We use a two-year panel of individual accounts in an S&P 500 index mutual fund to examine the trading and investment behavior of more than 91,000 investors who have chosen a low-cost, passively managed vehicle for savings. We identify classes of momentum investors and contrarian investors. We...

We study the role played by the informal links, or “connections,” between the chief executive officer (CEO) and the divisional managers of conglomerate organizations. Using data on a large sample of multisegment U.S. corporations from 1996 to 2004, we show that segments run by connected...