With the migration to a unified first-price auction, minimum bid to win feedback is shared with each bidder after the auction (which specifies the amount that would have needed to be paid to win the auction). This helps losing bidders bid more competitively into the auction, improving publisher yield.
When a publisher additionally has a mediation chain, accessing analogous data will be helpful in further improving the competitiveness of bidders, and hence publisher yield. Starting the first week of October 2019, a model that generates random samples to represent eCPM from potential mediation competition will be shared with bidders, informed by the eCPM and fill rate for the mediation chain, from demand sources that are placed before and after bidder.