New Zealand's quota management system (QMS) was introduced in 1986 to enhance the sustainability of New Zealand's fishery. This paper examines trends in quota and catch share concentration across a range of important fish stocks. It demonstrates that continuing concentration is occurring in the ownership of quota for deepwater species. At the same time there has been an increase in participation by small scale fishers in the inshore fishery. This appears to be driven by the introduction of the Annual Catch Entitlement (ACE) regime, allowing annual catch shares to be accessed at reduced transaction cost.