"Marketplace Facilitator Laws: What Sellers Still Owe"

10/11/2026

"Amazon handles the sales tax" is one of the most common things an accountant hears from an e-commerce client, and it is about half right. Marketplace facilitator laws do move the job of collecting and remitting sales tax on marketplace sales from the individual seller to the platform. They do not make the seller's sales tax obligations disappear. Sellers who treat the platform's collection as the end of the matter tend to discover the rest during a notice, a registration review or an audit.

This post explains what a marketplace facilitator is, what facilitator laws do, and the obligations that stay with the seller: direct sales, registration, threshold counting, physical presence from inventory, records and returns. The rules are written state by state and differ in detail, so the post describes the common mechanisms and the questions to ask, not a state list. Each state's revenue department publishes its own guidance on marketplace sellers, and that is the source to check for any specific client.

What a Marketplace Facilitator Is

A marketplace facilitator is a business that operates a platform through which third parties sell goods or services, and that takes part in the transaction, typically by processing the payment, directly or through an arrangement. Large online marketplaces are the familiar examples, but state definitions can also reach smaller platforms, craft and resale sites, food delivery apps, short-term rental platforms and others, depending on the wording of each state's law.

A marketplace seller is the third party listing and selling through the platform.

The definitions matter because a platform that does not meet a state's definition is not required to collect, and the seller then keeps the full obligation. If a client sells through a smaller or niche platform, do not assume it collects; confirm it.

What Facilitator Laws Do

After South Dakota v. Wayfair in 2018 removed the physical-presence requirement for sales tax collection, states adopted economic nexus thresholds for remote sellers. Almost immediately they also adopted marketplace facilitator laws, because collecting from one platform is far easier than chasing thousands of small sellers. Every state with a statewide sales tax, along with the District of Columbia, now has such a law; Missouri's took effect at the start of 2023, completing the set.

The core rule is the same everywhere: for sales made through the marketplace, the facilitator is treated as the seller (or retailer) for collection purposes. The platform calculates tax at checkout, collects it from the buyer, files returns and remits the tax. In most states the facilitator, not the seller, is liable for errors on those sales, subject to the state's rules about relief when the seller gave the platform incorrect information.

Facilitators generally become subject to collection when their own marketplace sales into a state, including sales on behalf of third parties, exceed the state's economic nexus threshold. For the large platforms this is a given everywhere.

What the Seller Still Owes

Here is the part clients miss.

1. Tax on direct sales

The facilitator collects only on sales made through its marketplace. Sales through the seller's own website, at trade shows and craft fairs, through wholesale accounts, by phone or through a platform that is not a facilitator in that state remain the seller's responsibility. A client selling on a large marketplace and on its own storefront has two compliance streams, not one.

2. Registration, which may still be required

Whether a seller that makes only marketplace sales into a state must register there varies by state. Some states do not require registration if all of the seller's sales into the state are facilitated. Others require registration, and sometimes filing, even when every sale was facilitated, particularly where the seller has physical presence in the state. Never assume a state does not want to hear from the seller; check the state's marketplace seller guidance.

3. Threshold counting for direct sales

This is the most technical issue, and one where the states genuinely disagree. When determining whether a seller has crossed a state's economic nexus threshold, some states include the seller's marketplace sales in the count, and others exclude them.

The consequence: a seller whose direct website sales into a state are well below the threshold may still be over it in a state that counts marketplace sales too, and therefore must register and collect on the direct sales. A seller with large marketplace sales and modest direct sales is exactly the profile that falls into this.

The practical approach for each state where the client has meaningful sales:

1. Pull total sales into the state, split into marketplace and direct.
2. Check whether the state counts marketplace sales toward the seller's own threshold.
3. Apply the state's own measure (gross, retail or taxable sales; transaction count if any; measurement period).
4. If over, register and collect on direct sales from the point required by the state.

Because thresholds and counting rules change, recheck them for each state when you take on a client and periodically after that.

4. Physical presence from inventory

Many marketplace sellers use the platform's fulfillment network, and the platform decides where inventory sits. Inventory stored in a state is physical presence, which can create nexus without regard to any economic threshold. A seller using fulfillment warehouses can therefore have nexus in states where it has never considered itself present.

For marketplace sales, the facilitator still collects. But physical-presence nexus can create registration and filing requirements in some states, and it means any direct sales into those states must be taxed. It can also matter for state income or franchise taxes, which marketplace facilitator laws do not address at all. Clients should obtain inventory location reports from the platform; the sales tax question and the income tax question both start there.

5. Returns and reporting of marketplace sales

Where a seller is registered in a state, its sales tax return may require it to report gross sales, including marketplace sales, and then deduct the facilitated portion, rather than simply leaving those sales off. Reporting conventions differ by state. Reconcile the platform's reports to the amounts on each return so that what you deduct as facilitated matches what the facilitator reported.

6. Records and documentation

The seller should keep the platform's sales tax reports showing what was collected and remitted by state, and any certification from the facilitator that it is collecting. If a state questions the seller's sales, these records are the proof that tax on marketplace sales was handled by someone else.

7. Exempt sales and exemption certificates

Platforms handle exempt buyers in different ways. For direct sales, exemption certificate management remains entirely the seller's job, and missing or invalid certificates are where most audit assessments arise, as our post on sales and use tax nexus rules explains.

8. Use tax on the seller's own purchases

Marketplace laws change nothing about the seller's own purchases. Equipment, packaging materials used other than for resale, software and supplies bought without tax still create use tax obligations where they are used.

9. Other taxes and fees

Some states impose fees or taxes other than general sales tax (certain product-specific fees, for example), and facilitator laws do not always cover them. Where a client sells products subject to special fees, check whether the platform collects them in each state.

10. Income and franchise taxes

Facilitator laws concern sales tax collection. A seller's income or franchise tax nexus, including from inventory stored in the state, is a separate analysis. Clients often confuse "the platform takes care of tax" with "I have no tax obligations in that state."

A Worked Example (Without State Numbers)

A client sells home goods. Most sales go through a large marketplace using the platform's fulfillment service; the client also runs its own website and sells at two regional trade shows a year.

• Marketplace sales: the facilitator collects in every state with a sales tax. The client keeps the platform's tax reports.
• Inventory: the platform's reports show inventory in several states. Each is a physical-presence question for both sales and income tax.
• Website sales: in each state, the client measures direct sales against the threshold, adding marketplace sales where that state counts them. In some states it is over; it must register and collect on website sales there.
• Trade shows: in-person sales in the host state may create a collection obligation of their own; some states have specific temporary-seller rules.
• Registration where only marketplace sales occur: checked state by state.
• Purchases: packaging and equipment bought without tax are reviewed for use tax.

The client thought it had one obligation. It has five or six, and the platform covers one of them.

When a Client Has Missed Obligations

If the review shows the client should have been registered and collecting on direct sales in states where it was not, the decision about how to correct it is significant. Registering immediately can disclose a start date to the state, while many states' voluntary disclosure programs offer penalty relief and a limited lookback only to taxpayers who have not yet been in contact with the state. Quantify the exposure and consider voluntary disclosure before registering. Our nexus rules post walk through that sequence.

Technology Helps, Within Limits

Sales tax engines and connectors to marketplace platforms can separate facilitated from direct sales automatically and track thresholds by state. They are only as good as their configuration, and the counting rules they apply should be checked against current state guidance. Our post on AI for sales and use tax compliance covers what automation can and cannot do.

A Marketplace Seller Review Checklist

• [ ] List every channel: marketplaces, own site, wholesale, in-person events
• [ ] Confirm each marketplace is a facilitator under each relevant state's law
• [ ] Obtain platform tax-collected reports by state
• [ ] Obtain inventory location reports from fulfillment programs
• [ ] Measure direct sales against each state's threshold, using that state's counting rule for marketplace sales
• [ ] Check registration requirements for marketplace-only states
• [ ] Reconcile marketplace sales reported and deducted on each return
• [ ] Review exemption certificates on direct sales
• [ ] Review use tax on purchases
• [ ] Consider income and franchise tax nexus from inventory

Training on Sales and Use Tax Determinations

Marketplace questions are, at bottom, determination questions: who is the seller for this sale, whether it counts toward the threshold, and whether it is taxable where it is delivered. The Relieving Sales and Use Tax Determination Headaches webinar focuses on making those sales and use tax determinations. Our wider sales and use tax training catalog and sales and use tax FAQs cover the rest of the topic.

Frequently Asked Questions

What is a marketplace facilitator?

A marketplace facilitator is a business that operates a platform through which third-party sellers sell goods or services and that participates in the transaction, usually by processing payment. Under state marketplace facilitator laws, the facilitator is treated as the seller of facilitated sales for sales tax collection purposes, so it collects tax from buyers, files returns and remits. Each state defines the term in its own law, so whether a smaller or specialized platform qualifies depends on the state.

Do all states have marketplace facilitator laws?

Every state that imposes a statewide sales tax, plus the District of Columbia, has adopted a marketplace facilitator law. Missouri was the last, with its law taking effect at the start of 2023. The details differ: definitions of a facilitator, the threshold at which the facilitator must collect, whether sellers must also register, and how marketplace sales count toward a seller's own threshold all vary, so check each state's guidance for the specifics.

If a marketplace collects sales tax, does the seller still need to register?

Sometimes. Some states do not require registration when all of a seller's sales into the state are made through a facilitator that collects. Others require registration, and in some cases returns, even when all sales are facilitated, especially where the seller has physical presence such as inventory in a fulfillment warehouse. Any direct sales into a state where the seller has nexus also require registration and collection. Check each state's marketplace seller guidance.

Do marketplace sales count toward a seller's economic nexus threshold?

It depends on the state. Some states include a seller's marketplace sales when determining whether the seller has crossed the economic nexus threshold for its own direct sales, and others exclude them. In states that include them, a seller with modest direct sales but large marketplace sales can be required to register and collect on those direct sales. Run the calculation state by state, using each state's own measure and measurement period.

Does storing inventory in a marketplace warehouse create nexus?

Inventory located in a state is generally physical presence, which can create sales tax nexus regardless of any economic threshold. For marketplace sales the facilitator still collects, but the seller may have registration or filing requirements in that state, must collect on any direct sales delivered there, and may have income or franchise tax nexus as well. Request inventory location reports from the fulfillment program so the analysis is based on where stock actually sat.

Does a marketplace facilitator law cover the seller's own website sales?

No. Facilitator laws cover only sales made through the marketplace. Sales through the seller's own website, in person, by phone or through a platform that is not a facilitator in a given state remain the seller's responsibility. The seller must determine whether it has nexus in each state for those sales and, if so, register, collect and file. This is the obligation multichannel sellers most often overlook.