FTX founder Sam Bankman-Fried has been sued in U.S. court by investors alleging the company's yield-bearing crypto accounts violated Florida law, according to court papers.

The proposed class action filed late Tuesday night in Miami alleges that FTX yield-bearing accounts were unregistered securities that were unlawfully sold in the U.S.

When the crypto exchange faltered on liquidity concerns, U.S. investors sustained $11 billion in damages, the lawsuit alleges.

The lawsuit seeks damages from Bankman-Fried and a number of celebrities who allegedly helped promote FTX, including National Football League quarterback Tom Brady and tennis star Naomi Osaka.

(Reporting by Abinaya Vijayaraghavan in Bengaluru and Jody Godoy in New York; Editing by Chizu Nomiyama)