Knowledge that Transforms

Abstract We introduce markup equilibrium—an extension of Walrasian equilibrium in which consumers pay a fixed percentage markup over producer prices. In quasilinear markets, markup equilibria exist despite nonconvexities. They are resource-feasible and envy-free, incur no budget deficit, and require little more communication and computation than ordinary Walrasian equilibrium. The associated markup mechanism is asymptotically incentive-compatible. We also introduce a Bound-Form First Welfare Theorem, which states that for any feasible allocation, the welfare loss compared to the first-best is bounded, using any price vector, by the sum of the resulting (i) budget surplus and (ii) rationing losses suffered by the participants. Using producer prices, this bound implies that any markup equilibrium with a small markup and few unallocated goods is nearly efficient.

Abstract Government intervention in the financial market through its own trading fundamentally changes the market’s structure, function, and outcome. I develop a general equilibrium framework to study the impact of government trading on investor welfare. I show that with incompleteness and information asymmetry, the market equilibrium is in general suboptimal, and government intervention can potentially improve investor welfare even with no additional information. However, the actual welfare impact of government intervention is sensitive to the details of the economy and the policy design. Popular policy targets such as price stability, market liquidity, and informational efficiency can have different welfare implications.