Steve Pagliuca and Larry Tanenbaum have committed to 'lifetime ownership' of Chelsea if their joint bid to buy the club is successful.
Pagliuca, co-owner of the Boston Celtics basketball team, and Tanenbaum, who backs the Toronto Maple Leafs, also promised to add to the stream of trophies won under Roman Abramovich.
The other groups in the running are one led by Sir Martin Broughton, the former Liverpool chairman, and another by LA Dodgers part-owner Todd Boehly.
Steve Pagliuca (left) has confirmed NBA chairman Larry Tanenbaum (right) as co-managing partner in the Boston Celtics co-owner's bid to buy Chelsea
Pagliuca, who also owns a stake in Serie A side Atalanta, said: 'Larry and I have known each other for over 20 years and we are committed to this being a lifetime ownership.