Floyd Mayweather Jr. talks with DJ Khaled after the game between the Golden State Warriors and the Los Angeles Clippers on February 20, 2016 at STAPLES Center in Los Angeles, California.

Pro boxer Floyd Mayweather and music producer DJ Khaled pumped up initial coin offerings without telling investors they were getting paid a promotional fee, according to a settlement announced Thursday.

The Securities and Exchange Commission said they are the first cases to charge touting violations regarding ICOs, a relatively new phenomenon that has attracted billions of investor dollars to new cryptocurrencies, often with little to back them up.

Mayweather didn't disclose a $100,000 promotional payment from Centra Tech Inc., while Khaled didn't disclose a $50,000 payment.

The two men settled the charges without admitting or denying the findings. The SEC says its investigation is ongoing.

Mayweather touted Centra's ICO on his Twitter account saying it "starts in a few hours. Get yours before they sell out, I got mine." Khaled called it a "game changer" on his social media accounts, the SEC said.

Mayweather also failed to disclose $200,000 he was paid to promote two other ICOs. He posted on his Instagram account that he would make a large amount of money on another ICO. On Twitter he boasted "You can call me Floyd Crypto Mayweather from now on."