The Securities and Exchange Commission (SEC) on Thursday slapped $30 million in penalties and fees on cryptocurrency exchange Kraken, part of the agency’s ongoing pushback against unregistered crypto products.

Since 2019, Kraken, the business alias of Payward Ventures and Payward Trading, offered clients the chance to lock up, or “stake,” their cryptocurrency tokens. The clients could then validate other blockchain transactions with their staked crypto assets and earn up to 21 percent interest. While investors who affirmed blockchain transactions received rewards, those who did not risked having the value of their staked crypto assets “slashed” or even destroyed, according to the SEC’s complaint, filed in U.S. District Court for the Northern District of California.

The SEC said the arrangement represented an investment contract and should have been registered with the agency. It said investors were depending on Kraken’s platform and strategies to turn a profit on the arrangement and essentially lost control of their tokens, taking on the “risks associated with those platforms, with very little protection.”