We argue that active management's popularity is not puzzling despite the industry's poor track record. Our explanation features decreasing returns to scale: As the industry's size increases, every manager's ability to outperform passive benchmarks declines. The poor track record occurred before...

We show that firms intermediating trade have incentives to overinvest in financial expertise, and that these investments can be destabilizing. Financial expertise in our model improves firms' ability to accurately estimate value when trading a security. It creates adverse selection, which under...