Each period the seller moves first, announcing the quality of the product he promises to buyers. Highquality products are more profitable, so the seller will always promise high quality. Buyers then compete with one another in a Vickrey auction and, therefore, bid amounts equal to their expected valuation of the transaction outcome. The winning bidder sends payment to the seller. The seller then has the choice of either “cooperating” (delivering a high-quality good) or “cheating” (delivering a low-quality good). It is easy to see that this game has a unique subgameperfect equilibrium. In equilibrium, the seller always cheats (delivers low quality), buyers each bid 1, each buyer’s expected payoff is 0, and the seller’s expected payoff is 1.