This study uses hazard function estimations and time‐series and cross‐sectional growth regressions to examine the impact of exit through merger and acquisition (M&A) or failure, and internally generated growth, on the firm‐size distribution within the U.S. credit union sector. Consolidation through M&A was the principal cause of a reduction in the number of credit unions, but impact on concentration was small. Divergence between the average internally generated growth of smaller and larger credit unions was the principal driver of the rise in concentration. (JEL G21)