Open Marketplace (OMP), or Open Exchange, is inventory that is made available to everyone. The first true form of programmatic auctions, OMP provides a cost effective way to buy audiences at scale, but does not give publishers much control over who is accessing their inventory.
Private Marketplace (PMP), unlike OMP, requires buyers to be invited in order for them to be able to access this inventory. This gives publishers more control over who advertises on their site.
Unreserved Fixed Rate (UFR), or Programmatic Direct, bypasses the traditional auction, by creating a one to one agreement with an advertiser, where the CPM is prenegotiated at a fixed rate. However, the inventory is not guaranteed, and there are no spend commitments.
Programmatic Guaranteed (PG) also uses the one to one agreement between a publisher and an advertiser with a prenegotiated fixed rate. However, unlike UFRs, impression volumes and spend commitments are guaranteed.
