IAB Australia today published the recording of a session in which Mars United Commerce and Tenet Advisory told the Sydney summit that retail media spending has outrun the industry's ability to prove what it delivers, with the local market valued at just over $2 billion and projected to double by 2030.

The 22-minute presentation, titled Retail Media Maturity and Ecosystem Review, was delivered on 7 July 2026 at the NSW Teachers Federation Conference Centre in Surry Hills during the IAB Australia Commerce & Retail Media Summit Sydney 2026. The recording went live on the trade body's YouTube channel today. Kelly Wearmouth, a leader at Mars United Commerce based in Sydney, shared the stage with Paul Brooks, a partner at Tenet Advisory and Investments who previously worked on the agency and publisher side and most recently ran a retail media network inside a retailer.

Their argument was narrow and specific. Growth is no longer the question. Whether the sector can evidence the returns behind that growth is.

A $2 billion market entering its accountability phase

According to Brooks, the Australian market was worth just over $2 billion at the end of FY25 and is expected to reach $4 billion by the end of 2030. He described seven in 10 advertisers as looking to increase expenditure on retail media, drawing partly on newly unlocked budgets and partly on money moving across from what he called above-the-line traditional media.

The roster picture has widened alongside the money. Brooks said the vast majority of advertisers now work with three or more retail media networks, a figure growing year on year, and that a brand of the scale of L'Oreal would typically work with somewhere between five and eight retailers. That fragmentation was already visible in Australia a year earlier, when PPC Land documented brands expanding from one or two retail media partners to seven or eight simultaneously at the 2025 edition of the same summit.

The framing Wearmouth used came from the trade body's own research release that morning. "Bigger money, bigger questions," she said, referring to the press release issued alongside the Commerce Report and the Commerce & Retail Media State of the Nation, both launched at the summit by Natalie Stanbury, IAB Australia's director of research.

Brooks put the diagnosis plainly. Spend is still rising and rosters are widening, he said, but confidence has not kept pace with expenditure. That gap has a measurable precedent locally: IAB Australia's Wave 3 research, released in July 2025, found 79% of existing retail media advertisers planning to increase spending while only 44% rated their experience as good.

Scale, in Brooks's phrasing, creates complexity. On measurement, he was blunter still, telling the room it is not the new battleground but simply the battleground, and that proving incrementality while digitising assets across an omnichannel environment is difficult enough that no retailer is currently doing it to the standard it wants.

What the buy side is changing

Wearmouth described a shift in how budget owners approach planning. Brand partners are pushing for retail media to sit inside the wider media plan rather than beside it, she said, with shared creative, shared audience targeting and comparable key performance indicators across channels. She characterised the discipline as still nascent but noted the conversation itself had changed within twelve months, having been siloed a year earlier.

A second change concerns where retail media sits inside a retailer's business. According to Wearmouth, the partners gaining traction are those treating commerce media as core business infrastructure rather than a side project staffed by a small team. Networks that make performance transparent for brand partners, she said, are the ones able to attract more revenue.

The organisational point cuts both ways. Brooks argued that retailers face a profit-and-loss question about where trade, media and e-commerce teams converge, and that unresolved internal structure slows partners down. External integration, in his account, is what makes through-the-line planning possible at all.

Measurement remains the maturity gap

Brooks identified measurement and incrementality as the largest maturity gap in the market. Naming conventions are part of the problem: every retailer defines viewability differently, he said, and the same divergence applies to measurement and incrementality themselves.

"To demonstrate a sales lift beyond what would have happened already is the really difficult part," Brooks said.

That definitional problem is not unique to Australia. IAB and IAB Europe published Guidelines for Incremental Measurement in Commerce Media on 3 November 2025, establishing incrementality as the causal impact of marketing compared to what would have happened without any campaign activity, following an incrementality framework issued in September 2025. IAB Australia had already released its own measurement principles and guidance in August 2024, adopting IAB and Media Rating Council standards including the 50%-of-pixels, one-second viewability threshold for display.

Standards exist. Adoption is the variable.

The in-store problem

The structural constraint Brooks returned to is physical. Around 85% to 90% of Australian sales still take place in store, he said, and where a transaction is not digital it becomes difficult to deliver an identifiable transaction record. Loyalty programs, in his assessment, are not yet where they need to be or sufficiently tethered to those transactions.

That makes the Australian incrementality question harder than it is in higher e-commerce penetration markets such as the United States and the United Kingdom, which Brooks characterised as largely digital commerce stories. Australia, he noted, received what he described as a free kick during the pandemic, compressing roughly ten years of e-commerce growth into eighteen months, but the non-digital side of the business has not kept up.

The in-store measurement gap has been a live global question for two years. IAB and IAB Europe released the first industry-wide in-store retail media measurement standards for public comment in September 2024. More recently, research from In-Store Marketplace and Catalyst Media Consulting argued that the obstacle is misaligned definitions of success rather than absent measurement technology, a diagnosis that maps closely onto Brooks's naming-conventions complaint.

Standardisation as direction, not destination

Asked from the floor what was holding standardisation back, Brooks had already set out his position during the presentation. "I think standardization 100% is probably unrealistic," he said, adding that it is "easy to say really hard to do." His preferred formulation was a guiding light towards standardisation rather than a fixed endpoint, with clean rooms and mixed-media modelling folded into holistic planning, and the sector converging on measurement, incrementality and alignment.

The modelling question has an active dispute attached to it. IAB published a white paper in April 2026 arguing that marketing mix modelling is structurally ill-suited to retail media and causes brands to undervalue the channel, urging closed-loop and incremental methods instead. Separate analysis covered by PPC Land in June 2026 found that siloed attribution across search and demand-side platform activity misses a substantial share of retail media's contribution.

The ecosystem response

The presentation split its recommendations across retailers and networks, brands, and agencies.

For networks, Wearmouth pointed to third-party audited measurement published transparently. Doing so, she said, "will make life a lot easier than having to amalgamate 10 separate dashboards 10 separate Excel reports," and would make it easier for advertisers to allocate more investment.

For brands, her point concerned team composition rather than reporting. Creator commerce and AI discoverability are pulling together functions that never previously had to speak to each other, she said, and brands should not wait for a formal restructure before assembling virtual teams. She repeated a line she had used in the same room a year earlier, noting its continued relevance: "Customers don't care about org charts. They just care about one joined up message that's getting the right product into the right hands."

For agencies, the ask was network-agnostic measurement frameworks and a single key performance indicator sitting above an entire plan, including activity running through brand and sales teams inside the same retailer.

Agentic commerce as the pacing threat

Both speakers flagged agentic AI as the variable most likely to outrun current market capability. Brooks said the impact of agentic commerce within retail and retail media networks is likely to outpace where the market currently sits, spanning agentic shopping, search and purchase journeys through to supply chain and delivery.

Wearmouth was more pointed about the organisational consequence. "AI is going to force that and force it really fast," she said of cross-functional team formation, adding that the change is coming very quickly.

The observation aligns with material IAB Australia itself published a month earlier. Its 2026 agentic AI search report, covered by PPC Land in June 2026, described a purchase funnel collapsing into seconds when an agent handles discovery, comparison and transaction within a single session. Commerce media technology vendors have been moving in the same direction: research published on 10 June 2026 examined how agentic AI reshapes control and monetisation across commerce media, and LiveRamp began piloting agentic AI to close the workflow gap between commerce data and campaign outcomes in June 2026.

The question from the floor

The session closed with an audience question that put the confidence gap directly: if confidence in retail media is so low, why do brands keep investing more, and when does that become a problem?

Brooks answered by separating promise from delivery. Expectations start high, he said, and the promise of retail media - reaching the right customer at the right moment with a relevant message, bringing customers and suppliers closer together - is easier to state than to execute. Drawing on his time at Coles, he described proving measurement and returns as the biggest challenge facing networks, one that depends on digitisation and identifiable transactions.

His verdict on the timing was the sharpest line of the session. The ambition and the opportunity are present, he said, but the sector "is just being outpaced by consumer behavior and expectations."

Wearmouth's closing framing returned to the morning's headline. More investment in a channel, she said, means everybody needs to be more accountable.

Why this matters for the marketing community

For brands and agencies buying across three, five or eight Australian networks, the practical consequence is reconciliation cost. Each additional network adds a dashboard, an export and a definition of viewability that may not match the last one. Third-party audited reporting, if it arrives, removes work rather than adding capability.

For retail media networks, the accountability phase changes what wins budget. Reach and proximity to purchase were sufficient arguments during the growth years. Australian buyers have signalled for two consecutive research waves that return on ad spend and incrementality are the metrics that decide allocation, and the local market's in-store weighting means those proofs are harder to produce here than in comparable markets. Brooks projected 15% to 20% annual growth over the next four to five years; whether that materialises depends on evidence rather than enthusiasm.

For the wider ecosystem, the timing matters because the measurement debt is being incurred at the same moment agentic commerce arrives. A sector that cannot yet standardise viewability definitions across a handful of retailers faces a harder version of the same problem once agents mediate discovery and purchase at machine speed.

Brooks summarised the position at the close of the session. The sector has proven it can grow across five or six years of existence, he said, and now needs to prove it can deliver on trusted acceleration through the next phase.

Timeline

Summary

Who: Kelly Wearmouth of Mars United Commerce and Paul Brooks, partner at Tenet Advisory and Investments, speaking at an IAB Australia event opened by chief executive Gai Le Roy, with research released by Natalie Stanbury, the trade body's director of research.

What: A 22-minute maturity and ecosystem review arguing that Australian retail media has entered an accountability phase, with the market valued at just over $2 billion at the end of FY25, a projection of $4 billion by the end of 2030, seven in 10 advertisers intending to raise spend, most advertisers running three or more networks, and 85% to 90% of sales still occurring in store.

When: The session was delivered on 7 July 2026 at the Commerce & Retail Media Summit Sydney 2026. IAB Australia published the recording on its YouTube channel today, 28 July 2026.

Where: NSW Teachers Federation Conference Centre, Surry Hills, Sydney, covering the Australian and New Zealand market with comparisons to the United States and United Kingdom.

Why: Spending in Australian retail media continues to rise while confidence in measurement has not kept pace. The speakers argued that inconsistent definitions of viewability, measurement and incrementality across retailers, combined with a predominantly physical retail base and loyalty programs not yet tethered to transactions, prevent networks from evidencing incremental returns. Agentic commerce is expected to compress purchase journeys faster than the sector resolves those gaps.