I investigate whether changes in stock market participation costs can explain the long-term increase in the number of U.S. stockholders. I separate these costs into two components: an information cost (the cost of collecting market information), and an entry cost (all other costs, including commissions and fees), and disentangle their general equilibrium implications in a noisy rational expectations economy. While a falling information cost cannot explain the observed increase in stock market participation, a falling entry cost can account for this plus several other features of the U.S. economy, including the falling equity premium, rising return variances, and the boom in passive relative to active investing.

We document that long-run excess returns following announcements of share buyback authorizations and insider purchases are a U-shaped function of firm centrality in the input–output trade-flow network. These results conform to a model of investors endowed with a large but finite capacity for analyzing firms. Additional links weaken insiders’ informational advantage in peripheral firms (simple firms whose cash flows depend on few economic links), provided investors’ capacity is large enough, but eventually amplify that advantage in central firms (firms with many links) as a result of investors’ limited capacity. These findings shed light on the sources of managerial market-timing ability.