As part of a wider campaign against the sector, the US has accused the largest cryptocurrency trading platform in the nation of operating illegally.
The Securities and Exchange Commission said Coinbase had acted as a broker, exchange and clearing agency for investments that are subject to SEC rules, without properly registering.
The company was able to avoid oversight, including a review of its books, according to the financial regulator.
Coinbase did not comment immediately.
The company had issued a warning in March that the SEC might sue the business.
It called the development disappointing and said it had been working with authorities to try to register, but that there was no clear path for crypto firms to do so.
The complaint against Coinbase comes as a day after the SEC sued Binance, the world's largest crypto trading platform, accusing the firm of mishandling customer funds and taking steps to evade US regulation.
