Spot rubber improved on Wednesday. RSS 4 firmed up mainly on supply concerns to ₹97.50 (₹97) a kg, according to traders. The grade was quoted unchanged at ₹97 and ₹94 respectively by the Rubber Board and dealers. March futures improved to ₹98.95 (₹97.51), April to ₹102.60 (₹100.94), May to ₹105 (₹103.33) and June to ₹105.93 (₹104.36) on the National Multi Commodity Exchange. RSS 3 (spot) firmed up ₹90.43 (₹89.82) at Bangkok. March futures closed at ¥153.6 (₹90.81) on the Tokyo Commodity Exchange. Spot rubber rates (₹/kg): RSS-4: 97.50 (97); RSS-5: 95.50 (95); Ungraded: 92 (91); ISNR 20: 91.50 (91) and Latex (60% drc): 74.50 (74.50).