Is an investing institution one shareholder or a collection of separate funds?

There is much discussion about the merits of co-ordinated action between investing institutions. But many institutional holdings consist of subholdings managed by separate fund managers. We examine the extent to which the fund managers within a given institution behave in a co-ordinated manner, in terms of their trading around the announcement of major takeovers. We find evidence of material disagreement within institutions, suggesting that blocks, at the level of the institution, do not always exist.