5 SSPs vs 15 SSPs: diminishing returns and the latency wall

5 SSPs vs 15 SSPs: diminishing returns and the latency wall

Benchmark drop. Marginal CPM lift per added demand partner (n=110 sites):

— Partners 1-5 ▮▮▮▮▮▮▮▮ +cumulative 22%
— Partners 6-10 ▮▮▮ +6%
— Partners 11-15 ▮ +1.3% and rising latency

Each SSP (supply-side platform) you add raises auction pressure but also page weight and timeout risk. Past ~8 partners, the bid-density gain flattens while cookie-sync calls and latency keep climbing.

Audit quarterly: drop any partner winning under 2% of auctions or contributing under 1% of revenue. More bidders is not more money past the elbow.

So what: Trimming 14 SSPs to 8 by win-rate — latency ▼ 24%, revenue flat to ▲ 1%.