U.S. Securities and Exchange Commission (SEC) chief Gary Gensler said Tuesday that most digital assets are under his agency’s jurisdiction and platforms trading them must be registered with the regulator. However, he also sharply criticized digital asset exchanges, claiming that some platforms are evading the rules and betting against their customers, Bloomberg writes.

Gensler said he is concerned that cryptocurrency exchanges are not erecting proper “partitions” between the different branches of their business, such as securities custody, market making and providing a trading platform. this “blending” of services may not be in the best interest of customers.

“Crypto exchanges have a lot of these problems – platforms often trade against their customers because they are turning the market against them.”

The head of the securities and exchanges regulator also raised the issue of stablecoins, digital assets that are typically pegged to the dollar or other fiat currency. Gensler said the 3 largest steblecoins – Tether, USD Coin and Binance USD – are linked to exchanges.

“I don’t think it’s a coincidence,” he said. – Each of these 3 major assets were founded by trading platforms to facilitate trading on those platforms and potentially avoid anti-money laundering and customer scrutiny.”

The largest stablecoin, Tether, which has a market value of $83 billion, is linked to cryptocurrency exchange Bitfinex. Another major currency, USDC, is issued by a consortium of several companies, including Coinbase Global Inc. The world’s largest cryptocurrency exchange, Binance, is linked to Binance USD, which has a market value of $17 billion.

Concerns about stablecoins intensified last week on Capitol Hill after the Terra USD token, or UST, lost its peg to the dollar over the weekend.

UST is a so-called algorithmic stablecoin, meaning it is not backed by hard (fiat) assets such as cash or cash equivalents. Instead, it relies on trading to maintain its value.