The supervisory board's nomination committee, which proposes management candidates, is unanimous in replacing Cryan, one person said.
Deutsche Bank has been weighing a few options for a new CEO, even approaching Goldman Sachs worldwide chief Richard Gnodde to ask if he would be interested in taking the helm, CNBC reported last month. "However, following a comprehensive analysis we came to the conclusion that we need a new execution dynamic in the leadership of our bank".
While Cryan's contract runs until 2020, press reports in recent days have suggested a rift over strategy with supervisory board chairman Paul Achleitner, who called Sunday's meeting.
He has been on the management board of the bank since January 2015. Deutsche Bank Ag (Call) has $28.35 billion MC.
He has neutralised the worst legal threats, in part by paying billions in fines and compensation, strengthened Deutsche's capital foundations with an €8-billion ($9.8 billion) share issue past year and floated asset management division DWS on the stock market in March.
Sewing succeeds John Cryan, who'll leave the German bank at the end of April.
Cryan was on the supervisory board for two years before being made co-CEO in 2015 and then the only chief executive the following year.
"He had to battle serious problems that his predecessors swept under the rug for years", Markus Riesselmann, analyst at Independent Research, told AFP. But I doubt a new chief executive could successfully make that transition.
Just prior to the IMF's assessment in June 2016, Deutsche Bank's U.S. division failed a stress test conducted by the Federal Reserve, America's central bank.
Deutsche Bank confirmed late Saturday that its "supervisory board will have a discussion on the banks' CEO position".
Sewing, 47, is now a vice president at Germany's biggest bank and head of its private and commercial banking division. "We trust in the great ability of this bank and its many talents".
Sewing, who joined Deutsche in 1989, was co-deputy CEO along with investment banking co-head Marcus Schenck.