The Friedkin Group has reached an agreement to buy Farhad Moshiri's majority 94% stake in Everton.
The deal is subject to regulatory approval from the Premier League, the Football Association and the Financial Conduct Authority.
It is believed to be worth in excess of £400m, leaving Moshiri with little return on his substantial investment.
The US-based group is led by chairman Dan Friedkin, who also owns Roma. He has a net worth of £5.7bn according to Forbes., external
Everton would become the 10th club in the Premier League under majority American ownership.
The deal would bring to a conclusion the turbulent Moshiri reign. The British-Iranian businessman has invested more than £750m in the club since 2016, but many supporters have been deeply unhappy about his ownership.
Everton, who have not played outside the top flight during the Premier League era, have been in the bottom half for the last three seasons, finishing 16th, 17th and 15th.
Last season they were deducted points twice - amounting to a total of eight after an appeals process - for breaching Premier League financial rules on the level of losses clubs are allowed to make.
A spokesperson for the Friedkin Group said in a statement on Monday: "We are pleased to have reached an agreement to become custodians of this iconic football club. We are focused on securing the necessary approvals to complete the transaction.
"We look forward to providing stability to the club and sharing our vision for its future, including the completion of the new Everton Stadium at Bramley-Moore Dock."
The Friedkin Group had agreed a deal in principle to purchase current owner Moshiri's 94% stake in June.
But talks were called off a month later after the two parties failed to finalise an agreement. That followed Miami-based 777 Partners being unable to a complete a deal earlier this year.
In a complex saga surrounding the takeover, American businessman and Crystal Palace co-owner John Textor then jumped in for talks but could not complete a deal because Premier League rules prohibit individuals from owning more than one team.
The Friedkin Group is already a lender to the club after injecting £200m, though this could be converted to equity as part of the deal.
The agreement between the group and Moshiri's Blue Heaven Holdings has been signed and finances are in place for completion.
The group's due diligence on the club was done when they were given exclusivity in June and concerns around a separate £200m loan provided by 777 Partners have been resolved.
In June, it was said that Friedkin wanted Roma and Everton to sit at the top of "a multi-club model".
Everton's appeal to the Friedkin Group was said to be based on the club's history, fanbase and the new stadium being built on Bramley-Moore Dock.
The group remains fully committed to Roma and has no concerns regarding the two clubs co-existing under Uefa rules.
The Friedkin Group assumed control of Italian side Roma in 2020 and guided the club to Europa Conference League success under Jose Mourinho in 2022.
Last week, the club sacked boss Daniele de Rossi just four games into the new season and on Sunday supporters displayed their anger at the decision to dismiss the club legend, while chief executive Lina Souloukou stepped down from her role.
In a statement to Roma fans on Monday, Friedkin said: "The potential addition of Everton to our portfolio does not alter our focus on AS Roma. If anything, the multi-club symbiosis will only help Roma.
"Each club in our portfolio operates independently and AS Roma remains at the heart of our football ambitions."
British-Iranian businessman Moshiri first bought a 49.9% stake in Everton in 2016, before increasing his holding to 94.1% in 2022.
But he and the club were hit hard by Russia’s invasion of Ukraine with Everton suspending commercial sponsorships with USM Holdings, which was part-owned by Alisher Usmanov.
The billionaire had his assets frozen by the European Union and Moshiri resigned from his role as chairman in the company when Usmanov was sanctioned.
Moshiri had been looking for a buyer and agreed to sell his stake to 777 Partners in September 2023, but eight months later they missed a deadline to complete the takeover.
Sean Dyche's side are joint-bottom of the Premier League and yet to win this season, collecting just one point from their opening five games.
During Moshiri's tenure, Everton have had eight permanent managers and two caretakers in charge of the team.