1. As that you would be able to see in the instance, the maximum bidder from the DSPs didn’t end up profitable the auction, due to second price public sale model utilized by most exchanges. To recap, second price auctions send the price of the second highest bidder plus one cent. In a header bidding scenario like the one above, the second price auction model is not top-rated, because the maximum bid was prevented from winning.
The end result is lost income to the writer, and a handicapped atmosphere for advertisers. The obvious answer would be to modify to a primary price auction, where the highest bids are undergone without reduction. Update: As of March 21, 2019, most of the major exchanges have moved to the first price model for the aforementioned purposes, including Google. Before header bidding, exchanges would commonly see impressions only once — when it was their turn to fill it in the waterfall. We will ignore edge cases for now. As for DSPs, they may see that very same impression two or 3 times, as it cascades down the waterfall from one trade to the next.
However, with the addition of a header public sale, exchanges now see an identical impression twice, which nearly doubles the variety of calls going to their servers. It’s no shock that Rubicon spent $25 million on just hardware infrastructure last year. And with their new dedication to header bidding, expect that number to rise sharply.