New Star Asset Management has cut a top executive in its bid to slash £20 million (US$29.9 million) in costs.

Stephen Whitaker, co-chief investment officer and manager of the firm’s £343 million (US$512.1 million) UK Growth Fund, has left the firm. According to New Star, Chairman John Duffield “asked Stephen to leave after a prolonged period of underperformance.” Whitaker had worked at New Star for more than six years.

Whitaker is the first fund manager to leave the firm in a reshuffle designed to save £20 million in costs annually, but dozens are expected to lose their jobs at the London firm in the next few weeks. All told, some 15% of the firm’s employees are expected to be cut.

Whitaker’s fund, which lost 16.5% in September, is to be merged with another of its funds. All told, six New Star funds have been merged into three, with several managers, including Tim Steer, promoted.

New Star has already begun looking for a new co-CIO to work alongside Whitaker and Gregor Logan.