Abstract: English auctions with posted prices are widely used in the Internet to sell identical items.We propose a weakly dominant bidding strategy.Consumer whose valuation is lower than the posted price should participate in the auction and it is optimal to bid his true valuation.Consumer whose valuation is higher than the posted price would make a decision between participating in the auction and buying at the posted price directly.It is optimal to bid the posted price if he participates in the auction.We find that his decision on whether to participate in the auction or buy at the posted price significantly depends on the time remaining to the end of the auction Finally,we make a numerical analysis on the impact of factors on his decision and obtain some conclusions.

Key words: online auctions, posted price mechanism, bidding strategy