Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004: We develop a general theoretical framework of trade on a platform on which buyers and sellers interact. The platform may be owned by a single large, or many small independent or vertically integrated intermediaries. We...

This paper analyzes the effects of specific and ad valorem taxation in an industry with downstream and upstream oligopoly. We find that in the short run, i.e. when the number of firms in both markets is exogenous, the results concerning tax incidence tend to be qualitatively similar to models...

We consider a model of oligopolistic firms that have private information about their cost structure. Prior to competing in the market a competitive advantage, i.e., a cost reducing technology, is allocated to a subset of the firms by means of a multi-object auction. After the auction either all...

Two-sided market models in which platforms compete via two-part tariffs, i.e. a subscription and a per-transaction fee, are often plagued by a continuum of equilibria. This paper augments existing models by allowing for heterogeneous rading behavior of agents on both sides. We show that this...

We consider takeover bidding in a Cournot oligopoly when firms have private information concerning the synergy effect of merging with a takeover target. Two auction rules are considered: standard first-price and profit-share auctions, supplemented by entry fees. Since non-merged firms benefit...

We study the incentives to share private information ahead of contests, such as markets with promotional competition, procurement contests, or R&D. We consider the cases where firms have (i) independent values and (ii) common values of winning the contest. In both cases, when decisions to share...

Does the internet increase competition? To address this question, I exploit two institutional details unique to Germany: (1) Some municipalities received glass fibre cables that cannot be upgraded to DSL; I use these municipalities as a treatment group with reduced online competition. (2) German...

Colluding firms often exchange private information and make transfers within the cartels based on the information. Estimating the impact of such collusive practices" - known as the 'lysine strategy profile (LSP)" - on cartel duration is difficult because of endogeneity and omitted variable bias....

We consider a software vendor first selling a monopoly platform and then an application running on this platform. He may face competition by an entrant in the applications market. The platform monopolist can benefit from competition for three reasons. First, his profits from the platform...

Consumers often purchase more than one differentiated product, assembling a portfolio, which might potentially affect substitution patterns of demand and, as a consequence, oligopolistic firms' pricing strategies. To study such consumers' portfolio considerations, this paper develops and...