Most large ocean vessels are powered by varying types of marine fuels and oils. Oil prices fluctuate rapidly for a number of reasons - factors as uncontrollable as the weather or geopolitics can have a massive influence on the price of oil. Since fuel is a huge portion of a ship’s operating cost, ocean carriers currently do their best to mitigate these price swings with a bunker adjustment factor (BAF) surcharge. By contrast, an emergency bunker surcharge (EBS) is a last-minute fee that occurs when actual market fuel prices are higher than was originally anticipated by the carriers.