We solve the principal-agent problem of a monopolist insurer selling to an agent whose riskiness (chance of a loss) is private information, a problem introduced in Stiglitz (1977)'s seminal paper. We prove several properties of optimal menus: the highest type gets full coverage (efficiency at...

We solve the principal-agent problem of a monopolist insurer selling to an agent whose riskiness (loss chance) is private information, a problem introduced in Stiglitz's (1977) seminal paper. For an \emph{arbitrary} type distribution, we prove several properties of optimal menus, such as...

We study a general screening model that encompasses a health insurance market in which consumers have multiple dimensions of private information and a price-setting insurer (e.g., a monopolist or a social planner) offers vertically differentiated contracts. We combine theory and empirics to...

We analyze price transparency in a dynamic market with private information and correlated values. Uninformed buyers compete inter- and intra-temporarily for a good sold by an informed seller suffering a liquidity shock. We contrast public versus private price offers. In a two-period case all...

I examine the impact of state policy decisions on the early impact of the ACA using data through the first half of 2014. I focus on the individual health insurance market, which includes plans purchased through exchanges as well as plans purchased directly from insurers. In this market, at least...

We review the theory of leverage developed in collateral equilibrium models with incomplete markets. We explain how leverage tends to boost asset prices, and create bubbles. We show how leverage can be endogenously determined in equilibrium, and how it depends on volatility. We describe the...