OpenSea, which calls itself the "world's largest" nonfungible token (NFT) marketplace, received a Wells notice from the SEC, the company said in a blog post Wednesday, indicating the regulator may soon bring a lawsuit against the company.

In a tweet, CEO Devin Finzer says the SEC is claiming NFTs on OpenSea's platform are unregistered securities. He later notes that cryptocurrency companies have "long been in the crosshairs of the SEC," which has brought similar claims against Binance and Coinbase. The crypto industry has long argued that tokens are not traditional securities, despite the fact they are tradable assets that can store value.

"The SEC does not comment on the existence or nonexistence of a possible investigation," said an SEC spokesperson in an email to TechCrunch.

OpenSea's CEO says he plans to "fight for our industry," and is pledging $5 million to cover legal fees for NFT creators and developers that also received a Wells notice.