Shipping companies now know that within three years all vessels involved in international trade will be required to use fuel with a sulfur content of 0.5% or less—an aggressive standard, considering that in most of the world today, ships are currently allowed to use heavy fuel oil (HFO) bunker fuel with up to 3.5% sulfur. This is a big deal. Ships now consume about half of the world’s residual-based heavy fuel oil, but starting in January 2020 they can’t—at least in HFO’s current form. How will the global fuels market react to a change that would theoretically eliminate roughly half the demand for residual fuels? How will ship owners comply with the rule? What are their options? Today we discuss the much-lower cap on sulfur in bunker fuels approved by the International Marine Organization, and what it means for shippers and refineries.