On October 6, fuel oil settled at ¥4,434/t, up 0.36%, while bitumen dropped to ¥5,013/t, down 3.50% on the day. The fuel-to-bitumen spread reopened to ¥579/t (bitumen premium), forcing refiners to re-rank their residue yield slate.

Bitumen fell on weak road-construction demand and slow social-stock draw; fuel oil is propped by steady very-low-sulfur fuel oil (VLSFO) bunker demand from scrubber-fitted vessels. Shifting residue to VLSFO pays better than pushing it into bitumen, so the same barrel of residue is now worth more on the marine-fuel line.

For traders in ESPO or Urals cargoes, this spread is not cosmetic: residue disposition drives the refinery discount in delivered cost. The more residue leans to VLSFO, the less supply elasticity on the bitumen side and the firmer the spot discount. Expect fuel oil to stay relatively firm against bitumen until winter stocking starts or bunker restocking eases.