A practical way to think about economic nexus

Economic nexus is often treated as a bright-line rule in U.S. sales tax compliance. Cross a threshold, register, collect, file.

In reality, it is not a single rule. It is a decision-making framework with long-term consequences.

After the Wayfair decision, each sales tax state enacted its own version of economic nexus. While many states adopted similar headline thresholds, the similarities largely end there.

The differences matter because registration is not a one-time act. It creates recurring compliance obligations that continue even in periods with no taxable sales. Once registered, a business is committing to filings, recordkeeping, and exposure to notices, penalties, and audits.

This is why blanket advice like “register everywhere you have nexus” is often harmful for small businesses.

A thoughtful economic nexus approach requires context. It considers what is being sold, whether customers are taxable or exempt, how sales are routed through marketplaces, and how thresholds are calculated in practice. It also weighs the cost of compliance against the actual tax at issue, rather than treating registration as a purely moral or binary decision.

In practice, there are situations where a business technically meets a state’s economic nexus threshold, but the cost and administrative burden of registration materially outweigh the potential exposure. In those cases, the decision is not about ignoring the rules. It is about evaluating risk, timing, and proportionality.

Economic nexus should be treated as a risk management exercise, not a moral one.

When it comes to sales tax, the goal is not theoretical perfection across every jurisdiction. The goal is informed, defensible decision-making that aligns with a business’s size, risk tolerance, and growth plans.

For small businesses, fear-driven compliance decisions often create more problems than they solve. Clarity comes from understanding how the rules actually work, when registration is truly required, and what obligations follow.

Economic nexus is not about registering everywhere.
It is about knowing when registration makes sense and why.

What the Wayfair Ruling actually changed for online sellers

Before 2018, sales tax obligations were largely tied to physical presence.

If a business had an office, warehouse, employees, or inventory in a state, that state could require the business to collect sales tax. If it did not, the burden technically fell on the customer through use tax, which was rarely enforced in practice.

That framework changed with the Supreme Court’s decision in South Dakota v. Wayfair.

The Court eliminated the physical presence requirement and allowed states to impose sales tax obligations based on economic activity alone. This concept is known as economic nexus.

In theory, the ruling was meant to modernize the tax system and level the playing field between online sellers and brick-and-mortar retailers. In practice, it shifted enormous administrative responsibility onto businesses that had never dealt with multistate sales tax before.

After Wayfair, states moved quickly to enact their own economic nexus laws. While the Court suggested that small businesses should be protected by safe harbor thresholds, it did not require states to adopt uniform rules.

The result is a patchwork of laws that differ by state.

Thresholds vary. Measurement periods vary. Definitions of what counts toward those thresholds vary. Registration timing varies.

For many small and mid-sized sellers, Wayfair did not just create new tax obligations. It created continuous monitoring obligations.

Every sale now carries the potential to trigger new compliance requirements in a state the business has never registered in before.

I’ve written previously about Wayfair’s unintended consequences for small remote sellers. What has become clear in practice is that the ruling exposed businesses to the full complexity of the U.S. sales tax system at scale.

Wayfair did not simplify sales tax.

It multiplied exposure to it.

Wayfair’s unintended consequences: compliance challenges for small remote sellers

To mitigate the impact on small remote sellers, the federal Wayfair ruling required states to include a safe harbor provision in their sales tax laws. These provisions are meant to lessen the compliance burden by exempting businesses that fall below certain thresholds—typically based on sales volume or transaction count, like $100,000 in sales or 200 transactions—from the obligation to collect and remit sales tax.

While this was a step in the right direction, the varying safe harbor thresholds and requirements across states have created an overwhelming burden for small remote sellers. They must first determine where they have economic nexus based on the 46 different safe harbor provisions and then navigate the various requirements related to registration, return filings, notice responses, and audits.

Sales tax compliance in this environment is highly complicated, costly, and stressful for small remote sellers. Unlike large corporations with dedicated tax teams, these small businesses often lack the resources to confidently comply with the myriad state tax laws. Many small remote sellers who decide to pursue compliance turn to software solutions and external consultants, while others attempt to handle compliance in-house, often with less favorable outcomes.

Managing Sales Tax Compliance as a Small Business

If you’re a small remote seller, here are a few strategies to manage compliance more effectively:

1. Evaluate Software Solutions: Look for sales tax software that can automate calculation and reporting to ease (though not replace) the compliance process.

2. Consult an Expert: A sales tax consultant can help you understand nexus thresholds and manage filings across states, saving time and reducing the risk of errors.

Six years after the Wayfair ruling, challenges for small remote sellers persist. The ruling, while addressing inequities for local businesses, has inadvertently created barriers to small business creation, growth, and entrepreneurial spirit. Non-compliance—whether intentional or unintentional—poses a high risk, and many small sellers are increasingly anxious about potential audits in the coming years.

A brief history of U.S. sales tax

The Birth of U.S. Sales Tax

The complexities of the United States (U.S.) sales tax system are not new; they have deep historical roots. The U.S. sales tax system was born out of necessity during the Great Depression in the 1930s and expanded to additional states throughout the following decades. From its inception, sales tax has been monitored at the state level rather than federally, with multiple jurisdictions within each state levying taxes on top of the state tax, leading to a complex and varied tax landscape across the country.

The authority of states to impose taxes on interstate commerce has long been limited by the Commerce Clause in the U.S. Constitution. The landmark 1977 case Complete Auto Transit, Inc. v. Brady established that a "substantial" connection must exist between the state and the activity being taxed. However, the definition of what constituted a "substantial connection" was not particularly clear from this outcome, leading to another landmark case in 1992.

The Impact of Quill and Physical Nexus

In the 1992 case Quill Corp. v. North Dakota, the U.S. Supreme Court reinforced the physical presence—known as "physical nexus"—rule, clarifying that a company must have a physical presence, such as offices, warehouses, or employees in a state, for that state to require the company to collect and remit sales taxes. Until that time, states were limited in their ability to require a “remote seller”—an out-of-state seller that does not have a physical presence in the state—to collect and remit sales tax on transactions. Instead, the burden fell on the buyer in those transactions to remit a "use tax" to the state, which had a notoriously low compliance rate.

The Wayfair Ruling and Modern Implications

This all changed on June 21, 2018, when the U.S. Supreme Court overturned the Quill decision in its landmark decision in South Dakota v. Wayfair Inc. et al., commonly referred to as the "Wayfair ruling." The Court overturned the long-standing physical nexus rule, making it lawful for states to require remote sellers to collect and remit sales tax based on "economic nexus," a significant economic connection to a state, in addition to physical nexus. This decision, passed by a narrow 5-4 vote, has had far-reaching implications. Each state has since enacted its own sales tax laws related to economic nexus, adding to the already complex web of regulations that businesses must navigate.

The Wayfair ruling was seen as a logical evolution, reflecting the growing importance of e-commerce and aiming to level the playing field between online sellers and local businesses. Over the past few decades, the U.S. retail landscape has transformed, with online sellers gaining a competitive edge over brick-and-mortar stores due to the absence of sales tax obligations. The ruling sought to address this disparity by allowing states to capture revenue from remote sellers who had a significant economic presence within their borders.

How These Changes Affect Businesses Today

For e-commerce and other remote sellers, understanding and complying with these complex sales tax laws can be daunting. Each state has its own regulations around economic nexus thresholds, and new businesses may struggle to keep up with compliance requirements, especially as they expand their market reach. My work with e-commerce companies has shown me just how overwhelming these changes can be—particularly for those new to navigating U.S. sales tax requirements.