One Supreme Court case changed the sales tax landscape for every online seller in America. If you’ve ever wondered why your ecommerce business suddenly owes sales tax in states you’ve never visited, this is the decision that explains it.
What Is South Dakota v. Wayfair?
South Dakota v. Wayfair, Inc. is a 2018 Supreme Court ruling that eliminated longstanding protection for remote sellers. Before June 21, 2018, states could only require a business to collect sales tax if it had a physical presence there: a store, warehouse, employee, or office. No physical footprint meant no obligation, full stop.
After Wayfair, location became irrelevant. States can now require sales tax collection based purely on economic activity, so how much you sell into a state, not whether you have a building there.
The Rule That Protected Remote Sellers for 26 Years
To understand why Wayfair mattered so much, you need to meet its predecessor.
In Quill Corp. v. North Dakota (1992), the Supreme Court ruled that a mail-order company with no physical presence in a state couldn’t be forced to collect that state’s sales tax. The logic made sense at the time: in 1992, forcing businesses to navigate thousands of different tax jurisdictions felt like an unreasonable burden on interstate commerce.
But that was 1992. The internet didn’t exist as a commercial force. Mail-order sales totaled roughly $180 billion across the entire country. By 2017, e-commerce alone had reached $453.5 billion. States were losing somewhere between $8 billion and $33 billion annually in uncollected sales tax. Funding that would otherwise go to schools, roads, and emergency services.
The old rule hadn’t just aged poorly. It had created a genuine competitive imbalance. Online retailers without a physical presence could advertise lower prices because they weren’t collecting tax. Brick-and-mortar stores (which had no choice but to collect) were losing customers because of it. Wayfair, the home goods retailer, reportedly used “we don’t have to charge sales tax” as an actual marketing point. Justice Kennedy called it a “subtle offer to assist in tax evasion.”
Something had to give.
How South Dakota Forced the Issue
South Dakota doesn’t have a personal income tax. Its government runs largely on sales tax revenue. Watching billions in potential revenue evaporate into the internet economy wasn’t sustainable.
In 2016, the state passed Senate Bill 106, a law designed not just to collect taxes, but to force a Supreme Court showdown. It required out-of-state sellers to collect sales tax if they exceeded $100,000 in annual sales or 200 separate transactions into South Dakota. The Supreme Court opinion noted South Dakota was losing an estimated $48 to $58 million annually from the Quill loophole, a number that helps explain the urgency.
The state then sued four major online retailers: Wayfair, Overstock.com, Newegg, and Systemax. Systemax complied. The other three fought back, confident that Quill still protected them.
They were wrong.
The 5–4 Decision That Changed Everything
On June 21, 2018, the Court ruled 5–4 in favor of South Dakota. Justice Kennedy wrote the majority opinion, joined by Justices Thomas, Ginsburg, Alito, and Gorsuch. Their conclusion was blunt: Quill’s physical presence rule was “unsound and incorrect,” and it was overruled.
The ruling introduced economic nexus as the new standard. A business now establishes nexus in a state simply by doing enough business there. No physical presence required.
Chief Justice Roberts dissented, joined by Justices Breyer, Sotomayor, and Kagan. His concern wasn’t that the old rule was good, he agreed Quill had been wrongly decided, but that the Court, not Congress, was rewriting rules that millions of businesses had built around. Fair point. Didn’t change the outcome.
What Economic Nexus Means in Practice
Here’s the practical reality: you may now owe sales tax in states you’ve never set foot in, simply because your customers live there.
Most states modeled their laws directly on South Dakota’s threshold. By January 1, 2023, every state with a sales tax had enacted economic nexus rules. But the details vary, sometimes significantly. HOST’s Economic Nexus by State Chart tracks current thresholds for every state, but here’s a snapshot:
- Most states: $100,000 in sales triggers nexus
- California and Texas: $500,000 threshold — more room before you’re on the hook
- New York: $500,000 AND 100 transactions — both required
- Connecticut: $100,000 AND 200 transactions — both required
The transaction threshold is also quietly disappearing. As of July 1, 2025, at least 15 states have dropped it entirely, including South Dakota, which removed its own 200-transaction test in 2023. The trend is toward simpler, sales-only thresholds.
Once you cross a state’s threshold, you’re required to register for a sales tax permit, collect from customers there, and file returns on that state’s schedule.
The Compliance Burden Is Real
The U.S. has over 11,000 tax jurisdictions (state, county, city, special district) each with its own rates, rules, and filing deadlines. A growing ecommerce business can find itself managing obligations in a dozen states simultaneously, each with different definitions of what’s even taxable.
It’s not a paperwork nuisance. It’s a genuine operational challenge. Miss a threshold crossing and you’re looking at back taxes, penalties, and interest. Get your software configured wrong and you’re either overcharging customers or underremitting to the state. Neither outcome is pleasant.
One more thing worth knowing: Wayfair didn’t replace the physical nexus, it added an economic nexus on top of it. If you have employees, inventory, or office space in a state, you have physical nexus there from dollar one, no threshold required. Sellers using Amazon FBA often discover physical nexus in states where they had no idea their inventory was sitting.
A note on retroactivity: The Court specifically pointed to South Dakota’s law being non-retroactive as one reason it was likely constitutional. That protection doesn’t extend to sellers who’ve been quietly ignoring their obligations. States can and do pursue back taxes for periods before a seller registered. If past exposure exists, a Voluntary Disclosure Agreement is often the cleanest path forward.
What about Amazon and Etsy sellers? Wayfair directly enabled marketplace facilitator laws, which are rules requiring platforms like Amazon, Etsy, eBay, and Walmart to collect and remit sales tax on behalf of their third-party sellers. Every state with a sales tax has now enacted one. This is good news if you sell exclusively through those platforms — the marketplace handles collection for you. But it doesn’t mean you’re off the hook entirely. If you also sell through your own website, have inventory stored in Amazon FBA warehouses (which creates physical nexus), or sell through multiple channels, you likely still have independent filing obligations that no marketplace is managing for you.
Where Things Stand in 2026
The post-Wayfair landscape keeps evolving. Missouri was the last state to implement economic nexus, effective January 1, 2023. A 2022 study in the Journal of Public Economics found the decision increased state sales tax revenues by 7.9%, concentrated in states with the most rigorous enforcement. States continue refining their rules by eliminating transaction thresholds, adjusting measurement periods, clarifying what counts toward the threshold. The HOST Economic Nexus by State Chart is the fastest way to check where any given state currently stands.
If you’ve been selling online since before 2018 and haven’t done a full nexus review, there’s a real chance you have unregistered obligations sitting out there. The good news is that most states offer Voluntary Disclosure Agreements (VDAs). A way to come forward, limit your lookback period, and resolve past liability without the worst penalties. Acting proactively almost always produces a better outcome than waiting for a notice to arrive.
How HOST Helps
At Hands Off Sales Tax (HOST), we’ve been focused entirely on sales tax compliance since 1999. Long before Wayfair, and through every shift that followed it.
- Nexus Analysis — We review your sales data to map exactly where you’ve crossed economic or physical nexus thresholds.
- Sales Tax Registration — We handle permit applications in every required state, start to finish.
- Sales Tax Filings — Monthly, quarterly, or annual returns across all jurisdictions, including local and special district filings.
- VDA Support — If past exposure exists, we file voluntary disclosure agreements to limit lookback periods and reduce penalties.
- Audit Defense — When states come calling, we handle it.
- Free Sales Tax Software Review — Using TaxJar or Avalara? We audit your configuration to find costly errors before they become audit triggers.
Wayfair created obligations that don’t disappear on their own. Contact HOST today. You handle the sales, we handle the tax.
Frequently Asked Questions
Do marketplace facilitator laws mean I don’t have to worry about sales tax?
Partially. If you sell exclusively through Amazon, Etsy, eBay, or Walmart, those platforms handle collection and remittance in states with marketplace facilitator laws, which is now every state with a sales tax. But if you also sell through your own website, store inventory in Amazon FBA warehouses (which creates physical nexus), or operate across multiple channels, you likely have independent obligations no marketplace is covering. A Nexus Analysis will clarify where you stand.
What did South Dakota v. Wayfair decide?
The Supreme Court ruled on June 21, 2018, that states can require out-of-state sellers to collect sales tax based on economic activity alone, no physical presence required. It overturned Quill Corp. v. North Dakota (1992), which had shielded remote sellers from out-of-state collection obligations for 26 years.
What is economic nexus?
Economic nexus is a sales tax obligation triggered by reaching a state’s sales or transaction threshold regardless of physical presence. Most states use $100,000 in annual sales as their trigger. See HOST’s Economic Nexus by State Chart for every state’s current threshold.
Do I have to collect sales tax in every state?
Only in states where you’ve established nexus, economic or physical. A Nexus Analysis is the most reliable way to identify your exact obligations.
What if I’ve been selling past my nexus date without registering?
You likely owe back taxes, penalties, and interest. Many states offer Voluntary Disclosure Agreements that limit lookback periods and reduce penalties. The sooner you act, the better the outcome tends to be.
Has anything changed since the 2018 ruling?
Consistently, yes. At least 15 states dropped their 200-transaction threshold by July 1, 2025, and Missouri became the last state to implement economic nexus in January 2023. Track current thresholds on HOST’s Economic Nexus by State Chart.
Is physical nexus still relevant after Wayfair?
Completely. Wayfair added economic nexus, it didn’t replace physical. Employees, inventory, and property in a state create physical nexus from the first sale. HOST’s Nexus Analysis covers both.
