First-Price vs. Second-Price Auction — What’s the Difference?

bespectacled man staring at a computer screen, thinking

If you have ever bought anything on eBay, you are probably familiar with the second-price auction, where the winner pays the second highest bid rather than their own. For years, programmatic ad buying ran in a second-price auction format with the whole transaction happening in milliseconds. However, there has been a recent shift among many publishers to a first-price auction model, where what you bid is what you pay if you win the impression.

Bidding in a first-price auction with a second-price strategy can get expensive quickly. Yet, nearly half of buyers are still in the dark on the basic differences of the first-price versus second-price auction according to The Drum. Without a clear understanding of the mechanics in play for each auction, how can you know the right price to pay to get the best value from your media?

Let’s start with clearing up a few quick terms:

  • First-Price Auction – Digital buying model where if your bid wins, you pay exactly what you bid. This maximizes revenue potential for the seller.
  • Second-Price Auction – Digital buying model where if your bid wins, you pay $0.01 above the second highest bid in the auction. In this type of auction, it is in your best interest to bid the highest amount you are willing to pay, knowing that often you will end up paying less than that amount.
  • Header Bidding – A popular type of first-price auction where publishers place a piece of code on their webpage headers that allows a limited number of advertisers to bid on inventory outside of their primary ad server. This lets advertisers compete for premium, reserved inventory prior to or in lieu of the second-price auction.
  • Price Floor – The minimum price a publisher will accept for its inventory. Publishers ignore all bids below that price. This, in effect, turns a second-price auction into a type of first-price auction.
  • Clearing Price – The final price paid for an impression.


Here’s a quick example of what happens when you place a bid in a first-price versus second-price auction:


first-price vs. second-price auction chart


  1. Look for machine learning technologies built for the new environment that can identify first-price auctions, predict price floors and adjust your bids accordingly.
  2. Find a DSP that operates effectively in both auctions and can handle the increase in bid density.
  3. Rather than concentrating solely on the data from bids won, regularly evaluate lost impression data as well to improve your bidding strategy.

Now that you know bidding basics, are you ready to find out if you are getting the most value from your media? Reach out to us to learn more.


Noah is a 15-year agency veteran who brings his deep cross-channel and cross-vertical media experience to the digital table. He co-created an agency trading desk, leading a trading team into the real-time-bidding environment before it was an industry-accepted practice. As a member of the sales-enablement team, he lives on the front lines of the digital world providing our clients holistic strategy recommendations, insightful research, and in-depth analysis and evangelizing all things programmatic. You can find him in an airport near you on his way to a client meeting.

2018-03-06T22:45:13+00:00 Education|