The power of hedge fund activism should never be underestimated. After months of disputes between Deutsche Börse and two activist investors, Atticus Capital and The Children's Investment Fund Management, on various changes sought by the hedge funds at the German stock market operator, the hedge funds have got what they wanted - partially, anyway.

On Sunday, Deutsche Börse's supervisory board chairman Kurt Viermetz announced his intention to depart by the end of this year, ostensibly because he has reached the age of 70, even though last week he had said that he was in a 'fighting mood' and would not be pushed out early.

A nominating committee is currently considering potential successors for Viermetz and is scheduled to present proposals at the company's annual shareholders meeting in May. Atticus has said it wishes to work together with the board in finding a new chairman.

Atticus Capital and London-based TCI, Deutsche Börse's second-largest shareholder, had earlier asked the company to hold an extraordinary shareholder meeting that would vote on ousting Viermetz.

The funds, which between them hold 19 percent of the voting rights, have also demanded changes in governance and strategy, including the sale of some business units, to boost the share price. It's little more than three years since they engineered the departure of Viermetz's predecessor Rolf Breuer, along with chief executive Werner Seifert, having disagreed with Deutsche Börse's ambition to acquire the London Stock Exchange.

Viermetz is a figure of some controversy, having become the target of criticism recently following the near-collapse of Hypo Real Estate, where he was also chairman. However, his departure will be seen by the funds as a sign that they are capable of obtaining the other changes that they want.