Sufficiency, stability and security in the budgets of anti-corruption institutions and systems are recognised as fundamental to their capacity and potential performance, but how do we assess sufficiency of resources, and what represents adequate stability? This article re-evaluates how these basics of integrity system capacity might best be approached, using an exploratory comparison of the financial resources of select integrity agencies across different jurisdictions over time. Using a ‘most different systems’ design, we present data on the ratio of the budget expenditures of key institutions to total public expenditure of 10 national/subnational jurisdictions, from three settings covered by National Integrity System assessments: Bangladesh, New Zealand and Australia. The exploration confirms the potential for more systematic comparative and longitudinal analysis to inform debate on key policy issues confronting institutionalised anti-corruption efforts, but importantly, also affirms this is likely best achieved if ‘system’ and ‘sub-system’ approaches, not just individual agency approaches, are taken towards this assessment task.