Blog

Fee breakdowns from real seller dashboards. Platform analysis with verified rate cards. And the story of building the financial intelligence platform that assembles what no seller has time to read.

Two series. One about the numbers. One about what we're building.

What Did They Keep?

Real sellers. Public dashboards. We run the full fee stack against published rate cards and show what the dashboard doesn't — the fees nobody computed, the thresholds nobody checked, and the gap between what they think they're keeping and what they actually are.

Building FineMargins

What we're building, how the data works, what decisions we're making, and why. The build journal — updated as we go.

Latest posts
What Did They Keep?
$2.5M Beauty Brand on Amazon — What Did They Actually Keep?
24 June 2026

A beauty seller targets 45% gross margin on $2.5M in Amazon revenue. Two definitions of that number. $678K difference between them.

What Did They Keep?
$2.6M Haircare Brand on Amazon — What Did They Actually Keep?
24 June 2026

A haircare seller says 5% vs 15% return rates look identical on the surface. They don't. The fee difference is $45,752 per year — in platform costs alone.

What Did They Keep?
$21M Pet Brand on Amazon — What Did They Actually Keep?
24 June 2026

A pet brand scaled from $60K/week to $400K+/week and dropped TACOS from 30% to 5%. The ad savings are enormous. The platform fees didn't move.

What Did They Keep?
$746K/Month in Health & Household — What Did They Actually Keep?
24 June 2026

At $25 ASP, Amazon's fulfilment fee is higher than the referral fee. That changes which lever matters. Most sellers don't know which side they're on.

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Every fee. Every connection. Every alternative. Computed for your products. Launching September 2026.