When Gartmore lost its star portfolio manager and several of his colleagues two weeks ago, its share price duly plunged - but one of the striking things was how few short-sellers were involved. Until shortly after the announcement, that is.

Gartmore told the market about the resignation of star manager Roger Guy, together with the firm's chief investment officer Dominic Rossi, on November 8. That day, the company's shares dropped 15% as the market digested the unwelcome news.