For 20 years, ever since Euromoney began its annual foreign exchange surveys in 1979, Citigroup came top. Now Deutsche Bank has dislodged it by a convincing margin. While critics accuse Deutsche of buying its way into the business with huge salaries, the real reason is its global markets model that brings together commercial and investment banking. Over the past year interbank forex flows fell while M&A and institutional business grew, favouring investment banks and those that combine both functions. Philip Moore reports; research by Andrew Newby.