UPDATE 1-Man Group surprises with new finance director

* Jonathan Sorrell is new FD in unexpected move

* Kevin Hayes leaves company with immediate effect

* Flagship fund AHL has been performing poorly

LONDON, June 18 (Reuters) - Man Group has named a new finance director on the day Europe's largest listed hedge fund manager is due to exit Britain's blue-chip trading index after an extended period of poor performance at its flagship fund AHL.

Jonathan Sorrell, currently Man's Head of Strategy and Corporate Finance, in an unexpected move is taking the role from Kevin Hayes, who is leaving the company with immediate effect to pursue other professional and personal interests, Man said in a statement.

Chief Executive Peter Clarke said Sorrell had played an instrumental role in Man's recent acquisition of FRM, a move welcomed by analysts as a way of reducing the company's dependence on computer-driven AHL, which has struggled to cope with recent market turmoil.

The $21 billion 'black box' fund, named after 1980s founders Michael Adam, David Harding and Martin Lueck, is down an estimated 1.4 percent so far this year, after losing 6.4 percent last year.

"In his new position, Jonathan's experience in financial markets, especially his deep working knowledge of the hedge fund industry, will be extremely valuable as we continue to develop and evolve in challenging world markets," Clarke said.

"He has a strong background in strategy and execution and will bring clear focus on costs and financial efficiency."

Sorrell joined Man less than a year ago as Head of Strategy and Corporate Finance after a decade of service in the Investment Management, Securities and Investment Banking Divisions at Goldman Sachs, where he latterly led investments in a broad range of hedge fund firms.