Deutsche Bank mistakenly paid $6bn to a US hedge fund client after a junior trader processed the wrong figure, the Financial Times has reported.
The bank recovered the amount from the client the next day and the incident was reported to the US Federal Reserve, the European Central Bank and the UK Financial Conduct Authority, the newspaper reported.
The trade was processed by a junior member of the bank's London-based forex sales team in June while his boss was on a holiday, FT reported, citing two people familiar with the matter.
The error occurred when the trader processed a gross figure instead of a net value that resulted in the trade having "too many zeroes", the newspaper said.
Such mistakes are common but of this size are rare, the FT reported two people familiar with the matter as saying.
Deutsche Bank was not immediately available for comment.
The error adds to the sense of an institution that spun out of control under its previous leadership.
German and US regulators have chastised the bank for inadequate housekeeping.
Deutsche spent an additional €1.3bn in 2014 on meeting regulatory standards compared to a year earlier.
Germany's biggest bank is restructuring its business, splitting its investment bank in two and parting ways with some of its top bankers as the new chief executive, John Cryan, sets out its most "fundamental" overhaul.
The bank reported a record pre-tax loss of €6bn in the third quarter and warned of a possible dividend cut earlier this month.
