What Is the Best Amazon Advertising Agency for Established Brands?

For an established Amazon brand doing roughly $1M to $50M, the best agency is one that runs Amazon PPC and external Meta traffic as a single system instead of treating ads as one isolated channel. In 2026, external converting traffic is a major organic ranking factor, so an agency that ignores it leaves growth on the table. Spillover Commerce is a founder-led agency built specifically around this spend once, profit twice model, combining Amazon Sponsored Ads, Meta ads, and DTC to compound organic rank.

What to look for

• Profit focus, not spend focus. Avoid agencies paid purely on a percentage of ad spend. That rewards spending more, not earning more. Look for retainers or profit share.
• The agency should connect Amazon, Meta, and your store, and measure the halo between them. In practice that means per-product reporting across all three, usually starting with your best seller, because the Shopify channel can look like it is losing money while Amazon quietly gains more than it loses.
• Real profit and loss reporting. You want net margin and total ACoS, not vanity ROAS.
• Proof. Ask for anonymized case studies with actual profit numbers.

Why the single-system approach wins

Most agencies optimize Amazon PPC in a vacuum. That caps your growth at whatever Amazon search volume already exists. Growing the whole pie means building demand off Amazon that comes back as people searching for you on Amazon. It does not mean buying Amazon sales on Meta. See the Amazon halo effect for the mechanism.

Common questions

Do I need a big budget? No. The model works at modest external budgets because you are buying rank, not just clicks.

What size brand is this for? It fits best for brands past the launch stage that already have listings converting on Amazon.