What is sales tax nexus?

Sales tax nexus is the connection between a seller and a state that is strong enough to obligate the seller to register for a sales tax permit, collect tax from buyers in that state, and remit it to the state. Nexus takes two main forms. Physical nexus comes from a tangible presence such as employees, an office, or inventory stored in the state. Economic nexus comes from sales activity alone, once a seller crosses a state's dollar or transaction threshold. A business can have nexus in a state where it has never had a single employee or location.

What is economic nexus?

Economic nexus is sales tax nexus created purely by economic activity in a state, without any physical presence. A remote seller that ships enough goods or sells enough services into a state crosses that state's economic-nexus threshold and must then register, collect, and remit sales tax. Economic nexus became enforceable nationwide after the 2018 South Dakota v. Wayfair decision, which let states tax remote sellers based on sales volume rather than physical footprint. Every state with a sales tax now has some form of economic-nexus rule, though the specific thresholds differ.

What changed with South Dakota v. Wayfair?

In South Dakota v. Wayfair, Inc., decided June 21, 2018, the United States Supreme Court overturned the physical-presence rule of Quill Corp. v. North Dakota (1992). Before Wayfair, a state generally could not require a seller to collect sales tax unless the seller had physical presence in the state. Wayfair held that physical presence is not required and that economic activity alone can establish sales tax nexus. The decision opened the door for states to enforce economic-nexus rules against remote and online sellers.

What is use tax, and how does it relate to sales tax?

Use tax is the complement to sales tax. It applies to taxable goods or services a buyer uses, stores, or consumes in a state when sales tax was not collected at the point of sale, for example on an out-of-state purchase. The buyer is responsible for self-assessing and remitting use tax in that case. Together these are usually administered as one regime, which is why states refer to sales and use tax: the sales tax is collected by the seller, and the use tax backstops it when the seller did not collect. The rate is generally the same.

What is the Streamlined Sales and Use Tax Agreement (SSUTA)?

The Streamlined Sales and Use Tax Agreement (SSUTA) is a multistate effort to simplify and standardize sales and use tax administration, definitions, and registration so that compliance across states is more uniform. It currently has 23 full member states plus Tennessee as an associate member. Member states accept a common registration system and shared definitions, which can ease multistate compliance for sellers. SSUTA membership does not change whether a seller has nexus, but it can streamline how that seller registers and reports once nexus exists.

How does a business know where it has sales tax nexus?

It starts with a nexus study: a review of where the business has physical presence (people, property, inventory, including third-party warehouse locations) and where its sales activity crosses each state's economic-nexus threshold. Because thresholds, measurement periods, and transaction-count rules differ by state and change over time, the study has to be checked against current, dated state guidance. Lightbridge ERP, as a vendor-neutral ERP advisory firm, helps organizations map this footprint and design the systems and processes that keep collection and filing accurate as the business grows.

How does software help with sales tax nexus and economic nexus?

Modern ERP and dedicated tax engines (neutral examples include Avalara and Vertex) can monitor sales by state, flag when a business approaches or crosses an economic-nexus threshold, calculate the correct rate at the point of sale, and prepare returns. This automation matters because manual rate lookups do not scale across thousands of jurisdictions. See the companion guide on sales tax automation for how that fits an ERP. Lightbridge ERP evaluates and configures these tools on the merits, with no vendor kickbacks and no partner quotas, so the choice follows fit rather than commission.

JH Written by Jully Hayasaka with Robert LabardeeNetSuite Advanced Accounting Lead and Founder and CEO

Last updated June 2026.

Sales tax nexus and economic nexus after Wayfair

Lightbridge ERP defines sales tax nexus as the connection between a seller and a state that obligates the seller to register, collect, and remit sales tax there. Nexus comes in two forms: physical nexus, from a presence like people or inventory, and economic nexus, triggered by sales volume alone after the 2018 Wayfair decision.

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Sales tax nexus is the connection that obligates a seller to collect tax in a state.

Sales tax nexus is the legal link between a seller and a state that is strong enough to require the seller to register, collect sales tax from buyers there, and remit it to the state. Without nexus, a state cannot compel a seller to collect. With nexus, the obligation attaches, and failing to meet it creates back-tax, penalty, and interest exposure that grows quietly until a state notices.

Nexus exists in two principal forms. Physical nexus comes from a tangible presence in a state: people, property, or inventory. Economic nexus comes from sales activity alone, with no physical footprint at all. A single business can have nexus in one state from an office and in another state purely from the volume of orders it ships there. The growth of remote selling is exactly what made the second form a daily compliance question rather than an edge case.

Sales tax nexus is created in several distinct ways.

States establish sales tax nexus through more than one kind of connection. A seller can trip nexus through its own presence, through related parties, or through the marketplaces it sells on. Each path carries its own registration and collection consequences.

Physical nexus

A tangible connection to a state: an office, employees, contractors, owned or leased property, or inventory stored in the state (including goods held in a third-party fulfillment warehouse). Physical presence has always created sales tax nexus and still does.

Economic nexus

A connection based on sales activity alone, with no physical footprint. A seller crosses an economic-nexus threshold (a dollar amount of sales, sometimes a transaction count) into a state and must then register and collect, even if it never sets foot there.

Affiliate and click-through nexus

Some states attribute nexus through related entities or in-state referral relationships. These rules predate Wayfair and still apply, so a seller can have nexus through an affiliate or marketing arrangement, not only through its own presence.

Marketplace nexus

When a seller transacts through a marketplace facilitator, many states require the facilitator to collect tax on the seller's behalf. This shifts collection but does not erase the seller's own registration and filing duties, which still depend on its total nexus footprint.

Economic nexus stems from the 2018 South Dakota v. Wayfair decision.

Economic nexus became enforceable across the country because of South Dakota v. Wayfair, Inc., decided by the United States Supreme Court on June 21, 2018. Wayfair overturned the physical-presence rule of Quill Corp. v. North Dakota (1992), which had held that a state could not require a seller to collect sales tax unless the seller was physically present there. After Wayfair, physical presence is no longer required: economic activity alone can establish sales tax nexus.

The figure most people associate with economic nexus, 100,000 dollars in sales or 200 separate transactions into a state, is South Dakota's own threshold, the specific safe harbor the Court reviewed in the case. It is not a national rule. Economic-nexus thresholds vary by state. The dollar amounts differ, the measurement periods differ, and several states (including South Dakota itself) have since dropped the 200-transaction prong and now use a sales-dollar test only.

Because these rules continue to change, no static list stays accurate for long. A seller should confirm each state's current threshold against a current, dated state-by-state table maintained by the relevant tax authority or a reputable tax provider, rather than assume a single number applies everywhere. The companion guide on sales tax automation explains how systems can track these thresholds continuously instead of by hand.

This guide is general information, not accounting, tax, or legal advice. Sales and use tax rules vary by state and change frequently. Confirm your obligations with a qualified tax professional and current state guidance.

Use tax is the buyer-side complement that completes sales and use tax.

Sales tax and use tax are two halves of one regime, which is why states refer to it as sales and use tax. Sales tax is collected by the seller at the point of sale. Use tax applies to taxable goods or services that a buyer uses, stores, or consumes in a state when no sales tax was collected, most commonly on out-of-state purchases. In that case the buyer must self-assess and remit use tax directly, usually at the same rate the sales tax would have been.

The two taxes are designed so that one or the other applies, not both. When a seller has nexus and collects sales tax correctly, the buyer's use tax obligation on that purchase is satisfied. When the seller does not collect, the use tax obligation falls to the buyer. For businesses, this means accounts payable and procurement need a process to accrue use tax on untaxed purchases, not only a process to collect sales tax on sales.

The SSUTA standardizes sales and use tax administration across member states.

The Streamlined Sales and Use Tax Agreement (SSUTA) is a cooperative effort among states to simplify and standardize sales and use tax: common definitions, uniform rules, and a shared registration system that reduces the friction of multistate compliance. It currently has 23 full member states plus Tennessee as an associate member. SSUTA does not change whether a seller has nexus, but for sellers that do, it can streamline registration and reporting across the member states.

Knowing where you have sales tax nexus is the first step. Acting on it correctly, across registration, configuration, collection, and filing, is where most of the work lives. Lightbridge ERP is an independent, vendor-neutral ERP advisory firm. It helps organizations map their nexus footprint, design the finance and order-to-cash processes that keep collection accurate, and select and configure the right tax tooling on the merits. Lightbridge accepts no vendor kickbacks and no partner quotas, so the recommendation follows fit, not commission.

Sales tax nexus: frequently asked questions

What is sales tax nexus?: Sales tax nexus is the connection between a seller and a state that is strong enough to obligate the seller to register for a sales tax permit, collect tax from buyers in that state, and remit it to the state. Nexus takes two main forms. Physical nexus comes from a tangible presence such as employees, an office, or inventory stored in the state. Economic nexus comes from sales activity alone, once a seller crosses a state's dollar or transaction threshold. A business can have nexus in a state where it has never had a single employee or location.
What is economic nexus?: Economic nexus is sales tax nexus created purely by economic activity in a state, without any physical presence. A remote seller that ships enough goods or sells enough services into a state crosses that state's economic-nexus threshold and must then register, collect, and remit sales tax. Economic nexus became enforceable nationwide after the 2018 South Dakota v. Wayfair decision, which let states tax remote sellers based on sales volume rather than physical footprint. Every state with a sales tax now has some form of economic-nexus rule, though the specific thresholds differ.
What changed with South Dakota v. Wayfair?: In South Dakota v. Wayfair, Inc., decided June 21, 2018, the United States Supreme Court overturned the physical-presence rule of Quill Corp. v. North Dakota (1992). Before Wayfair, a state generally could not require a seller to collect sales tax unless the seller had physical presence in the state. Wayfair held that physical presence is not required and that economic activity alone can establish sales tax nexus. The decision opened the door for states to enforce economic-nexus rules against remote and online sellers.
Is the 100,000 dollar or 200-transaction threshold a national rule?: No. The 100,000 dollar or 200-transaction figure that people often quote is South Dakota's own threshold, the safe harbor the Supreme Court reviewed in Wayfair. It is not a national standard. Economic-nexus thresholds vary by state: the dollar amounts differ, the measurement periods differ, and several states (including South Dakota itself) have dropped the 200-transaction prong and now rely on a sales-dollar test alone. Because these rules change, a seller should confirm each state's current threshold against a current, dated state-by-state table rather than assume one number applies everywhere.
What is use tax, and how does it relate to sales tax?: Use tax is the complement to sales tax. It applies to taxable goods or services a buyer uses, stores, or consumes in a state when sales tax was not collected at the point of sale, for example on an out-of-state purchase. The buyer is responsible for self-assessing and remitting use tax in that case. Together these are usually administered as one regime, which is why states refer to sales and use tax: the sales tax is collected by the seller, and the use tax backstops it when the seller did not collect. The rate is generally the same.
What is the Streamlined Sales and Use Tax Agreement (SSUTA)?: The Streamlined Sales and Use Tax Agreement (SSUTA) is a multistate effort to simplify and standardize sales and use tax administration, definitions, and registration so that compliance across states is more uniform. It currently has 23 full member states plus Tennessee as an associate member. Member states accept a common registration system and shared definitions, which can ease multistate compliance for sellers. SSUTA membership does not change whether a seller has nexus, but it can streamline how that seller registers and reports once nexus exists.
How does a business know where it has sales tax nexus?: It starts with a nexus study: a review of where the business has physical presence (people, property, inventory, including third-party warehouse locations) and where its sales activity crosses each state's economic-nexus threshold. Because thresholds, measurement periods, and transaction-count rules differ by state and change over time, the study has to be checked against current, dated state guidance. Lightbridge ERP, as a vendor-neutral ERP advisory firm, helps organizations map this footprint and design the systems and processes that keep collection and filing accurate as the business grows.
How does software help with sales tax nexus and economic nexus?: Modern ERP and dedicated tax engines (neutral examples include Avalara and Vertex) can monitor sales by state, flag when a business approaches or crosses an economic-nexus threshold, calculate the correct rate at the point of sale, and prepare returns. This automation matters because manual rate lookups do not scale across thousands of jurisdictions. See the companion guide on sales tax automation for how that fits an ERP. Lightbridge ERP evaluates and configures these tools on the merits, with no vendor kickbacks and no partner quotas, so the choice follows fit rather than commission.

From knowing where you have nexus to collecting it correctly.

When the question shifts from what sales tax nexus is to where your business has it and how to comply, Lightbridge ERP maps the footprint and builds the systems that keep collection accurate as you grow.

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