以等價競標機制展現競標者之議價能力

Abstract

由於網際網路與電子商務之興起，促進拍賣網站的蓬勃發展，也對於競標價格之決定及撮合買賣方之機制產生革命性的衝擊。拍賣機制不僅可快速、自動化地決定出得標者是誰，近來更被廣泛採用於各大交易系統中。今日於拍賣網站上出售的商品已不具有唯一性，但現存的線上競標機制，如 eBay，仍延用過去英式拍賣之往上加價的特性來競標，其實並不恰當。因此，本研究最主要之貢獻是希望提出一個等價競標機制，除了解決目前存在於線上拍賣網站的弊端，更希望透過等價的概念、透過供給與需求的市場機制，讓買方能充分展現自己所擁有之時間優勢，以較有效率及較低之價格得到此商品。 本研究中，第一部分運用機制設計，提出一個創新的等價線上拍賣機制，探討在等價競標機制下買方之優勢策略為何，並以賽局理論證明此為strategy-proof之完美機制。第二部分系統開發完成具備以軟體代理人出價之等價競標拍賣網站，除了協助使用者在競標時，可節省更多的競價時間外，透過本系統之交易，在研究之第三部分我們期望能更了解此等價機制之經營型態實際運用於電子商務中之可行性，並藉由系統模擬來完成測試與實驗，進而探討透過智慧型代理人，是否能讓買方意識到自己擁有多少議價能力，以及如何擅用自己的時間優勢及對於市場供給和需求量之瞭解，透過此系統中的參數設定與策略選擇，充分展現出自己的議價能力，做出最有利的決策。最後期望買方能以低於市價甚多的價格購買到此商品，創造出一個防止「最後一秒搶標」及「贏者的詛咒」之競標場所。

Auctions, which account for an enormous volume of trading/transactions on the Internet, are a fundamental mechanism for automating price negotiations in electronic commerce. The recent growth in Internet auctions has opened a new window on bidding behavior in all kinds of auction mechanisms. Although they are so popular and widely used, there are still some challenges to be considered. First, commodities in online auctions today are not as unique as those in traditional ones. As we know, the price of commodities is decided by the quantity of supply and demand in whole market. Consequently, it will stay in equilibrium and also each consumer can gain the product with the same price in the market. Since the mechanism of English auction is originally designed for unique-artifact bidding, it does not fit in the current online scenario. The mechanism of Dutch auction, on the other hand, allows bidding at the same price to deal with the trading of quantities of commodities. However, many online auctions are used to sell single unit of non-unique commodities, for which both English and Dutch auctions do not fit. Second, automations of auctions, like proxy bidding, are not widely used in complicated auctions like Dutch ones. Therefore, the rule of that the earliest successful bids get the goods determines the winning bids; it causes great pressure to human bidders since timely bids are important. On the other hand, most online English auctions leverage proxy bidding to increase automations; however, it suffers the problem of last-minute-bidding if the proxy bidding mechanism is ill designed. Finally, the problem of winner’s curse exits in online auctions. It is well-known that under information asymmetry, almost common-value auction mechanisms inherently exhibit a serious welfare problem known as the winner’s curse, stating that the winner of the auction always overbids. Although it can be resolved by minimizing bidding increments in English auctions, it is argued here that it can be eliminated completely by the mechanism of equal-price bidding in English auctions. In short, we study how to design a strategy-proof mechanism for equal-price bidding. It demonstrates three advantages: First, bidders can demonstrate his bargaining power by staying at the same price. Second, proxy bidding is allowed without the problem of last-minute bidding. Third, winner’s curse is avoided since the winning bid needs not to be the highest bid.