Baltic International Freight Futures Index (BIFFEX). The dry cargo tramp charter market is usually volatile. Both shipowners and cargo interests may be uncertain about movements in the freight rates. BIFFEX allows shippers, shipowners and charterers to “hedge” against changes in freight rates by buying or selling “future” contracts at an expected price. If, for example, in March, it is expected that freight rates for a particular route will rise by October, the price per contract unit for settlement in October will be higher than the March BIFFEX.