Floyd Mayweather Jr.
A month before taking on Conor McGregor in a highly publicized world championship boxing match in late August 2017, Floyd Mayweather Jr., the lightweight champion, took time from his workouts to notify his 17 million Instagram followers on July 27 that he was supporting the ICO for STOX, a prediction market. The STOX ICO, which ended on August 8, 2017, succeeded in raising $33 million.
Mayweather went on to endorse Centra Tech's ICO in September 2017. It raised $32 million. On April 3, 2018 the U.S. Securities and Exchange Commission (SEC) charged Centra Tech's founders with fraudulent activities in connection with the ICO in addition to violating securities law by offering unregistered securities in the form of tokens.
In late November 2018, the SEC fined Mayweather, along with celebrity music producer DJ Khaled, $300,000 for failing to disclose that he had been paid for his endorsement by Centra Tech. Mayweather's fine included penalties for promoting two additional ICOs.