We study the second-price offer feature of eBay auctions in which the seller has multiple units. Perhaps surprisingly, the opportunity to make second-chance offers can reduce seller profit. This happens if her marginal cost function is sufficiently steep. Hence, sellers should be wary about the possibility that buyers anticipate second-chance offers, and it may be advantageous for a seller to a...

This paper studies optimal auction design when the seller can affect the buyers’ valuations through an unobservable ex ante investment. The key insight is that the optimal mechanism may have the seller play a mixed investment strategy so as to create correlation between the otherwise (conditionally) independent valuations of buyers. The paper establishes conditions under which the seller can, i...

In large scale online systems, such as electronic marketplaces and peer-to-peer systems, users often act in their self interest without considering whether their actions lead to efficient outcomes for the system. This thesis studies two important classes of mechanisms that can be used to incentivize users to act in a way that promotes efficiency. Aggregation mechanisms provide aggregate informa...

In many auction problems, we consider a selfinterested seller who is allocating item(s) to bidders in exchange for payments. The highly celebrated VCG mechanism provides an auction mechanism in this case that is efficient, strategy-proof, and ex post individually rational (IR). If the seller’s goal is to maximize revenue, alternative mechanisms include the Myerson optimal auction, which maximiz...

This paper analyzes the e¤ects of buyer and seller risk aversion in …rst and secondprice auctions. The setting is the classic one of symmetric and independent private values, with ex ante homogeneous bidders. However, the seller is able to optimally set the reserve price. In both auctions the seller’s optimal reserve price is shown to decrease in his own risk aversion, and more so in the …rst-p...

Several architectures were proposed in the literature for modeling the interactions between agents. This paper deals with the integration of the multi-agent system in the electronic commerce architecture. Within the framework of this work, we describe three architectures based on the Multi-Agents design. In these systems, buyer and seller agents interact in an environment, which is similar to a...

Information systems can serve as intermediaries between the buyers and the sellers in a market, creating an “electronic marketplace” that lowers the buyers' cost to acquire information about seller prices and product offerings. As a result, electronic marketplaces reduce the inefficiencies caused by buyer search costs, in the process reducing the ability of sellers to extract monopolistic profi...

When an agent enters in an e-Market for the first time, it has no historical information that can be used to determine the strength of business relationship with participant agent, and must therefore rely on the reporting of other agents to prepare for negotiation with that agents. Beliefs of individual agents change through interaction with participant agents and are reflected in their on-goin...