Thesis advisor: Utku Unver / This dissertation consists of two chapters. The first chapter: Dynamic reserves in matching markets with contracts. In this paper we study a matching problem where agents care not only about the institution they are assigned to but also about the contractual terms of their assignment so that they have preferences over institution-contractual term pairs. Each institution has a target distribution of its slots reserved for different contractual terms. If there is less demand for some groups of slots, then the institution is given opportunity to redistribute unassigned slots over other groups. The choice function we construct takes the capacity of each group of seats to be a function of number of vacant seats of groups considered earlier. We advocate the use of a cumulative offer mechanism (COM) with overall choice functions designed for institutions that allow capacity transfer across different groups of seats as an allocation rule. In applications such as engineering school admissions in India, cadet-branch matching problems at the USMA and ROTC where students are ranked according to test scores (and for each group of seats, corresponding choice functions are induced by them), we show that the COM with a monotonic capacity transfer scheme produces stable outcomes, is strategy proof, and respect improvements in test scores. Allowing capacity redistribution increases efficiency. The outcome of the COM with monotone capacity transfer scheme Pareto dominates the outcome of the COM with no capacity transfer. The second chapter: On relationships between substitutes conditions. In the matching with contracts literature, three well-known conditions on choice functions (from stronger to weaker)- substitutability, unilateral substitutability (US) and bilateral substitutability (BS) have proven to be critical. This paper aims to deepen our understanding of them by separately axiomatizing the gap between the BS and the other two. We first introduce a new “doctor separability” (DS) condition and show that BS, DS and irrelevance of rejected contracts (IRC) are equivalent to IRC and US. Due to Hatfield and Kojima (2010) and Aygün and Sönmez (2012), it is known that US, “Pareto separability” (PS), and IRC are equivalent to substitutability and IRC. This, along with our result, implies that BS, DS, PS, and IRC are equivalent to substitutability and IRC. All of these results are given without IRC whenever hospital choices are induced from preferences. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

Diese Dissertation besteht aus drei unabhängigen Kapiteln in den Bereichen Matching Market Design, Industrieökonomie und Wettbewerbspolitik. Kapitel 1 behandelt den Matching-Markt für juristische Referendariatsstellen in Deutschland. Wegen übermäßiger Nachfrage müssen Anwälte oft warten, bevor sie zugewiesen werden. Der aktuell verwendete Algorithmus berücksichtigt nicht die Zeitpräferenzen der Anwälte. Daher werden viele wünschenswerte Eigenschaften nicht erfüllt. Basierend auf dem matching with contracts Modell schlage ich dann einen neuen Mechanismus vor, der die Wartezeit als Vertragsterm verwendet, so dass die Mängel des gegenwärtigen Mechanismus überwunden werden können. In Kapitel 2 analysiere ich den Wettbewerb von zweiseitigen Online-Plattformen, wie sozialen Netzwerken oder Suchmaschinen. Werbetreibende zahlen Geld, um ihre Anzeigen zu platzieren, während Nutzer mit ihren privaten Daten "bezahlen", um Zugang zu der Plattform zu erhalten. Ich zeige, dass das Gleichgewichtsniveau der Datenerhebung verzerrt ist, abhängig von der Intensität des Wettbewerbs und den Targeting-Vorteilen. Weniger Wettbewerb auf jeder Marktseite führt zu mehr Datensammeln. Wenn jedoch Plattformen Geldzahlungen auf beiden Marktseiten verwenden, wird die effiziente Menge an Daten gesammelt. Kapitel 3 untersucht die dynamische Preissetzung auf Märkten für Flug- oder Reisebuchungen, auf denen Wettbewerb während einer endlichen Verkaufszeit mit einer Frist stattfindet. Unter Berücksichtigung der intertemporalen Probleme von Firmen und vorausschauenden Konsumenten hängen die Gleichgewichtspreispfade von der Anzahl der nicht verkauften Kapazitäten und der verbleibenden Verkaufszeit ab. Ich ermittle, dass mehr Voraussicht der Konsumenten die Konsumentenrente erhöht, aber die Effizienz reduziert. Ferner ist Wettbewerbspolitik besonders wertvoll, wenn die Marktkapazitäten zu hoch sind. Des Weiteren kann die ex-ante Produktion von Kapazitäten ineffizient niedrig sein. / This thesis consists of three independent chapters in the fields of matching market design, industrial organization and competition policy. Chapter 1 covers the matching market for lawyer trainee-ship positions in Germany. Because of excess demand lawyers often must wait before being allocated. The currently used algorithm does not take lawyers’ time-preferences into account. Hence, many desirable properties are not satisfied. Then, based on the matching with contacts model, I propose a new mechanism using waiting time as the contractual term, so that the shortcomings of the current mechanism can be overcome. In Chapter 2 I analyze competition of two-sided online platforms, such as social networks or search engines. Advertisers pay money to place their ads, while users “pay” with their private data to gain access to the platform. I show that the equilibrium level of data collection is distorted, depending on the competition intensity and targeting benefits. Less competition on either market side leads to more data collection. However, if platforms use monetary payments on both market sides, data collection would be efficient. Chapter 3 studies dynamic pricing as in markets for airline or travel bookings, where competition takes place throughout a finite selling time with a deadline. Considering the inter-temporal problems of firms and forward-looking consumers, the equilibrium price paths depend on the number of unsold capacities and remaining selling time. I find that more consumer foresight increases consumer surplus yet reduces efficiency. Further, competition policy is especially valuable when market capacities are excessive. Moreover, ex-ante capacity production can be inefficiently low.