US Sales Tax Nexus Audit for DTC Brands

The problem sales tax nexus audits solve

South Dakota v. Wayfair happened in 2018. Every state with a sales tax now has economic nexus rules. Your brand, which started in one state with a clear tax footprint, has been selling into all fifty for several years. Nobody has ever sat down to check which states you have nexus in, which states you should have been collecting tax in, and how far back the exposure goes. Your CFO asks about sales tax exposure during due diligence for a funding round and the honest answer is that nobody knows. That is the point at which a nexus audit becomes urgent rather than prudent.

The mechanical problem is that every state has its own thresholds, its own rules about what counts toward the threshold, and its own filing frequencies. Some states count gross sales. Some count taxable sales only. Some count marketplace sales toward the threshold. Some exclude them. Some use one hundred thousand dollars as the threshold. Some use two hundred transactions. Some use both, and some use either. A DTC brand selling into all fifty has fifty potentially distinct analyses, and the answers change every time a state amends its rules.

The consequence of getting this wrong is not usually existential but is often expensive. A state that discovers uncollected tax going back three years can assess the tax, interest, and penalties. The tax itself is often recoverable from customers in theory but almost never in practice. Interest compounds. Penalties can double the liability. A brand that discovers six states of exposure during due diligence can watch a funding round valuation discount by several percent while the acquirer prices in the remediation cost. The right time to find this is before a transaction, not during.

Our approach

We run a four week US sales tax nexus audit engagement. We are not a CPA firm and we do not provide tax advice in a regulated sense, so we partner with a specialist SALT firm for the legal opinion where the work crosses into that territory. The operational and analytical work is what we do.

Step one is the data assembly. We pull three years of order data from Shopify and any marketplace you sell on, broken by ship-to state, ship-to ZIP for jurisdictions that matter below state level, and gross versus taxable amount. We reconcile against Shopify financial reports. We document every physical footprint: offices, employees, contractors treated as employees, warehouses, fulfillment partners, trade shows attended, and inventory locations including Amazon FBA and third-party logistics.

Step two is the state-by-state analysis. For each state we apply the current economic nexus threshold, the physical nexus rules, the marketplace facilitator rules, and the taxability rules for your product categories. We produce a state matrix showing where nexus exists today, when it was first crossed, and the magnitude of any historical exposure.

Step three is the registration and filing roadmap. For states where nexus exists but registration does not, we document the registration path, the voluntary disclosure option if exposure is material, the filing frequency, and the recommended tax calculation and filing stack. For states where nexus is approaching, we document the monitoring cadence.

Step four is ongoing monitoring. Nexus analysis is not a one-time exercise. We set up a monitoring dashboard showing rolling twelve month sales by state against each state's current threshold, with alerts when a state crosses seventy-five percent of threshold. We document the quarterly review cadence.

What you get

▸ Three year order data assembly by state, reconciled to Shopify financials. ▸ Physical footprint register covering offices, employees, fulfillment, inventory, and trade shows. ▸ State-by-state nexus analysis across all fifty states plus DC. ▸ Historical exposure estimate where nexus was crossed before registration. ▸ Registration roadmap with filing frequency and calculation stack recommendation. ▸ Voluntary disclosure agreement guidance where exposure warrants it, with SALT firm referral. ▸ Shopify Tax, TaxJar, or Avalara configuration review if already deployed. ▸ Nexus monitoring dashboard with rolling twelve month sales versus threshold alerts. ▸ Quarterly review template and calendar. ▸ Documentation package suitable for due diligence or audit response.

Timeline

Four weeks in three phases.

Week one is data assembly and physical footprint documentation.

Weeks two and three are the state-by-state nexus analysis.

Week four is the roadmap, voluntary disclosure guidance where applicable, monitoring dashboard setup, and handoff.

Mini case anatomy

A home goods brand in the ten to twenty million revenue range prepared for a Series B and the data room required a sales tax position paper. The brand had been collecting in three states: the home state and two others where a founder had moved at various points. Three years of sales data showed sales into all fifty and DC.

The audit identified economic nexus in seventeen states beyond the three where registration existed, most crossed between two and three years prior. Historical exposure totaled into the low seven figures inclusive of interest. We engaged a SALT firm partner on voluntary disclosure agreements in the eleven highest exposure states. Registrations were filed in the remaining six. Shopify Tax was configured for the new state set.

The funding round closed on schedule with a specific escrow carve-out for the tax exposure. The voluntary disclosure agreements capped look-back at three years in most participating states and waived penalties. Eighteen months later the exposure had been resolved under the VDAs and the brand was current in twenty states. Annual re-audit is standard practice.

FAQs

See frequently asked questions below. Sales tax is one of several compliance exposures that get examined during funding diligence. Pair this with our privacy compliance audit and WCAG accessibility audit for a complete compliance posture. For the broader picture see our compliance audits hub and our claim substantiation leaf.