IAB: US digital ad spend rose 35% YoY to $189B in 2021, the largest gain since 2006; 10 publishers and platforms took 78.6% of the total, up from 78.1% in 2020
78.6%—of total digital ad revenue...” ~$40b+ remaining is a lot, but that % should trend the other way. Why? https://twitter.com/... Meg Graham / @megancgraham : New IAB report on 2021: Digital ad revenue in the U.S. jumped 35% to $189 billion last year. The top 10 digital publishers/platforms took the lion's share—78.6% of that spend: https://www.wsj.com/... Neil Saunders / @neilretail : Retail media networks are a big driver of this. In 2021, Amazon's advertising revenue was $31 billion. Walmart's was $2.1 billion - and is growing rapidly. Even Nordstrom brought in $40 million. Ads are a great offset to crimped margins and weakening demand in retail. https://twitter.com/... See also Mediagazer
Context & Ripple Effects
The IAB's 2021 tally is a sharp acceleration off the 2020 base of $139.8B, when growth was just 12.2% and H2 political spending had to offset an H1 falloff. The bigger story in the concentration line: the top 10's share crept from 78.1% to 78.6% even as the pie grew 35%, meaning the largest players captured most of the incremental dollars.
Retail media is the named engine — Neil Saunders points to Amazon at $31B in ad revenue, Walmart at $2.1B growing fast, and even Nordstrom pulling $40M — extending Amazon's run as it built toward the 10.3% US ad-market share eMarketer measured for 2020.
First-order effects
- Amazon, Walmart, and Nordstrom convert shopper data into ad inventory, with Amazon alone at $31B — retailers now sit on the demand side of the ad market they once only supplied through shelf space.
- The roughly $40B left outside the top 10 is split among everyone else, so mid-tier publishers grew into a market whose incremental dollars flowed disproportionately to incumbents.
Second-order effects
- Walmart's rapid growth from a $2.1B base pressures every large retailer to stand up its own media network or cede that margin to Amazon, turning retail media into table stakes.
- Brands reallocating budgets to retailer networks shift pricing power toward whoever owns the transaction data, squeezing ad-tech intermediaries and open-web publishers dependent on third-party signals.
Third-order effects
- If retail media keeps compounding, the structural endpoint is an ad market where commerce platforms capture intent at the point of sale and the long tail competes for what remains — though the follow-on data cuts both ways, since growth cooled sharply to 10.8% in the 2022 IAB/PwC report after this 35% spike.
The trend: US digital advertising is concentrating around platforms that own purchase data, with retail media networks converting commerce margins into ad revenue through boom-and-normalization cycles.