Gartmore Group, the UK fund manager whose initial public offering today raised £340m (€378m), has given its investors an unusual warning - it can no longer count on being able to pay the bonuses necessary to keep its star managers.

Though Gartmore's warning was included in the standard-form list of risks that the business is exposed to, a specific clause on bonuses is not normal practice, according to a source familiar with the drawing-up of the prospectus document.