For a while, World Fuel Services boasted the fastest revenue growth in the Fortune 500 over a 10-year period — faster even than Apple. The drop in oil prices since late 2014 led to a 25% decline in revenue in 2015, however, with profits falling by a little less. WFS specializes in the generally unloved, low-margin business of selling fuel to shipping companies and airlines. Although revenue fell again in the first quarter of 2016, profit margins were stable due to strong demand from airlines. WFS also transports crude oil by rail. Last year, it agreed to pay $110 million into a compensation fund for victims of the Lac Megantic disaster in Quebec in 2013, when a train carrying its crude derailed and exploded, killing 47 people and devastating the small town.