Marketplace facilitator laws for multi-channel ecommerce sellers

Answer this without looking anything up: how many states do you have economic nexus in? If you answered from your storefront data, the real number is probably higher, and marketplace facilitator laws are the reason you haven’t noticed.

Under these laws, Amazon, Etsy, and eBay handle the sales tax on your marketplace orders. But in most states those sales still count toward your thresholds. The gap between those two numbers is where back tax accumulates.

By the end of this guide you’ll be able to count your nexus states with every channel included.

We’ll cover what facilitator laws handle and the one channel they never touch, which states count marketplace sales toward your threshold, and the full math for a $3M two-channel seller, with a state-by-state table to run your own footprint through.

Sales tax nexus is calculated across all your sales channels, not per platform

By storefront data, we mean the numbers from your own Shopify, WooCommerce, or BigCommerce store. For most multi-channel sellers, that’s the only side of the business their nexus tracking actually sees.

A seller with $1.8M on Amazon and $1.2M on Shopify doesn’t have two separate nexus pictures, one for each channel. They have one, and only the combined view is meaningful.

Each platform reports its own slice of the business, and no platform reports the whole, which is why so many compliance setups look complete when they aren’t.

The rest of this guide is about building that combined view: what the marketplaces handle, what still counts toward your thresholds, and where the back tax builds up.

What marketplace facilitator laws cover, and which platforms they apply to

A marketplace facilitator is a business that contracts with third-party sellers to list and sell their products through its platform, and that collects payment from the buyer. Under marketplace facilitator laws, the facilitator, not the seller, is responsible for collecting and remitting sales tax on those sales, as the SST Governing Board’s general definition puts it.

For a multi-channel seller, that means the tax on your Amazon and Etsy orders is collected and paid with no action needed from you. Individual states define the term more narrowly or broadly, which is one reason the state table below exists.

The major facilitators are Amazon, Etsy, eBay, Walmart Marketplace, and TikTok Shop, each confirmed in its own seller tax documentation. The platforms that are not facilitators are Shopify, WooCommerce, and BigCommerce: those are ecommerce platforms, and the seller is responsible for every storefront transaction.

The reassuring part: on marketplace sales, the platform collects and remits the tax, and your transaction-level obligation on those orders is zero. The question that decides everything else is whether those sales still count toward your thresholds.

Do marketplace sales count toward your nexus thresholds?

This is the question that decides everything, and it deserves a straight answer. In most states, yes: marketplace sales count toward the seller’s nexus thresholds regardless of who remits the tax. A meaningful group of states excludes them. Which group each of your states belongs to decides where you have to register.

Here is what that means in practice. A seller doing $2M to $4M across channels may believe they have nexus in three states based on storefront data alone, and the real number can be six or eight depending on which of their states count marketplace sales. The nexus thresholds by state differ too, which compounds the counting problem.

27 of the 46 jurisdictions with facilitator laws, 45 states plus Washington DC, count marketplace sales toward the seller’s threshold, and Alaska’s local marketplace rules add one more. The table at the end of this guide shows the treatment state by state.

If you only sell on marketplaces, here’s your simpler picture

If every sale you make runs through Amazon, Etsy, eBay, Walmart, or TikTok Shop, your situation is simpler, and mostly good news. The facilitators collect and remit the tax on all of it. There is nothing for you to collect on, because you have no storefront orders.

One obligation still surprises marketplace-only sellers, and it comes up constantly. In some states, crossing the threshold on marketplace sales alone still means you have to register with the state, and some of those states then require zero-dollar or informational returns, even though the marketplace paid every dollar of the tax.

The return exists so the state can see your activity, not to collect more money. The SST Governing Board’s marketplace sellers guidance covers the pattern, and the state table below flags these states in the notes.

A multi-channel nexus example

Now let’s make this concrete. Take a seller doing $3M a year, with $1.8M through Amazon and $1.2M through their own Shopify store, selling into 15 states.

Their tracking runs on Shopify data, so here is what their tracking shows next to their actual combined totals, in three states confirmed to count marketplace sales toward the seller’s threshold:

On storefront data, this seller has crossed nothing. On combined data, they have nexus in all three, and the unpaid tax is all on the storefront side: facilitator laws never cover their own store, and once nexus exists, every Shopify order into that state should have been taxed.

Here is the back-tax math, using each state’s base rate.

In California, $240,000 of storefront sales at 7.25% is $17,400 a year in uncollected tax. In Ohio, $60,000 at 5.75% is $3,450. In Pennsylvania, $48,000 at 6% is $2,880.

Across the three states, that is $23,730 a year before penalties and interest, and it grows every filing period it goes uncorrected.

To rerun this with your own numbers, take your revenue per state across every channel, compare it with that state’s threshold, and apply the state’s rate to your storefront sales.

Two channels, one nexus picture, and only the combined view was ever meaningful.

FBA inventory can create nexus before any threshold does

Thresholds are not the only trigger. Storing inventory in a state creates physical nexus in most states, and physical nexus applies from the first dollar, with no threshold to cross.

This matters for FBA sellers specifically because Amazon distributes inventory across its fulfillment network without asking, a practice described in Amazon’s own FBA documentation.

Amazon can place your stock in warehouses in states you have never sold into, and in many of those states, that inventory alone creates an obligation. It is a separate trigger from everything above: the threshold analysis tells you where your sales created nexus, and the inventory analysis tells you where your stock did.

Both are part of the same single nexus picture, which is why the tracking approach in the next section matters.

How to track nexus across every channel

Three paths bring every channel into one view.

Shopify integration

Marketplace orders from Amazon, eBay, Etsy, Walmart, TikTok, and others flow into Shopify and sync to TaxCloud, where facilitator orders are automatically tagged and kept distinct from direct sales, with threshold alerts as you approach a state’s threshold (marketplace support for Shopify sellers, Shopify integration). The full list of recognized marketplaces, more than 35 of them, is in TaxCloud’s help center.

CSV upload

If a marketplace doesn’t flow through Shopify, export its order data and upload it directly.

API

For custom workflows, the tax calculation API brings marketplace data in programmatically.

TaxCloud does not have pre-built integrations with Amazon, Etsy, or eBay. Marketplace data gets in through the three paths above instead.

Two things are worth knowing about how that data is treated.

1. First, marketplace transactions are imported for nexus calculations and reporting only, and TaxCloud does not file them.
2. Second, you can upload unlimited historical and marketplace transactions, so marketplace data builds your nexus picture without adding billable filing volume.

Marketplace facilitator laws by state

All 45 states with a statewide sales tax, plus Washington, DC, now have marketplace facilitator laws.

The table below answers the question from your side of the transaction, describing whether each state counts marketplace sales toward your threshold, not just when the marketplace has to collect.