Multi-State Taxes for Fractional Executives: Which Client States You Actually Owe
A fractional CFO based in Denver signs four clients: one in Boston, one in New York, two in California. She invoices from her Colorado LLC, files a Colorado return, and considers the tax question settled. Fourteen months later a notice arrives from Massachusetts asking why a business earning revenue from a Boston company never registered there. Nothing about the engagement was improper. She just assumed her tax home is where she sits, and most states decided years ago that it is where the client sits.
Multi-state taxes for fractional executives are the least-discussed cost of a portfolio career. Rates, retainers, and health insurance get argued about constantly. Almost nobody warns you that four clients can mean four filing obligations, and that the rules were written for corporations with sales forces, not for one person with a laptop and a standing Zoom.
Your client's state, not your desk, decides where the income is taxed
States use one of two methods to decide where service revenue belongs. Cost of performance sources revenue to wherever the work physically happened, which for remote advisory work is your home office. Market-based sourcing puts it where the customer receives the benefit. States now predominantly apply market-based sourcing, as the Tax Adviser's analysis of service apportionment lays out, and a few look further through to where the client's own customers sit.
The translation for a portfolio practice is blunt. A retainer paid by a Boston company is Massachusetts revenue even if you never leave Colorado. Whether that revenue rises to a filing obligation depends entirely on the state. Some publish a bright-line dollar threshold: California treats an out-of-state business as doing business there once California sales cross an annually indexed figure that has run north of $600,000, per the Franchise Tax Board. Others assert income tax nexus on far less, or on any meaningful in-state activity at all. One $8,000 monthly retainer will not trip California. It can absolutely trip a state with no threshold.
The federal shield for out-of-state sellers does not cover services
Public Law 86-272 is the reason a manufacturer in Ohio can ship into twenty states and file in a handful. It bars states from imposing net income tax when the only in-state activity is soliciting orders for tangible personal property. The last four words are what leaves advisory work exposed: the protection covers sales of goods, not services or digital products, as the Tax Adviser's review of the statute explains.
Someone selling software licenses gets a federal safe harbor. Someone selling senior judgment does not. States have also been consistent in ruling that an out-of-state business cannot dodge tax by hiring in-state contractors to do work employees would otherwise do, which is the same logic pointed the other direction. A solo practice ends up with less statutory protection than a mid-market widget company.
Travel days are the trigger most people miss
Remote retainers raise sourcing questions. On-site days create physical presence, which is the oldest and least arguable form of nexus there is. Two days a quarter in a client's office, a quarterly board meeting, an annual offsite: each one puts you personally in a state that may want a nonresident return.
You would hope for a grace period. Mostly there is not one. Illinois, Indiana, Louisiana, and Montana are the only states with day-count thresholds that apply broadly to nonresidents regardless of where they live, according to Tax Foundation's state-by-state nonresident filing data. A federal fix has been introduced in every session of Congress since 2006 without ever clearing the Senate, which is why the Council On State Taxation keeps pushing a uniform 30-day safe harbor.
Worth knowing: most of those thresholds were written for wage income and employer withholding. Business income earned through your own entity often sits outside them, so the on-site question deserves a real answer before you agree to monthly travel, not after you have already booked six trips.
Nobody is going to flag this for you
An employer running payroll has a compliance team that notices when someone moves. A client paying your invoice has none of that. They issue a 1099-NEC, book the expense, and move on. No withholding happens, no state gets notified in a way that lands on your desk, and the first signal that anything is wrong usually arrives years later as correspondence.
That lag is the trap. Interest and penalties accrue from the original due date, so a small obligation ignored for three years is not three times worse, it is worse than that plus late-registration fees. The states are also getting better at matching 1099 data against their own registration records, which shrinks the odds that quiet non-filing stays quiet.
Registering to do business is a separate problem from paying tax
Two obligations get conflated constantly. One is tax: file a return, pay what you owe. The other is qualification, meaning registering your LLC or S corp as a foreign entity with a state's secretary of state, appointing a registered agent, and paying an annual fee. A state can consider you to be doing business there for qualification purposes even when the tax owed rounds to nothing.
The penalty for skipping registration is rarely a large bill. It is usually a modest fee, back franchise tax, and one genuinely painful consequence: an unregistered entity often cannot bring a suit in that state's courts. If a client stops paying and your agreement names their state as governing law, that detail matters far more than the fee ever did. Read it alongside the contract clauses that actually protect you, because the two interact.
The version of compliance that is actually manageable
None of this justifies a compliance function. It justifies four habits. Track revenue by client state rather than only by client, since your bookkeeping already holds the data and tagging it turns a year-end scramble into a ten-minute conversation. Keep a travel log with dates and states, because reconstructing one in April is guesswork with penalties attached. Review the whole list once a year with a CPA who specializes in state and local tax, which is a different discipline than the one that files your 1040. And treat a new state as a business decision with a price on it, the same way setting your rate is.
Concentration helps more than any spreadsheet. Three clients across two states is a materially simpler practice than five clients across five, at similar revenue. That is not a reason to turn work away. It is a reason to know what the fifth state costs before deciding the fifth client is worth it. The same instinct applies once clients start showing up outside the country, where the friction is higher still.
Price the friction before you meet it
The direction of travel here is one way. States moved to market-based sourcing because services became the economy, and enforcement gets a little sharper every year as data matching improves. The cost of handling it well is one spreadsheet column and one annual conversation. The cost of handling it badly compounds silently and then shows up as certified mail.
Pick one thing this week: tag last year's revenue by client state and count how many states you are genuinely operating in. Most people are surprised by the number. It is far easier to fix while it is still small, and easier still if the next client you add is one you chose with the full cost in view.
Getting found by the right companies is what makes that choice yours instead of whatever happens to walk in.