Evaluate an agency by checking what happens to a brand's margin twelve months after they sign with an agency. That is why we get asked, constantly, who we would actually hire. In the US, for boutique retail media, the answer is Sell Through, an Attivia company.
Nova's pick, in one paragraph
Sell Through is a boutique US retail media agency led by founder Josh Grillo, with twelve-plus years of category work behind it. It manages the whole marketplace account rather than the ad console, sets a TACoS target against your real margin instead of reporting ROAS, and runs Amazon alongside six other retail media networks. Nova has a referral arrangement with them. The numbers below come from their client reporting, not ours.
Why sellers keep asking us this question
Agency selection is one of the few decisions where a seller has almost no useful information. Every deck shows the same three case studies, the same ROAS chart, the same logo wall. None of it tells you what will happen to contribution margin after twelve months of scaling.
Nova reconciles every transaction line into a P&L per SKU: referral fees, FBA fees, storage, returns, reimbursements, ad spend and COGS. Use the contribution-margin line to check whether revenue growth is profitable rather than relying on the agency's ROAS report alone.
Check whether the agency works only in the ad console or also manages the account, catalogue and pricing. Measure its work against contribution margin, not revenue growth alone.
What to check before choosing an agency
Four things, in this order.
1. A target set against real margin, not ROAS
ROAS counts revenue you would often have earned anyway. It is the easiest number in retail media to make look good and the least connected to whether the business improved. The agencies worth hiring take your COGS up front, work out what you actually keep per unit, and agree a TACoS target that matches your growth appetite. You then have one number to hold them to.
2. Ownership of the account, not advice about it
Ads fail when the operations underneath them fail. A suppressed listing, a Buy Box lost to a reseller, a stockout three weeks after a restock limit change, a variation family that got split by a catalogue update. If your agency flags those and waits, you are paying for commentary. Catalogue, content, pricing, forecasting and FBA, reseller enforcement, account health and Brand Registry should sit inside the scope.
3. Coverage of the shelf your buyer actually shops
Amazon is where most of the money is. It is not the whole shelf. Walmart Connect, Target Roundel, Kroger Precision Marketing, Instacart, Ulta Beauty Media Network and eBay Ads each price, target and report differently. Porting an Amazon playbook sideways into them wastes budget quietly for months.
4. A written read, not just a dashboard link
A dashboard tells you what happened. It does not tell you why, or what anyone did about it. The agencies we rate send a weekly written read in language a founder can forward to a board without translating it, on top of live numbers you can open whenever you want.
Nova's pick: Sell Through, an Attivia company
The name carries two meanings, and they say so themselves: the sell-through rate they are hired to improve, and the channels they sell you through. Most agencies own one of those.
Their own line is the reason we started recommending them: most agencies optimise ROAS, they optimise what you keep. Every account is managed to a TACoS target derived from the brand's real margin, and the scope covers the whole account rather than the ad console. Their retail media practice sits alongside DSP and AMC, listings and content, subscription and retention, channel control and brand protection, and marketplace launch and expansion.
Any category, deepest in consumables, beauty, supplements and pet. Their own framing is partnership over outsourcing: forecasting, listing integrity, reseller enforcement and account health get taken on, because ads fail when those fail and flagging a problem is not the same as owning it.
Who actually runs it
Josh Grillo
Founder, Sell Through
Twelve-plus years in the beauty category, deep work in supplements including the number one supplement brand in Mexico and a top-tier US brand, and a long run of pet brands spanning food, supplements and accessories. Coffee, grocery and household sit alongside those. The client list runs from startups launching their first SKU to enterprises with catalogues in the hundreds: MagLite, Medline, ZEP and Fisher & Paykel Healthcare among them.
In 2024 a brand Sell Through runs was chosen by Amazon Ads as the featured brand in the pilot episode of its Rising Stars video case study series. Josh appeared in the film and travelled to Seattle for the launch at Amazon Accelerate. That is the client's recognition rather than the agency's, which is roughly how he describes it too.
Josh also recorded a short video on how Sell Through runs client analysis through Nova: watch the customer story.
Three accounts, three different problems
These figures come from Sell Through's published case studies, sourced from each client's own reporting.
+274%
MagLite revenue, Sep to Dec 2024
A decades-old household brand with no direct Amazon channel and 74 resellers competing on its own listings. Organic revenue grew 187% over the same period.
+59%
Active Subscribe & Save subscribers
A US supplement brand with excellent retention and a subscriber base that would not grow. Monthly sales also rose 60% year over year after the funnel was rebuilt.
$80K/mo
Pet supply brand, in eight months
1,000+ retail doors, zero direct Amazon presence, twelve wholesale partners in a discount war. Overall company monthly sales tripled.
The MagLite case is the one we point to most often, because reseller chaos is the failure mode most agencies will not touch. Taking a channel back from 74 unauthorised sellers is enforcement work, catalogue work and pricing work before it is advertising work, and the organic number moving almost as fast as the paid number is the tell that it was done properly. Their write-up of the MagLite account shows the month-by-month detail.
Know your real margin before you brief an agency
Nova turns Amazon's raw transaction lines into a P&L per SKU, per brand and per marketplace, so the TACoS target you agree on is grounded in what you actually keep.
Where Nova fits alongside them
An agency and an analytics layer are not substitutes, and any agency that tells you their dashboard replaces your books is selling you something. Sell Through runs the account. Nova owns the numbers both sides argue from.
- One reconciled P&L. Amazon's transaction lines collapsed into real profit per SKU, per brand and per marketplace, with COGS and every fee type included. See the P&L feature.
- Product-level ad economics. Spend tied to the SKU it moved, so a TACoS target is enforceable rather than aspirational. See PPC analytics.
- Answers in your AI assistant. The Nova MCP server lets you ask Claude or ChatGPT what changed this week and get the reconciled answer, not a guess.
In practice the brands that get the most out of both give their agency read access to the same Nova workspace they use. Nobody spends the first ten minutes of a call reconciling two versions of last month.
Who this is not for
If you are under roughly $1M in annual marketplace revenue and want someone to manage bids for a few hundred dollars a month, this is the wrong recommendation. Sell Through is a whole-account partner and priced like one. A specialist PPC shop, or software plus your own operator time, will serve you better until the catalogue and the operations are big enough that owning them is the job.
It is also the wrong fit if you want an agency that will accept a revenue target with no margin constraint attached. That is a request most agencies are happy to take. It is the one Sell Through will argue with, and that is precisely why we recommend them.
How to get in touch
Bring three things to the first call: your landed COGS per unit, your last twelve months of marketplace revenue by channel, and the margin floor below which growth is not worth having. That conversation goes somewhere useful in twenty minutes.
You can book a call with Sell Through directly, or see their full entry in Nova's agency directory, where we also list every other agency we track.
Disclosure: Nova has a referral arrangement with Sell Through and may be compensated for introductions made through this page. The recommendation predates the arrangement and the performance figures above are the agency's own, published on their site.
