What Is Sales Tax Nexus?

Sales tax nexus is the legal connection between your business and a state that gives that state authority to require you to register, collect sales tax from your customers there, and remit it on a recurring filing schedule. Nexus is not a choice you make. It is a status you acquire, sometimes without realizing it, based on where you sell, where your people are, and where your inventory sits.

For most of the last century, nexus meant physical presence. If you had no office, no employees, and no property in a state, that state generally could not compel you to collect its sales tax. That standard collapsed in 2018, and the compliance landscape for any business selling across state lines changed permanently. Understanding where your obligations now sit is a core part of accounting and compliance for any business that ships products or delivers services outside its home state.

Physical Nexus vs. Economic Nexus

There are two distinct paths to nexus, and a business can have either or both in a given state. Understanding the difference matters because they are triggered by completely different facts and are measured in completely different ways.

Physical Nexus

Physical nexus is created by having a tangible connection to the state: an office, a warehouse, a retail location, an employee, a contractor performing services, or inventory stored in the state. Physical nexus generally has no dollar threshold. One employee, one storage location, or one piece of owned property is typically enough to create the obligation immediately, regardless of how little revenue the state generates.

Economic Nexus

Economic nexus is created purely by the volume of business you do with customers in a state, with no physical presence required. Most states set the bar at 100,000 dollars in gross sales or 200 separate transactions during the current or prior calendar year. Once you cross the threshold, you generally must register and begin collecting within a short window, often 30 to 60 days.

The Wayfair Decision and Why It Changed Everything

In June 2018, the Supreme Court decided South Dakota v. Wayfair, overturning the physical presence requirement that had governed state sales tax authority for decades. The Court held that a state may require an out-of-state seller to collect sales tax based on economic activity within the state alone. Within roughly two years, nearly every state with a sales tax had enacted economic nexus legislation.

The practical effect for small businesses was immediate and significant. A company operating from a single location that ships nationwide went from having sales tax obligations in one state to potentially having them in twenty or thirty. Many small businesses still have not evaluated their post-Wayfair exposure, and the liability continues to accumulate quietly in every state where a threshold has been crossed.

What Triggers Nexus: The Full List

Nexus triggers extend well beyond the obvious. Businesses frequently discover obligations arising from activities they never associated with tax consequences.

Inventory in Third-Party Fulfillment Centers

If you use Amazon FBA or a third-party logistics provider, your inventory may be distributed across warehouses in multiple states. In most states, inventory you own that is physically located in the state creates immediate physical nexus regardless of sales volume. Fulfillment providers move inventory for operational reasons without notifying sellers, which means nexus can appear in a state where you have never made a deliberate business decision to operate.

Remote Employees and Contractors

A single employee working from home in another state generally creates physical nexus there. This affects sales tax, and it typically also creates state income tax withholding and unemployment insurance obligations, which is a payroll compliance matter as much as a sales tax one. Businesses that hired remote staff without evaluating the multi-state consequences often carry unregistered obligations across several states simultaneously.

Affiliate and Referral Relationships

Several states have click-through nexus provisions under which in-state affiliates who refer customers to your website through links can create nexus once referred sales exceed a threshold, often around 10,000 dollars annually. Businesses running affiliate marketing programs should evaluate where their affiliates are located, because the affiliate presence rather than the business presence is what triggers the obligation.

Trade Shows and Temporary In-State Activity

Attending trade shows, conferences, or temporary sales events in another state can create nexus in some jurisdictions. Rules vary considerably: some states exempt limited attendance below a specified number of days per year, while others treat any in-state solicitation as nexus-creating. Businesses with active trade show calendars should evaluate each state where they exhibit.

Marketplace Facilitator Laws

Every state with a sales tax now has marketplace facilitator legislation requiring platforms such as Amazon, Etsy, eBay, and Walmart Marketplace to collect and remit sales tax on behalf of third-party sellers. If all of your sales into a given state flow through a marketplace, the platform handles the collection and remittance and you generally have no separate obligation for those transactions.

The complication arises for hybrid sellers. If you sell through both a marketplace and your own website, the marketplace handles its portion, but your direct sales may still create an independent obligation. Some states count marketplace sales toward your economic nexus threshold even though the marketplace remits the tax, meaning marketplace volume can push you over a threshold that then applies to your direct channel.

How to Monitor Nexus Before You Cross a Threshold

Monitoring nexus requires sales data segmented by ship-to state and reviewed continuously rather than at year end. Most e-commerce platforms and accounting systems can produce this reporting if configured correctly, but the configuration is rarely done by default. ClearPath CFO structures monthly bookkeeping for multi-state sellers to report sales by destination state and flag states approaching a threshold before it is crossed, which is the difference between a planned registration and a retroactive assessment.

Practical monitoring means reviewing state-by-state sales at least quarterly, tracking both the dollar total and the transaction count where a state uses both tests, and separating marketplace sales from direct sales because some states treat them differently for threshold purposes. Businesses growing quickly should review monthly, since a threshold crossed in March creates an obligation well before an annual review would catch it.

What to Do If You Already Have Unregistered Nexus

If you discover that you have had nexus in a state for months or years without registering, the exposure is real but manageable. The liability includes uncollected tax plus interest and penalties, and it generally falls on the business rather than the customers who should have paid it. Working through this correctly requires assessing the exposure period, evaluating whether a Voluntary Disclosure Agreement is available, and then registering in the right sequence. This is a situation where professional guidance materially changes the outcome.

Common Nexus Triggers and What They Mean for Your Business

Frequently Asked Questions

What is sales tax nexus in simple terms?

Sales tax nexus is the legal connection between your business and a state that gives the state authority to require you to register, collect sales tax from customers in that state, and remit it to the state. Nexus can be created by physical presence such as an office, employee, or inventory, or by economic activity such as exceeding a sales dollar or transaction count threshold.

What changed after the Wayfair Supreme Court decision?

Before the 2018 decision in South Dakota v. Wayfair, states could generally only require sales tax collection from businesses with a physical presence in the state. Wayfair overturned that standard, allowing states to require collection based on economic activity alone. Nearly every state with a sales tax has since enacted economic nexus rules, most commonly using a threshold of 100,000 dollars in sales or 200 separate transactions.

What are the typical economic nexus thresholds by state?

The most common threshold is 100,000 dollars in gross sales or 200 separate transactions in the current or prior calendar year, though states vary. Some states use sales dollars only and have eliminated the transaction count test. California and Texas use a higher 500,000 dollar threshold. New York uses 500,000 dollars combined with 100 transactions. Because thresholds and measurement periods differ, each state must be evaluated individually.

Does storing inventory in another state create nexus?

Yes, in most states. Inventory owned by your business and physically located in a state generally creates physical nexus with no dollar threshold. This is particularly relevant for businesses using Amazon FBA or third-party logistics providers, because fulfillment networks may relocate your inventory between state warehouses without notification. Reviewing your fulfillment provider inventory placement reports is the only reliable way to identify this exposure.

Do remote employees create sales tax nexus?

In most states, yes. An employee working from home in a state where your business has no other presence generally creates physical nexus in that state, which can trigger sales tax registration obligations and often state income tax and payroll withholding obligations as well. Businesses that hired remote workers across state lines without evaluating tax consequences frequently discover unregistered obligations later.

What is a marketplace facilitator and how does it affect my obligations?

A marketplace facilitator is a platform such as Amazon, Etsy, eBay, or Walmart Marketplace that is required by state law to collect and remit sales tax on behalf of third-party sellers using the platform. If all of your sales into a state go through a marketplace facilitator, the platform handles the tax. However, some states still count marketplace sales toward your economic nexus threshold, which can create a registration obligation for your direct sales.

What happens if I have nexus but never registered?

A business with unregistered nexus is liable for the sales tax it should have collected, plus interest and penalties, and the liability generally falls on the business rather than the customers. States have no statute of limitations for unfiled returns in most cases, meaning exposure can extend back to the date nexus was first established. Many states offer Voluntary Disclosure Agreements that limit the lookback period and may waive penalties for businesses that come forward proactively.

How do I know if I have crossed a nexus threshold?

You need sales data segmented by ship-to state, tracked continuously rather than reviewed annually. Most states measure the threshold against the current or immediately preceding calendar year, so a business can cross a threshold mid-year and have a registration obligation within 30 to 60 days. Configuring your bookkeeping and e-commerce platform to report sales by destination state is the practical first step in monitoring nexus.

Does nexus for sales tax also mean I owe state income tax?

Not automatically, but frequently. Sales tax nexus and income tax nexus are evaluated under separate standards. Federal Public Law 86-272 provides limited protection from state income tax for businesses whose only in-state activity is soliciting orders for tangible goods, but that protection does not apply to services, digital products, or many modern e-commerce activities. Businesses with sales tax nexus should evaluate income tax nexus separately.

How does ClearPath CFO help with multi-state sales tax nexus?

ClearPath CFO structures client bookkeeping to track sales by destination state, monitors activity against state economic nexus thresholds, reviews fulfillment network reports for physical nexus from inventory placement, and flags approaching thresholds before they are crossed. Where registration is required, we coordinate with state tax specialists on the registration approach, including evaluating Voluntary Disclosure Agreements when historical exposure exists.