The American Securities and Exchange Commission (SEC) has sent a warning to the popular crypto exchange Coinbase.

CEO Brian Armstrong made the announcement on Twitter Wednesday (March 22), revealing that Coinbase had received a Wells notice from the SEC in regards to the listing of certain unregistered securities across its products and services.

Per the statement, the potential enforcement actions would be connected to Coinbase spot market, Coinbase Earn, Coinbase Prime and Coinbase Wallet.

Wells notices are not official charges, but could potentially lead to them in the future.

The issue of securities has recently been brought to the fore as Paxos, a New York-regulated blockchain infrastructure and financial services platform, was issued a Wells notice. As a result, the company was forced to retire its BUSD stablecoin.

The SEC pressure on Coinbase has already been felt, as the firm has reportedly stopped offering staking rewards for the Algorand token. The Algorand CEO tweeted that he found out Coinbase had halted its rewards service due to “recent regulatory scrutiny”.

However, Coinbase users can still earn staking rewards from the Ethereum, Cosmos, Tezos, Cardano and Solana blockchain.

During an investor call last month (Feb. 21), Armstrong insisted that Coinbase had not violated any securities laws, and that the staking products and USDC stablecoin were not securities.

“Two years ago the SEC reviewed our business in detail and approved Coinbase to go public. Our S1 clearly explained our asset listing process and included 57 references to staking. Coinbase runs a rigorous asset review process and has rejected more than 90% of assets that have applied to be listed on the platform,” tweeted Armstrong.

Coinbase stock has dropped around 12% following the news.

The outcome of the Wells notice may have wide-reaching implications, as it could potentially lead to greater clarity regarding the services that come under U.S. securities laws.