Seungjin Han

Menu Theorems for Bilateral Contracting

This paper studies the bilateral contracting environment where multiple principals negotiate contracts with multiple agents independently. It is shown that equilibrium allocations associated with (pure strategy) perfect Bayesian equilibria relative to any ad hoc set of negotiation schemes can be supported by pure strategy perfect Bayesian equilibria relative to the set of menus. It is also shown that equilibrium allocations associated with all perfect Bayesian equilibria relative to any ad hoc set of negotiation schemes can be supported by correlated equilibria relative to the set of menus, where the set of states is simply the set of feasible probability distributions over payoff-relevant variables. Moreover, equilibrium allocations associated with all equilibria relative to the set of menus persist even if principals use more complex negotiation schemes.

Strongly robust equilibrium and competing-mechanism games

Abstract This paper formulates the notion of a strongly robust equilibrium relative to a set of mechanisms specified in any competing-mechanism game of complete information with multiple principals and multiple agents. It shows that when agents’ efforts are contractible, any strongly robust pure-strategy equilibrium relative to single-incentive contracts persists, regardless of the continuation equilibrium that agents play upon any principals deviation to any complex mechanism.

Compensating Wage Differentials in Stable Job Matching Equilibrium

This paper studies implicit pricing of non-wage job characteristics in the labor market using a two-sided matching model. It departs from the previous literature by allowing worker heterogeneity in productivity, which gives rise to a double transaction problem in a hedonic model. Deriving sufficient conditions under which assortative matching is the unique stable job-worker matching, we show that observed wage differentials between jobs reflect not only compensating wage differentials, but also worker productivity gaps between the jobs. We find that the job-worker matching pattern determines the extent to which compensating wage differentials are confounded with the worker productivity gap effect.

Asymmetric first-price menu auctions under intricate uncertainty

This paper studies asymmetric first-price menu auctions in the procurement environment where the buyer does not commit to a decision rule and asymmetric sellers have interdependent costs and statistically affiliated signals. Sellers compete in bidding a menu of contracts, where a contract specifies a vector of characteristics and a payment required from the buyer for delivering these characteristics. The buyer does not commit ex-ante to a decision rule but rather upon observing all the menus offered by sellers chooses the best contract. This paper establishes the existence of a continuum of separating monotone equilibria in this game bounded above by the jointly ex-post efficient outcome and below by the jointly interim efficient outcome. It shows that the jointly ex-post efficient equilibrium outcome is the only ex-post renegotiation-proof outcome and it is also ex-ante robust to all continuation equilibria.

Sellers' Implicit Collusion in Directed Search Markets

Abstract This paper studies a competing-mechanism game for directed search markets in which multiple sellers simultaneously offer selling mechanisms to multiple buyers in order to compete for trading opportunities and profits. Buyers approach any particular seller via directed search, but there can be mis-coordination among buyers in the sense that they choose all the sellers offering the same mechanism with equal probability. A seller’s mechanism can be sufficiently general to make his trading price contingent on participating buyers’ messages, which may reflect changes in trading prices somewhere else. This allows sellers to sustain implicit collusion. This paper focuses on symmetric equilibria in which sellers offer the same mechanism that induces buyers’ ex-post truth telling on market information. It provides the characterization of all symmetric ex-post truth telling equilibrium allocations and comparative statics regarding the range of equilibrium prices and profits. In a large market, the probability that sellers can sell their products at collusive prices depends on the ratio of buyers to sellers.

CEO Pay with Perks

This paper develops an equilibrium matching model for a competitive CEO market in which CEOs’ wage and perks are both endogenously determined by bargaining between firms and CEOs. In stable matching equilibrium, firm size, wage, perks and talent are all positively related. Perks are more sensitive than wage to changes in firm size if there are economies of scale in the cost of providing perks. Productivity-related perks provide common value by increasing both the CEO’s productivity and utility while non productivity-related perks provide private value by increasing the CEO’s utility only. The more perks enhance the CEO’s productivity, the faster perks increase in firm size. We test the predictions of the model using information on CEO wage and perks for S&P 500 companies and find consistent empirical evidence.