Credit unions in Northern Ireland are subject to a unique combination of statutory over-
sight and self-regulation. This paper investigates the association between prudence and
the monitoring of financial ratios by credit union trade associations. We find that
compliance with the mandated level of capital reserves is uniformly high, regardless of the
existence or extent of self-regulation. However, after controlling for cross-sectional
differences in profitability, age, size, growth and common bond type a positive association
exists between self-regulation and financial ratios measuring prudence and loan book
quality. These findings have policy implications for the regulation of credit unions in
Northern Ireland and elsewhere regarding potential regulatory cost savings from reliance
on self-regulation provided by trade associations.