Nippon Credit Bank President Tadayo Honma committed suicide Wednesday night and did not die from a heart attack, as was originally reported.
Honma hanged himself Wednesday in an Osaka hotel room, where he was staying during a business trip, police said.
Several suicide notes addressed to his family and others were found in the room.
Initial reports said Honma, 60, died of a heart attack. It is not known how the false information was released.
The contents of the suicide notes were not disclosed, but sources speculate that differences in business philosophy and management policies among NCB's buyers were a source of stress for Honma.
They also said that Honma may have been feeling the pressure of having to resurrect NCB and ensure the smooth entry of a nonfinancial entity into the domestic financial market.
Yoshinobu Kotera, NCB's senior managing director, will act as president for the time being. No decision has been made on how the next president will be chosen, NCB officials said.
Honma had frequently complained of fatigue recently, but had not seemed depressed, NCB officials said.
He traveled to Osaka on business Tuesday afternoon and visited NCB branches and major clients.
A member of staff accompanying Honma went to his room Wednesday morning and found him hanging by a curtain rope, investigators said.
Honma was taken to a hospital but was pronounced dead on arrival.