[We explore the implications of financial system design for financial innovation. We begin with assumptions about the investment opportunities of firms, their observable attributes, and the roles of commercial banks, investment banks, and the financial market. We examine the borrower's choice between bank and financial market funding, the commercial bank's choice of monitoring capacity, and the investment bank's choice of whether to invest in financial innovation. Our main result is that financial innovation in a universal banking system is stochastically lower than innovation in a financial system in which commercial and investment banks are functionally separated

We develop a dynamic model of the adoption of financial innovations. Each period, firms decide whether or not to adopt an innovation of uncertain value, and the profitability of each period’s adoptions reveals information about the innovation’s value. We show that characteristics of financial innovation waves cited by critics as evidence of irrational excess are, in fact, consistent with fully rational behavior. We also show that social welfare is enhanced when more firms adopt innovations of questionable value and that financial intermediaries have an incentive to encourage such adoption

[We develop a dynamic model of the adoption of financial innovations. Each period, firms decide whether or not to adopt an innovation of uncertain value, and the profitability of each period's adoptions reveals information about the innovation's value. We show that characteristics of financial innovation waves cited by critics as evidence of irrational excess are, in fact, consistent with fully rational behavior. We also show that social welfare is enhanced when more firms adopt innovations of questionable value and that financial intermediaries have an incentive to encourage such adoption