US Sales Tax for Marketplace and DTC Sellers: Nexus Basics
When you sell on Amazon or Walmart, the marketplace usually collects and remits US sales tax for you. When you add your own Shopify store, a wholesale channel or another site that doesn't collect tax, the rules change: you may have to register and collect tax yourself in states where your sales pass certain thresholds. This guide explains the two ideas that matter most, economic nexus and marketplace facilitator laws, with official thresholds from four large states.
Two rules every seller should know
1. Economic nexus
Since the 2018 Supreme Court decision in South Dakota v. Wayfair, states can require out-of-state sellers to collect sales tax once their sales into the state pass a threshold, even with no office or warehouse there. Each state sets its own threshold and its own way of measuring it. Note that inventory stored in a state (for example, in a fulfillment center) can create a tax obligation there on its own, separate from these sales thresholds.
2. Marketplace facilitator laws
Most states with a sales tax now make the marketplace (the "marketplace facilitator" or "marketplace provider") responsible for collecting and remitting tax on sales made through it. For example, the Texas Comptroller says a remote seller that sells only through a marketplace provider that certifies it collects and reports the tax on the seller's behalf does not need a Texas tax permit, but "all sellers must keep required records of all marketplace sales for at least four years."
Thresholds in four large states
| State | Threshold for remote sellers | Measured over | Source |
|---|---|---|---|
| California | More than $500,000 in total combined sales of tangible personal property for delivery in California (related persons' sales count) | Preceding or current calendar year | CDTFA |
| Texas | Total Texas revenue of $500,000 or more (safe harbor below that) | Preceding 12 calendar months | Texas Comptroller |
| Illinois | $100,000 or more in gross receipts, or 200 or more separate transactions | Preceding 12 months, tested quarterly | Illinois Department of Revenue |
| Florida | Taxable remote sales over $100,000; no transaction count test | Previous calendar year | BDO, on Florida's 2021 law |
Two details that are easy to miss. First, states differ on whether sales made through a marketplace count toward your own threshold, and some official pages don't say; ask a tax adviser for each state. Second, the timing differs: Texas requires a permit and collection no later than the first day of the fourth month after the month you pass the threshold, while Illinois says that once a threshold is met for a 12-month period, the retailer must collect and remit for one year. Some secondary sources report recent changes to Illinois's transaction test; the IDOR page we reviewed still lists both tests, so check the current rule before relying on either.
Which channels need your attention
- Amazon, Walmart, TikTok Shop, Temu, SHEIN, eBay, Etsy: generally the marketplace collects and remits in states with facilitator laws. Keep your records anyway.
- Your own website (Shopify, WooCommerce and similar): you are the seller of record. If you pass a state's threshold, you register, collect and file there. Platform tax tools can calculate tax, but registering and filing remain your responsibility.
- Wholesale and B2B: sales for resale are often exempt if you collect a valid resale certificate. Without one, you may owe the tax.
- Fees and other taxes: separate from sales tax on your products, some states tax services sold to you. Texas, for example, has taxed marketplace fees as data processing since October 2025 and is now moving to reverse that; see our Texas marketplace fee tax update.
Step-by-step: a simple sales tax check
- Export sales by state for the last 12 months and the last calendar year, split into marketplace sales and direct sales.
- Compare with each state's threshold and measurement period, starting with your largest states.
- List where you hold inventory, including 3PL and fulfillment center locations.
- Register before you start collecting in any state where you have an obligation.
- Turn on tax collection for those states in your store settings and test a checkout.
- File on time, even when you owe little or nothing, if the state requires it.
- Keep records of all sales, including marketplace sales, for at least the period each state requires (four years in Texas).
- Review every quarter, because growth can push you over a threshold mid-year.
If you have already passed a threshold without collecting, many states offer voluntary disclosure programs that can reduce penalties. Talk to a sales tax professional before contacting a state.
This article is general information, not tax advice. Thresholds and rules change; always confirm with the state's revenue department or a qualified adviser.
How Atronia Innovations can help
We help brands and factories sell on Amazon, Walmart and TikTok Shop and expand to new channels. We can pull the sales-by-state reports your tax adviser needs and set up channels so the right party collects tax. See our US market entry checklist or contact us.
Sources
- California Department of Tax and Fee Administration — Tax guide for out-of-state retailers (Wayfair) (accessed Oct 12, 2026)
- Texas Comptroller — Remote sellers (accessed Oct 12, 2026)
- Illinois Department of Revenue — Retailers' Occupation Tax (accessed Oct 12, 2026)
- BDO — Florida enacts economic nexus and marketplace legislation (2021)
