Spot rubber was firm on Monday. RSS 4 improved to ₹108 (₹107) a kg, according to traders and the Rubber Board. The grade firmed up to ₹105 (₹104) as quoted by the dealers. The trend was mixed. March futures increased to ₹110.50 (₹108.92), April to ₹112.09 (₹111.36), May to ₹114.45 (₹113.41) and June to ₹117 (₹114.54) on the National Multi Commodity Exchange. RSS 3 (spot) inched up to ₹ 96.69 (₹96.27) at Bangkok. March futures closed at ¥156.6 (₹92.46) on the Tokyo Commodity Exchange. Spot rubber rates ₹/ kg were: RSS-4: 108 (107); RSS-5: 105.50 (105); Ungraded: 102 (100); ISNR 20: 103 (103) and Latex (60% drc): 78.50 (78.50).