Jonghee Hahn

I analyze a durable‐goods monopolist's incentives to introduce a damaged good (a stripped‐down version of the original good) in an infinite‐horizon framework. The damaged good helps the monopolist to mitigate the Coasian time‐inconsistency problem. However, it may lead to a welfare reduction: low‐valuation buyers are induced to purchase the low‐quality damaged good early rather than buy the high‐quality original good later, and when the players are patient the surplus loss from quality reduction

In markets subject to network effects, firms often remove some functions of their original products and sell a functionally-downgraded version at a lower or zero price. This paper aims to provide a pure network effect based explanation of such a practice. Building a functional degradation model with asymmetric network effects, we investigate when and why firms have incentives to introduce a functionally-degraded good and discuss its welfare implication.

This paper considers competition in a telecommunications industry, where heterogeneous consumers have private information about their preferences for telephone service and firms are allowed to use nonlinear tariffs. Networks, which directly compete for customers, are interconnected and pay access charges to one another. In a symmetric equilibrium, each network's profit-maximising pricing policy generally involves a distortion in call allocation for all types, except when the (reciprocal

This paper discusses monopoly pricing in a market with congestion-type negative externalities. Two broad classes of situations are considered: communications network congestion for the case of pro?t maximization and road congestion for the case of welfare maximization. We allow the firm to screen consumers with different preferences using a nonlinear tariff, which has been largely neglected in the previous literature. It turns out that the level of overall congestion in the market is too low due

Abstract This paper examines the profitability of interfirm bundling among independent single‐good producers in a two‐dimensional Hotelling framework. We show that interfirm bundling tends to relax price competition by preventing consumers from mixing and matching (i.e., making it difficult to switch brands) and therefore is more profitable than separate sales, provided that firms are sufficiently symmetric. Hence, firms have mutual incentives to offer their products as a bundle or to make exclu

This paper considers a functional quality degradation of software with twoway features (such as reading and writing in word-processors). A software monopolist differentiates products by introducing a functionally down-graded version (e.g. the read-only version) by eliminating some functions of the full version. A simple two-type model is presented to explain the firm’s incentive to introduce a functionally down-graded version. It is shown that the functional quality degradation is an effective c

This paper investigates how call and network externalities affect a monopolist’s optimal nonlinear pricing of a two-way telecommunication service. The existence of call externalities results in all types of subscribers (even the highest type) making suboptimal quantities of calls in the optimum. This is because the firm being not allowed to charge incoming calls cannot control the quantities of incoming calls. Due to call externalities, there may exist some subscribers who only receive calls wit

Cryopyrin-associated periodic syndrome (CAPS) is a hereditary autoinflammatory syndrome caused by mutations in NLRP3 (encoding cryopyrin), which presents with fever, fatigue and arthralgia. Thus far, however there have been no reports of CAPS in Korea. Herein, we report 3 cases of CAPS for the first time in Korea. The first case, a 28-year-old man with recurrent urticaria, arthralgia and fever induced by cold, all of which were observed in his father, showed elevated erythrocyte sedimentation ra

최근 미국, 유럽을 비롯한 각국 경쟁당국이 수직결합 사건의 심사에 경제분석 기법을적극적으로 도입하고 있는 추세이고, 이에 따라 수직결합의 경제효과 평가를 위한 이론 및실증분석에 대한 수요가 크게 증가하고 있다. 이에 본 논문은 수직결합의 봉쇄효과 평가를위한 정량적 분석기법을 소개하고, 이를 실제 사례에 적용하기 위한 개념적 틀을 제공하고자 한다. 결합기업이 경쟁기업에 대한 요소 또는 판로 제공을 완전히 차단할 유인을 지니는지 여부를 평가하는 Vertical Arithmetic 기법을 비롯하여, 결합기업이 가격인상을 통해 경쟁기업의 경쟁력을 약화시킬 유인을 측정하는 수직가격인상압력지수(vGUPPI), 그리고 Comcast- NBCU 결합 건에서 미국 연방통신위원회에 의해 채택된 바 있는 협상모형에 기초한 가격인상효과 측정기법에 대해 알아본다. 각각에 대해 각국 경쟁당국이 실제 사건에 적용한 사례를 소개하고 그 정책적 의미를 살펴본다. 끝으로 위 세 가지 분석기법의 장단점을 비교하고,