416 In the first round of COE bidding for July, the COE premium for Cat A and Cat E slipped, while the premium for Cat B took a small climb. The small changes in premiums for this month may have been due to the introduction of the increase in VES surcharge for more pollutive vehicles, which may have prompted dealers to take more conservative bids. Cat A COE - Largest mover this bidding session Premiums for Cat A, for cars up to 1,600cc in engine capacity and with an output of no more than 130bhp, saw the biggest change this bidding session, dropping by $2,820 (5.9 per cent) and ended at $45,001 this bidding round.