Both rubber lines moved lower today: natural rubber front-month at ¥19,890/t, off 0.08%, and butadiene rubber at ¥15,935/t, down 0.25%. The NR-BR spread sits at ¥3,955, on the wide side of its recent range. Softness on both is not all bad — it reopens room for tyre-blend substitution.

In truck tyre compounds NR and BR substitute for each other with real elasticity: when NR trades more than about ¥3,800/t above BR, compounders shift weight toward BR, and vice versa. The spread is now pinned at ¥3,955, right at the upper edge of that substitution threshold, giving BR a reason to take a larger blend share. For SNSUC, which holds bonded NR receipts, that means downstream lock-up demand tracks the blend window.

On the funding side, rubber turnover has always been squeezed by receipt collateral. Once SNSUC's bonded digital warehouse receipts are on-chain, the SHA-256 title fingerprint compresses confirmation from visiting the warehouse to verifying a hash, and bank pledge lending moves from T+3 to T+0. A 50kt NR receipt worth about ¥995m frees up the same day to take the next vessel, lifting the turnover multiple from 9x to above 10x.

The risk is equally clear: if the spread oscillates around ¥3,955, the blend-switch cadence gets disrupted and downstream will not shift all at once. On receipts, watch bonded-zone inventory and in-transit vessel schedules so that pledge lending never runs ahead of title.