The chairman of the world’s richest basketball league has joined one of the consortia preparing to table final takeover bids for Chelsea Football Club this week.

Sky News has learnt that Larry Tanenbaum, who chairs the National Basketball Association (NBA) and owns a host of North American sports teams, is among the investors backing Steve Pagliuca’s offer for the Stamford Bridge club.

City sources said on Monday that Mr Tanenbaum, a Canadian, was among several wealthy individuals who have agreed to back Mr Pagliuca, the private equity billionaire who has made a fortune from his career at Bain Capital.

Among the group’s other co-investors are said to be John Burbank, founder of the San Francisco hedge fund Passport Capital, and Eduardo Saverin, the Facebook co-founder who was the first investor in the tech behemoth.

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Mr Saverin and Raj Ganguly, two co-founders of investment firm B Capital Group, are both understood to have agreed to back Mr Pagliuca.

Last week, Sky News revealed that Bob Iger, the former Walt Disney chairman, had also been approached about joining the bid.

The Bain Capital chairman is reported to have attended Chelsea’s 6-0 win at Southampton on Saturday, having travelled to the UK for talks with club executives and advisers about his offer.

Mr Pagliuca co-owns the Boston Celtics NBA team, as well as a large stake in the Italian Serie side Atalanta, which he could be obliged to offload if he is successful with his Chelsea bid.

One source close to Mr Pagliuca’s bid said that Mr Tanenbaum’s work on combating antisemitism was likely to be well-received by Roman Ambramovich, the Chelsea owner who has been hit by UK government sanctions following Russia’s invasion of Ukraine.

The four remaining consortia plotting to replace Roman Abramovich as Chelsea’s owner must table final bids on Thursday, two days after the crucial second leg of the London club’s Champions League quarter-final against Real Madrid.

Chelsea trail 3-1 after last week’s first leg.

Raine Group, the merchant bank overseeing the sale process, extended the deadline last week in order to give the four bidders a full and fair opportunity to finalise the details of their proposals.

Raine is considering awaiting clearance from the Premier League for all four consortia before presenting a preferred bidder to the government.

Scrutiny of the four bids by English football’s top flight has already got underway after the remaining consortia submitted details of their key investors to Raine ten days ago.

The Premier League is expected to take the remainder of this month to evaluate those involved in the bids – who include a string of US billionaires and pillars of the British corporate establishment – and its work to approve all four consortia means the process may need to be extended.

One of the bidders, who spoke on condition of anonymity, said they now anticipated that a final recommendation would be made to ministers later than the original target date of the week beginning April 18, with the deal now likely to complete in May.

In addition to Mr Pagliuca’s consortium, the bidders comprise: a group led by Sir Martin Broughton, the former Liverpool and British Airways chairman, which includes the billionaire Crystal Palace shareholders Dave Blitzer and Josh Harris; a bid spearheaded by Todd Boehly, the LA Dodgers part-owner, which includes backing from Clearlake Capital, a US investment firm; and the Chicago Cubs-owning Ricketts family, who have teamed up with Cleveland Cavaliers-owner Dan Gilbert and the hedge fund tycoon Ken Griffin.

The four remaining bidders visited London last week to meet Chelsea board members, executives and Raine as they vie to end Mr Abramovich’s 19-year tenure.

They have all been told they must provide legal undertakings that they will guarantee at least £1bn of investment in the club’s infrastructure, its academy and women’s team if they acquire it in the coming weeks.

The sale process has been complicated by the sanctions against Mr Abramovich and the frenzy of interest in buying last season’s Champiosn League-winners.

Between them, the final bidders either control or own stakes in a legion of North American teams spanning baseball, basketball and ice hockey.

The cluster of American sports billionaires circling Chelsea underlines the extent to which the English Premier League has become a magnet for financiers from across the Atlantic during the last 20 years.

Arsenal, Liverpool and Manchester United have all been acquired by US-based businessmen during that period, and a significant number of other top-flight clubs also have American backing.

Last season’s Champions League-winners have been thrown into disarray by Russia’s war on Ukraine, with Mr Abramovich initially proposing to place the club in the care of its foundation and then formally putting it up for sale.

By the standards of conventional takeover processes, the Chelsea auction has moved at breakneck speed, with executives at other major investment banks suggesting that such a complex sale would typically have taken at least six months.

Prior to being sanctioned, Mr Abramovich had said he intended to write off a £1.5bn loan to the club and hand the net proceeds from the sale to a new charity that he would set up to benefit the victims of the war in Ukraine.

A rapid sale is seen as essential if Chelsea is to avert the uncertainty that would trigger the break-up of one of the top flight’s most valuable playing squads.

The current Fifa Club World Cup-winners have been thrown into disarray by Russia’s war on Ukraine, with Mr Abramovich initially proposing to place the club in the care of its foundation and then formally putting it up for sale.

Mr Abramovich had initially slapped a £3bn price tag on the Stamford Bridge outfit, with the net proceeds being donated to a charitable foundation set up to benefit the victims of the war in Ukraine.

As well as government consent in the form of a special licence, Chelsea’s new owners will also require the approval of the Premier League under its fit and proper ownership test.

A spokeswoman for Mr Pagliuca declined to comment, while none of those understood to be joining his consortium could be reached for comment.