In the Medicare Advantage (MA) market, private health insurers compete to offer plans with the most attractive premium and benefit package. Medicare provides a subsidy, based on a "benchmark payment rate", for each Medicare beneficiary a plan enrolls. We investigate how this subsidy, the primary...

We study a model where some agents have private information about risky asset returns and trade to obtain capital gains, while others acquire the risky asset and hold it to maturity, forming expectations of returns based on market prices. We show that under such a structure, in addition to fully...

Limits to arbitrage play a central role in behavioral finance. They are thought to interfere with arbitrage processes so that security prices can deviate from true values for extended periods of time. We describe a recent financial innovation that allows limits to arbitrage to be sidestepped,...

An endogenous growth model is developed where each period firms invest in researching and developing new ideas. An idea increases a firm's productivity. By how much depends on how central the idea is to a firm's activity. Ideas can be bought and sold on a market for patents. A firm can sell an...

Existing literature continues to be unable to offer a convincing explanation for the volatility of the stochastic discount factor in real world data. Our work provides such an explanation. We do not rely on frictions, market in completeness or transactions costs of any kind. Instead, we modify a...

We offer a critique of the popular notion that the log-change of the real exchange rate equals the log-difference between the IMRSs of economically distinct agents in two economies. Contrary to existing claims, we show that this interpretation does not hold true in reduced-form SDF models that...

In most sectors, technological progress boosts efficiency. But financial technology and the associated data-intensive trading strategies have been blamed for market inefficiency. A key cause for concern is that better technology might induce traders to extract other's information from order flow...

We analyze dynamic trading by an activist investor who can expend costly effort to affect firm value. We obtain the equilibrium in closed form for a general activism technology, including both binary and continuous outcomes. Variation in parameters can produce either positive or negative...

This paper is about the effectiveness of qualitative easing, a form of unconventional monetary policy that changes the risk composition of the central bank balance sheet with the goal of stabilizing economic activity. We construct a general equilibrium model where agents have rational...