Oracle boss Larry Ellison may have had enough of the America's Cup.

Leading US sailing journalist Bob Fisher, writing for Yachts & Yachting, says former Oracle syndicate leader Kiwi Sir Russell Coutts had confirmed Ellison might not be at the next Cup in Auckland in 2021.

In an email to Fisher, Coutts said: "My understanding is that Oracle/Larry will not be entering."

Fisher said it appeared "one Rich American Called Larry Ellison has had enough - the cost of the Cup has proved too high even for him. Which leaves one to wonder just who will show up?

"Maybe there will be several challenges from Europe too - another Italian one is on the cards, and possibly one from France.

"The presence of Bruno Trouble is needed to return some semblance of the grandeur of earlier days and then the Cup is up and running once more. Thank you Kiwis for winning."

Writing on the sailingillustrated.com website former Cup legend Tom Ehman said he didn't think the cost of the Cup was an issue for Ellison.

"As I said earlier this week with my take on the number of teams/countries for AC36, never count Larry out.

"That doesn't mean that I think he will muster Another challenge, but it is too early to tell.

"Everyone, including Larry, is waiting for the protocol to be issued by RNZYS and CNDS, promised later this month."

Billionaire Ellison, founded BMW Oracle Racing in 2003 to compete in his first America's Cup. In 2010 Cup in Valencia, Ellison's yacht USA 17 beat Ernesto Bertarelli's Alinghi to return the Cup to America for the first time since 1995.

In 2013 Oracle beat Team New Zealand in San Francisco but this year Team NZ had revenge in Bermuda to return the Cup to New Zealand.

Four-time America's Cup winner Dennis Conner has predicted Ellison would not attempt to regain the Cup in Auckland.

Conner believes "it's the end of the Coutts era" and that would likely mean no further involvement from Ellison.

"Coutts looked like he'd had enough of the Cup to me," Conner observed of the Kiwi legend's organisational efforts in Bermuda.

"He has made more money from sailing than anyone in the entire world. He will return to his homeland and be well received as one of the greatest America's Cup sailors ever.

"It will take a little while for them to forget that he was the one that took the Cup off them ... but he has a lot of friends there.

"He will help bring the youth of New Zealand along even faster than we might have expected."

Conner predicted such a move would impact on Ellison, who had employed Coutts as his right-hand man in yachting.

"Who will Larry trust to run his team if Russell Coutts has gone? I think we will see Larry retiring and moving on to other things that Larry does."

Conner said the strong word he was hearing was that Richard DeVos, a co-founder of Amway and owner of the Orlando Magic NBA team, was set to challenge.