2018년 3월 11일 일요일

탐색: 이베이, eBay // Proxy bidding


※ 발췌 (excerpts):

출처 1: https://en.wikipedia.org/wiki/Proxy_bid

Proxy bidding is an implementation of an English second-price auction used on eBay, in which the winning bidder pays the price of the second-highest bid pls a defined increment. If differs from a Vickrey auction in that bids are not sealed; the "current highest bid" (defined as second-highest bid plus bid increment) is always displayed.


출처 2: eBay Proxy Bid Mysteries Revealed: "e Sniping" Hacks For Smart Bidders (AuctionWinner, Jul 2011)

Placing a bid on eBay is not at all like placing bid in a traditional, you're-there-in-the-flesh auctions. If you go to the country fair and start bidding for a prize goat, for example (and who among us hasn't), the process is simple. The auctioneer almost certainly issues a starting bid representing the lowest possible price for the goat, then opens up the floor to other bidders.

( ... ... )

eBay doesn't work like this. If it did, eBay would be little more than a highly specialized chat room, a form of online chaos that probably wouldn't work well to anyone's advantage. ( ... ... )

eBay proxy bid: The Answer to Possible Auction Chaos

The answer to the problem ( ... ) is that eBay takes your maximum possible bid but does not actually place that amount unless it must. eBay acts like your best friend in the bidding process, keeping the bid as low as possible while still keeping your bid higher than the rest. This is called proxy bidding.

( ... ... ) If you've bid $250 on [an] eBay auction and the current bid is $110, eBay will keep your bidding price to $115, which is the current bid plus the minimum bid increment at the $100 level.

( ... ... )


출처 3: Last-Minute Bidding and the Rules for Ending Second-Price Auctions: Evidence from eBay and Amazon Auctions on the Internet (Alvin E. Roth, Axel Ockenfels | AER, which date?)

Auctions on the Internet provide a new source of data on how bidding is influenced by the detailed rules of the auction. Here we study the second-price auctions run by eBay and Amazon, in which a bidder submits a reservation price, and has this (maximum) price used to bid for him by proxy. That is, a bidder can submit his reservation price (called a proxy bid) early in the auction and have the resulting bid register as the minimum increment above the previous high bid.

As subsequent reservation prices are submitted, the bid rises by the minimum increment until the second highest submitted reservation price is exceeded. Hence, an early bid with a reservation price higher than any other submitted during the auction will win the auction and pay only the minimum increment above the second highest submitted reservation price.

eBay and Amazon use different rules for ending an auction. Auctions on eBay have a fixed end time (a "hard close"), while auctions on Amazon, which operate under otherwise similar rules, are automatically extended if necessary past the scheduled end time until ten minutes have passed without a bid. These different rules give bidders more reason to bid late on eBay than on Amazon. ( ... ... )

Last-minute bidding, a practice called "sniping," arises despite advice from both auctioneers and sellers in eBay that bidders should simply submit their maximum willingness to pay, once, early in the auction. For example, eBay instructs bidders on the simple economics of second price auctions, using an example of a winning early bid. And they discuss last-minute bids on a page explaining that they will not accept complaints about sniping, as follows:

( ... ... )


출처 4: 이베이 경매 방법 - 비딩/입찰 (네이버 블로그, 2015년 6월)


출처 5: 경매장 입찰 방식 (오늘의유머, 2012년 6월)


출처 6: eBay에서 배우는 인터넷 경매 영어 (2005년 12월)

Proxy bid: Placing a maximum bid which is held in confidence by the system. System will use only as much of this amount as it needed to maintain bidder's high bid position.


출처 7: 인센티브 경매: 경매 규칙 설계를 위한 FCC 제안을 중심으로 (김주현, 정보통신정책연구원, 2014년 2월)

Descending clock auction의 경우는 유찰의 위험성이 존재한다. 만약 현재 가격이 입찰자가 일반적으로 생각하는 승낙 의사보다 현저하게 낮게 되면 모든 입차자가 경매를 포기할 수 있다. 이러한 위험성을 막기 위해 FCC는 입찰자에게 "proxy bid" 옵션을 제공한다. 이는 입찰자가 경매 시작 전에 자신의 최소 승낙 의사(minimum willingness to accept)를 경매 주관에 제출하면, 매 라운드마다 경매 소프트웨어는 입찰자가 제출한 proxy bid를 고려하여 자동적으로 입찰액을 생성한다. ( ... ... )

댓글 쓰기