A search to replace Davis, who has chaired the bank for nearly seven years, will begin and a further announcement regarding timings of his retirement and news of his successor will be made in due course, it said.
The announcement comes five months after Sainsbury's completed a strategic review of its financial services business, which made an underlying operating profit of just 20 million pounds ($26 million) in the six months to August 31.
At its capital markets day in September, Sainsbury's detailed a plan to double the division's underlying profit within five years.
It stopped mortgage sales and said it would not inject any more group capital into the division after 35 million pounds in the first half of its 2019-20 year.
Sainsbury's said last month that Simon Roberts, currently retail and operations director, will succeed group Chief Executive Mike Coupe in June.
Given its performance, Sainsbury's Bank is unpopular with investors and some analysts have speculated that a new group CEO may not retain it in its current shape despite the recent strategy change.
(Reporting by James Davey; editing by Kate Holton and Jason Neely)
