Sellers may have already experienced this phenomenon. You put up a wonderful item that you know to be desirable to collectors. Vigorous bidding ensues. It sells for a good or great price. And then you wait. And wait. The high bidder has disappeared, or creates other problems that result in a failed transaction. You approach your underbidders about their interest and find that lo, their ardor has cooled or they try to dicker you down on the price. You are forced to re-list the item but now it has lost some of its cache. It sells for a fraction of its earlier price. Sometimes to the very underbidders who coyly averred earlier.

I've encountered this situation before where collectors of a specific type of collectible collude with one another in their narrow collecting niche on ebay. They get to know one another because they are generally competing for the same items. Maybe they have even met each other at auctions or big shows. What such collectors have discovered is that they can "divvy up" desirable listings among themselves as a strategy for suppressing bidding and keeping the price down. It can be as simple as two competing collectors deciding between them that they will not compete ("You take this one Jack.") Sometimes the tactics are more elaborate involving the use of ghost bidders as well as fall away underbidders.

I have had such collectors brag to me about their cabals. There used to be (and perhaps still is) an active group of Pickard collectors, for example, who engage in such "friendly" bidding strategies. I am sure there are others. What can a seller do in defense? Here are some ideas:

• First, be on your guard when you are listing certain rare and unusual collectibles. These are high end items that fall in a narrow collecting category where there is a limited supply, usually antique and vintage.
• Put a very short time frame for the initial contact required from your winning bidder. I use 24 hours. If I do not hear from the bidder within that time I will call them. This often reveals whether you have a real bidder or not.
• If there is any false contact information REPORT FALSE OR MISSING CONTACT INFORMATION to Ebay's Trust and Safety.
• If the underbidders fall away, block such bidders from future bidding on your auctions. I have found this to be a very effective strategy for defeating future attempts by such bidders. Sometimes I will get a "gee, its all in good fun" email from such bidders, more often an irate "why have I been blocked." but I believe in the long run I am better off not having these game players participating in my auctions. And if enough good ebay sellers do this, perhaps these collectors will stop using such tactics.

If you have other ideas and strategies for defeating such cabals, please share them with me. I will add them to this ebay guide.