I study the effects of risk and ambiguity (Knightian uncertainty) on optimal portfolios and equilibrium asset prices when investors receive information that is difficult to link to fundamentals. I show that the desire of investors to hedge ambiguity leads to portfolio inertia and excess...

I study the effects of aversion to risk and ambiguity (uncertainty in the sense of Knight (1921)) on the value of the market portfolio when investors receive public information that they find difficult to link to fundamentals and hence treat as ambiguous. I show that small changes in public...

The restructuring of Greece's debt offers a clean case study of the dynamics of sovereign restructuring. This essay discusses the powerlessness of sovereign creditors, Greece's predicament, and its resolution through (a) a two-step refinancing with bond accumulation and value injection and (b)...

We propose a dynamic asset-market equilibrium model in which (1) an "innovative" asset with as-yet-unknown average payoff is traded, and (2) investors delegate investment to experts. Experts secretly renege on investors' orders and take on leveraged positions in the asset to manipulate...

We analyze a dynamic model of informed trading where a shareholder accumulates shares in an anonymous market and then expends costly effort to change the firm value. We find that equilibrium prices are affected by the position accumulated by the shareholder, because the level of effort...