Black Friday Is a Nexus Event: Your Pre-Q4 Sales Tax Check for 2026

Most sellers find out they crossed a state line in January. The Q4 numbers get pulled together, somebody looks at sales by state for the first time in a year, and there it is — $118,000 into a state nobody registered in, with an obligation that started somewhere back in November.

The tax was never collected from customers, so it comes out of margin. Add penalties and interest, and a good holiday quarter turns into an expensive one.

The fix is unglamorous and takes about an hour: run the check in September, while there is still time to register cleanly.

What changed in 2026

The direction of travel is clear. States are abandoning transaction-count triggers and keeping revenue thresholds.

Illinois dropped its 200-transaction test on 1 January 2026, moving to gross receipts over $100,000 in the previous twelve months. Kentucky followed on 1 August 2026, also landing on a straight $100,000 standard. Utah had already removed its count in 2025.

That is good news if you sell high volumes of low-ticket items — a seller doing 400 orders at $12 into Kentucky is no longer in scope. It is neutral-to-worse if you sell few expensive things, because revenue is now the only thing between you and a registration.

It also cuts both ways for your books. The states you were registered in last year may not be the states you belong in this year, and deregistering incorrectly creates its own mess.

Do not assume $100,000 everywhere

California and New York sit at $500,000. Texas also uses $500,000, but measures it on a rolling twelve months rather than a calendar year — which means a January-to-December report will quietly give you the wrong answer for Texas.

Why Q4 is when nexus quietly happens

For most e-commerce and DTC businesses, the fourth quarter is 30–50% of annual sales. A seller who spent nine months comfortably at $60,000 in a state can clear $100,000 in the eleven days between Black Friday and the Cyber Monday shipping cutoff.

Nexus does not wait for your fiscal year to close. In most states the obligation begins almost immediately after the threshold is met, and several look at the prior or current calendar year in ways that pull the start date earlier than you would expect.

The practical problem is timing. Registration takes days to weeks depending on the state. Discover the crossing in January and you have already sold a full quarter without collecting — and you cannot go back and charge those customers. Discover it in September and the worst case is that you register early and file a few zero returns.

The pre-Q4 check, in four steps

1. Pull a rolling twelve-month sales-by-state report

Rolling, not calendar. Ship-to state, not bill-to. Gross sales, not net of refunds, unless a specific state says otherwise.

If your accounting system cannot produce this without a manual export and a pivot table, that is the first thing worth fixing. This should be a monthly artifact, not an annual archaeology project — which is exactly the kind of thing a reporting layer is for.

2. Split marketplace sales from your own channels

Marketplace facilitator laws mean Amazon, Etsy, Walmart and similar platforms collect and remit on your behalf in every state that has one. But states differ on whether those sales still count toward your threshold.

Blending Shopify and Amazon revenue into one number is the most common way sellers overstate their exposure — and occasionally understate it. Tag the channel at transaction level so the split is a filter, not a reconstruction.

3. Flag every state above 80% of its threshold

Anything at 80% going into Q4 should be treated as a state you will be registering in. Build the list now, decide the registration date, and get collection settings staged in your cart or billing system so switching them on is a checkbox rather than a project.

4. Do not forget physical nexus

Economic thresholds get the attention, but inventory in a third-party fulfilment warehouse, a remote employee, a contractor, or stock sitting in an Amazon FBA facility can create nexus at $0 in sales.

If you added a 3PL location or a remote hire this year, that is a nexus review trigger regardless of revenue. It is also worth checking how those workers are classified while you are in there — see our contractor vs employee check.

If you have already crossed and did not notice

Say the report shows you passed a threshold last spring. Do not simply register and start filing as though nothing happened — that often flags the back period without limiting it.

Most states offer a voluntary disclosure agreement, which typically caps the lookback at three or four years, frequently waives penalties, and can often be negotiated anonymously through a representative. The catch is that a VDA is generally only available before the state contacts you.

Coming forward is a decision to make with your CPA or a state and local tax specialist, and it is far easier to make when your books can substantiate the numbers.

A note for Canadian sellers

The same logic applies north of the border with different mechanics. GST/HST registration is generally required once you exceed CAD $30,000 in taxable supplies over four consecutive calendar quarters, and a strong Q4 is exactly what tips a small supplier over.

British Columbia, Saskatchewan and Manitoba each run their own provincial sales tax regimes with separate registration rules for out-of-province sellers, and Quebec has its own QST rules. If you sell into both countries you need two versions of this report — and neither should be built for the first time in January. Our GST/HST guide covers the bookkeeping side.

The point is not the check. It is the reporting behind it.

A once-a-year nexus review beats none, but it is still a snapshot of a moving target.

What actually protects margin is a monthly sales-by-state report sitting in your close checklist, with threshold percentages next to each state and a named owner for anything above 80%. Build it once and the annual scramble stops being an event.

If that report does not exist today, we can build it and run it monthly — for e-commerce sellers and for CPA firms carrying multi-state clients.

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Rules cited here reflect guidance published as of September 2026 and change frequently. Confirm current thresholds with each state's department of revenue, or with your tax advisor, before acting.