Multistate Tax Nexus Rules for Businesses: The Questions Every Remote-Era Practice Gets Asked

Nexus questions rarely arrive labeled as nexus questions. They arrive as "we hired a developer in Colorado," or "our sales into Texas doubled," or "do we really have to file in a state where we have no office?" Behind each one sits the same underlying issue: which states can tax this business, for which taxes, starting when, and the answer is different in every state, and often different for each tax type within the same state.

01Physical presence still counts, and so does economic presence

The traditional trigger is physical: property, payroll, or people in the state. One remote employee working from home can be enough to create nexus for the employer, which is why the remote-work era turned nexus from a specialty topic into an every-engagement question. Since the Supreme Court's Wayfair decision, states can also assert nexus based on economic activity alone: cross a state's sales or transaction threshold and you can owe sales tax collection (and in many states, income or franchise tax filings) with no physical presence at all. The thresholds, the measurement periods, and what counts toward them differ state by state.

02Economic nexus thresholds: sales tax first, then income tax

Wayfair upheld South Dakota's standard of $100,000 of in-state sales or 200 separate transactions, and most states built their sales tax economic nexus rules on a similar frame. The details diverge immediately: the dollar threshold, whether a transaction count applies at all (a number of states have dropped it), whether the measurement period is the previous calendar year, the current year, or a rolling twelve months, whether exempt sales and marketplace sales count toward the threshold, and how quickly a seller must register after crossing it. Marketplace facilitator laws shift collection to the platform for marketplace sales but usually leave the seller's own direct sales, and its own threshold math, in place.

Income and franchise tax economic nexus is a separate question with separate rules. Some states adopt a bright-line factor presence standard, in the style of the Multistate Tax Commission's model (for example, $500,000 of in-state sales, $50,000 of property or payroll, or 25 percent of total activity). Others assert nexus on "doing business" or "deriving income from sources within the state" with no numeric safe harbor. A seller can be well under a state's sales tax threshold and still have income tax nexus, or the reverse. Research the two taxes separately in every state.

03Remote employees: payroll, withholding, and the convenience rule

One employee working from home in a state generally gives the employer physical presence there for income or franchise tax, and it almost always triggers employer obligations that arrive sooner than the tax return: registering for state income tax withholding, state unemployment insurance, and in some states paid-leave or disability programs. Reciprocal agreements between neighboring states can simplify withholding for commuters but do not help a fully remote hire. A handful of states apply a convenience-of-the-employer rule, treating a nonresident employee's remote days as worked in the employer's state unless the remote arrangement is for the employer's necessity, which can leave the employee taxed by two states and the employer withholding for one the employee never enters.

04Pass-throughs: nexus flows to the owners

When a partnership or S corporation has nexus in a state, its nonresident owners usually do too, through their share of the entity's in-state income. That brings a second layer of obligations: nonresident owner filing, the entity's withholding on nonresident owners' shares, composite returns that let the entity file once on the owners' behalf, and, in most states with an income tax, a pass-through entity tax election that can turn the state tax into an entity-level deduction. Each of those is governed by its own state provisions, and the answer for the entity and the answer for each owner's home state must be researched together.

05P.L. 86-272 protects less than clients think

The one federal shield in this area, Public Law 86-272, bars a state from imposing a net income tax on a business whose only in-state activity is soliciting orders of tangible personal property, approved and shipped from outside the state. Every limit in that sentence matters: it protects only net income taxes (not franchise, gross-receipts, or sales taxes), only sales of tangible personal property (not services or software delivered electronically), and only solicitation. States have also taken the position that certain internet activities, like a website that does more than solicit, fall outside the protection. Whether a specific client's activities stay inside the shield is a facts-and-authorities question, state by state.

06Franchise tax versus income tax

Several states impose a franchise or gross-receipts tax instead of, or alongside, a net income tax, and these taxes generally sit outside P.L. 86-272's protection entirely. A business can be shielded from a state's income tax and still owe its franchise tax. Getting this distinction right per state is one of the most common places multistate answers go wrong.

07A state-by-state research checklist

For each state a client touches, the same questions, in the same order, answered from the state's own law:

1. Physical presence.Employees, contractors, inventory (including inventory held by a fulfillment service), owned or leased property, and visits by salespeople. Any one can be enough.
2. Sales tax economic nexus.Threshold, transaction count if any, measurement period, what counts toward it, marketplace treatment, and the registration deadline after crossing.
3. Income or franchise tax nexus.Factor presence standard or doing-business standard; whether the state imposes a franchise or gross-receipts tax that P.L. 86-272 does not reach.
4. P.L. 86-272.Only if the client sells tangible personal property. Confirm which in-state activities, including website activities, the state treats as outside solicitation.
5. Filing mechanics.Form, due date, extension, minimum tax, apportionment formula, and estimated payment schedule.
6. Pass-through layer.Nonresident withholding, composite return availability, and the PTE election's eligibility, deadline, and rate.
7. Employer registrations.Withholding, unemployment insurance, and any state-run leave program, each with its own registration and its own start date.

08Fifty answers to the same question

Once nexus exists, the follow-on questions multiply: which form, what rate, when is it due, is there a minimum tax, how is income apportioned, does a pass-through owe withholding for nonresident owners? Answering for one state is research; answering for six is an afternoon of revenue-department websites. That's the problem our State Tax Matrix was built for: pick the states and the attributes, and compare income tax and sales & use tax treatment side by side, with every cell cited to the state's own authority.

09Ask it in one line

For the questions a table can't hold ("does one remote employee in Colorado create income tax nexus for a Delaware corporation selling software?"), the AI Tax Assistant answers from the statutes, regulations, and state guidance themselves, with clickable citations to the authority behind every claim. Ask in one line; verify the source in one click.