Multistate Payroll Tax Nexus Guide 2026: Wayfair, Remote Workers, and State-by-State Withholding Triggers

The Supreme Court decision in South Dakota v. Wayfair, Inc. in 2018 reshaped how states think about taxing out-of-state activity. The case concerned sales tax, not payroll tax, but its broader effect was to confirm that states can require out-of-state businesses to comply with state tax obligations under economic nexus rules without a physical presence in the state. Each state has updated its sales tax framework in response, and many states have also revisited the nexus rules for corporate income tax, gross receipts taxes, and pass-through entity taxes. Payroll tax sits at a different layer because the trigger for payroll withholding is generally the location where the employee performs services, not the location of the employer.

The post-2020 expansion of remote work added a second layer. Employees now live and work in states where the employer has never had an office, never advertised, and may not even have customers. When an employee performs services from a home in another state, the employer typically becomes responsible for state income tax withholding, state unemployment insurance contributions, and possibly local taxes in that state. The combination of Wayfair-era state aggressiveness and remote-work demographics has made multistate payroll a routine compliance issue rather than an exotic one.

This page focuses on the payroll-side issues. It covers state withholding nexus, state unemployment insurance, the convenience-of-employer rule, reciprocal agreements, and the practical decisions an employer must make when an employee crosses a state line. It cites state department of revenue and state department of labor pages for the principal frameworks. The actual nexus analysis still depends on facts in each state, and complex situations should be reviewed with a qualified state and local tax adviser.

State income tax withholding nexus is generally created when an employee performs services in the state. The most common trigger is residency: an employee who lives in the state and works from home triggers withholding for that state, even if the employer is otherwise based elsewhere. The next common trigger is days worked: an employee who travels to a state on business for more than a state-specific number of days triggers withholding for income earned during those days. The threshold varies by state. Some states use a 30-day rule, some use a 14-day rule, some apply de minimis exceptions for very short travel, and others apply withholding from day one.

The Mobile Workforce State Income Tax Simplification Act has been introduced in Congress for many years to standardize these rules at 30 days, but the bill has not been enacted as a comprehensive federal standard. As a result, employers must still consult each state's department of revenue page for the specific rule. New York, California, Illinois, and several other large states publish guidance for nonresident wages and short-term presence. Pennsylvania and several New England states have particular rules that interact with reciprocal agreements with neighboring states.

The convenience-of-employer rule, used in some form by New York, Connecticut, Pennsylvania, Delaware, and Nebraska, treats an employee's wages as sourced to the employer's office state when the employee works remotely for the employee's convenience rather than the employer's necessity. The result can be double taxation if the employee's home state also taxes the same wages. Resident credits often mitigate the result, but not always cleanly. The rule is the single most important issue for many remote-work payroll questions.

State unemployment insurance contributions are reported and paid in the state to which the employee's services are localized under the four-factor test that most states use under U.S. Department of Labor guidance. The factors are localization of service, base of operations, place of direction or control, and residence. The test is sequential: localization is the first question, and only if services are not localized in any single state does the analysis move to base of operations, then to direction or control, then to residence.

For most employees who consistently work in one state, the answer is simple: SUI is paid to that state. For employees who work in multiple states or who work remotely from a state different from the employer's main office, the analysis can become technical. Errors are costly because once SUI is reported to the wrong state, fixing it requires amended filings in two states and may involve interest and penalties.

Many states publish guidance specifically for remote workers and traveling employees. The federal Unemployment Insurance Program Letter series provides background, and individual state department of labor or workforce agency pages provide registration steps for new out-of-state employers. New employer rates, experience rating periods, and wage bases vary, and the wage base is one of the most expensive variables for high-wage employees.

A reciprocal agreement is a state-to-state arrangement under which residents who work across the state line pay income tax only to their state of residence. Pennsylvania and Maryland have reciprocity, as do New Jersey and Pennsylvania. Indiana has reciprocity with several neighboring states. The District of Columbia has agreements with Maryland and Virginia in the form of a long-standing rule that wages earned in D.C. by Maryland or Virginia residents are not subject to D.C. income tax.

Reciprocal agreements apply to wage withholding, not to the underlying state income tax obligation in unusual cases. They typically require an employee to file a non-resident certificate with the employer so that the employer can withhold for the employee's residence state. Without the certificate, the employer must default to the work state. Employers should track reciprocal agreement certificates and confirm them annually because employees can move and forget to update the form.

Reciprocity does not exist with most state pairs. There is no reciprocity between New York and New Jersey, or between California and any other state. For these pairs, the employer must withhold for the work state and the employee may obtain a credit for taxes paid to another state on the resident return.

Local payroll taxes add a third layer in many states. New York City and Yonkers impose local income tax in New York. Pennsylvania has a complex web of earned income taxes administered by tax collection districts. Ohio uses a wide network of municipal income taxes, with both a regional income tax authority and the Central Collection Agency for many cities. Maryland counties impose local income tax through the state return. Indiana, Michigan, Missouri, and Kentucky also have meaningful local payroll tax exposure. Employers with new remote employees should check whether the employee's home address falls within a local taxing jurisdiction.

For many states, the obligation to withhold local tax follows from the state income tax registration. For others, separate registration with a city or tax collection district is required. The penalties for missed local tax withholding are real and can compound across multiple years if undetected.

The state-by-state picture is not uniform. Below is a focused subset of patterns that affect most multistate payroll planning. Each state's department of revenue page should be confirmed for current details.

The workflow for a new remote hire in a state where the employer is not yet registered should run in a defined sequence. First, determine the employee's primary work state by physical work location and confirm the residence. Second, register the employer with the state department of revenue for income tax withholding and obtain a withholding account. Third, register with the state department of labor or workforce agency for unemployment insurance and obtain an SUI account number, taking the new-employer rate as assigned. Fourth, register for any state-specific paid family leave, disability, or workers compensation programs.

Fifth, identify the local tax jurisdictions, register for any required local accounts, and configure the payroll system. Sixth, collect a state-specific withholding certificate from the employee, such as a state W-4 equivalent, and apply correct allowances. Seventh, schedule deposit and return cycles with the new state-required frequency, which may be different from the employer's home state. Eighth, document the analysis in a remote-work file so future hires in the same state can be onboarded quickly.

For employees who travel, a separate process is needed. The employer should track days worked in each state, apply the day-count thresholds, and either source wages to the work state once the threshold is exceeded or treat the wages as fully sourced to the home state if the threshold is not exceeded. A simple time-tracking field in the HRIS or a quarterly travel log can be enough.

The convenience-of-employer rule is the most controversial multistate payroll issue. New York applies the rule under New York Tax Law and TSB-M guidance. The rule treats an employee assigned to a New York office as earning all wages in New York unless the employee is performing services from outside New York for the necessity of the employer rather than the convenience of the employee. The IRS does not preempt this kind of state rule, and the employee's resident state may still tax the same wages, often with a credit but not always with a complete offset.

For 2026, employers with New York offices and remote employees in other states should expect to withhold New York income tax for the New York office allocation under the convenience rule, while also confronting the resident state's claim on the same income. Resident credits typically mitigate but do not eliminate the issue, particularly when the resident state has higher rates or different definitions. The same general framework applies to Connecticut, Pennsylvania, Delaware, and Nebraska, with state-specific variations.

Employers can sometimes change the analysis by formally documenting that remote work in a particular role is required by the employer rather than offered for the employee's convenience. The documentation must be specific and credible. Job descriptions, role requirements, and operational reasons need to support the necessity claim. Casual or after-the-fact documentation has been challenged in audits.

Adding an employee in a new state often does more than create payroll obligations. Many states treat employee presence as creating substantial nexus for corporate income tax, gross receipts tax, or franchise tax purposes. Public Law 86-272 protects only solicitation of orders of tangible personal property and is not a defense for employees engaged in services, software-as-a-service, or information products. The Multistate Tax Commission has issued guidance suggesting narrower interpretations of P.L. 86-272 in the post-Wayfair era, and several states are following that guidance.

For sales tax purposes, an in-state employee almost always creates physical presence nexus for sales tax in addition to economic nexus that may already apply under Wayfair. Companies that had been operating below an economic threshold in a state may be pushed above it once they hire an employee there. The combined effect is that hiring in a new state can change three different tax registrations: payroll, corporate, and sales tax.

Cross-functional review before hiring in a new state, including review by the controller, payroll lead, and any state-tax adviser, helps avoid surprise registrations and missed filings. The cost of fixing a missed nexus position is usually higher than the cost of opening accounts proactively.

Primary references for this page are state department of revenue pages including New York, California Franchise Tax Board, Pennsylvania, Illinois, Ohio, and Maryland. The Supreme Court decision in South Dakota v. Wayfair, Inc., 585 U.S. 162 (2018) is available at the Supreme Court's website. Public Law 86-272 is codified at 15 U.S.C. 381. The Multistate Tax Commission publishes statements at mtc.gov. Convenience-of-employer guidance is available in state-specific TSB-M and similar publications.