Front-month fuel oil settled at CNY 4,434/t, up 0.36% on the day, while bitumen fell 3.50% to CNY 5,013/t. The fuel oil–bitumen spread flipped to a CNY 579/t discount — fuel oil now trades below bitumen, a rare configuration outside the road-building off-season.

Refiners run the numbers on residue yield. Bitumen is produced by blowing or blending the vacuum residue into paving grade; fuel oil is the same residue stream sold directly as boiler and bunker feed. When bitumen demand softens and inventories build, plants route more residue into bunker blending. Since the IMO2020 0.5% sulfur cap, VLSFO has absorbed most of that incremental volume.

The VLSFO–HSFO spread still sits near the scrubber economics threshold. When HSFO gets cheap enough to cover scrubber amortization, owners swing back to HSFO; otherwise they stay on VLSFO. That threshold reprices daily and decides where the residue goes.

For SNSUC, this matters on the transfer desk. Medium-sulfur grades like Oman and Dubai yield more residue, and bunker blending is the monetization channel for that by-product. When residue tilts to VLSFO, fuel oil strengthens against bitumen, and the grade coefficient inside the listed-price formula needs a parallel re-rate.