Leveling the Playing Field for Risk-Averse Agents in Security-Bid Auctions

We introduce risk-averse bidders in a security-bid auction to analyze how the security design affects bidders’ equilibrium behavior and, as a result, the revenue and efficiency of the auction. We show that steeper securities provide more insurance because they allow bidders to smooth payoffs across realizations. Such insurance levels the playing field for more-risk-averse bidders, inducing them to bid more aggressively. As a consequence, the auction’s allocative efficiency weakly increases when the seller switches from a flatter to a steeper security. Furthermore, we prove that when bidders are homogeneously and sufficiently risk averse, the only security that guarantees Pareto efficiency is the steepest, that is, a call option. We also determine the relationship between the security design and the auction format. In particular, we show that for convex and superconvex families of securities, the first-price auction yields higher expected revenues, provided a technical condition, whereas for subconvex families, the second price yields higher expected revenues, provided that bidders are moderately risk averse. Finally, we show that steeper securities also attract higher entry from an ex ante perspective, when entry is costly, and discuss the effects that the presence of risk aversion has on informal auctions. This paper was accepted by Gustavo Manso, finance.

Charity auctions from an economic perspective — literature review

One of the most common means of raising funds is the charity auction. At charity auctions, money is collected for a good cause, and the products are purchased for private consumption — the bidders may achieve both public and private gains. The charitable nature of this type of auction makes them different from standard auctions. The paper aims to present the main characteristics of this fundraising strategy as well as make a comparison with other formats of raising money for a good cause, i.a. lotteries. Furthermore, the main differences between charity and non-charity auctions will be explained. The studies do not clearly demonstrate whether the charity auction is a more effective mechanism of raising funds than the lottery. However, there is evidence that both formats outperform voluntary contributions. From the perspective of charity organizations, the most effective charity auction format seems to be the all-pay auction. The studies have also revealed that revenues at charity auctions are higher than at standard auctions.

Expectation, Disappointment, and Exit: Evidence on Reference Point Formation from an Online Marketplace

We study disappointment and platform exit among new bidders in an online auction marketplace. In particular, we study a hybrid auction format with a “Buy-It-Now” option which, when executed, will abruptly end the auction and cancel any standing bids. When this happens, if the formerly leading bidder is new to the platform, then they are 6 percentage points more likely to exit the marketplace for every additional day they spent in the lead. This is rationalized by disappointment-averse bidders with outside options and rational expectations about the likelihood of winning. Our explanation is validated by three ancillary predictions: when expectations are lowered by higher competing bids, there is no effect; sensitivity of exit is declining in prior experience, and, for bidders who do not exit, time in the lead during the first experience predicts a subsequent preference for fixed-price, rather than auction, listings.

EXPRESS: First-Price Auctions in Online Display Advertising

We link the rapid and dramatic move from second-price to first-price auction format in the display advertising market to the move from the waterfalling mechanism employed by publishers for soliciting bids in a pre-ordered cascade over exchanges, to an alternate header bidding strategy that broadcasts the request for bid to all exchanges simultaneously. First, we argue that the move by the publishers from waterfalling to header bidding was a revenue improving move for publishers in the old regime when exchanges employed second-price auctions. Given the publisher move to header bidding, we show that exchanges move from second-price to first-price auctions to increase their expected clearing prices. Interestingly, when all exchanges move to first-price auctions, each exchange faces stronger competition from other exchanges and some exchanges may end up with lower revenue than when all exchanges use second-price auctions; yet, all exchanges move to first-price auctions in the unique equilibrium of the game. We show that the new regime hinders the exchanges’ ability to differentiate in equilibrium. Furthermore, it allows the publishers to achieve the revenue of the optimal mechanism despite not having direct access to the advertisers.

On Optimal Auctions for Mixing Exclusive and Shared Matching in Platforms

Platforms create value by matching participants on alternate sides of the marketplace. Although many platforms practice one-to-one matching (e.g., Uber), others can conduct and monetize one-to-many simultaneous matches (e.g., lead-marketing platforms). Both formats involve one dimension of private information, a participant’s valuation for exclusive or shared allocation, respectively. This paper studies the problem of designing an auction format for platforms that mix the modes rather than limit to one and, therefore, involve both dimensions of information. We focus on incentive-compatible auctions (i.e., where truthful bidding is optimal) because of ease of participation and implementation. We formulate the problem to find the revenue-maximizing incentive-compatible auction as a mathematical program. Although hard to solve, the mathematical program leads to heuristic auction designs that are simple to implement, provide good revenue, and have speedy performance, all critical in practice. It also enables creation of upper bounds on the (unknown) optimal auction revenue, which are useful benchmarks for our proposed auction designs. By demonstrating a tight gap for our proposed two-dimensional reserve-price-based mechanism, we prove that it has excellent revenue performance and places low information and computational burden on the platform and participants. This paper was accepted by Chris Forman, information systems.

IDENTIFICATION AND ESTIMATION IN A THIRD-PRICE AUCTION MODEL

The first novelty of this paper is that we show global identification of the private values distribution in a sealed-bid third-price auction model using a fully nonparametric methodology. The second novelty of the paper comes from the study of the identification and estimation of the model using a quantile approach. We consider an i.i.d. private values environment with risk-averse bidders. In the first place, we consider the case where the risk-aversion parameter is known. We show that the speed of convergence in process of our nonparametric estimator produces at the root-n parametric rate, and we explain the intuition behind this apparently surprising result. Next, we consider that the risk-aversion parameter is unknown, and we locally identify it using exogenous variation in the number of participants. We extend our procedure to the case where we observe only the bids corresponding to the transaction prices, and we generalize the model so as to account for the presence of exogenous variables. The methodological toolbox used to analyse identification of the third-price auction model can be employed in the study of other games of incomplete information. Our results are interesting, also from a policy perspective, as some authors recommend the use of the third-price auction format for certain Internet auctions. Moreover, we contribute to the econometric literature on auctions using a quantile approach.

Number of Bidders and the Winner’s Curse

Within an affiliated value auction setting, we study the relationship between the number of bidders and the winner’s curse in terms of its frequency of occurrence and its expected harm. From a design perspective, we find that both the number of bidders and the level of affiliation are instrumental when choosing an auction format and whether to encourage or discourage bidder participation.

Discrimination via Symmetric Auctions

Discrimination (for instance, along the lines of race or gender) is often prohibited in auctions. This is legally enforced by preventing the seller from explicitly biasing the rules in favor of bidders from certain groups (for example, by subsidizing their bids). In this paper, we study the efficacy of this policy in the context of a single object: independent private value setting with heterogeneous bidders. We show that restricting the seller to using an anonymous, sealed bid auction format (or, simply, a symmetric auction) imposes virtually no restriction on her ability to discriminate. Our results highlight that the discrepancy between the superficial impartiality of the auction rules and the resulting fairness of the outcome can be extreme. (JEL D44, D82)