GFI group Inc. said on Friday that the now-former head of the firm's North American Product brokerage resigned and the company acknowledges more desertions are pending GFI said.

GFI believes that Mr. Fewer's departure is part of a concerted effort by one of its competitors to raid GFI's highly successful North American credit product brokerage business by hiring members of GFI's New York credit brokerage staff, the company said in a statement.

In addition, GFI commented that over twenty of its North American credit brokers could be in the process to change to the competitor side, however the company has the intention to respond aggressively to the situation.

Shares of GFI Group Inc. fell as much as 23.77 percent to $11.93 a share on closing trade Friday. The company estimated a first quarter profit of 28 cents a share or more, according to the source.