<b>The price your ad sells for isn't the bid that won</b>

<b>The price your ad sells for isn't the bid that won</b>

In most header bidding auctions the winner pays slightly more than the second-highest bid, not their own bid. That's a "second-price auction."

Why it matters: a buyer can bid $5 safely, knowing they'll likely pay closer to the runner-up's $2.10, not the full $5.

Tiny example:
— Bidder A offers $5.00
— Bidder B offers $2.00
— A wins, pays $2.01

The catch: many networks quietly switched to first-price (you pay what you bid), so the same demand now bids lower on purpose. That's normal, not a bug.

One thing to try: ask your partners which auction type they run. Mixed types explain weird revenue swings.

In plain English: winning bid and paid price are two different numbers.