This paper draws on graduate research conducted by the authors: Colvin, C. L., ‘Religion, competition and liability: Dutch cooperative banking in crisis, 1919-1927’ (unpub. PhD thesis, London School of Economics and Political Science, 2011); and McLaughlin, E., ‘Microfinance institutions in nineteenth century Ireland’ (unpub. PhD thesis, National University of Ireland, Maynooth, 2009). They thank Ewen Cameron, Vincent Comerford, David Greasley, William Smyth, and participants at the European Historical Economics Society Conference (Dublin, 2011) and the Women’s Committee Workshop of the Economic History Society (Oxford, 2011) for commenting on an earlier version of this paper. ; What was the recipe for the success of Raiffeisen’s banking model? What made it possible for imitations of this German rural cooperative microfinance institution to work well in some European countries, but fail in others? This paper answers these questions with a comparison of Raiffeisenism in Ireland and the Netherlands. Raiffeisen banks arrived in both places at the same time, but had drastically different fates. In Ireland they were almost wiped out by the early 1920s, whilst in the Netherlands they proved to be a long-lasting institutional transplant. Raiffeisen banks were successful in the Netherlands because they operated in a niche market with few viable competitors. Meanwhile, rural financial markets in Ireland were unsegmented and populated by long-established incumbents, leaving little room for new players, whatever their perceived advantages. Whereas Dutch Raiffeisen banks were largely self-financing, closely integrated into the wider rural economy and took advantage of socioreligious division, their Irish counterparts did not.