Crystal Palace’s chairman, Steve Parish, and the club’s biggest investor, John Textor, have fallen out despite the American increasing his stake to more than 40% when he completed his takeover of Lyon last month.

The Guardian understands the pair have barely been on speaking terms in the weeks since Textor added the French club to a portfolio that includes stakes in Palace, the Brazilian side Botafogo and RWD Molenbeek in Belgium.

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Textor is believed to have been left extremely disappointed by significant delays he faced in completing the £800m deal for Lyon after Parish initially refused to allow him to switch his shares in Palace to his holding company Eagle Football Holdings. That was required for the Premier League to approve his takeover, with regulations stipulating that if an owner wants to acquire a significant interest in a foreign club they are obliged to notify the league through a “dual interest notice”.

“As of today, we have not yet obtained the consent of Crystal Palace and its shareholders (other than myself), which is a prerequisite for Premier League approval,” Textor said in a statement on 5 December. “We have made significant progress over the past few days and believe we are on a good path to find an agreement in the next few days.”

It is understood that in exchange for the approval, which was granted more than a week later to allow his purchase of Lyon to go through on 22 December, Textor agreed to pay £20m for an unknown number of new shares that takes his holding in Palace beyond 40%.

“We have a lot to do in our club and welcome new people involved with Eagle Football, welcome the investment, and are really pleased with John,” said Parish to Palace’s website at the time. “But it doesn’t really change anything for us. We’re very focused on Palace: it doesn’t change the governance, doesn’t change the control structure, doesn’t change what I do day to day.”

Parish, who also sold an 18% stake in Palace to a consortium led by the US investors David Blitzer and Josh Harris in 2015 before Textor was announced as “as an investor, director and fourth partner” in August 2021, is believed to own just over 10% of the club he helped to save from administration in 2010. The 57-year-old businessman continues to run the club and is the executive chairman of the managing company which is in charge of the club, with the four partners having equal voting rights on the board. Palace declined to comment.

It is understood that Textor – who attended Wednesday’s draw against Manchester United with Michele Kang, owner of the Washington Spirit women’s side – has grown frustrated at Parish’s hands-on approach and would like the club to show more ambition in the transfer market after a promising first 18 months under Patrick Vieira that included an FA Cup semi-final in his first season. Parish is believed to have met Textor on Thursday for the first time in weeks to discuss potential transfer targets.

Textor – a digital media entrepreneur whose previous company specialised in making visual effects for Hollywood films – is believed to have plans to float Eagle Football Holdings on the US stock market this year, with the Financial Times reporting on Wednesday that agreement was in place for a potential future merger with the investors Iconic Sports Management that values the company at $1.2bn (£970m). It is understood that although Textor’s shares in Palace are now part of Eagle Football Holdings, the managing company overseen by Parish remains in full control of the club.

A banner in the Holmesdale Road end during Palace’s game against United was critical of Textor. “Multi-club ownership. Stock market gambling. Textor we don’t trust you,” it read.