You open your quarterly sales report and see strong growth in California, Texas, and Illinois. That growth feels great until you realize multi-state sales tax nexus for ecommerce may have quietly attached to your business in each of those states.
Nexus is simply the legal connection that gives a state the right to make you collect its sales tax. Cross a line you never saw, and the uncollected tax comes out of your own margin, not your customer’s wallet.
Most sellers miss it because Amazon collects tax on marketplace orders, Shopify shows a tax setting, and everything looks handled. AMZ Accountant works with Amazon and Shopify sellers who discover, often two or three years in, that combined channel revenue pushed them over a threshold nobody was watching. Economic nexus counts your total sales into a state across every channel, not your sales on one platform.
Keep reading to learn how physical and economic nexus start, how to spot triggers across your sales channels, how to separate taxable from exempt sales, and how to register, collect, and file cleanly. Catch this early, and you protect margin you would otherwise hand to a state auditor.
How a State Tax Connection Begins
A single state can reach back three or four years and bill you for tax you never charged. On $400,000 of taxable sales at a 7% average rate, that is roughly $28,000 out of your profit, before penalties.
Nexus in Plain English
Nexus means your business has enough of a connection to a state that the state can require you to collect and remit its sales and use tax, based on where your customers, inventory, and people are, not where you live or where your LLC was formed.
Once nexus exists, four duties follow: register, collect at checkout, file returns, and remit the money. Skipping the first step does not pause the other three.
Why the Wayfair Decision Changed Remote Selling
Before 2018, physical presence was the only trigger. The U.S. Supreme Court changed that in South Dakota v. Wayfair, Inc., ruling that the Commerce Clause does not require boots on the ground. States may tax remote sellers based on economic activity alone.
That decision moved the burden onto out-of-state sellers. A Shopify brand run from a kitchen table can now owe sales tax obligations in 30 states without ever crossing a state line.
Physical Footprints That Create Obligations
Physical nexus still applies and is often the first trigger a growing seller hits. Common examples include an office, a retail booth, a warehouse, a 3PL location, stored inventory, or a person working in the state.
Economic Activity That Crosses the Line
Most states model their threshold on South Dakota’s original $100,000-in-sales, 200-transaction test, though a growing number of states, including Illinois, Utah, and Alaska, have dropped the transaction-count prong and now trigger nexus on revenue alone. Gross sales means revenue before fees, refunds, and cost of goods sold, so thin margins do not protect you.
Low-ticket sellers can still get caught by the transaction count in the states that kept it. Two hundred orders at $12 is $2,400 in revenue and still creates a filing duty there, even though the same seller would owe nothing yet in a revenue-only state.
Knowing the rules is one thing; finding your own triggers across Amazon, Shopify, and everywhere else is the harder job.
Find Every Nexus Trigger Across Your Sales Channels
Sellers rarely have one trigger. They have three or four, spread across FBA warehouses, a Shopify store, and a contractor in another state.
Amazon FBA Inventory and Fulfillment Locations
Amazon moves your units between fulfillment centers without asking. The moment a pallet lands in a new state, you may have physical nexus there, even with zero employees and zero local ad spend.
Pull your Inventory Event Detail report to see every state that has held your stock. That list is your starting map, not your final answer, and feeding it into clean, reconciled books makes it far easier to pin down the exact month nexus actually began.
Direct Store Sales and Combined Threshold Tracking
Your Shopify, Walmart, eBay, and Etsy sales generally stack together when you test a threshold. Many sellers assume $70,000 on Amazon and $45,000 on Shopify keeps them safe. In most states, that is $115,000, and nexus is already live.
Remote Workers, Contractors, and Other Physical Activity
Hiring one remote VA in Georgia can create nexus for both sales tax and, in some states, income tax. Watch for these often-missed triggers:
- Employees, contractors, or a customer service rep working from home in another state
- Inventory at a third-party fulfillment center or prep center
- Trade shows, pop-ups, or in-person sales events
- Returns processing or repair work handled locally
- Company-owned equipment or delivery vehicles stationed in the state
Marketplace Sales That Still Affect Your Analysis
Marketplace facilitator laws require Amazon, eBay, Etsy, and Walmart to collect and remit tax on orders they process. That does not erase those sales from your math. Most states still count marketplace revenue when measuring whether you crossed the economic nexus threshold for your direct sales.
Once you know where you have nexus, the next question is which of your products are actually taxable there.
Separate Taxable Sales From Exempt Transactions
Collecting tax on an exempt product is just as expensive as missing it. Overcharge 5,000 customers by $4, and you are looking at $20,000 in refund requests or a state credit you have to chase.
How Product Taxability Changes by State
Tangible personal property, meaning physical goods you ship, is taxable in nearly every sales tax state. Categories like clothing, groceries, supplements, and medical items break that pattern. Clothing is exempt in Pennsylvania and Minnesota but fully taxable in Texas.
Rates change too. A single state can carry state, county, city, and district layers, so a $50 order may face 6.25% in one ZIP code and 9.5% a few miles away.
Digital Products, Services, and Tangible Goods
Digital products are the messiest category. Ebooks, courses, templates, and software downloads are taxable in some states, exempt in others, and taxed differently depending on whether the buyer gets permanent access.
Services usually escape sales tax, but bundling matters. If you sell a physical planner with a coaching call as one price, some states tax the entire amount.
Exemption Certificates and Customer Documentation
Wholesale and resale buyers don’t pay sales tax, but only if you have a valid exemption certificate on file. Without a certificate, the auditor treats the sale as taxable and bills you for tax you never collected.
Store certificates digitally, tie each one to the customer record, and track expiration dates. Manufacturing and nonprofit buyers often use different forms by state.
Why Sales Tax Is Not VAT, Customs Duty, or Income Tax
Sales tax is a consumption tax collected from the buyer at checkout. VAT applies at each stage of production abroad, and customs duty applies at import. Neither replaces state sales tax.
Income tax nexus is separate again. A remote worker can create corporate income tax obligations even when sales tax does not apply. With taxability settled, registration comes next.
What to Do Once Nexus Is Established
The order matters. Collecting tax before you register is illegal in most states, and the penalty can exceed the tax itself.
Register Before Turning On Collection
Apply for a sales tax permit through the state’s revenue department. You will need your EIN, entity details, NAICS code, and the date nexus began. Be honest about that date; it drives your first filing period.
Registration is usually free or under $100. Expect a permit number within a few days to a few weeks depending on the state.
Configure Accurate Rates and Checkout Collection
Turn on collection in Shopify only after the permit arrives, and match the state and local rates to the destination address. Tools like Avalara handle rooftop-level tax calculation when your volume justifies the cost.
Test a few orders across different ZIP codes before you trust the setup. A misconfigured rate on 1,000 orders becomes a real liability fast.
File Returns, Remit Tax, and Retain Records
Most states assign monthly, quarterly, or annual filing based on your volume. You must file even in periods with zero sales, or you risk a late-filing penalty on a $0 return.
Keep transaction-level records for at least four years, including exempt sales and certificates.
Build a Recurring State-by-State Compliance Calendar
Deadlines cluster around the 20th, but not everywhere. Track each state’s due date, filing frequency, and login credentials in one place, and reconcile collected tax to remitted tax monthly.
Current compliance is only half the picture if you crossed a threshold two years ago.
Address Past Exposure Before It Becomes an Audit Issue
Back exposure grows quietly. Three years of uncollected tax in five states can easily reach $60,000 to $120,000 once penalties of 5% to 25% and monthly interest stack on top.
Review Historical Sales, Inventory, and Filing Dates
Pull sales by state, by month, for the last four years across every channel. Overlay your FBA inventory history. The earliest date either signal crossed a line is your likely nexus start date.
Estimate Uncollected Tax, Interest, and Penalties
Multiply taxable sales in each state by that state’s average combined rate. Marketplace-collected sales usually come out of the calculation, which often shrinks the number more than sellers expect.
Do this before you contact any state. Knowing the size of the problem changes which option makes sense.
Evaluate Voluntary Disclosure Options
A voluntary disclosure agreement lets you come forward first. States typically limit the lookback to three or four years and waive most penalties, which can cut a $90,000 exposure by a third or more.
You generally cannot use a VDA after a state contacts you. Timing is the whole advantage.
Create Ongoing Controls for New States
Set threshold alerts at 70% of each state’s limit so registration happens before, not after. That habit turns compliance into a planning task rather than a cleanup project, the same quarterly discipline that keeps tax planning for Amazon sellers proactive instead of reactive.
Turn State Growth Into a Proactive Compliance Plan
The goal is precision: register exactly where required, on time, so you never pay tax out of margin.
Use Sales Data to Spot the Next Registration Requirement
Run a combined sales-by-state report monthly across Amazon, Shopify, and every other channel. Watch gross sales and order counts together, since either can trigger nexus.
A holiday quarter or one viral product can push a state from $40,000 to $110,000 in eight weeks. A monthly review catches that; an annual review does not.
Know When an eCommerce CPA Review Adds Value
A nexus study makes sense when you add a 3PL, hire remotely, launch a second channel, or plan to sell the business. Buyers price unresolved sales tax exposure straight out of your valuation.
Get Support for a Multi-State Compliance Strategy
Generalist accountants rarely read FBA inventory reports or A2X payout mappings. eCommerce-specific expertise is what separates a clean nexus map from a guess.
Frequently Asked Questions
When Does an Amazon Seller or Shopify Store Owner Create Sales Tax Nexus in Another State?
Nexus starts when you store inventory, employ someone, or cross a state’s sales threshold. Many states use $100,000 in gross sales, though a growing number have dropped the 200-transaction option in favor of revenue alone, and a few states set materially higher thresholds. In most states, combined revenue across Amazon, Shopify, and other channels counts toward that test.
What Are the 2026 Economic Nexus Sales Thresholds for Online Sellers by State?
Most states use $100,000 in gross sales, with some adding a 200-transaction option. California, Texas, and New York use higher dollar thresholds, and several states have dropped the transaction count entirely. Confirm each state’s current rule before you register.
Do Amazon FBA Inventory Warehouses Create Sales Tax Nexus Even If I Have No Employees There?
Yes, in most states, stored inventory alone creates physical nexus. Because Amazon redistributes stock without notice, your Inventory Event Detail report is the only reliable way to see which states have held your goods.
How Do I Register For, Collect, and Remit Sales Tax in Multiple States Without Missing Filing Deadlines?
Register with each state first, then enable collection at the correct destination rate, then file on the schedule the state assigns. Keep a single calendar of due dates and filing frequencies, and file zero returns when you have no sales.
Does a Marketplace Facilitator Collect Sales Tax for Amazon Sales, and What Must Sellers Still Report?
Amazon collects and remits tax on marketplace orders in all sales tax states. You are still responsible for tax on your own website sales, and many states require you to report marketplace sales as exempt or excluded on your return.
What Happens If an eCommerce Seller Exceeds a State’s Sales Tax Threshold but Does Not Register or Collect Tax?
The state can assess the uncollected tax against you personally, plus penalties often between 5% and 25% and interest from the original due date. Since you never charged customers, the full amount comes out of your profit.
Protect Your Margin Before the State Finds You
Multi-state compliance comes down to knowing exactly where your sales, inventory, and people have created obligations, then handling each one before it turns into an assessment you fund out of pocket.
Sellers who stay ahead treat sales by state as a monthly number, not a tax-season surprise. Pull the report, check the thresholds, register where required, and keep the records clean.
If you are not sure whether your current setup is costing you money, AMZ Accountant offers a free 15-minute strategy call for eCommerce sellers, with no obligation. Bring your sales-by-state numbers and find out where you actually stand.