I propose a centralized clearinghouse for college admissions in which students can signal enthusiasm by commitment, like early-decision programs. Furthermore, students can specify financial aid in their preferences and they can be matched with multiple colleges at the same time. This clearinghouse keeps the desirable properties of the decentralized college admissions like signalling and yield management while getting rid of the undesirable aspects such as unfairness and unraveling. To study centralized college admissions, I advance the theory of stability for many-to-many matching markets with contracts. In particular, I show that stable matchings exist even when colleges do not have path-independent (or substitutable) choice rules. I provide two results on comparative statics for the student-proposing deferred acceptance algorithm. Furthermore, I introduce a new monotonicity condition on choice rules to study yield management for colleges and generalize the rural-hospitals theorem when contracts may have different weights. My framework opens new venues for market-design research and raises questions about the standard assumptions made in the literature.
