Butadiene (BR) settled at 16,170 RMB/t, +1.51%, outrunning natural rubber (NR) at 19,700, +0.43%. The NR-BR spread narrowed to 3,530 RMB/t from above 3,800. Tight butadiene supply is the main driver behind BR's strength, and tire makers are rebalancing blend ratios against spread hedging.

NR and BR both fall, yet the spread widens; channel inventory stalls price transmission.

NR front-month settled at ¥20,980/t, up 3.76% on the day to a multi-month high; butadiene rubber followed with a 2.6% gain to ¥16,795. Tire makers that left fixed-price coverage short took larger mark-to-market losses, and bonded warehouse receipts became the tool of choice to lock stock.