The Maya oil discount has been broadening for the past few weeks because of the continued sharp widening of the WTS (West Texas Sour) differential as the bottlenecks in the Midland Basin have not abated.

The differential has widened by more than $12 per barrel (bbl) this year and accounts for 40% of Maya pricing, which is formulaically determined by Pemex, the Mexican state-owned oil company, said Paul Cheng, an equity analyst for Barclays.