Commerce media spending is projected to surpass $80 billion in the US this year, according to EMARKETER’s forecast, but not every network is winning buyers’ trust equally.

“Trust is earned campaign by campaign, and even the earned have to keep earning it," said Rob Rubin, head of EMARKETER Advisory, at EMARKETER’s Ad Buyer Strategies Summit. He shared findings from a new survey of 231 senior ad buyers collectively responsible for more than $8 billion in commerce media spend.

The survey evaluated 24 commerce media networks across categories including mass retail, grocery, travel, apparel, and financial services. Buyers had each worked with an average of six networks over the past year, giving a broad view into how marketers assess performance, measurement, and long-term value.

Most commerce media networks still have something to prove

Only two networks have fully “earned” buyer trust by demonstrating both strong performance and credible measurement, according to Rubin: Amazon and Nordstrom.

“Premium price, provable value,” he said. “Earned is the only group that clears both bars.”

The top-performing networks stood apart in several key areas. Buyers were significantly more likely to rate them as critical or important partners, dedicate larger shares of spend to them, keep campaigns always-on, and report strong return on ad spend (ROAS).

For the remaining 22 networks, the challenge centers on demonstrating value.

Where most commerce media networks are still stuck in what Rubin called the “proof phase,” where buyers continue questioning whether campaigns are truly incremental and effective. Buyers increasingly want networks to prove not just that campaigns perform, but that they drive outcomes beyond what would have happened anyway.

Campaign duration appears to play a major role. Buyers running campaigns longer than four weeks reported significantly higher satisfaction with both ROAS and incrementality measurement quality than those running shorter campaigns.

Rubin argued that longer campaigns allow networks and advertisers to calibrate measurement against the advertiser’s actual brief rather than relying on default metrics.

“The customers who’ve graduated you to earned are the ones who are getting answers to the question they’ve actually asked,” he said.

Performance gaps shape how buyers view networks

The survey also uncovered meaningful differences in how buyers talk about various tiers of networks.

For “contender” networks that sit in the middle of the pack, frustrations centered on inconsistent performance, immature incrementality capabilities, and limited audience scale. For lower-priority “discretionary” networks, complaints shifted toward broader relevance concerns, with buyers describing them as too small or unimportant to prioritize.

Even the top networks weren’t immune to criticism.

One respondent cited “ease of integration” as the most important issue, while another admitted that one network generates most of their sales, but they “wish it wasn’t the case.”

Rubin closed with a warning to both advertisers and networks: Trust in commerce media is fragile and must continually be earned.

“If you buy media, whether you’re a brand or an agency, you need to specify what incrementality means in the brief and defend it through intake,” he said. “The brief is your asset, and the network’s template is the threat.”

Watch the full session

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