1. In fact the opposite normally happens. Bidders will often want to do something called "splitting the bid" which means they want to move up their bidding in smaller increments. So let's say the current bid is at $5 million and the auctioneer is moving up $250k at a time... https://twitter.com/bendreyfuss/status/1302805387729666048

2. A bidder may offer a bid of $5.1 million instead of $5.25 million and the auctioneer can decide whether or not to allow them to split the bid. Often it helps to move the price up, especially when there are just two bidders left

One notable exception to this has to do with MBS

3. Saudi Crown Prince had a rep bidding for a Da Vinci at Christies. Lot was at $355 million...auctioneer said "$360 million is next". The person who turned out to be the underbidder took it to $370 mil. Big jump.

Then, MBS jumped to $400 million even though he didn't need to.

4. The lot went to MBS for $400 million hammer plus premium which meant that he ended up paying a total of $450.3 million.

So, it's rare for someone to go above bidding increments but when you're playing with Saudi national wealth...it's much easier.