Open auction vs PMP: when each beats the other
Open auction and PMP are the two most-used programmatic buying lanes. Open auction is the unrestricted auction across all eligible inventory; PMP is the invite-only auction on curated inventory. The right lane depends on what you're trying to accomplish, not on which is "better" in the abstract.
What each lane actually is
| Open Auction (OMP) | PMP | |
|---|---|---|
| Who can bid | All DSPs connected to the exchange | Only invited buyers via deal ID |
| What's available | All eligible inventory | Publisher-curated slice |
| Floor price | Set by publisher per ad slot | Set per deal, usually higher |
| Auction type | First-price (mostly) | First-price, with deal priority |
| Typical CPM | $1-$8 display, $5-$25 CTV | $5-$25 display, $20-$60 CTV |
| Brand safety | Depends on filters | High by curation |
| Volume | Very high, scalable | Lower, capped by curation |
| Optimization speed | Fastest | Fast within deal constraints |
Where open auction wins
- Scale prospecting at low CPMs. When the goal is reach, open auction is the cheapest path. Filter aggressively for IVT, viewability, and brand safety; the remaining inventory delivers efficient reach.
- Tail audiences. Niche behavioral segments often have most of their volume on long-tail publishers, accessible only through the open auction.
- Optimization speed. Open auction gives you the most freedom to move budget between audiences, creatives, and bid strategies.
- Test budgets. A new audience or creative concept is cheaper to test in open auction than to negotiate a PMP for.
Where PMP wins
- Brand-safe environments. Premium publisher inventory at a price you know in advance, in known editorial contexts.
- Audience-curated inventory. Publishers package their first-party audiences (subscribers, registered users) into PMPs that no open-auction targeting can reproduce.
- Premium video and CTV. Most quality CTV inventory moves through PMP and PG. Open auction CTV is the long tail; not where premium budgets should go.
- Compliance-sensitive categories. Pharma, financial services, and regulated industries usually require PMP-level inventory certainty.
- Tentpole moments. Awards shows, sports events, premieres — PMP locks the inventory in advance at a known price.
The hybrid pattern
Most mature programmatic budgets split roughly: 40-60% open auction (after rigorous filtering) for prospecting reach and optimization, 30-50% PMP for premium inventory and audience-curated buys, 5-15% PG for tentpole and guarantee. The exact split depends on category — luxury skews PMP and PG, performance-DTC skews open auction, B2B skews PMP because the LinkedIn-Bombora-RollWorks ecosystem is mostly PMP-delivered.
The price-quality tradeoff in practice
A common buyer error is comparing open auction CPM to PMP CPM and concluding open auction is cheaper. The accurate comparison is open auction after filtering versus PMP. A filtered open-auction campaign (whitelist, viewability floor 70%+, IVT under 1%, brand-safety 95%+) often has working CPMs 50-80% higher than unfiltered open auction, narrowing the gap to PMP considerably. The PMP premium is often 20-40% over filtered open auction, not 200-300% over raw open auction.
When to convert open-auction performance into a PMP
The mature optimization pattern: run open auction broadly, identify the top-performing publisher placements, then negotiate a PMP with each high-performer at a price slightly above their open-exchange clearing. Result: lock in the inventory that's already working at a known price, free up budget from the long tail to invest in proven supply. This loop runs continuously in well-run programmatic accounts.
Is open auction always lower quality than PMP?
Not after filtering. A well-filtered open-auction campaign can match PMP quality on most dimensions. The cost is operator effort: someone has to maintain whitelists, exclusion lists, and quality filters. PMP outsources that work to the publisher's curation, which is why the premium exists.
Can I do programmatic without any PMP?
Yes, and many performance-focused accounts run 80%+ open auction. The tradeoffs are brand-safety risk (managed via filters) and limited access to premium inventory (you pay open-auction prices when you can win, but premium publishers often hold their best inventory in PMP).
How do I price a PMP against the open auction equivalent?
Pull the publisher's open-exchange clearing CPM for the same inventory from your DSP's marketplace insights or your SSP partner's data. Add 20-50% for standard PMP, 50-150% for premium inventory or audience-curated PMPs.
What's the IVT difference?
Open auction IVT (sophisticated invalid traffic) commonly runs 1-3% with filters, 5-15% without. PMP IVT runs under 1% by curation. The gap is real but closes with disciplined filtering.
Does open auction work for CTV?
The long tail does. Premium CTV inventory (major streaming platforms, FAST channels with significant viewership) is mostly PMP and PG. Open-auction CTV is real but more variable in quality.
Is PMP still relevant after consolidation?
Yes. Consolidation of SSP/DSP pipes hasn't eliminated the need for curated inventory packages. PMPs and curated marketplaces are growing as a share of total programmatic spend, not shrinking.
Operating checklist
- Map campaign goals against platform strengths before launch.
- Negotiate fee transparency in writing; require ANA-style supply-chain disclosure.
- Configure pre-bid filters for IVT, viewability, and brand safety.
- Apply supply-path optimization to reduce duplicate auctions.
- Run weekly delivery, pacing, and quality reviews.
- Reconcile DSP-side vs publisher-side reporting monthly.
- Document seats, deals, owners, and lessons in a runbook your successor can read.