Liquidity constraints and credit subsidies in auctions

I consider an auction with participants that differ in valuation and access to liquid assets. Assuming credit is costly (e.g. due to moral hazard considerations) different auction rules establish different ways of screening valuation-liquidity pairs. The paper shows that standard auction forms result in different allocation rules. When the seller can deny access to capital markets or offer credit subsidies, she gains an additional tool to screen agents. The paper derives conditions under which the seller increases profits by way of subsidizing loans. In particular, in a second price auction, the seller always benefits from offering small subsidies. The result extends to a non-auction setting to show that a monopolist may use credit subsidies as a price discrimination device

Efficiency Guarantees in Auctions with Budgets

In settings where players have a limited access to liquidity, represented in the form of budget constraints, efficiency maximization has proven to be a challenging goal. In particular, the social welfare cannot be approximated by a better factor then the number of players. Therefore, the literature has mainly resorted to Pareto-efficiency as a way to achieve efficiency in such settings. While successful in some important scenarios, in many settings it is known that either exactly one incentive-compatible auction that always outputs a Pareto-efficient solution, or that no truthful mechanism can always guarantee a Pareto-efficient outcome. Traditionally, impossibility results can be avoided by considering approximations. However, Pareto-efficiency is a binary property (is either satisfied or not), which does not allow for approximations. In this paper we propose a new notion of efficiency, called \emph{liquid welfare}. This is the maximum amount of revenue an omniscient seller would be able to extract from a certain instance. We explain the intuition behind this objective function and show that it can be 2-approximated by two different auctions. Moreover, we show that no truthful algorithm can guarantee an approximation factor better than 4/3 with respect to the liquid welfare, and provide a truthful auction that attains this bound in a special case. Importantly, the liquid welfare benchmark also overcomes impossibilities for some settings. While it is impossible to design Pareto-efficient auctions for multi-unit auctions where players have decreasing marginal values, we give a deterministic $O(\log n)$-approximation for the liquid welfare in this setting

LIQUIDITY CONSTRAINTS AND CREDIT SUBSIDIES IN AUCTIONS

I consider an auction with participants that differ in valuation and access to liquid assets. Assuming credit is costly (e.g. due to moral hazard considerations) different auction rules establish different ways of screening valuation-liquidity pairs. The paper shows that standard auction forms result in different allocation rules. When the seller can deny access to capital markets or offer credit subsidies, she gains an additional tool to screen agents. The paper derives conditions under which the seller increases profits by way of subsidizing loans. In particular, in a second price auction, the seller always benefits from offering small subsidies. The result extends to a non-auction setting to show that a monopolist may use credit subsidies as a price discrimination device.

Generalized reduced-form auctions: a network-flow approach

We develop a network-flow approach for characterizing interim-allocation rules that can be implemented by ex post allocations. Our method can be used to characterize feasible interim allocations in general multi-unit auctions where agents face capacity constraints, both ceilings and floors. Applications include a variety of settings of practical interest, ranging from individual and group-specific capacity constraints, set-aside sale, partnership dissolution, and government license reallocation.Reduced-form auctions, network-flow approach, feasible circulation flow, paramodular capacity constraints