Originally Posted by
Eregion2
If you could retract your bid they'd have to do something else to balance it as well, since as soon as you are outbid you get your money back through the mail system; then if the person who outbid you retracts his bid there's no money placed on the item at all and the guy selling it gets screwed (also this tactic could possibly be used by someone who is selling something at a higher price than someone else; he and a friend would drive the other player's price even higher than his own before retracting his bid and spending no money at all while making sure his item is the "cheapest" one in the AH).