For years, programmatic buyers could see who was getting paid in a transaction. They rarely saw all the companies processing a request for quotation before it came to them.
The IAB Tech Lab wants to change that.
Today, the organization offered an update to its OpenRTB SupplyChain object, commonly known as schain, exposing both the business and technical journey of a request for quotation. If adopted, the change could reshape procurement journey optimization by showing buyers not only who earned revenue from a transaction, but also who touched them along the way.
The proposed standard, SupplyChain v1.1, is available for public comment until August 21, 2026.
Look beyond the money trail
The current Schain standard gives buyers visibility into the financial journey of a transaction by identifying companies participating in the payment flow. It does not necessarily reveal all companies that process, route, enrich or transmit a request for quotation.
This distinction is all the more important as programmatic infrastructure becomes more and more complex. A unique impression opportunity may pass through ad servers, Prebid implementations, SDKs, server-side ad insertion platforms, wrappers, and other technologies before reaching a buyer.
According to the proposal, buyers would also be able to see these participants. “This is one of the most significant transparency improvements to the digital advertising supply chain in years,” Anthony Katsur, CEO of IAB Tech Lab, said in a statement.
The update aims to give buyers a more complete record of inventory available on the open internet.
Why Advertisers Care
The proposal comes as advertisers look for ways to reduce waste and optimize supply chains. Much of the industry’s SPO work focuses on finding the shortest path from publisher to buyer. The prevailing hypothesis is that fewer intermediaries lead to greater efficiency.
SupplyChain v1.1 challenges this assumption.
Longer supply chains do not automatically represent lower quality supply chains if buyers can see and evaluate each participant. This idea may have broader implications than the technical update itself.
Instead of simply counting intermediaries, buyers could assess the contribution of each participant. A procurement journey with more participants can provide more value than a shorter journey if each participant serves a useful function and the process remains transparent.
The conversation moves from “How long is this path?” » to “Who is participating in this path and why?” »
Transparency creates winners and losers
Not all companies in the ecosystem will like this change.
Advertisers have spent years demanding better visibility into what inventory is packaged, shipped and sold. Greater transparency could reveal redundant infrastructure, duplicate requests for bids and intermediaries who add little value.
This scrutiny could create difficulties for suppliers who struggle to explain their role in the transaction chain. At the same time, businesses that deliver measurable value are more likely to differentiate themselves from their competitors.
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The proposal turns technical participation into something buyers can evaluate rather than something hidden behind the scenes.
How the update works
The working group behind the proposal evaluated several implementation approaches before selecting one that integrated technical conservation information directly into the existing chain framework. Companies that technically support a request but do not participate in the payment flow would receive the designation hp=0.
According to the IAB Tech Lab, this approach preserves compatibility with the existing standard while expanding visibility into requests as they move through the ecosystem.
The organization also expects longer lead times as transparency increases. To support adoption, the IAB Tech Lab plans to release deployment guidance encouraging SSPs and DSPs to conduct phased testing, validate analytics behavior, monitor auction status, and incrementally increase traffic using the new specification.
The position Advertisers can finally see who is actually touching their bid requests appeared first on MarTech.
