The NZ ETS is highly linked to international carbon markets as it allows the importing of most of the Kyoto Protocol emission units. However, as of June 2015, the scheme will effectively transition into a domestic scheme, with restricted access to international Kyoto units (CERs, ERUs and RMUs). The NZ ETS has a domestic unit; the 'New Zealand Unit' (NZU), which is issued by free allocation to emitters, with no auctions intended in the short term. Free allocation of NZUs varies between sectors. The commercial fishery sector (who are not participants) have a free allocation of units on a historic basis. Owners of pre-1990 forests have received a fixed free allocation of units. Free allocation to emissions-intensive industry, is provided on an output-intensity basis. For this sector, there is no set limit on the number of units that may be allocated. The number of units allocated to eligible emitters is based on the average emissions per unit of output within a defined 'activity'. Bertram and Terry (2010, p 16) state that as the NZ ETS does not 'cap' emissions, the NZ ETS is not a cap and trade scheme as understood in the economics literature.