This study investigates whether the relation between aggregate fund flow and market returns differs between retail and institutional funds. For the retail fund sample, we document a contemporaneous relation between flow and market returns and also find evidence of feedback trading. In contrast, there is little evidence of a relation between flow and market returns for the institutional fund sample. Consequently, it appears that retail and institutional fund investors use different investment strategies, with retail investors following a more naive strategy. We find no evidence of flow inducing price pressure for either type of fund.