Notes on exploiting auctions

– pva: independently distributed, according to some prior, in cva: common value independently drew from a common distribution,
learning about values of others important,
– hard vs soft closing rules (may favor sniping, bidders can collude)
– in the fpa colussion is not self-enforcing, in the spa is self-enforcing (deviation punished), “shills”
– revenue vs efficiency tradeoff, optimal auction cannot be efficient
– truthful value weakly dominant in 2nd price, shading (less than value)
– revenue maximizing seller should use reserve prices higher than the equity
– has a seller made a commitment regarding own bidding?
– symmetric and increasing equilibrium of any auctions, assuming risk neutrality results in the same revenue
– expected revenue in fpa higher when dealing with risk averse bidders
– if some bidders are subject to financial constraints then fpa generates more than spa
– with asymmetric bidder present, expected revenue in fpa may exceed the spa (or the other round if values are not chosen from a finite set)
– 2nd price: bidders must trust the auctioneer, 1st price: auctioneers can “shill”
– for asymmetric bidders with asymmetrically dist values, spa always allocates the object efficiently, fpa not
– first price with asymmetric bidders with a resale does not improve efficiency
– spa does not allow price discovery
– spa bidders maximize their utility by true valuation but there are tricks here (datacritic)
– shilling works in spa auctions and vcg is vulnerable to collusion
– expected payments in incentive compatible mechanism with the same allocation rule are equivalent up to a constant
– individual rationality shapes local strategy as well as choice of auction
– for a symmetric and regular design problem, spa with a reserve price is optimal
– vcg maximizes payment for efficient, incentive compatible and individual rationality
– the expected revenue from a second-price auction is at least as great as the expected revenue from a first-price auction
– symmetric equilibria may be inefficient
– unique equilibrium of (k+1) price auction is symmetric
– release of public information may result in revenue decrease in spa
– spa equilibria are undominated but also discontinuous and inefficient
– reserve prices and entry fees serve to exclude buyers with low estimated values but does not hold when bidders are informed
– crossing condition: bidder influences own value more than value of others
– for many bidders there is always and equilibrium in the english auctions for valuations satisfying the average crossing
– with many bidders spa may not have an efficient equilibrium
– spa with reserve price – efficient collusion depends on identity, but not on value, ie. rings affects ring-bidders only
– the more info payment is based on, the higher will be the expected revenue
– ring increase causes the reserve price for seller to increase, optimal reserve price is greater (seller) if there is a ring

About misha

Imagine a story that one can't believe. Hi. Life changes here. Small things only.
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