The Bid Decrement is the minimum dollar amount by which a Seller’s total bid price must decrease when submitting a rebid, and only applies during the rebid process.  The Bid Decrement is determined by the Buyer on each individual buy, and can be viewed on the Terms page of the buy when you are placing your bid.

For example, if the initial bid is $10,000, and the Bid Decrement set by the Buyer is $10, the total bid price must decrease at least $10 from the initial bid in order to submit a rebid.  In this example, the total bid price would have to be $9,990 or lower to submit a rebid.