To choose a retail media agency, judge it on five things: its minimum spend, its fee structure, who actually works on your account, which retail media networks it runs natively, and how it measures a sale. Most published agency rankings are paid placements or directory listings, so they tell you who markets well rather than who performs. The fastest way to separate the two is to ask about methodology and staffing before you ask about results. An agency that answers those plainly is usually the one that will still be answering plainly six months in, when a month goes badly.
1. Ask the minimum before anything else
Most large retail media agencies start around a million dollars in annual ad spend, and several say publicly that they serve mid-market and enterprise brands. That is useful honesty. If your budget is well under the minimum, you will be the smallest account in the building, and the seniority you met during the pitch is not the seniority you will get afterward.
2. Understand how they get paid
A percentage of ad spend is the industry default and it contains an obvious conflict. The agency earns more when you spend more, whether or not the spending sold anything. Flat fees remove that. Performance components can be fair when they are tied to something the retailer itself records, such as platform-attributed sales, rather than a number the agency calculates for itself.
You are not looking for the cheapest arrangement. You are looking for one where their incentive and your shelf point the same direction.
3. Find out who is on the account
Ask for names and hours. Ask who logs into your accounts on a Tuesday. In a lot of agencies the answer is a junior analyst supervised at a distance, which is fine for a large account with structure and bad for a small one that needs judgment.
4. Check which networks they truly run
Everyone lists Amazon, Walmart, Instacart and Target. Fewer run Kroger Precision Marketing, Albertsons Media Collective, Sam’s Club MAP, DoorDash or the regional networks where a local brand is often strongest. Ask which ones they have personally run in the last ninety days, not which ones appear on the website.
5. Make them explain measurement
This is the one that separates real operators from good presenters. Albertsons Media Collective published research in April 2026 finding that incremental ROAS can vary by 6.5 times, and can flip entirely in 83% of campaigns, depending on the measurement method used.
So ask what window they attribute over, what baseline they compare against, and whether the number comes from the retailer or from their own model. If the answer is vague, the reporting will be too.
A shortcut
Ask what they would fix before they would spend. An agency that wants to run ads immediately is selling media. An agency that wants to see your product pages first is selling growth. Only one of those survives a quarter where the numbers are flat.
If you are below the minimums the big shops require, start here instead: retail media agency for small brands.