In a case brought by the US Securities and Exchange Commission (SEC) it was found that GLG had engaged in manipulative short-selling which enabled it to make profits of $2.2 million between July 2003 and July 2005.
The SEC uncovered 16 transgressions on the part of the fund relating to 14 separate public offerings.
The fine consists of $2.2 million in disgorgement, a further payment of $489,455 to cover prejudgement interest and a penalty fine of $500,000. GLC also agreed to forego the profits accrued as a result of the illegal deals.
Linda Chatman Thomsen of the SEC said: "With this action against GLG, the SEC reaffirms its commitment to protecting investors by upholding the integrity of the public offering process."
News of the fine comes as London-based GLG this week announced that it is to go public in the US through a $3.4 billion combination with Freedom Acquisition Holdings.