Floyd Mayweather Jr. (L) greets Oscar De La Hoya at a news conference after Mayweather defeated De La Hoya by split decision in their WBC super welterweight championship fight at the MGM Grand Garden Arena May 5, 2007 in Las Vegas, Nevada.

Floyd Mayweather Jr. (L) greets Oscar De La Hoya at a news conference after Mayweather defeated De La Hoya by split decision in their WBC super welterweight championship fight at the MGM Grand Garden Arena May 5, 2007 in Las Vegas, Nevada.

*Hours after Richard Schaefer’s Monday resignation as chief executive of Golden Boy Promotions following months of infighting with company co-founder/majority shareholder/president Oscar De La Hoya, pound-for-pound king Floyd Mayweather Jr. dumped the company, reports ESPN.

Mayweather, whose fights generate the biggest pay-per-view numbers in the sport, has worked with Golden Boy on a fight-by-fight basis for all of his nine bouts since his 2007 blockbuster against De La Hoya, which set the all-time pay-per-view buy record at nearly 2.5 million subscriptions.

But Mayweather, whose own company, Mayweather Promotions, co-promoted his fights, only worked with Golden Boy because of Schaefer, with whom he has grown close over the years. Mayweather and De La Hoya do not like each other and have never hidden that fact.

So when Mayweather, the junior middleweight and welterweight champion, returns for his next fight on Sept. 13, Golden Boy will no longer be involved, Mayweather Promotions chief executive Leonard Ellerbe told ESPN.com Monday night.

When asked if Mayweather would work with Golden Boy again without Schaefer, Ellerbe said, “Absolutely not.”

That is a big hit worth millions of dollars to De La Hoya’s company.

Richard Schaefer, CEO of Golden Boy Promotions, greets undefeated boxer Floyd Mayweather Jr. of the U.S. at the MGM Grand Hotel and Casino in Las Vegas, Nevada September 10, 2013.

Richard Schaefer, CEO of Golden Boy Promotions, greets undefeated boxer Floyd Mayweather Jr. of the U.S. at the MGM Grand Hotel and Casino in Las Vegas, Nevada September 10, 2013.

“We have a great working relationship with Richard Schaefer and that will never change,” Ellerbe said. “Richard is a good friend and a great businessman and an excellent promoter. Richard will have an impact in anything that he decides to do, a tremendous impact. He built that company from the ground up and did a phenomenal job. We’ve had a very close relationship for a number of years and worked hand-in-hand on a number of great fights.

“Mayweather Promotions will continue to promote Floyd’s fights and Floyd will continue to put on the biggest fights in boxing. I have a tremendous team and staff and we continue to expand year by year and we’re ready to go.”

Golden Boy Promotions had no comment.

Schaefer, the former Swiss banker who co-founded Golden Boy Promotions with close friend De La Hoya in 2002, has served as its only CEO. His exit from the company was not unexpected, given the public issues between Schaefer and De La Hoya over the past few months, but the timing was a bit surprising — a few days before De La Hoya’s induction on Sunday into the International Boxing Hall of Fame.

“After more than 10 years with Golden Boy, it is time to move on to the next chapter of my career,” Schaefer said in a statement earlier Monday. “This decision has required a great deal of personal reflection, but ultimately I concluded that I have no choice but to leave. I have succeeded in banking and I have succeeded in boxing, and I look forward to the next opportunity.

“I am proud to remain a shareholder, so I have a strong interest in the continued success of the company. I am proud of what we have accomplished at Golden Boy, but I now look forward to new challenges.”

Under Schaefer’s guidance, Golden Boy became a powerhouse. Schaefer was the point person in multiple record-breaking promotions, developed close relationships with HBO and later Showtime, closed an output deal for a boxing television series on Fox Sports 1, worked with numerous mainstream sponsors and made a deal to serve as the exclusive promoter of fights at the Barclays Center in Brooklyn, New York, while also maintaining a close relationship with the MGM Grand in Las Vegas.

Schaefer has promoted the two biggest-selling pay-per-view events in boxing history, the 2007 showdown between Mayweather and De La Hoya, which generated a record of nearly 2.5 million buys, and the 2013 fight between Mayweather and Canelo Alvarez, which set the all-time pay-per-view revenue record ($150 million), all-time gate record ($20 million) and sold the second-most units (2.2 million).

There has been wide speculation that Schaefer will eventually join Mayweather Promotions or found his own company and continue to work closely with Mayweather and his adviser, Al Haymon, who has a deep stable of fighters besides Mayweather.

Mayweather’s September opponent has not been determined. Ellerbe said Mayweather is on vacation following his May 3 victory against Marcos Maidana, and when he returns “we’ll figure it out. We don’t know who we’re fighting yet or where we’re fighting.”