Gartmore dropped as much as 9.2 percent and traded down 5.5 percent at 104 pence as of 9:26 a.m. in London, giving the company a market value of 320 million pounds ($490 million).
Rambourg said he is leaving the firm after 14 years to focus on the investigation by the Financial Services Authority into his conduct following an earlier suspension by the money manager, the London-based company said in a statement yesterday.
“Guillaume was a key player with a good track record, so it wouldn’t be wrong to say that his exit will have some impact,” said David Buik, markets analyst at BGC Partners in London. The market will want to see what contingency plans the company has in mind after Rambourg’s exit, Buik said.
Gartmore shares fell 31 percent on March 30 after the firm said it was investigating Rambourg for breaking internal rules by directing orders to buy or sell stock from favored brokers. Rambourg, who previously helped run the firm’s two biggest hedge funds with Roger Guy, returned to work at Gartmore as an investment analyst in April.
Gartmore first sold shares at 220 pence in December 2009.