Reference library · Inventory pricing
Private Marketplace (PMP) vs Open Exchange
Private Marketplace (PMP) is an invite-only programmatic deal in which a publisher grants a specific buyer access to defined inventory at a negotiated CPM floor, with that buyer's bids evaluated ahead of the open pool. Open Exchange is the unreserved auction where any connected buyer competes in real time for any available impression at the market-clearing price. The choice is about trading cost and scale for control over context, placement, and data access.
Worked example
A Czech buyer splits a €20,000 display budget: €10,000 into a PMP deal with a premium news publisher at an €8.00 CPM floor, and €10,000 into Open Exchange at an average €3.20 CPM. The PMP portion delivers 1,250,000 impressions (10,000 / 8.00 × 1,000), all on the named domain; the Open Exchange portion delivers 3,125,000 impressions (10,000 / 3.20 × 1,000) spread across thousands of sites. Total delivery is 4,375,000 impressions, but only the PMP share carries the context guarantee the brand paid the premium for.
How it is used
Planners route budget to PMP when a specific publisher, section, or first-party data match matters more than unit cost, and to Open Exchange when the goal is reach or frequency at the lowest CPM. Deal IDs are set up bilaterally through the publisher or SSP with a negotiated floor, and DSPs are configured to evaluate that deal before falling into the open auction for the same impression. Buyers frequently under-pace PMP deals because they set the floor too close to open-market CPMs, so the deal never wins enough auctions to spend the allocated budget.
The common mistake
Don't treat a PMP floor price as a guaranteed cost or guaranteed delivery; it's a minimum bid in an auction the buyer can still lose, unlike a programmatic guaranteed (PG) buy.