Deutsche Bank's Frankfurt offices have been raided by German prosecutors in connection with client securities transactions.
The raid comes just days after the banks two co-chief executives offered their resignation after a string of regulatory problems had undermined their leadership at the bank.
Deutsche Bank declined to give details about the purpose of the raid, but a source told Reuters that it was related to a tax rebate strategy used by some clients known as "dividend stripping".
The tactic involves buying a stock just before it goes ex-dividend, then selling it, taking advantage of a now-closed legal loophole which allowed both the buyer and the seller to reclaim capital gains tax, Reuters said.
Deutsche Bank has appointed veteran British banker John Cryan as its new chief executive, replacing Anshu Jain and Juergen Fitschen.
Cryan will succeed Jain when he steps down at the end of the month. Fitschen will stay on until 2016 and Cryan will become the sole boss of the bank following his departure.
