A mutual-fund manager is more likely to hold (or buy, or sell) a particular stock in any quarter if other managers in the same city are holding (or buying, or selling) that same stock. This pattern shows up even when controlling for the distance between the fund manager and the stock in...

We investigate the idea that stock-market participation is influenced by social interaction. We build a simple model in which any given quot;socialquot; investor finds it more attractive to invest in the market when the participation rate among his peers is higher. The model predicts higher...