However, in many industries there is concern about the basic eectiveness of quotas due to non-compliance. We develop an enforcement model of a quota-regulated resource and focus on a situation with signicant non-compliance and exogenous constraints on nes and enforcement budget. We propose a new enforcement system based on self-reporting of excess extraction and explicit dierentiation of inspection rates based on compliance history. We show that such a system increases the eectiveness of quota management by allowing the regulator to implement a wider range of aggregate extraction targets than under the traditional enforcement system, while ensuring an ecient allocation of aggregate extraction.