What Is Payroll Nexus? A Plain-Language Guide for Remote-First Employers

When a company hires its first remote employee in another state, something significant happens on the legal side of the business — something most founders and HR managers don’t notice until a state revenue department sends a notice. That moment is the creation of payroll nexus: a legal connection between your business and a state that triggers a set of tax and compliance obligations you didn’t have the day before.

Understanding nexus isn’t just a tax issue. It determines where you’re required to register as an employer, which state’s unemployment insurance you fund, what you withhold from employee paychecks, and in some cases, whether your business owes income or franchise taxes in that state. As remote work has moved from a pandemic accommodation to a permanent fixture of how companies operate, payroll nexus has become one of the most consequential — and most overlooked — compliance issues facing small and mid-sized businesses.

This guide explains what payroll nexus is, how it’s triggered, what it obligates you to do, and why the stakes have gotten considerably higher in recent years.

The Basic Concept: What “Nexus” Actually Means

The word nexus comes from Latin, meaning connection or link. In tax law, nexus refers to the minimum level of contact between a business and a state that gives that state the legal authority to impose its taxes on the business. The concept applies across multiple tax types — sales tax, income tax, franchise tax — but in the context of a remote workforce, the most immediately relevant application is payroll nexus, sometimes called employer nexus.

The foundational legal principle comes from the U.S. Supreme Court’s decision in Complete Auto Transit, Inc. v. Brady (1977), which established a four-part test for when a state can constitutionally tax an out-of-state business. Later, Quill Corp. v. North Dakota (1992) reinforced a physical presence standard for sales tax — a standard that was ultimately overturned for sales tax purposes by South Dakota v. Wayfair (2018). That last decision is important context: it opened the door for states to assert nexus based on economic activity alone, without any physical footprint in the state.

For payroll purposes, however, physical presence has always been the primary trigger — and a single remote employee working from a home office constitutes physical presence in the eyes of virtually every state tax authority in the country.

How Payroll Nexus Is Triggered

There are two primary ways a business establishes payroll nexus in a state where it isn’t domiciled:

1. Physical Presence Nexus

This is the most common trigger for remote-first employers. When one of your employees performs work from a location within a state — even if that location is their personal residence and even if your company has no office, warehouse, or property there — most states consider your business to have a physical presence sufficient to create nexus.

The key point that surprises many employers: nexus does not require intent. You don’t need to have deliberately expanded into a state. You don’t need to be generating revenue from customers in that state. The act of compensating an employee for work performed within the state’s borders is, by itself, sufficient.

This position is well established in state administrative guidance. California’s Employment Development Department, for example, explicitly states that an out-of-state employer is subject to California payroll tax requirements when it employs individuals who work within California, regardless of where the employer is headquartered. Similar language appears in guidance from New York, Illinois, and most other states with a personal income tax.

2. Economic Nexus

Following South Dakota v. Wayfair, many states expanded their nexus standards beyond physical presence to include purely economic thresholds — typically $100,000 in annual sales into the state or 200 separate transactions. While economic nexus is most commonly discussed in the context of sales tax, some states have extended similar concepts to income and business activity taxes.

For payroll purposes specifically, economic nexus is less commonly the direct trigger than physical presence — but it matters because it can compound your obligations. A company that already has payroll nexus due to a remote employee may also find it has income tax nexus or franchise tax nexus based on revenue thresholds, creating a broader set of filing requirements than payroll alone.

What Payroll Nexus Obligates You to Do

Once nexus is established in a state, the compliance obligations typically include some combination of the following, depending on the state:

Employer Registration

Most states require out-of-state employers to register with the state’s department of revenue or department of labor before the first payroll is run for an employee in that state. This is not optional, and the failure to register — even if you’re otherwise compliant on the tax side — can result in penalties.

State Income Tax Withholding

If the state has a personal income tax (currently 41 states plus the District of Columbia do), you’re required to withhold state income tax from the wages of employees working in that state and remit it to the state on a regular schedule. The withholding rates, filing frequencies, and remittance deadlines vary by state.

State Unemployment Insurance (SUTA)

Every state operates its own unemployment insurance program, and employers are required to pay into the state fund for each employee working in that state. SUTA is an employer-paid tax — not withheld from employee wages — and the rate and taxable wage base vary significantly by state. Washington’s taxable wage base, for example, is $68,500 for 2024, while Florida’s is just $7,000. A company with remote employees in both states faces dramatically different cost structures for those two workers even if their salaries are identical.

Additional State-Specific Obligations

Several states impose obligations beyond income tax withholding and SUTA. Oregon requires employers to withhold a Statewide Transit Tax of 0.1% on wages earned in the state regardless of where the employer is located. Washington requires registration for Paid Family and Medical Leave (PFML) and the WA Cares Fund. New Jersey imposes State Disability Insurance (SDI) and Family Leave Insurance (FLI) contributions. Pennsylvania’s 3,200+ local taxing jurisdictions mean that a remote employee’s municipality determines an additional withholding requirement on top of state income tax.

Why Enforcement Has Intensified

For much of the 2000s and early 2010s, states lacked the data infrastructure to effectively identify out-of-state employers who had nexus but hadn’t registered. That has changed substantially.

States now routinely share data with each other through programs coordinated by the Federation of Tax Administrators. W-2 data filed with the IRS is cross-matched against state employer registrations. Unemployment insurance records are compared across state lines. The result is that the “quiet payroll nexus” problem — where a company hires remote talent in another state and simply doesn’t realize it has compliance obligations — is increasingly likely to surface through automated data matching rather than a human audit.

When a state identifies an unregistered employer, the consequences typically include back taxes owed for all open tax years (usually three to four years, sometimes longer), interest on unpaid amounts, and civil penalties. In egregious cases, criminal penalties are possible, though rare for unintentional non-compliance.

The practical reality is that the risk calculus has shifted. What was once a low-probability enforcement outcome has become a reasonably foreseeable one for companies with multi-state remote workforces who haven’t addressed nexus.

The “Trailing Nexus” Problem

One aspect of payroll nexus that catches employers off guard is what tax practitioners call trailing nexus — the obligation that persists in a state for a defined period after the activity that created nexus has ceased.

If your last remote employee in Illinois leaves the company in March, your Illinois payroll nexus doesn’t end in March. Illinois maintains nexus for 12 months after the last nexus-creating activity. California requires continued compliance through the end of the quarter in which activity ceases. Texas requires four consecutive quarters below the nexus threshold before the obligation ends.

This matters most for companies that are actively managing their compliance posture — or planning a reduction in force that affects employees in specific states. An exit strategy that doesn’t account for trailing nexus windows can result in missed filing obligations during the tail period.

A Note on “No Income Tax” States

A common misconception is that employees in states without a personal income tax — Florida, Texas, Washington, Nevada, Wyoming, South Dakota, Tennessee, New Hampshire, and Alaska — create no payroll nexus obligations. This is incorrect in an important way.

While there’s no income tax withholding obligation in these states, employers with employees in them are still required to register for and pay state unemployment insurance (SUTA). Washington adds PFML and WA Cares Fund obligations on top of that. Alaska has municipal income taxes in some jurisdictions. The absence of a state income tax reduces the compliance burden but doesn’t eliminate it.

What to Do If You Have Unaddressed Nexus

If you’ve read this far and suspect your company has payroll nexus in states where you haven’t registered, the recommended course of action is:

1. Identify all states where current or recent employees have performed work, going back at least three to four years
2. Assess the obligations in each state — registration requirements, tax types triggered, filing frequencies
3. Consider a voluntary disclosure with states where you have unregistered nexus — most states have voluntary disclosure programs that limit the look-back period and waive some penalties in exchange for coming into compliance proactively
4. Register and begin complying prospectively, and work with a qualified payroll tax professional to address any back-period exposure