Questions were raised on Monday about the validity of a vote that could decide the future of Rolf Breuer, chairman of Deutsche Börse, after it emerged that some shareholders had been sent proxy voting forms for the May annual meeting that omit the crucial 10th proposal to sack him.

The shareholders, largely US and UK hedge funds that use Goldman Sachs as the custodian of their shares, are among the most vocal critics of the company's go-for-growth strategy that led it to bid for the London Stock Exchange in December. Goldmans Sachs is investment banking adviser to Deutsche Börse.