PubMatic's charge for publishers that send more inventory than the platform will take is lower than it was a year ago, not new. The web history of the company's Supply Policy page shows that a version effective September 9, 2025 already set an Excess Inventory Fee of $0.005 per thousand impressions, and that the April 16, 2026 rewrite cut the rate to $0.001, a reduction of 80%. The current version, effective October 7, 2026, keeps the $0.001 rate, and sits alongside a second, larger charge that PPC Land's earlier coverage did not report: an Inventory Quality Fee of $0.02 CPM on impressions PubMatic flags as low quality.

In Short

PubMatic, a company that sells ad space on behalf of websites and apps, has a rulebook that can charge publishers small fees when they send too much traffic or traffic it considers low quality. Old copies of that rulebook show the fee for sending too much traffic existed in 2025 at five times today's rate, and that a separate quality fee has been there all along. The newest rulebook, dated October 7, 2026, adds many technical rules that can get traffic blocked rather than billed.

Three versions of one page

PPC Land checked the web history of PubMatic's Supply Policy page. The page carries no version number, only an effective date under its heading, and that history shows three versions since September 2025: one effective September 9, 2025, a rewrite effective April 16, 2026, and the current text, effective October 7, 2026. The fee rates, the caps and most of the publisher requirements discussed below changed between those versions.

The structure changed as much as the wording. The 2025 text reads like a contract schedule, built around defined terms such as "Publisher Inventory" and "PubMatic Services", with six sections that open on content guidelines and close on ad request requirements. The April 2026 rewrite shortened the language, switched to addressing publishers as "you", and added sections on data privacy and enforcement. The October 2026 version reorganized the whole document into eight sections, moving authorization and identity to the front and adding a long technical section on bid requests.

The Excess Inventory Fee, line by line

All three versions tie the fee to a daily ceiling PubMatic calls the Max Cap. The ceiling has never been published as a number in any version.

The September 2025 text described the cap as follows: PubMatic "shall perform ongoing analysis of Publisher's impression traffic and marketplace value and may establish maximum daily impression request levels in its commercially reasonable discretion ('Max Cap')." The fee clause read: "In the event that Publisher exceeds Max Caps, the Publisher shall be subject to the then current 'Excess Fee'. As of the Effective Date, the Excess Inventory Fee is $0.005 per thousand impressions and will be rounded up to the nearest $10 for the applicable month. The Excess Inventory Fee will not be charged for the first daily instance of overage against the Max Cap in a given month, but for all other daily instances."

Two phrases in that clause matter. "The then current" fee signals a rate PubMatic can change, and "as of the Effective Date" fixes $0.005 only from September 9, 2025.

The April 2026 version compressed the clause into two sentences: "Exceeding Max Caps may incur an Excess Inventory Fee of $0.001 CPM (rounded up to nearest $10/month). The first daily overage each month is not charged." The October 2026 version, under section 7.3, repeats those two sentences verbatim.

The October text adds one clarification that neither earlier version spelled out. Its new section 8.3, titled "Financial Consequences", lists the "Excess Inventory Fee - $0.001 CPM for impressions exceeding Max Cap (Section 7.3)." The fee, on that reading, applies to the impressions above the cap, not to a publisher's entire daily volume.

What the documents settle, and what they leave open

Reduced to its mechanics, the current version of the fee works like this, according to PubMatic:

  • Rate: $0.001 per thousand impressions, which equals $1 per million.
  • Base: impressions exceeding the Max Cap, per section 8.3.
  • Threshold: a daily maximum that PubMatic sets "based on traffic quality and market value". No figure is published.
  • Free allowance: the first day of overage in each month carries no charge.
  • Rounding: the monthly total is rounded up to the nearest $10.
  • Minimum: unlike the quality fee described below, no version of the Excess Inventory Fee carries a waiver for small amounts.

PPC Land's own arithmetic shows what the rounding rule does at the low end. A publisher that exceeds its cap by two million impressions on a second day in a month would owe $2 at the stated rate, which rounds up to $10. At the other end, one billion excess impressions in a month cost $1,000 at today's rate, compared with $5,000 under the September 2025 rate.

The unit of measurement is less settled than the rate. The 2025 version spoke of "maximum daily impression request levels". The April and October versions say "daily maximum impression limits". The fee itself has always been priced per thousand impressions. None of the versions mentions queries per second.

Notice is also uneven across the documents. On suspension, the October version says PubMatic "will attempt to notify you beforehand unless platform stability is at risk." No version promises notice before the Excess Inventory Fee is charged, and none sets out how a publisher learns its cap.

Suspension remains a parallel consequence. According to the current text, "Exceeding the Max Cap can result in suspended monetization until resolved." The 2025 version allowed suspension "until such time that the issue is remedied or monetization improves" - a second exit condition the newer versions dropped.

Corrections to PPC Land's earlier coverage

PPC Land reported on June 21, 2026 that PubMatic was charging publishers for sending too much inventory, based on enforcement emails publishers had shared and the policy page as it stood then. The $0.001 rate and the $10 rounding in that article match the April and October texts. Three points need correcting or completing.

First, the April 16, 2026 update did not introduce daily caps or the fee. That article's timeline described the April update as "introducing daily maximum impression and bid request limits per publisher", and PPC Land's company explainer later said the update introduced the fee. The September 2025 version already contained both the Max Cap and the Excess Inventory Fee, at a rate five times higher. The April update lowered the rate.

Second, the earlier article did not mention the free first overage day, which every version contains.

Third, the earlier article did not report the Inventory Quality Fee. It has appeared in all three versions.

The larger charge: the Inventory Quality Fee

The Inventory Quality Fee is 20 times the current excess rate. It applies to impressions PubMatic flags under what the policy calls "Inventory Quality Risk".

The October 2026 version defines that risk as "fake impressions (bots, manipulated placements, redirects with no human view) or brand safety issues (ads near prohibited content)." When such risks are detected, according to section 6.2, "PubMatic may charge an Inventory Quality Fee of $0.02 CPM for impressions flagged as low-quality. Monthly charges are rounded up to the nearest $10 and waived if under $100."

The 2025 wording was narrower about which impressions were billed. It applied the fee to "Inventory Quality Risk impressions made available to PubMatic for auction", set it at "presently $0.02 per thousand impressions", and added that "no charge will apply if the Inventory Quality Fee for a particular month is less than $100." The 2025 text also stated that when PubMatic detects such risk, it may "not send that impression through to auction". Read together, those clauses describe a charge on impressions offered to PubMatic, including ones it then declines to auction. The two newer versions do not repeat that link.

The rate has not moved since the September 2025 version. The $100 waiver means that, by PPC Land's calculation, a publisher with fewer than five million flagged impressions in a month pays nothing under this clause. Above that, ten million flagged impressions cost $200, and one billion cost $20,000.

None of the versions says which tools decide that an impression is low quality, or whether a publisher can contest a flag. Section 6.1 of the current text says PubMatic "adopts the IVT definitions published by the Media Rating Council (MRC) and continuously enhances detection using proprietary and third-party technologies." The policy classifies "any fraudulent, invalid, non-human, involuntary, duplicate, or otherwise illegitimate traffic" as invalid traffic. The word "duplicate" in that list is notable. The same document requires one ad request per impression opportunity, so duplicate traffic now sits inside the fraud definition as well as the request rules.

Withheld and unpaid impressions

The third financial lever is not a fee but a deduction. According to section 6.3 of the October version, "PubMatic may withhold payment for impressions under investigation" and publishers "will not be paid for fraudulent impressions."

The 2025 text was more precise about how that worked. PubMatic could withhold payments "solely for the applicable impressions until PubMatic has completed its good faith investigation with respect to such impressions and concluded any negotiation with the applicable Demand Partners", and where it found violations, it would "reduce pending payments by the amount otherwise payable to Publisher for the Fraudulent Impressions, and pay Publisher the resulting net amount in the ordinary course." The newer versions drop the reference to negotiations with demand partners and the netting language. No version sets a deadline for an investigation.

Section 8.3 of the current version gathers the three money consequences in one list: the Inventory Quality Fee, the Excess Inventory Fee, and withheld payment. The April 2026 version had a shorter equivalent in section 9.3. The 2025 version had none.

Technical rules that block traffic rather than bill it

Most of what the October 2026 version adds carries no price tag. The consequence is rejection or blocking. For publishers, lost bids are a cost of a different kind, and the list of conditions grew substantially in the latest version.

Authorization and identity

Section 1 requires ads.txt and app-ads.txt files, sellers.json and the SupplyChain Object, and states that PubMatic "transacts only on inventory authorized through the applicable ads.txt or app-ads.txt specification." Several requirements are new in October:

  • Publishers must not block crawler access to sellers.json, app-ads.txt and ads.txt files, because "PubMatic uses a crawler to verify these files."
  • The OWNERDOMAIN variable "must be formatted as ownerdomain=xyz.com and must resolve in a browser without redirects."
  • Where someone other than the owner handles programmatic sales, the MANAGERDOMAIN variable must be declared.
  • "Ad requests referencing invalid, incomplete, or non-transparent seller declarations may be blocked."

The ads.txt rule itself shifted. In 2025, PubMatic required its account to be listed only "if the Publisher Property in question has published an ads.txt file". The current text makes publication of accurate ads.txt and app-ads.txt files a condition for all inventory owners.

Supply chain limits

The SupplyChain Object rules are the most consequential change for intermediaries. The April 2026 version said that "no more than two hops inbound to PubMatic will be accepted." The October version keeps two inbound nodes for web, mobile web and in-app inventory, cuts the limit to one for CTV, and excludes the Google Open Bidding node from the count. It also states: "Resellers not sending schain will be blocked due to authorization error." Schain from direct sellers "will be ignored if sent."

CTV and apps

CTV bid requests must carry an AppID from one of seven named stores: "Roku, Vizio, LG, Samsung, Google TV, tvOS, or Fire TV". Otherwise a storeURL is required. Where both an application owner and a content owner sell inventory, the application owner must declare the content owner with the inventorypartnerdomain directive, and bid requests must populate app.ext.inventorypartnerdomain. For mobile apps, the policy states that "Effective Q4 2026, non-canonical App IDs are prohibited unless explicitly approved by PubMatic as a documented business exception." Requests from apps "that have been delisted, suspended, or removed from their app store may be rejected."

The lists of approved app stores are not consistent within the October document. Section 1.4 names the Google Play Store, Apple App Store and Amazon Appstore. Section 4.4 adds the Microsoft Store. The 2025 version named only "Apple iTunes store or Google Play Store".

Signal integrity and request structure

A new section 2.3 prohibits "modifying, fabricating, masking, or otherwise manipulating publisher-originated signals", including rewriting "identifiers, domains, application identifiers, device attributes, geographic information, or content metadata." According to PubMatic, "Sellers or intermediaries found to have manipulated signals with intent to falsely influence auction behavior may be blocked or terminated."

A signal table lists fields marked as required, among them publisher ID, site.domain and site.page for web, app.bundle for apps and CTV, country-level geo, device.ip, source.tid, and device.ifa for in-app and CTV "when device.lmt = 0". The rules on request volume carry over from earlier versions: one request per impression opportunity, multi-format and multi-size handling in a single request, and no "price waterfalling". The 2025 and April versions also told publishers to disable ad server settings that create duplicate impressions; the October version drops that sentence while keeping the one-request rule.

Ad experience thresholds

Section 4 of the October version turns several earlier guidelines into numbers. The 2025 text said that "for most pages, no more than 3 ads in view at the same time is appropriate." The current text states flatly: "No more than 3 ads visible in a viewport at any given time." It also adds a ratio absent from earlier versions: the "Ads-to-content ratio (A2CR) must remain below 35%."

Refresh rules gained a mobile app threshold. Ads may refresh after "at least 30 seconds (MRC-verified) on web; at least 10 seconds on mobile app," with a maximum of 20 refreshes per user session. Earlier versions set only the 30-second rule. A new page performance rule reads: "Page weight must be below 100 MB." For CTV, the limits are unchanged from 2025: in-stream only, a maximum of five ads per block, and content at least four times longer than the ad block. Video requests must now declare player and playback features "per oRTB 2.6 fields", and rewarded placements must use "rwdd = 1".

Content rules: MFA and AI-generated sites

Made-for-advertising inventory has been banned since at least the 2025 version, which said domains "categorized as 'Made for Advertising' using Jounce Media's definition are banned from the PubMatic platform." The April 2026 version widened the reference to "Jounce Media or similar verification providers" and added "'AI Slop' sites with auto-generated low-value content." The October text replaces that phrase with "AI-generated low-quality content sites with templated UI and poor UX."

A new section 3.3, "High-Risk Inventory", lists three further prohibited types that "may be blocked or removed": AI-generated low-quality content "characterized by templated UI, poor UX, or lack of meaningful editorial oversight", "Pop-sourced or pop-creator inventory", and "Any inventory exhibiting MFA characteristics as defined by third-party verification providers." The policy does not define "pop-creator".

The brand safety references also changed. The 2025 version cited the 4A's brand safety floor, the WFA's GARM framework and IAB's content taxonomy 2.2. The newer versions refer only to "industry standards from the 4A's and IAB".

How enforcement escalates

The April and October versions describe four tiers: warning, restriction, suspension and termination. According to section 8.2 of the current text, PubMatic "reserves the right to bypass the tiered process and take immediate action (including suspension or termination) for severe violations, including fraud, malware distribution, or content involving the exploitation of minors." The 2025 version had no tiered framework, but stated that PubMatic could "immediately stop/pause monetization for any publishers in violation of these policies without notice."

What the documents do not contain

Several costs a publisher might expect to find are absent from all three versions. None states PubMatic's revenue share or take rate, payment terms or payment timing, or any fee tied to ads.txt, sellers.json, schain or bid request volume as such. None charges for SDK or wrapper use, and none sets a queries-per-second limit. Breaches of the technical rules lead to blocking, rejection or suspension, not to a listed charge. Commercial terms of that kind may sit in individual publisher agreements; the policy page does not say.

Why the follow-up matters

The figures fit a pattern PPC Land has followed through 2026. PubMatic's second-quarter results in August showed revenue of $78.6 million, up 11%, while gross impressions processed fell 2% from the previous quarter and monetized impressions rose 4%. Management described the reduction as deliberate. A fee schedule that charges for volume above a cap and for flagged impressions points in the same direction, though nothing in the policy documents links the two.

The wider industry has moved on the same problem with tools rather than fees. Amazon donated its Dynamic Traffic Engine to IAB Tech Lab in April 2026 to help DSPs signal bidding priorities to SSPs and cut wasted bid requests. IAB Tech Lab's Programmatic Governance Council released voluntary best practices on duplicate bid requests on September 16, 2026, asking that requests go to each partner only once per ad opportunity and that schain be included in every request. That guidance sets no node limit. PubMatic, a founding member of the council, now enforces one. DataBeat data reported in May 2026 found a 46% duplicated domain rate across Tier 1 SSPs, the kind of multi-path supply the October node limits restrict. Publishers have been throttling bids on their own side since at least mid-2025.

For a supply-side platform that reported revenue declines for three quarters before the second-quarter rebound, the trade-off is visible in the documents themselves. PubMatic lowered the charge on excess volume and left the charge on flagged volume unchanged. It also added a long list of conditions that remove nonconforming traffic before any fee applies. Whether that combination reduces the number of fees publishers actually pay, or shifts more inventory into outright rejection, cannot be determined from the policy text. PubMatic publishes neither the caps nor the volume of impressions flagged or billed.

Timeline

Summary

Who: PubMatic, the Nasdaq-listed supply-side platform, and the publishers and supply partners that sell inventory through it, including resellers and CTV app owners.

What: The web history of PubMatic's Supply Policy page shows three versions. The Excess Inventory Fee for exceeding a daily Max Cap was $0.005 CPM from September 9, 2025 and $0.001 CPM from April 16, 2026, with the first overage day each month free. An Inventory Quality Fee of $0.02 CPM on flagged impressions, waived under $100 a month, appears in all three. The October 7, 2026 version adds schain node limits, signal integrity rules, an ads-to-content ratio and page weight limits enforced by blocking.

When: The current version took effect on October 7, 2026; earlier versions took effect on September 9, 2025 and April 16, 2026. PPC Land compared them using the page's web history.

Where: PubMatic's Supply Policy page, applying to all publisher properties monetized through PubMatic across web, mobile web, in-app and CTV.

Why: PPC Land's earlier coverage presented the Excess Inventory Fee as introduced in April 2026, when it had existed at a higher rate since at least September 2025, and it omitted the larger Inventory Quality Fee. The documents show PubMatic pricing excess and low-quality volume while widening the set of conditions under which it rejects traffic outright.