continue to gain steam. In the meantime, it doesn’t sound like Gates will be investing in either.