If you forgot to charge sales tax, the business still owes the money to the state, even though the customer was the one who should have paid it at checkout. The fastest way to contain the damage is a Voluntary Disclosure Agreement, a state program that caps how far back you have to pay and waives most of the penalties in exchange for coming forward before the state finds you. Waiting is expensive: interest keeps running, and once a state opens an audit, the discount disappears.
Yes, You Still Owe the Tax
States treat sales tax as money the seller collects on their behalf. The tax exists the moment a taxable sale happens, whether or not it appeared on the invoice. If you never collected it, you effectively owe it out of pocket.
This catches owners off guard because the customer is the one who’s supposed to pay at the register. The legal duty to collect, report, and remit sits entirely with the seller. It’s cheaper for a state to pursue one business than to chase thousands of buyers for small amounts, so that’s what they do.
Intent doesn’t matter. A business that genuinely didn’t know it had a collection obligation owes the same amount as one that skipped it deliberately. The state will assess the full tax that should have been collected, plus interest and penalties.
Owners Can Be Personally On the Hook
In serious cases, the debt doesn’t stay with the business entity. Most states have “responsible person” rules that let the revenue department pursue individual officers, directors, or managers for unremitted sales tax. The reasoning: someone at the company had the authority and duty to make sure the tax was paid, and that person can be held personally liable when it wasn’t.
States look at who signed checks, who oversaw tax filings, who ran day-to-day finances, and who benefited from the business during the period of non-compliance. Owner-operators, CFOs, and managing members are the usual targets, but the net can be wider.
These debts are generally not dischargeable in bankruptcy. Federal law excepts taxes from discharge when no return was filed or when a return was filed late, and this rule applies to state taxes as well as federal ones.1Office of the Law Revision Counsel. 11 U.S. Code 523 – Exceptions to Discharge If you never filed sales tax returns in a state where you should have been collecting, that liability can follow you personally and indefinitely.
Figure Out What You Actually Owe
Before contacting any state, you need a clean picture of the exposure. That means going through your sales history and identifying which transactions should have carried tax, in which states, at what rates.
Map Your Nexus by State
Sales tax only applies where your business has nexus. Physical nexus is the traditional trigger: an office, warehouse, employees, or inventory in the state. That rule hasn’t changed.
What has changed is economic nexus. After the Supreme Court’s 2018 decision in South Dakota v. Wayfair, Inc., states can require out-of-state sellers to collect based on sales volume alone, with no physical presence required.2Supreme Court of the United States. South Dakota v. Wayfair, Inc. Every sales tax state has since adopted some version. The original Wayfair threshold was $100,000 in sales or 200 transactions, and most states now use a dollar-based test around $100,000, though the specifics vary and have shifted repeatedly since 2018. Check each state where you sold; the date you crossed the threshold is the date your collection obligation began, and that’s how far back your liability runs.
Use the Right Rates and Strip Out What Isn’t Taxable
Sales tax rates are usually a combination of state, county, and municipal pieces, keyed to where the buyer is, not where you are. Applying a single statewide rate across every sale will produce numbers a state can pick apart. For anything beyond a handful of transactions, use a tax calculation tool or a professional.
Then peel off the sales that shouldn’t have been taxed in the first place. Most states exempt categories like groceries, prescription drugs, or clothing. B2B sales for resale or manufacturing are also exempt if the buyer would have provided a resale or exemption certificate. Some states let you collect those certificates retroactively, even during an audit; others don’t. Where it’s allowed, chasing certificates from your larger wholesale customers can meaningfully cut the bill.
Check Whether Marketplaces Already Handled It
If any of your sales ran through Amazon, eBay, Etsy, Walmart Marketplace, or a similar platform, that tax may already be paid. Every state with a sales tax now requires marketplace facilitators to collect and remit on behalf of their third-party sellers. Those transactions aren’t your problem. Sales through your own website, storefront, or direct invoicing still are. Separating the two during the audit reduces what you owe.
Don’t Miss Digital Products and Shipping
Two areas trip up more businesses than any others. Software subscriptions, downloads, streaming access, and other digital goods are taxable in some states and not others, and the classification often depends on administrative rulings rather than clear statutes. Shipping charges are similar: some states tax shipping whenever the underlying goods are taxable, some exempt it if separately stated, some look at the delivery method. If you shipped taxable goods and left shipping out of the tax base, there may be more owed than you first calculated.
File a Voluntary Disclosure Agreement
Once you know the numbers, the standard move is a Voluntary Disclosure Agreement, or VDA. Most states run these programs, and they exist to let non-compliant businesses come forward, pay what they owe, and walk away with substantially reduced penalties.
How It Works
The application is anonymous. Your tax advisor or attorney contacts the state without naming the business. If the state accepts, it issues a formal agreement setting the look-back period, the penalty relief, and the compliance terms. You then break anonymity, register, file back returns for the agreed period, and pay the tax plus reduced interest.
States generally accept a VDA only if the business has never registered for sales tax there and isn’t already under audit or investigation. Once either of those happens, the door closes.
The Look-Back Cap Is the Real Prize
Penalty relief matters, but the bigger benefit is often the look-back period. Instead of calculating tax back to the day your nexus started, a VDA typically limits you to a fixed window. Most participating states use a 36-month look-back; some go to 48 or 60 months.3Multistate Tax Commission. Lookback Periods for States Participating in National Nexus Program
Compare that to what happens if the state finds you first. The normal statute of limitations is around three years for filed returns, but in most states the clock never starts if no return was filed. That means the state can go back to the day nexus began, with no ceiling. A business that had nexus for eight years and files a VDA might only owe on the last three.
Multi-State Cases: Use the MTC Program
If you have exposure in several states, individual VDAs get expensive fast. The Multistate Tax Commission runs a Multistate Voluntary Disclosure Program that lets a business negotiate with multiple states through one coordinated process, at no charge to the taxpayer.4Multistate Tax Commission. Multistate Voluntary Disclosure Program MTC staff draft the agreements, submit them anonymously, and manage the back-and-forth. For a business with nexus in a dozen states, this is the practical option.
Get a Professional Involved
A VDA done properly resolves the whole problem. A VDA done poorly gets rejected, and rejection is worse than not applying: you’ve now told the state your business exists and hasn’t been paying. Anonymity is gone, penalty relief is gone, and the state can open a full audit. A state and local tax advisor who handles VDAs routinely is worth the fee.
What the Bill Will Look Like
Beyond the tax principal, there are two costs to plan for.
Penalties for late-filed and late-paid sales tax typically run from 5% to 25% of the unpaid amount, depending on the state and how overdue the tax is. Some states escalate monthly. A VDA usually waives most or all of these, and that waiver is often the largest single line of savings.
Interest is different. It accrues from the original due date of each missed return, and it’s rarely waived, even inside a VDA. Rates range from around 3% annually in some states to 18% or more in others, and several states tie their rate to the federal prime rate plus a margin, so it moves. Because interest compounds from the original due date, older periods generate disproportionately more of it. Delaying a VDA by even a year can measurably increase the payment.
If the state finds you before you come forward, the numbers get worse. You lose access to VDA benefits, you face the full statutory penalty, interest runs on the full look-back (which may extend well past what a VDA would have required), and additional fraud penalties become possible if the state considers the failure willful. States have gotten better at spotting non-compliance through marketplace data, payment processor records, shipping information, and cross-state data sharing.
Can You Bill the Customer Now?
Probably not, and in most cases not worth trying. Many states prohibit sellers from billing customers for sales tax after the fact. Where it’s technically allowed, the cost of identifying customers, reissuing invoices, and collecting small amounts usually outweighs the recovery. Chasing $14 on a $200 sale damages the relationship and rarely nets anything.
The exception is a small number of high-value B2B transactions. On a $500,000 equipment sale, the buyer likely expected tax and will handle a correction professionally. For everything else, treat the uncollected tax as a business cost.
Fix the Systems Before You Move On
Clearing the back liability solves half the problem. If the underlying process stays broken, the same bill lands again in a few years.
Automate the tax calculation. Manual rate lookups don’t scale across overlapping state, county, and city rates, and errors compound. Sales tax software that integrates with your e-commerce, POS, or invoicing tools applies the correct rate in real time and costs less than another round of non-compliance.
Track economic nexus continuously. Your sales into a state can be under the threshold one year and over it the next. Your system should monitor cumulative sales by state and alert you as you approach a threshold, so you can register and start collecting before you cross it. Missing that trigger is how this problem starts for most growing businesses.
Keep exemption certificates on file, valid, and current. Certificates expire, and an expired certificate is no better than a missing one during an audit. A simple process for collecting, verifying, and renewing them protects the exemptions you legitimately have.