The latest transparency saga to engulf the ad tech sector, or transaction-IDs or TIDs, has thrown up several terms that have had some of the industry’s most erudite names debating terms such as auction density, bidding rings and deduplication.

It all bubbled to the surface in mid-August when Prebid, the open-source consortium responsible for much of the internet’s programmatic advertising infrastructure, quietly altered how TIDs are generated in its 10.9 update, sparking impassioned debate over transparency.

It’s left those in the middle arguing over just what is, and what isn’t a fair way to do business, but now (it seems) there may be some light at the end of the tunnel, with a “grand bargain” recently tabled as a potential resolution.

How we got here

First introduced in 2023, TIDs are part of the Prebid and OpenRTB standards, providing a unique identifier that ties multiple bid requests for the same impression to a single auction. Since the August debate bubbled up, these have often been referred to as the global IDs, but officially they are also TIDs.

For buyers, particularly demand-side platforms, global IDs help buyers eliminate duplicate bid requests. However, supply-side platforms and some publishers claim they raise concerns about data leakage and further entrench buy-side power — i.e., suppress yield — by diminishing publishers’ (already) limited control over auction dynamics.

Prebid’s 10.9 update changed the handling of TIDs so that each bidder now received a unique TID, rather than the previous global ID, where a single TID was shared across all SSPs and bid paths, with advocates further arguing the privacy issues at play. This argument was primarily about the potential to stitch together multiple bid requests from different sellers using global IDs, enabling buyers to deduce connections between those requests and other IDs.

**Tense exchanges **

Of course, The Trade Desk led the counterargument on behalf of the buy-side, making its position clear with the September launch of OpenAds, an open-source framework for the auction stack that it claimed would restore efficiency and transparency across the open-web ecosystem. However, some argued this launch represented the industry’s largest independent DSP building sell-side tools.

However, this was an accusation that Jeff Green, The Trade Desk CEO, was quick to rebut when questioned at this year’s Prebid Summit. “I think it’s a mistake to sort of bring that mindset or paradigm to the table,” he told Garrett McGrath, a Prebid board member and svp of product at leading SSP Magnite, on stage, in what many interpreted as the highlight of this fall’s ad tech conference circuit.

“Without improvement to the supply-chain, we don’t see how the open internet can compete [with walled gardens for advertisers’ budgets]… the only people who don’t benefit from all the efficiencies we’re talking about are those that duplicate and obfuscate and sometimes lie,” he said on how The Trade Desk hopes to further work with Prebid.

This was extensively speculated upon, especially given that OpenAds effectively represented The Trade Desk “forking” Prebid’s open-source code, with Green telling McGrath that he believed Prebid was a “really important part of the ecosystem.” Although he further clarified, “If we have governance that allows it, so that some people in self-interest can delay progress or make the [open internet] option less effective, then this organization [Prebid] will cease to be as impactful and we’ll cease to engage as much.”

Such debate was echoed extensively online, with sell-side advocates arguing that TID would aid publishers’ price discovery, plus help counter “bidding rings,” whereby a group of buyers effectively collude to lower the price of assets on sale in an auction, address information asymmetry, and prevent publishers from being overly reliant on a single demand-path. Also, hat-tip to Raptive’s Paul Bannister for sparking this epic thread on the matter.

One Prebid Summit attendee, who asked for anonymity in exchange for candor, described the weeks-long exchange between both sides of the debate as “contentious,” adding that the timing of TIDs 10.9 may have accelerated pre-existing plans for OpenAds. “I think Jeff Green is using this [debate] as an excuse to do something TTD [sic] wanted to do for a while,” added the source.

Meanwhile, on the sidelines of the Oct. 14 Prebid Summit, the body’s publisher committee moved to bring a some resolution to this intense debate with a vote that resulted in it further updating its framework to give publishers a choice between global or SSP-specific TIDs, ultimately softening its earlier stance. This update, or “clarification,” was made public on Oct. 23.

Speaking previously with Digiday, Magnite and Prebid’s McGrath maintained the subsequent move wasn’t a U-turn; he later clarified to Digiday that the original 10.9 update was rolled out in response to DSPs’ insistence that publishers provide transaction-IDs, characterizing the August update as an attempt to meet them halfway on their requirements. “It wasn’t about breaking transparency — it was about giving publishers optionality,” he added.

**‘A grand bargain’ **

Separate sources consulted by Digiday since characterized the above debate as one that’s only likely to be understood by a minority of industry players, i.e., ad tech not the primary actors such as advertisers and publishers. Many noted how most advertisers and publishers simply defaulting to act on the counsel of their respective ad tech partners, or middlemen, whether they understand the mechanics or not.

However, such was the extent of the online wrangling that wider counsel was sought, with an additional meeting attended by leading DSPs, SSPs, and separate industry experts, convened in the days after the Prebid Summit, Digiday has learned. Here, attendees sought to reconcile the opposing factions.

Such are the feelings around the debate that all sources consulted by Digiday requested anonymity, with one source noting how “all the major constituents” were represented at the late-October meeting hosted in New York City, before the October 23 update. “It was generally a meeting about where we were with the whole transaction-ID thing, and where we were with trust,” noted one source.

A separate attendee noted claimed many publishers feel wary, noting how, “They don’t get rewarded for good behavior… they find that when they do the right thing and de-duplicate traffic, bring down the number of requests they send [the buy-side], all they see is that spend goes down.”

One attendee informed Digiday that a prominent media agency participant — the source declined to name this participant — tabled what’s been dubbed a “grand bargain” whereby publishers would agree not to duplicate traffic, send only one bid request per ad impression (including a transaction-ID) in return for assurances of increased bid density.

Digiday understands the three tenets of the grand bargain proposal include:

1. Publishers will send only one request per auction, including a transaction-ID to eliminate traffic duplication.
2. DSPs will submit five bids per request, increasing bid-density and creating a more transparent view of inventory value.
3. Publishers will not implement brand-level floor pricing, removing another layer of complexity in the auction process.

**What’s next? **

Intuitively, reactions were split: sources claimed the leading DSPs in attendance held different attitudes, with some dismissing it outright and others debating whether every bid request warranted five subsequent submissions — after all, not all impressions are created equal — with the subsequent spirited debate understood to have lasted hours.

Meanwhile, SSPs in attendance claimed they were open to such deliberations, with publishers predictably seeking some guarantee that doing the right thing will get them the right results in return for eschewing a tried-and-tested method of improving their ad yields.

While the reaction to said proposals may have differed, Digiday understands the reception has been such that the parties concerned are using it as a starting point to move ahead, ergo light could be at the end of the tunnel.

Multiple parties contacted by Digiday, including Prebid, were unable to provide comment by press time.