Removing 7 of 18 header-bidding partners raised yield 9%

Removing 7 of 18 header-bidding partners raised yield 9%

More demand partners is assumed to mean more competition. A publisher tested that assumption and found the opposite past a point.

1. They logged each of 18 header-bidding partners' bid rate, win rate, and average bid over 30 days.
— 7 partners had win rates under 0.5% and bid below the floor 90% of the time.
2. Those partners added latency to every auction (each bidder call extends the timeout window) without ever setting the price.
3. They removed the 7, narrowing the auction to 11 active bidders.

Evidence: average auction latency fell 280ms, letting them tighten the timeout and capture more complete bids from the 11 real competitors. Yield per impression rose 9%, and timeout-related bid loss on the strong partners dropped by a third. The dead-weight bidders had been inflating latency, which forced a wider timeout that hurt everyone.

Why it matters: in header bidding, each bidder is a latency cost paid on every auction. A partner that never wins and never sets the price adds delay without competition. Pruning non-competitive demand can raise yield by letting real bidders respond in time.