What is Bid Stacking?
Big stacking, or multi-bidding, is a bidding practice used by exchanges/DSPs in order to increase their chances of winning an impression. Instead of submitting a single bid for each single impression opportunity, some exchange/DSPs submit multiple bids to account for advertiser blocks, landing page blocks, etc. For exchanges, this can be particularly lucrative, as exchanges typically charge publishers a fee for each impression won.
Single vs. Multi-Bid Graphic
Single Bid Scenario
Multi-Bid Scenario
Images from Lift Letters.
Drawbacks
- DSP bids can be used against themselves.
- Longer processing time and cost for more bid signals.
- Unfair advantage compared to competitors.
- Overcharging publishers.
Potential Solution
Publishers can work around this practice by requesting log-level data from the exchanges. However, many vendors are unwilling to do this as they are concerned about security and privacy.
Sources
- https://digiday.com/media/wtf-what-is-bid-stacking/
- https://www.liftletters.com/all-letters/2018/9/14/dsps-and-multi-bid
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