According to Burniaux "et al". (2009, p. 37), the cost-saving potential of a well-functioning crediting mechanism appears to be very large. Compared to baseline costs (i.e., costs where emission reductions only take place in Annex I countries), if the cap on offset use was set at 20%, one estimate suggests mitigation costs could be halved. This cost saving, however, should be viewed as an upper bound: it assumes no transaction costs and no uncertainty on the delivery of emission savings. Annex I countries who stand to gain most from crediting include Australia, New Zealand, and Canada. In this economic model, non-Annex I countries enjoy a slight income gain from exploiting low cost emission reductions.