This response only applies to listings which allow limit bids (aka proxy bids). Please refer to the example below.
Assume Bidder A holds the current high bid at $90 and has a limit bid of $96 “stored” in the system (not disclosed to other bidders). Also assume that the minimum raise at this level is $10. Therefore, the next acceptable minimum bid shown on the bid form is $100.
If Bidder B subsequently bids $100, he/she will become the high bidder at $100. This occurs because Bidder B has no way of knowing the hidden limit bid of Bidder A (in this case $96) and can only bid based on the minimum amount presented. Thus, a bidder may “lose” an item for less than the minimum raise.
In the example above, Bidder A lost the item by $4 when the minimum raise at the $96 level was $10.