The number of contenders for a controlling stake in Aozora Bank was effectively trimmed Friday to two -- U.S. private equity fund Cerberus K.K. and the Sumitomo Mitsui Financial Group.

The bank's executives took the action after examining four bidders' business plans for Aozora during an extraordinary board meeting.

Cerberus and SMFG are competing for a 49 percent stake in Aozora that Softbank Corp. is trying to sell in order to fund its fledging broadband service.