PMP vs Open Marketplace vs Programmatic Guaranteed: The Deal Economics Guide

1. The Programmatic Transaction Spectrum

Programmatic media buying is not a monolith. Transactions span a continuum from completely public open exchanges to highly restricted 1-to-1 automated direct reservation contracts:

1. Open Marketplace (OMP / Open Auction): Public RTB auction where all DSPs compete for remnant impressions. High scale, lowest CPMs, variable inventory quality.
2. Private Marketplace (PMP / Private Auction): An invitation-only auction where a publisher grants a curated group of buyers priority access to premium inventory with a negotiated floor price via a Deal ID.
3. Preferred Deals (Unreserved Fixed Rate): A 1-to-1 deal giving a specific buyer "first look" at an impression at a fixed, pre-negotiated CPM before it drops into the open auction. The buyer is not required to bid.
4. Programmatic Guaranteed (PG): A 1-to-1 direct reservation contract executed programmatically. 100% reserved volume, fixed pricing, and mandatory buy commitments with delivery SLA penalties.

2. Architectural Comparison Matrix

3. OpenRTB Deal ID Mechanics

When an impression is eligible for a PMP or Programmatic Guaranteed deal, the SSP populates the imp[].pmp object inside the OpenRTB bid request:

{
  "id": "auction-deal-881203",
  "imp": [
    {
      "id": "1",
      "banner": { "w": 300, "h": 250 },
      "bidfloor": 8.50,
      "pmp": {
        "private_auction": 1,
        "deals": [
          {
            "id": "DEAL-PREMIUM-FIN-2026",
            "bidfloor": 8.50,
            "bidfloorcur": "USD",
            "at": 3,
            "wseat": ["seat-thetradedesk-104"]
          }
        ]
      }
    }
  ]
}

Important PMP Parameters

• pmp.private_auction = 1: Informs buyers that only bids submitted with a valid matching Deal ID will be accepted. Open marketplace bids without the Deal ID are discarded.
• deals[].id: The exact identifier mapped between buyer DSP and seller SSP.
• deals[].at = 3: OpenRTB auction type code 3 indicates a value-based / fixed-price deal, meaning the buyer's bid clears exactly at the agreed rate.
• deals[].wseat: Whitelist of DSP buyer seats authorized to bid on this specific deal token.

4. Programmatic Guaranteed: The "Sync Check" & Daily Pacing

In a Programmatic Guaranteed (PG) transaction, the publisher and buyer must complete an automated Sync Check before campaign live date:

1. The publisher sets up the line item in GAM 360 with a committed volume (e.g. 100,000 daily impressions).
2. The proposal pushes via API to the buyer's DSP (e.g. DV360).
3. The DSP buyer accepts the proposal, attaches pre-approved creatives, and confirms targeting alignment.
4. GAM continuously queries the DSP endpoint with test pings to verify that creative dimensions, audio/video specs, and domain whitelists match with 100% parity.

5. Solution Engineer Deal Troubleshooting: "Active PMP with Zero Delivery"

A publisher sales team escalates: "We set up a $12.00 PMP deal for an automotive advertiser. The deal has been active for 48 hours, but our dashboard shows 0 impressions delivered and 0 bids received. What is wrong?"

6. Real-World Interview Scenarios