Fuel oil front-month settled at ¥3,929/t, down 1.06% on the day and the lowest in about six weeks. Over the same window crude rose just 0.12% (Brent $95.84/bbl, WTI $91.18/bbl), indicating the move was not cost-pushed but driven by fuel oil's own supply-demand and structural factors. SNSUC Research Institute sees two core variables. First, the structural transition in bunker demand: high-sulphur fuel oil demand is concentrating in scrubber-fitted fleets, whose economics depend on whether the high-low sulphur spread covers scrubber depreciation and upkeep. As that spread narrows, marginal high-sulphur demand weakens and bonded-pool destocking slows. Second, the mismatch between tank capacity and laycans: East China bonded tankage remains tightly utilised, leaving sellers little room to wait as laycans approach and raising the odds of accepting discounts. The contrast with bitumen shows the other side of the divergence: bitumen at ¥5,005/t (-0.87%) fell less than fuel oil, holding the spread at ¥1,076/t. Bitumen draws support from the rigid cadence of road construction, whereas fuel oil faces demand that is substitutable and deferrable — which explains the difference in magnitude within a common downward move. For trading and procurement desks, SNSUC Research Institute offers three points: incorporate 'available tank-days' into the pricing model rather than reading only the futures spread; use digital warehouse receipts to lock title and delivery point for late-September arrivals, reducing forced pricing near expiry; and avoid one-way inventory bets on high-sulphur fuel oil while the sulphur spread compresses, smoothing timing mismatches through cross-grade combined listings instead.