Spot rubber continued to remain bullish on Wednesday. RSS 4 improved to Rs.137.50 (136.50) and Rs.137.00 (136.00) per kg respectively according to traders and the Rubber Board.  It firmed up to Rs.133.00 (132.00) per kg according to Dealers. Certain tyre companies were buyers on the grade but they preferred to keep a low profile, possibly to avoid a sharp rise in prices. In futures, the January contracts improved to Rs. 139.86 (139.00), February to Rs. 142.41 (140.12), March to Rs.144.98 (142.73) and April to Rs.148.61 (144.47) per kg on the Indian Commodity Exchange (ICEX). The near month January futures was up by 0.62% with a volume of 27 lots and total trade value of 37.71 lakh. RSS 3 (spot) slid to Rs.117.46 (117.67) per kg at Bangkok. The January futures weakened to Rs.111.87 (114.12), February to Rs.115.49 (118.30) and March to Rs.124.52 (125.07) per kg on the Tokyo Commodity Exchange (TOCOM).