ABSTRACT: We build a simple model that shows how the incentives and constraints facing three key types of market players—broker-dealers, hedge funds, and asset managers—interact to create a heightened level of fragility in the Treasury market, and how this fragility can become more pronounced as the supply of Treasury securities increases. After validating a number of the model's empirical premises and implications, we ask what it can tell us about how the Federal Reserve might best address future episodes of market dysfunction. In so doing, we take as given that an important priority for any Fed response to Treasury market dysfunction is that it be clearly separated from anything having to do with monetary policy.