The Client
A pure dropship e-commerce company doing roughly $100M a year across four consumer storefronts on one legal entity. About 77% of revenue runs through Amazon, where the marketplace collects and remits sales tax. The direct channel, where the company is seller of record, files returns across 44 states through a commercial tax engine.
The Situation
The engagement began as a routine compliance review of the direct channel filings. It became a recovery program within the first diagnostic pass.
What We Found
Returns never reached the tax engine. The order pipeline pushed sales into the tax engine correctly. The refund flow did not. When a customer returned an order, they received a full refund including the tax collected, but no credit document ever reached the engine. Every filing was computed on gross sales.
The result: the company was remitting sales tax to states on revenue it had already refunded. Tax paid twice, once to the customer and once to the state. The condition had run silently for years across two different filing regimes.
A sourcing defect compounding it. Import files built for credits were missing the ship-from origin address, which silently reclassified the tax type in several states and risked rejection of the very credits being claimed.
The Fix
Refunds and cancellations now flow into the tax engine as credit documents in the period they occur, with correct origin sourcing. The first corrected filing cycle loaded roughly $31K in credits across 1,306 documents in 44 states and cut that month’s remittance from about $158K to about $128K.
The leak is closed at the source. Every future return generates its credit automatically, which converts a one-time recovery into a permanent margin change.
On a thin-margin dropship model, 35 to 40 basis points is a material share of net margin — not a rounding adjustment. And it requires no ongoing effort beyond the normal filing cycle.
The Diagnostic Pattern
Checks that surface this class of defect at any e-commerce company, in order:
- Trace one refund end to end. Confirm the credit reaches the tax engine and appears on the filed return.
- Compare gross sales per the filings against net sales per the ledger, by period. A persistent gap approximates untaken deductions.
- Confirm the registration type matches the tax type actually filed, state by state.
- Verify import files carry the ship-from address. A missing origin silently reclassifies the tax type.
- Split marketplace from direct channel first. Facilitator rules cover the marketplace side; seller-of-record risk lives entirely in the direct channel.
Why This Matters If You Sell Online
If you run a multistate e-commerce business with meaningful returns, the single most common defect we find is refund tax that never gets credited back. It compounds monthly, it hides inside a routine compliance process nobody enjoys auditing, and the money is recoverable.
DMW Advisory is the fractional CFO practice of Di Mike Wang, CFA, FMVA, MBA (USC). Mike built his career at Morgan Stanley and Wells Fargo and now runs finance for founder-led companies from $5M to $100M. Identifying details withheld; the client is represented by counsel in historical recovery matters.
Think your tax engine might be leaking? Fifteen minutes is enough for a first look.