Boxer Floyd Mayweather and music producer DJ Khaled are paying a total 750,000 US dollars (£586,000) to settle charges they failed to disclose payments they received for promoting investments in digital-currency securities, regulators have said.

The Securities and Exchange Commission (SEC) said the cases are its first involving charges for violating rules on touting investments in so-called initial coin offerings, or ICOs.

An ICO allows a startup to use the technology behind bitcoin, known as blockchain, to fund projects.

The SEC said Mayweather failed to disclose promotional payments from three issuers of ICOs, including 100,000 dollars from Centra Tech Inc.

Khaled allegedly did not disclose a 50,000 dollar payment from Centra, which he touted on his social media accounts as a “game changer”.

Mayweather and Khaled neither admitted nor denied the allegations in agreeing to the settlements.

Mayweather’s promotions were said to include a message to his Twitter followers alerting them that Centra’s ICO “starts in a few hours. Get yours before they sell out, I got mine.” The boxer has almost eight million followers on Twitter.

DJ KhaledDJ Khaled has also settled charges he failed to disclose payments received for promoting investments in digital-currency securities (AP)

“You can call me Floyd Crypto Mayweather from now on,” he said in another tweet, according to the SEC.

The regulators allege that Mayweather neglected to disclose that he was paid 200,000 dollars to promote the other two ICOs, in addition to Centra’s.

With no disclosure of the payments, “Mayweather and Khaled’s ICO promotions may have appeared to be unbiased, rather than paid endorsements,” Stephanie Avakian, co-director of the SEC’s enforcement division, said in a statement.

Under the settlements, Mayweather agreed to pay a 300,000 dollar penalty, give up another 300,000 dollars and pay 14,775 dollars in interest.

Khaled is paying a 100,000 dollar penalty, giving up 50,000 dollars and paying 2,725 dollars in interest.

They also agreed not to promote any securities, digital or otherwise, for three years in Mayweather’s case and two years for Khaled.

Mayweather and Khaled were among a number of celebrities paid by ICOs to endorse them.

ICOs have soared in popularity in recent years, raising billions for startups.

With an ICO, a startup will issue currency, sometimes called a token, which can be used to buy services from the company. For example, a startup offering online storage could issue tokens that can be used to buy storage.

The SEC urges investors to be skeptical of investment advice on social media platforms and to not make decisions based on celebrity endorsements.

How the tokens are marketed is a central question for the SEC. When a company’s marketing implies that the tokens can appreciate in value, that can raise a red flag.

Kelly Swanson, a publicist for Mayweather, said he likely would not comment on the settlement.

Representatives for Khaled did not immediately respond to messages seeking comment.