The effects of membership expansion on credit union risk and returns

Between 1996 and 2022, regulatory changes led to over a thousand federally chartered credit unions converting to community charters, significantly increasing credit union membership. This study attempts to determine whether these developments improve safety and soundness by enabling credit unions to diversify their loan portfolios, or whether risk increases as the social capital of a tight common bond becomes diluted. We use two-way fixed effects, doubly robust and generalized synthetic control methods with state chartered credit unions and commercial banks as controls to estimate both intent-to-treat (ITT) and average treatment-effect-on-the-treated (ATT) impacts on credit union risk and returns. We find that conversions to community charter unambiguously improve credit union returns but the effects on risk are mixed: liquidity and capital fall, but there is no change in indicators of asset quality. Overall, during the 25-year period from 1998 to 2022, only 1.47% of community-chartered credit unions failed. The results suggest that social capital is no longer an important factor in reducing credit risk in countries with developed financial sectors like the U.S.