Share or Cycle

Growth across the field in 2025

Calendar 2025 tests whether the slowdown in spend crossing The Trade Desk's platform was the market's or the company's. Amazon's advertising revenue grew 22% and Alphabet's total advertising 11%, while Viant — the closest listed independent demand-side platform — grew contribution ex-TAC 18% and guided 17% for the first quarter of 2026 against a market it sizes at 13%. The competitive language new to TTD's FY2025 filing points at its agency clients as much as at Amazon.

The Trade Desk reports gross spend — the whole amount a client puts through the platform, of which revenue is roughly a fifth — and says plainly what the metric is for: "For internal management purposes, we utilize gross spend as a metric to assess our market share and scale" [1]. That market-share metric grew 11% in 2025, to $13.39 billion from $12.04 billion, while revenue grew 18% [2]. The gap between those two numbers is pricing, and the Toll on Ad Spend chapter has already set it out. The 11% is the volume figure, and by the company's own description it is the measure of market share and scale.

Sources: TTD FY2025 Form 10-K, Management Discussion and Analysis, Executive Summary [3]; Amazon FY2025 Form 10-K, disaggregated net sales [4]; Alphabet FY2025 Form 10-K, revenues by type [5]; Viant Q4 2025 earnings call [6]; Criteo Q4 2025 earnings call [7]. Percentages computed from the reported currency amounts.

Amazon's advertising services line went from $56.21 billion in 2024 to $68.64 billion in 2025, a 22% increase after a 20% increase the year before — an acceleration [8]. Alphabet's total advertising grew 11.4%, to $294.69 billion from $264.59 billion [9].

Inside that Alphabet figure sits the strongest evidence for the market explanation. Google Network — the part of Alphabet that monetises third-party publishers, the same open web TTD's clients buy — fell $567 million, to $29.79 billion, and the volume decline was steeper than the revenue decline: impressions dropped 7% while cost-per-impression rose 7% [10] [11]. The largest incumbent in third-party publisher monetisation shrank in 2025, on falling volume and rising prices. Against that benchmark, TTD's 11% volume growth is a gain.

Viant is the more exacting comparison, because it runs the same model: a buy-side platform, no owned inventory, revenue taken as a cut of client spend under master service agreements that charge "a platform fee that is primarily a percentage of spend" [12]. Its 2025 revenue rose 19% to $344.2 million and its contribution ex-TAC — the measure closest in character to TTD's revenue — rose 18% to $208.7 million [13]. Viant absorbed a hard political-advertising comparison in that year and still grew at that rate; TTD does not disclose a political headwind of its own in the FY2025 filing.

Not every independent grew. Criteo's contribution ex-TAC rose 3.5% at constant currency on $1.9 billion of revenue [14], and at Nexxen self-service contribution ex-TAC declined 5% in the fourth quarter while private-marketplace and display contribution ex-TAC each fell 9% [15], with its full-year contribution ex-TAC retention rate dropping to 92% from 102% [16]. Both are sell-side or retail-media businesses rather than pure demand-side platforms, so their weakness says more about supply-path and retargeting economics than about the DSP category. Independence alone neither guaranteed growth nor caused decline in 2025: the one company running TTD's exact model grew at 18%, and TTD's volume grew at 11%.

The forward line

The deceleration did not stop at the year end. On the quarterly series charted in Toll on Ad Spend, growth runs from 25.4% in the first quarter of 2025 to 8.1% implied for the second quarter of 2026.

First-quarter 2026 revenue rose 12%, which the 10-Q attributes to higher gross spend plus "increased pricing associated with value-added services, higher utilization of our value-added services and higher platform fees" [17]. Second-quarter guidance of at least $750 million [18] implies about 8% against the $694.0 million reported for the same quarter of 2025 [19]. Viant, on the same call cycle, guided first-quarter 2026 revenue up 20% and contribution ex-TAC up 17% at the midpoint, and told investors it expected to keep "outpacing the broader U.S. programmatic market, which is projected to grow approximately 13%" [20].

An analyst put the arithmetic to management directly on the Q1 2026 call: industry expectations for digital and video growth were above 8%, so the guide was "pointing to below industry growth" [21]. The reply did not contest the framing. It confirmed that continued weakness in consumer packaged goods and automotive would at least create easier comparisons later in the year, and added that "there is not really anything incremental to add on the agency front" [22]. Management's macro account of the slowdown is on the record and unchanged; what the peer set adds is that a macro account has to explain why the two largest platforms and the nearest independent all grew faster through the same quarters.

The Amazon explanation, tested

TTD's filings register a competitive shift, and the sequence is precise. The FY2023 10-K described its rivals as "divisions of large, well-established companies such as Google and Adobe" [23]. The FY2024 10-K replaced Adobe with Amazon in the same sentence [24], and the FY2025 10-K keeps that pairing [25].

The FY2025 filing then adds a paragraph absent from the four 10-Ks before it: "Historically, some of our competitors have sought to differentiate themselves to prospective customers primarily on the basis of artificially low prices, which are enabled by inherent conflicts of interest and a lack of objectivity" [26]. The same clause was inserted into the growth-drivers paragraph of the management discussion, where FY2024 had simply said growth "has been driven by expanding our share of spend by our existing clients and adding new clients" [27] and FY2025 says growth "has been largely driven by" that, before adding the ability to differentiate against "competitors' platforms that may offer artificially low prices" [28]. A company whose revenue grew 18% on 11% more client spend has, in the same document, written price competition into both its risk factors and its growth discussion. Neither passage names the competitor.

The evidence that the price pressure is converting into lost volume is weaker than the pressure itself. Amazon's $68.64 billion advertising line is described in its own filing as revenue "to sellers, vendors, publishers, authors, and others, through programs such as sponsored ads, display, and video advertising" [29] — a bundle dominated by sponsored placements on Amazon's own store, not by third-party open-internet buying. Asked in November 2025 whether Amazon's reported zero-percent DSP fees had raised competitive intensity, Viant's chief executive said no, that "most of their revenue is sponsored listings," that the DSP "is a very small portion," and that "we do not see them … in the competitive bake-off processes at the finish line" [30]. That is an interested witness, and a smaller one. But it is a witness competing for the same budgets, growing at 18%, and reporting no Amazon effect — which makes Amazon a poor sole explanation for a deceleration that shows up at TTD and not at Viant.

Where the concentration sits

Two agency holding companies accounted for 30% of gross billings in 2025, against one at 14% in 2024. No other client-facing disclosure in the FY2025 filing moved as far.

Sources: TTD FY2025 Form 10-K, Concentration of Risk [31]; TTD FY2023 Form 10-K, Concentration of Risk [32]. Two holding companies cleared the 10% threshold in 2021 and 2025; one did in 2022, 2023 and 2024, so the 2021 and 2025 bars aggregate two disclosed relationships and the middle bars one.

Aggregated to the holding-company level, one agency group accounted for 11% of gross billings in 2022, 12% in 2023 and 14% in 2024. In 2025 two groups together accounted for 30% [33] [34]. Receivables tell the same story from the other side: at December 2025 two clients accounted for 30% of consolidated accounts receivable [35]. The company does not say why the 2025 figure roughly doubled, and it does not name either group; the FY2021 through FY2023 filings did name the one above the threshold as Publicis Groupe [36], and the name disappears from the FY2024 and FY2025 10-Ks.

What sits behind that 30% is thin contractual paper. Clients hold master service agreements that "do not contain any material commitments on behalf of clients to use our platform," run one-year auto-renewing terms, and are "terminable at any time upon 60 days' notice by either party" [37]. Nearly a third of the volume the platform prices moves on 60 days' notice from two counterparties.

One of those relationships was in open renegotiation through the first half of 2026. Asked on the May 2026 call about "the Publicis discussions," the chief executive said the reported conflict had been "overdramatized," that TTD had done "billions of dollars of business with Publicis" since 2018, and that "our negotiations are ongoing," declining to say more [38]. Trade press reported in June 2026 that the two had settled privately and that the agency resumed recommending the platform after pausing client spend in March; no terms were disclosed, and no filing has since described the renewed agreement [39]. Three months before that call, defending OpenPath — the supply-path product for which TTD charges publishers 4.5% — the same executive said that "at a moment where many agencies are focused on principal-based buying, I think they're not doing as good of a job of representing their clients as they could" [40]. Principal-based buying is the practice of an agency buying media on its own book and reselling it to the client at a margin — a model that competes with a transparent percentage fee for the same dollar. TTD is arguing publicly against the economics of the channel its two largest billing relationships sit in.

That is a different competitive problem from the one usually named. Amazon can under-price a platform fee; an agency holding company that buys as principal removes the need for the platform fee to be quoted to the advertiser at all. The evidence for the second mechanism is on TTD's own pages — the concentration jump, the 60-day terms, the renegotiation, the public dispute over principal-based buying — while the evidence for the first is a risk-factor paragraph and a set of trade-press claims the corpus does not otherwise document.

What would change the read

The read here is that the 11% is more company-specific than the macro account allows, and that the sharpest identified pressure point is the agency channel rather than Amazon's platform. Three facts cut against that read.

The strongest is Google Network: the incumbent in third-party publisher monetisation shrank 1.9% on a 7% impression decline in the same year [41] [42]. If the open web is the relevant market, TTD grew and the incumbent contracted, and 11% is a share gain in a shrinking pool. Second, scale: Viant's $208.7 million of contribution ex-TAC is about a fourteenth of TTD's revenue, and a platform at that size can add a single flagship advertiser and move its growth rate by points [43]. Third, retention: TTD's customer retention rate exceeded 95% in each of the eleven years through 2024 [44], which is not what a departing client base looks like.

Three developments would settle it. A gross-spend growth rate for 2026 that recovers toward the low-to-mid teens while Viant's decelerates would vindicate the cyclical account. A concluded Publicis agreement disclosed on terms that hold the platform fee, or a 2026 concentration figure that falls back toward the mid-teens, would remove the channel risk that the FY2025 filing introduced. And a second consecutive year in which the nearest same-model competitor grows at roughly 18% while gross spend grows near 11% would make the share-loss reading hard to argue against, whatever the macro backdrop does.

The corpus cannot close two gaps. It contains no third-party measurement of open-internet or connected-TV spend growth for 2025 and 2026, so the 13% market figure quoted here is a competitor's estimate, not an independent one. And it carries no agency-side or advertiser-side account of the Publicis negotiation or of principal-based buying volumes — only TTD's and Viant's characterisations, plus a trade-press note of a settlement whose terms are undisclosed.