For football's new generation of ultra-rich investors — risk-tolerant billionaires, American hedge funds and wealthy Gulf states — the appeal of the new model of team ownership was its simple strategy.
The wealthy new owners believed that by incorporating not one team but multiple teams and hundreds of players into a vast multi-club network, they could leverage efficiencies, best practices and volume to achieve on-field success.
Energy drink maker Red Bull pioneered the model. Manchester City, the English champions backed by wealthy United Arab Emirates investors, has supersized it through City Football Group. Jim Ratcliffe, chairman of chemical giant Ineos, brought it to Manchester United after buying a majority stake in the club last year.
But one of the biggest attractions of multi-club ownership is now facing a major challenge as European football's governing body seeks to change the rules.
European soccer leaders say the problem is that matches between teams controlled by the same ownership group could undermine the fairness of continental competition and open the door to private deals in the $7 billion-a-year market for soccer players.
European football's chief executive, Aleksander Ceferin, has sought to bridge the gap, suggesting in a podcast interview last year that a multi-club system was dangerous for football while luring investors by saying a new Champions League format might relax such ownership rules.
The current dispute, one of the most talked about events of the recently concluded European football season, involves Spanish club Girona and their talented 20-year-old Brazilian forward, Savio.
Girona finished third in Spain's top flight last season – their fourth year in the country's top division – a result that qualified the team for next season's Champions League, Europe's richest club competition, and has put Girona's talent on the radar of some of the continent's biggest clubs.
Manchester City were favoured to sign Savio. Their owner is the brother of the emir of the UAE and also Girona's largest single shareholder, so there seems to be no doubt where Girona's breakout star will go next. The news was all but confirmed when Fabrizio Romano, a social media influencer who specialises in player trade news, declared the deal a done deal in February.
“Manchester City have signed all the papers to sign Savio from the 1st July,” Savio declared to X's 20 million-plus followers in a message that began with a red siren emoji.
However, Girona did not actually own Savio's rights as the player was on loan from French club Troyes, which is part of the City Football Group.
These types of multi-club ownership have become commonplace in global football over the past five years, with more than 180 teams worldwide now participating in multi-club networks, employing more than 6,500 players, according to data from the Union of European Football Associations (UEFA).
This has presented a problem for UEFA, which has previously focused primarily on how team ownership affects competitions, ruling that one owner cannot control multiple teams in the same competition.
But with growing multi-club control, critics grumbling about the fairness of Europe's biggest tournament and concerns that historic, proud clubs would be reduced to mere feeder teams, UEFA introduced temporary rule changes.
Under the revised rules, if the owners reduce their stake in the clubs to below 30 percent, both teams will be allowed to compete in UEFA tournaments, provided they ensure they are run separately and have no shared officials or other direct commercial or sporting ties.
These rules are: This would allow owners time to sell shares in rival clubs that are below the threshold required by UEFA.
Such a compromise was reached last season between the American owners of AC Milan and French club Toulouse, and in November it was reported that RedBird, which manages both teams, was seeking a buyer for Toulouse.
But revised rules on player transfers will be stricter: clubs with multi-club ownership agreements will be banned from loaning or trading players between teams competing in the same competition (a rule that also applied to AC Milan and several other teams last season).
This means that if both City and Girona qualify for the Champions League next season, Savio's move to Premier League champions Manchester City will be postponed – he could still feature, but it would be unlikely that he would do so in a sky blue City shirt.
(The same issue could also affect the transfer of defender Jean-Clair Todibo from Nice, the French club owned by Mr Ratcliffe, to Manchester United. Both United and Nice have qualified for next season's Europa League, UEFA's other competition. “We understand UEFA's regulations,” Mr Ratcliffe's company, INEOS, said in a statement, adding: “Our goal is for both clubs to play in the Europa League. We are now awaiting UEFA's decision.”)
City Football Group said it had been in contact with UEFA officials for months to ensure that both Manchester City and Girona could play in the Champions League, and all clubs had a deadline last Monday to submit their final paperwork.
UEFA declined to comment on the proposed deal, but a final decision on teams' eligibility is expected to be announced next month.