Any firm wishing to increase its emissions or any new firm entering the market is now obliged to acquire new certificates from existing firms at a price. It has the added advantage that the redistribution of environmental rent can be easily fine-tuned by the share of emission quotas that is allocated for free to existing firms (“grandfathering”) or sold off by government at an auction. The amount of rent transferred from the firms to the government is thus determined through the original price of the emission certificates. By the way, the final price in the market is determined by relative scarcity and is independent of the initial transfer price to firms.