Here is the uncomfortable truth buried in every media plan: the price you bid, the price the auction clears at and the price the publisher banks are three different numbers. All three can be correct at the same time.
PPC Land’s explainer on advertising price lays out the plumbing, and it is worth every marketer’s time. Because most arguments about “expensive” inventory are not arguments about money at all. They are arguments about units, measurement points and which fees were already skimmed off.
The unit is the whole story
A price means nothing without the unit attached. Display and video trade on CPM, the cost of a thousand impressions, a convention inherited from print, where circulation was the only countable quantity. Search sells clicks. Affiliate and performance channels sell completed actions under CPA or CPL.
Programmatic display leans so hard on CPM that the standard itself hard-codes it: in OpenRTB, the IAB Tech Lab spec that carries bid requests and responses, a bid’s price is expressed as CPM even though the transaction covers one single impression.
New surfaces are reviving the older mix. Per PPC Land, OpenAI added cost-per-click bidding to ChatGPT Ads Manager on 5 May 2026, alongside an existing $60 CPM and a suggested opening click bid of $3 to $5. Two units, one surface, and no clean conversion between them unless you assume a click-through rate.
How the number actually gets made
Inventory is created continuously and expires instantly, so most of it is never priced in advance. In programmatic, the price is manufactured in the few dozen milliseconds between a page request and an ad rendering.
The mechanics, in order:
- bidfloor — the seller’s minimum, in CPM, with bidfloorcur naming the currency (defaulting to US dollars).
- at — the auction rule: 1 for first price, 2 for second price, and 3 inside a private marketplace deal, where the floor is the agreed price.
- mincpmpersec — CTV pods get a floor per second, because a six-second slot and a thirty-second slot are not the same product.
- price — the buyer’s required bid value on the bid object.
- ${AUCTION_PRICE} — the clearing price reported back on settlement, plus ${AUCTION_MBR}, the market bid ratio showing how much of your bid the auction kept.
The spec’s own worked example is the clearest lesson in performance marketing you will read this quarter. Floor of $0.85, bids of $1.00, $0.90 and $0.80. Under first price, the winner pays $1.00. Under second price clearing a cent above the runner-up, it pays $0.91. Nine cents on the dollar, decided by nothing the bidders did differently.
Then the fees open the second gap
Google Ad Manager makes the split visible: its data transfer bid fields define BidPrice and seller reserve price after revenue-share calculations, so publishers read numbers already net of the exchange’s cut.
How big is that cut? Contested. PPC Land cites GroupM’s 2018 audit putting DSPs and SSPs at roughly 10% each, while a 2017 ANA study with Ebiquity put total fees near 40 cents in the ad dollar.
Why this matters right now
Prices are moving. DataBeat’s July 2026 report, distributed 4 August 2026 across a network tracking over 200 bidders, put US programmatic CPMs up 51.0% year over year — while absolute levels stayed low: app $1.70, web $1.42, mobile $1.72, desktop $1.77, CTV $5.74. And buyer type shows up in price: the June 2026 edition found conventional demand clearing at $6.95 versus $6.13 for agentic buyers, a 13.4% premium.
Disclosure is the sharper fight. On 31 August 2026 the FTC and 22 states sued Amazon over what internal documents called a surcharge — roughly $20 billion across 1.2 million advertisers, with advertisers charged their full bid 79% of the time. Amazon countered that no advertiser paid above its own bid and that relevance-weighted ranking saved advertisers more than $8 billion between 2021 and 2025. Different counterfactuals; both sets of figures can hold.
Meanwhile, on 2 September 2026 a Virginia judge found Google had illegally monopolised two ad markets and rewrote the auction rules instead of ordering a breakup: unified pricing rules deprecated, per-bidder floors restored, first look and last look banned on open-web display, AdX bid data shared with rival ad servers.
Your action list
Stop treating CPM as a property of an impression. It is a property of a transaction, measured somewhere. Label every price with its unit, its measurement point and its fee status before you compare it. Ask your DSP for clearing price versus bid price. Ask your partners for take rate against gross spend, not margin. And if AI agents are buying on your behalf, note that IAB Tech Lab shipped AAMP 2.3 on 30 July 2026 with a pricing provenance field — because agents were able to generate a plausible CPM where no market data existed. A fabricated price looks exactly like a real one.
Source: PPC Land
