Quote from UDon'tKnowMe:
A hedge fund manager can make an "override" on his hedge funds trading. It is called commission recapturing. He has an agreement with his Prime Brokerage for 5 cents per share for the hedge fund, but he has the Prime Brokerage charge the fund 10 cents a share and the Prime Brokerage gives the manager the 5 cent difference. However the hedge fund manager has to have this arrangement written in the hedge fund charter for the investors to see.
A fee per trade may not be charged for clients inside the US (or US protectorates) by the advisor of hedge fund ( Not talking about soft dollars here ).
Hedge funds have different structures including master/feeder setups where fee per trade may be charged offshore and rolled into the return on the US side in the return of the fund.
A single hedge fund can be made up of more than one entity and located in more than one jurisdiction, so your mileage may vary.