The FT reported that in June, a junior member of the bank's foreign exchange sales team accidentally sent $6bn to one of its customers, having processed a trade using a gross figure, rather than a net figure. Not surprisingly, the worker's manager was on holiday at the time.
Although the bank recovered its cash the following day, it was forced to report the incident to the Financial Conduct Authority, the European Central Bank and the US Federal Reserve.
The news comes days after Deutsche announced plans for a "fundamental reorganisation", with new boss John Cryan attempting to overhaul its management structure and investment bank following large penalties from various scandals and dissatisfaction from shareholders.
Although a number of senior executives and non-executives will depart, including long-term board member Stefan Krause and co-head of investment banking and trading unit Colin Fan; the most major change will be the dividing-up of the bank's corporate banking and securities business into two units. Those will comprise a corporate and investment banking unit, and a global markets business.
The news, announced on Sunday, caused shares to rise from just shy of $25 to almost $27 at the end of trading yesterday.
Deutsche Bank declined to comment.