IPO share allocation and conflicts of interest

The underwriter of an IPO has two sources of compensation for its services on behalf of the issuer. One is through a commission (spread), the other is by buying issued shares for itself (or its affiliates) and reselling them in the post-issue market. Profits from the former decrease along with the magnitude of underpricing while profits from the latter increase with it. Faced with these countervailing interests, the present paper analyzes how the underwriter decides upon the pricing and allocation of IPOs.      

The “Boston” school-choice mechanism: an axiomatic approach

The Boston mechanism is a popular student-placement mechanism in school-choice programs around the world. We provide two characterizations of the Boston mechanism. We introduce two new axioms; favoring higher ranks and rank-respecting invariance. A mechanism is the Boston mechanism for some priority if and only if it favors higher ranks and satisfies consistency, resource monotonicity, and rank-respecting invariance. In environments where each type of object has exactly one unit, as in house allocation, a characterization is given by favoring higher ranks, individual rationality, population monotonicity, and rank-respecting invariance.     

Group incentive compatibility for matching with contracts

Hatfield and Milgrom [Hatfield, John William, Milgrom, Paul R., 2005. Matching with contracts. Amer. Econ. Rev. 95, 913–935] present a unified model of matching with contracts, which includes the standard two-sided matching and some package auction models as special cases. They show that the doctor-optimal stable mechanism is strategy-proof for doctors if hospitals' preferences satisfy substitutes and the law of aggregate demand. We show that the doctor-optimal stable mechanism is group strategy-proof for doctors under these same conditions. That is, no group of doctors can make each of its members strictly better off by jointly misreporting their preferences. We derive as a corollary of this result that no individually rational allocation is preferred by all the doctors to the doctor-optimal stable allocation.     

Chances for a pacific free trade area

The establishment of the EEC was a major event of the 1960s. It has had a significant impact on international trade and investment and has wrought a profound change in the world balance of economic power. The emergence of the enlarged EEC and the implementation of a Pacific Free Trade Area (PAFTA) could have a more profound influence in shaping the world of the 1970s.     

Stability and instability of the unbeatable strategy in dynamic processes

A strategy is unbeatable if it is immune to any entrant strategy of any size. This paper investigates static and dynamic properties of unbeatable strategies. We give equivalent conditions for a strategy to be unbeatable and compare it with related equilibrium concepts. An unbeatable strategy is globally stable under replicator dynamics. In contrast, an unbeatable strategy can fail to be globally stable under best response dynamics even if it is also a unique and strict Nash equilibrium.     

MR imaging of traumatic hepatic laceration: Evaluation and course of healing after surgery

Six patients with hepatic laceration underwent magnetic resonance imaging (MRI) at 0.5T. Acute hepatic laceration was slightly hypointense on T1-weighted spin-echo (SE) image, and hyperintense on T2- and proton-weighted SE images. Subacute laceration was heterogeneously intense on T1-weighted image and hyperintense on T2- and proton-weighted images. Consistent changes in signal intensity of postoperative hepatic laceration were observed. On Tl-weighted image, the signal intensity at first increased and then decreased from periphery to the center. On the T2- and proton-weighted images, the laceration was uniformly hyperintense relative to the liver prior to the appearance and growth of a hypointense ring at its periphery. The appearance of the above changes in signal intensity was also observed in postoperative recurrent hemorrhage. The postoperative biloma had none of the above changes in signal intensity. Our cases show that MRI is effective in the evaluation of hepatic laceration and in the assessment of the course of healing after operation.     

Incentives in the probabilistic serial mechanism

The probabilistic serial mechanism (Bogomolnaia and Moulin, 2001 [9]) is ordinally efficient but not strategy-proof. We study incentives in the probabilistic serial mechanism for large assignment problems. We establish that for a fixed set of object types and an agent with a given expected utility function, if there are sufficiently many copies of each object type, then reporting ordinal preferences truthfully is a weakly dominant strategy for the agent (regardless of the number of other agents and their preferences). The non-manipulability and the ordinal efficiency of the probabilistic serial mechanism support its implementation instead of random serial dictatorship in large assignment problems.