Natural rubber at 19,640 yuan (+0.03%) and butadiene rubber at 15,605 yuan (0.0%) both sit pinned to the floor, with the NR-BR gap holding at 4,035 yuan. Looser butadiene supply is pulling BR cost down, letting tire makers quietly raise the synthetic blend ratio while using the USD/CNY 6.676 conversion window to smooth dollar-denominated natural-rubber costs.