U.S. regulators are continuing their crackdown on the cryptocurrency sector, with the Securities and Exchange Commission (SEC) targeting NFTs. As a result, OpenSea, the leading marketplace for NFTs, has delisted a number of NFTs that had been flagged as 'securities' by the SEC. This move is a significant development in the ongoing debate over whether or not NFTs should be regulated as securities. The SEC has not yet provided a clear definition of what constitutes an NFT security, but it has indicated that it will take a case-by-case approach. This has created uncertainty in the NFT market, as it is unclear which NFTs may be subject to regulation. OpenSea's decision to delist NFTs flagged by the SEC is a precautionary measure. The company does not want to be seen as facilitating the sale of unregistered securities. However, it is unclear whether this move will be enough to satisfy the SEC. The SEC's investigation into OpenSea is ongoing. It is possible that the agency could take enforcement action against the company if it believes that it has violated securities laws.