There is a number that crystallises the transformation of American advertising over the past decade better than any other: 73. In 2025, approximately 73 per cent of total US advertising investment flowed through digital channels. In 2015, that figure was closer to 40 per cent. The migration from print, linear television, radio, and outdoor formats toward search, social, programmatic, retail media, and connected television has been the defining commercial story of the media industry for a decade, and in 2025 it showed no sign of approaching the limits of its momentum.
The US digital advertising market closed 2025 at $361.9 billion, growing 13 per cent over the prior year, and the forward trajectory toward $413 billion in 2026 and well beyond reflects a market that is drawing from an expanding set of budget sources rather than simply growing within a fixed pool. Understanding why US advertising investment in digital channels keeps growing — and why that growth has proved far more durable than most analysts forecast five years ago — requires looking at the structural forces rather than the headline numbers.
Why Digital Keeps Taking Share
The shift toward digital advertising is not simply a story of audience migration, though audience migration is a real and significant driver. It is equally a story of measurement, accountability, and the changing economics of reaching commercial audiences at scale.
Traditional advertising channels — linear television, print, radio, outdoor — operated for decades on a model of estimated reach: a brand buys an audience approximated by ratings data, readership surveys, or foot traffic estimates, and accepts a level of uncertainty about whether the people reached were actually the intended targets. Digital advertising fundamentally changed the accountability framework. Every impression is logged. Every click is recorded. The conversion from exposure to consideration to purchase can be tracked, attributed, and reported in ways that traditional channels can only approximate.
This accountability gap has widened over the past five years rather than narrowed, as digital channels have developed more sophisticated attribution systems — particularly in retail media, where closed-loop measurement connects advertising exposure directly to purchase transactions — while traditional channels have struggled to improve their measurement infrastructure at equivalent pace.
| Year | Digital Ad Spend | Digital Share of Total US Ads | Key Channel Driving Share Gain |
|---|---|---|---|
| 2015 | ~$60 billion | ~40% | Search + social mobile expansion |
| 2018 | ~$107 billion | ~54% | Programmatic display; Instagram |
| 2020 | ~$152 billion | ~52% | E-commerce surge; search resilience |
| 2022 | ~$245 billion | ~64% | Retail media emergence; CTV growth |
| 2025 | $361.9 billion | ~73% | CTV breakout; Amazon $50B+ milestone |
The Three Budget Pools Fuelling Current Growth
The continued growth of digital advertising investment in the United States is drawing from three distinct pools, each with different dynamics and different implications for the channels that benefit.
The first is linear television migration. US national broadcast and cable television commanded approximately $55 billion in advertising revenue as recently as 2023. That figure is declining steadily as viewers migrate to streaming platforms, and as advertisers follow those viewers into connected television environments with programmatic buying access. Every dollar that migrates from a linear television upfront commitment to a CTV programmatic campaign flows through the digital advertising ecosystem and contributes to digital advertising totals. At current migration rates, an estimated $15 to $20 billion of additional digital demand will be generated from this source by 2028.
The second is trade budget conversion. Consumer goods brands maintain substantial trade promotion budgets — historically managed outside digital marketing infrastructure — that are increasingly being directed toward retail media platforms. As TechBullion’s analysis of the 17.9 per cent retail media growth rate establishes, this conversion is a multi-year process that is still in its early phases at many major FMCG companies.
The third is SMB expansion. The emergence of AI-powered campaign management tools — Meta’s Advantage+, Google’s Performance Max, Amazon’s automated bidding products — has materially reduced the complexity and minimum viable budget required to participate in digital advertising. Small and medium-sized businesses that could not previously manage digital campaigns efficiently are now entering the market at scale, adding incremental demand that does not come at the expense of existing large advertisers.
Why Growth Has Been More Durable Than Expected
The persistence of double-digit growth rates in a market at $362 billion confounded a significant portion of analyst opinion that formed around 2019 and 2020. The conventional wisdom at that point held that digital advertising would decelerate toward 7 to 9 per cent growth as it approached market maturity. That forecast was wrong, for structural reasons that were not well understood at the time.
The fundamental error was underestimating the size of the budget pools that had not yet converted to digital. In 2019, the retail media category barely existed. The opportunity to convert trade promotion budgets into measurable digital campaigns was theoretical rather than operational. The addressable market for digital advertising appeared large but finite, bounded by the existing pool of brand and performance advertising budgets that were already being allocated digitally.
What emerged instead was a category — retail media — that expanded the total addressable market by unlocking budget that had never previously been classified as advertising at all. Combined with the acceleration of CTV as a programmatic buying environment and the democratisation of digital advertising access through AI automation, the effective addressable market for digital advertising turned out to be substantially larger than the 2019 consensus assumed. As explored in TechBullion’s analysis of the 12.4 per cent CAGR from 2020 to 2025, the durability of growth was not accidental — it reflected structural market expansion rather than cyclical recovery.
The Outlook for Continued Growth
The factors sustaining digital advertising investment growth through 2026 and beyond remain largely intact. The US digital advertising forecast of $413 billion for 2026 implies approximately 14 per cent year-on-year growth, driven by the continued acceleration of CTV, the growth of retail media, and the 2026 election cycle providing incremental political advertising demand.
| Growth Driver | Budget Source | Durability | Primary Beneficiary |
|---|---|---|---|
| Linear TV migration | Broadcast/cable budgets | High — structural | CTV, streaming platforms |
| Trade budget conversion | FMCG trade spending | High — multi-year | Retail media networks |
| SMB democratisation | Net new advertisers | Medium — ongoing | Meta, Google, Amazon |
| Political advertising cycle | Campaign budgets | Cyclical — 2026, 2028 | CTV, social, programmatic |
The structural shift in American advertising investment toward digital channels is not a temporary phenomenon driven by a specific technology cycle or consumer behaviour moment. It reflects the irreversible migration of media consumption and commercial activity into digital environments, supported by measurement infrastructure that makes digital advertising accountability demonstrably superior to its traditional alternatives. For investors and practitioners in the AdTech ecosystem, the persistence of this migration is the most reliable long-term growth thesis available in the broader media and technology landscape.
Related reading: US Digital Advertising CAGR 2020-2025 | US Digital Ad Market 2025 | US Digital Ad Forecast 2026 | AdTech Investment Outlook
