You sold $103,000 worth of handmade candles last year. Customers in 31 states. You never set foot in any of them, never rented a warehouse, never hired a salesperson on the ground. And yet four state tax departments may now expect you to register, collect their sales tax, file returns, and remit money you never charged your buyers.
That is the reality of economic nexus — the rule that says a state can require an out-of-state seller to collect its sales tax based purely on how much business the seller does there, with no physical presence required at all. It became law nationwide after a single 2018 Supreme Court decision, and seven years later it is still the most underestimated compliance trap for online sellers.
This guide explains where economic nexus came from, how the thresholds work, why the rules are quietly shifting in 2026, and what a small seller should actually do about it.
Where Economic Nexus Came From
For decades, the rule was simple and seller-friendly. Under a 1992 Supreme Court case, Quill Corp. v. North Dakota, a state could only force a business to collect its sales tax if that business had a physical presence in the state — a store, an office, an employee, inventory in a warehouse. Mail-order and, later, internet retailers could ship into a state all day long without collecting a cent of that state's tax.
States hated this. As e-commerce exploded, they watched billions of dollars of sales tax go uncollected because the seller happened to sit across a state line. Technically the buyer owed "use tax" on those purchases, but almost nobody paid it, and states had no practical way to enforce it against millions of consumers.
In 2018, the Supreme Court changed everything. In South Dakota v. Wayfair, Inc., the Court overturned Quill by a 5–4 vote and held that a state may require an out-of-state seller to collect sales tax even with no physical presence — as long as the seller's economic activity in the state is substantial enough. South Dakota's law, which the Court blessed, set the bar at $100,000 in sales or 200 separate transactions into the state in a year.
Within about two years, nearly every state with a sales tax had copied that model. "Economic nexus" — a connection created by economic activity rather than physical presence — became the law of the land.
How the Thresholds Actually Work
Economic nexus is triggered when your sales into a particular state cross that state's threshold. Once you cross it, you are generally required to:
- Register for a sales tax permit in that state.
- Collect the correct sales tax from buyers in that state going forward.
- File returns on the state's schedule (monthly, quarterly, or annually).
- Remit the tax you collected to the state.
The threshold itself varies, and the variation is exactly what makes compliance hard.
The common $100,000 standard
Most states followed South Dakota almost exactly: nexus is created at $100,000 in sales into the state. This is the single most common number, and if you remember only one figure, remember this one.
The higher-threshold states
A handful of the largest markets set the bar higher, recognizing that $100,000 is a rounding error in a state of 30 or 40 million people:
- California, Texas, New York, Tennessee: $500,000
- Mississippi: $250,000
If most of your sales go to big states, a higher threshold buys you breathing room. But do not assume — a seller who does $300,000 of business spread across 40 small and mid-size states can have nexus in a dozen of them while never coming close to California's number.
Sales, transactions, or both?
The original South Dakota rule was "$100,000 OR 200 transactions" — meaning you triggered nexus by crossing either line. That "200 transactions" prong is where small sellers got ambushed. A craft seller doing 250 orders averaging $40 each — just $10,000 in sales — could trip a state's transaction count and owe registration despite tiny revenue.
A few states still pair the two differently. Connecticut, for example, requires you to exceed $100,000 and 200 transactions — both, not either — which is actually more forgiving.
The 2026 Shift: Transaction Counts Are Disappearing
Here is the most important recent development, and the reason this topic is worth revisiting in 2026.
States have realized the 200-transaction threshold was a mistake. It punishes low-priced, high-volume sellers — the smallest businesses — far more harshly than it punishes large ones. So states have been systematically removing the transaction count, leaving only the dollar threshold.
As of January 1, 2026, 16 states have eliminated the 200-transaction trigger, including South Dakota itself — the state that started it all. The most recent moves:
- Illinois removed its transaction threshold effective January 1, 2026. Remote sellers now establish nexus there only by crossing $100,000 in gross receipts, regardless of how many orders that took.
- Kentucky is scheduled to remove its transaction threshold effective August 1, 2026.
- Indiana, Louisiana, North Carolina, Wyoming, Utah, and North Dakota are among the states that dropped transaction counts in earlier years.
Why this matters to you: a change in the rules can end an obligation, not just create one. If you had nexus in Illinois only because you exceeded 200 transactions — say you did 240 small orders totaling $60,000 — Illinois removing its transaction threshold means you may no longer have economic nexus there. You could be able to deregister and stop collecting.
This is good news for small sellers, but it cuts both ways. It means the nexus map is not static. A state you weren't required to register in last year might require it this year — and vice versa. You cannot set up your sales tax once and forget it.
Marketplace Facilitator Laws — Help, But Not a Free Pass
If you sell on Amazon, Etsy, eBay, Walmart Marketplace, or a Shopify storefront that uses Shopify's tax service, you have probably noticed the platform already collects sales tax for you. That is marketplace facilitator law at work.
Every state with a sales tax now requires large marketplaces to collect and remit tax on behalf of their third-party sellers. For a seller who lists exclusively on Amazon, this removes most of the day-to-day collection burden — the marketplace handles it.
But three traps catch sellers who assume marketplace collection means they can ignore sales tax entirely:
Trap 1: Direct sales still count. If you sell on Amazon and run your own website, the marketplace covers only the Amazon orders. Your direct website sales can still create nexus and obligations that are entirely yours to manage.
Trap 2: Marketplace sales may still count toward your threshold. Several states — New York is a notable example — count marketplace sales toward your economic nexus threshold even though the marketplace remits the tax. You can be pushed over the line, and required to register, by sales you never personally collected tax on. Once registered, you may need to file returns reporting those marketplace sales even if the tax owed is zero because the platform already paid it.
Trap 3: Registration may still be required. Some states want you registered even when 100% of your sales run through a marketplace, simply so they have you on file. "The marketplace handles it" is a reason to relax about collection, not about registration and filing.
The Most Common — and Most Expensive — Mistakes
Treating sales tax nexus like income tax nexus. These are different regimes with different rules. Sales tax nexus is generally triggered at a much lower level of activity. A business can owe sales tax registration in a state where it owes no income tax at all. Do not let your income tax footprint lull you into assuming your sales tax footprint is the same.
Not tracking state-by-state sales totals. This is the big one. Most sellers look at total revenue, not revenue per state. Economic nexus is almost always crossed midyear, quietly, and you do not get a notification. By the time a seller realizes they blew past Pennsylvania's threshold in March, they have nine months of uncollected tax they now owe out of their own pocket — because you cannot retroactively charge customers who have already paid.
Assuming the marketplace covers everything. Covered above — the gaps are real.
Ignoring a problem once it's discovered. Uncollected sales tax does not expire. Interest and penalties accrue. States are increasingly aggressive: enforcement can escalate from assessments and penalties to liens, collection agencies, and in extreme cases criminal referral. The liability also follows the business — it can surface and kill a deal during due diligence if you ever try to sell the company.
What To Do If You've Already Crossed a Line
If you research this and realize you've had nexus in a few states for a year or two without registering, do not panic — but do not ignore it either.
The standard tool is a Voluntary Disclosure Agreement (VDA). You (usually through a tax advisor, often anonymously at first) approach the state, disclose the unregistered activity, and negotiate. In exchange for coming forward, states typically:
- Limit the lookback period — often to three or four years instead of "all the way back."
- Waive or substantially reduce penalties.
The catch: a VDA generally has to be initiated before the state contacts you. Once you receive an audit notice or a nexus questionnaire, the favorable terms are usually off the table. Coming forward voluntarily is almost always cheaper than being found.
A Practical Compliance Routine for a Small Seller
You do not need an enterprise tax department. You need a routine:
- Pull a sales-by-state report at least quarterly. Every major platform and most accounting tools can produce one. This single habit prevents the worst surprises.
- Compare each state's total to that state's current threshold. Keep a simple reference list of the states you sell into and their thresholds — and recheck it annually, because the rules move.
- Register promptly when you cross a line. The obligation starts at the threshold, not when you get around to it. Registering quickly limits the period of uncollected liability.
- Separate marketplace sales from direct sales in your records, so you can answer "who collected the tax?" for any state.
- Build sales tax into your accounting from the start, treating collected tax as a liability you owe the state — never as revenue. It is money you are holding for the government, and your books should make that crystal clear.
Why Your Bookkeeping Is Your First Line of Defense
Economic nexus compliance is, at its core, a data problem. You cannot manage what you cannot see. If your books cannot quickly answer "how much did I sell into Ohio this year?" you are flying blind toward a threshold you cannot see coming.
Sales tax collected from customers should sit in a dedicated liability account, clearly separated from revenue, so you never mistake the state's money for your own and never spend it. Sales should be tagged by destination state so a per-state total is one query away, not a weekend of spreadsheet archaeology. Get this structure right early and threshold monitoring becomes a five-minute quarterly check instead of an annual fire drill.
Keep Your Finances Organized from Day One
As your business grows across state lines, the difference between a calm sales tax season and a panicked one comes down to whether your records can tell you the truth on demand. Beancount.io offers plain-text accounting that gives you complete transparency and control over your financial data — every transaction tagged, every liability tracked, no black boxes and no vendor lock-in. Get started for free and see why developers and finance professionals are switching to plain-text accounting. You can also explore the documentation to learn how to structure tax-liability accounts, or see how Fava dashboards turn your ledger into clear, state-by-state views of where your business stands.