Last year, the impending implementation of International Maritime Organization’s rule mandating the use of lower-sulfur marine fuels starting January 1, 2020, widened the price spread between rule-compliant 0.5%-sulfur bunker and the 3.5%-sulfur marine fuel that has been a shipping industry mainstay. Traders’ thinking was that demand for high-sulfur bunker would evaporate in the run-up to IMO 2020, as the new rule is known. But since early January, the spread between low- and high-sulfur fuel at the Gulf Coast has narrowed from nearly $11/bbl to less than $2/bbl. The culprit is a shortage of heavy-sour crude caused by a number of factors. Today, we begin a two-part series on low-sulfur vs. high-sulfur fuel and crude values as IMO 2020 approaches.