Most business owners still operate under a dangerous assumption: if they don’t have a building, a warehouse, or employees in another state, they don’t owe that state anything. That assumption was shaky for years, and in 2018 it collapsed completely. The Supreme Court’s decision in South Dakota v. Wayfair rewrote the rules, and nearly a decade later, a surprising number of entrepreneurs still haven’t caught up. Understanding your business sales tax registration requirements is no longer optional for remote sellers, e-commerce operators, or service providers who cross state lines. It’s a legal obligation, and the states are getting better at enforcing it every year. This article explains what changed, what triggers a registration requirement now, how to spot the gaps in your own compliance, and what to do if you’ve been operating without the right permits. By the end, you’ll know exactly which questions to ask about your own business, and you’ll have a clear path to fixing any problems before a state revenue department finds them first.
Table of Contents
- The Wayfair Ruling Changed Everything—And Most Owners Missed It
- What Actually Triggers a Registration Requirement? (Nexus Explained)
- The Hidden Costs of Ignoring Registration (Penalties and Risk)
- How to Know If You’re Already Out of Compliance
- Step-by-Step: What to Do If You Need to Register
- Post-Registration Obligations (You’re Not Done Yet)
- Why Spencer Accounting Group Is the Right Partner for Compliance Resolution
The Wayfair Ruling Changed Everything—And Most Owners Missed It
For decades, the rule was simple: you had to collect sales tax only in states where your business had a physical presence. That meant an office, a storefront, a warehouse, or employees. If you sold from California to a customer in Texas and had no physical connection to Texas, you didn’t charge Texas sales tax. The customer technically owed “use tax” on the purchase, but almost nobody paid it, and states had no practical way to collect.
The South Dakota v. Wayfair decision in 2018 blew that framework apart. The Supreme Court ruled that states can require out-of-state sellers to collect and remit sales tax even if the seller has no physical presence in the state. The justification was simple: the old physical-presence rule gave online retailers an unfair advantage over local brick-and-mortar businesses, and it was costing states billions in lost revenue. The Court upheld South Dakota’s law, which set a threshold of $100,000 in sales or 200 transactions into the state. That threshold became the model for what’s now called economic nexus.
Today, 45 states plus Washington, D.C. have adopted some form of economic nexus law. The five states with no statewide sales tax, Alaska, Delaware, Montana, New Hampshire, and Oregon, remain the exceptions. If you sell into any of the other 45 states, you need to know their thresholds and whether you’ve crossed them. This applies to product sellers and, increasingly, to service providers, as more states expand their tax bases to include digital goods, software, and professional services.
What Actually Triggers a Registration Requirement? (Nexus Explained)
The word “nexus” simply means a connection. In tax law, it’s the connection between your business and a state that gives that state the legal right to require you to collect and remit sales tax. There are several types of nexus, and they can overlap.
Physical nexus is the traditional form. You have it if you own or lease an office, a store, a warehouse, or any real property in a state. It also triggers if you have employees working there, if you store inventory there, or if you send sales representatives into the state to solicit business. Even a single employee working remotely from a home office in another state can create physical nexus for your entire company.
Economic nexus is the newer, post-Wayfair standard. It’s based purely on your sales activity into a state. Most states set their threshold at $100,000 in gross revenue or 200 separate transactions in the current or previous calendar year. Some states use a higher threshold. Texas, for example, uses $500,000 in gross revenue for its economic nexus rule. But Texas also has a separate, lower trigger that catches many small sellers off guard: if you make three or more sales of taxable tangible personal property in a 12-month period, you may need a permit, even if you never come close to the $500,000 mark. That’s an unusually low bar, and it means Texas can require registration from businesses that wouldn’t trigger economic nexus in most other states.
Click-through nexus and affiliate nexus are secondary triggers. Click-through nexus applies when you pay commissions to in-state websites or influencers who refer customers to you via links. Affiliate nexus applies when an in-state affiliate, such as a related company or brand partner, sells similar products under a shared trademark or business interest. These rules are less common than economic nexus, but they exist in several states and can surprise business owners who think they’re in the clear.
The critical point is that thresholds vary wildly. There is no uniform national standard. A business doing $90,000 in sales to New York might not trigger economic nexus there, but the same sales volume into South Dakota would. You have to check each state individually.
Common Nexus Triggers Business Owners Overlook
Several activities create nexus that business owners routinely miss. Attending a trade show or conference in a state where you make sales can establish a temporary physical presence that some states treat as nexus-creating. Storing inventory in a third-party fulfillment center, such as Amazon FBA warehouses, creates physical nexus in every state where your goods are held. Using a remote employee or independent contractor based in another state creates nexus through that worker’s location. Selling through a marketplace facilitator like Amazon, eBay, or Etsy adds another layer: in most states, the marketplace collects and remits tax on your behalf, but in some situations, you may still need to register independently, especially if you also sell through your own website or have physical presence in the state.
The Hidden Costs of Ignoring Registration (Penalties and Risk)
Most online guides focus on how to register and stop there. They skip the consequences of getting it wrong. That’s a serious gap, because the penalties for non-compliance are not theoretical. States have become aggressive about enforcement, and the financial damage can be severe.
When a state discovers an unregistered seller, it can go back and assess back taxes for the entire period the business should have been collecting. Lookback periods typically range from three to four years, but some states can go back further if they determine the failure to register was willful. The state calculates the tax that should have been collected on every taxable sale during that period, then adds penalties and interest. Penalties can range from 5% to 25% of the tax due per month, with caps that can reach 50% or more of the total liability. Interest accrues from the original due date of each missed filing.
The audit risk is real and growing. States share data through the Multistate Tax Commission and use sophisticated data-mining tools to identify unregistered sellers. They cross-reference marketplace sales data, customs records, and even public business filings. If you’re selling into a state without collecting tax, the odds of eventually being found are higher than most owners think.
There’s also a personal liability risk. In many states, the responsible officers, members, or owners of a business can be held personally liable for unpaid sales tax. This means the state can pursue your personal assets, not just the company’s, if the business fails to pay.
The good news is that most states offer a voluntary disclosure program. If you come forward before the state contacts you, you can often negotiate a deal: the state waives penalties, limits the lookback period to three or four years, and allows you to pay the back tax in installments. Voluntary disclosure is not a get-out-of-jail-free card, but it’s dramatically better than waiting for an audit notice. The key is to act before the state finds you first.
How to Know If You’re Already Out of Compliance
If you’ve never done a multi-state nexus review, there’s a strong chance you have gaps. Start with a simple diagnostic. List every state where you have customers, employees, inventory, or affiliates. For each state, check the economic nexus threshold. Most states use $100,000 or 200 transactions, but verify each one. Then look at your sales data for 2026 and for 2025. If you crossed any state’s threshold in either year, you likely should have registered already.
Pay special attention to states where you have any physical connection. A remote employee, a fulfillment center, or even a laptop and a home office used by a traveling salesperson can create physical nexus that requires immediate registration regardless of sales volume.
If you sell only through a marketplace facilitator, do not assume you’re covered everywhere. Some states still require registration if you have physical presence in the state, even if the marketplace handles tax collection on your marketplace sales. And if you sell through multiple channels, your own website plus a marketplace, for example, the marketplace only covers the sales it processes. Your direct sales may still trigger registration requirements.
Step-by-Step: What to Do If You Need to Register
Once you’ve identified the states where you have nexus, the registration process is straightforward but detail-oriented. Follow these steps to get it right.
Step one: confirm which states require registration. Use the diagnostic above and, if you’re unsure about any state, consult a tax professional. Guessing wrong can create more problems down the line.
Step two: gather the required information. Every state will ask for your federal employer identification number, or EIN, or your Social Security number if you’re a sole proprietor. You’ll need your business entity details, your NAICS code, and information about owners, officers, or partners. Some states, like Texas, require Social Security numbers for all responsible parties. If a responsible party doesn’t have a Social Security number, Texas requires a paper application instead of the online system.
Step three: apply online through each state’s official Department of Revenue or Comptroller website. Never use a third-party service that charges a fee for registration. North Carolina’s Department of Revenue explicitly warns that there is no fee to apply for a certificate of registration and that third-party websites charging for this service are deceptive. The same is true in most states. Only use the official state portal.
Step four: allow for processing time. Texas advises new permit applicants to allow two to three weeks to receive their permit. Other states may be faster or slower. Plan ahead, especially if you have upcoming sales into a state where you’ve just discovered you need to register.
Step five: set up a system to track filing frequencies and due dates. When you register, the state will assign you a filing frequency, monthly, quarterly, or annually, based on your expected sales volume. Due dates vary by state but often fall on the 20th of the month following the reporting period. Missing a filing deadline, even if you owe no tax for that period, can trigger penalties in some states.
What About Marketplace Sellers? (A Common Point of Confusion)
Marketplace facilitator laws have simplified compliance for many online sellers, but they haven’t eliminated all obligations. In most states, marketplace facilitators like Amazon, Walmart, and Etsy are required to collect and remit sales tax on behalf of their third-party sellers. That means you don’t need to register solely because of your marketplace sales in those states, provided you have no other nexus.
But there are exceptions. California, for example, requires in-state sellers to register even if they sell only through a marketplace. Remote sellers who sell exclusively through a registered marketplace may not need to register, but if you also sell through your own website, you likely do. The rules differ by state, and the distinction between marketplace sales and direct sales is where many businesses get tripped up. Always verify your specific situation with a professional who understands multi-state e-commerce compliance.
Post-Registration Obligations (You’re Not Done Yet)
Getting the permit is just the beginning. Once you’re registered, you have ongoing obligations that require consistent attention.
Filing frequency is the first thing to track. Most states assign a frequency based on your sales volume. High-volume sellers file monthly, moderate sellers file quarterly, and low-volume sellers file annually. If your sales grow, the state may change your frequency. You need to monitor your notices and adjust your internal processes accordingly.
Due dates are typically the 20th of the month following the reporting period, but this varies. Some states use the 15th, others the 25th. A late filing can trigger a penalty even if you pay the full tax owed. Set calendar reminders for every state where you’re registered.
Renewal requirements differ by state. Some states, like Colorado, issue sales tax licenses that expire every two years and must be renewed. Other states, including Texas, do not require periodic renewal, but you must keep your business address and ownership information current. Failing to update your address can result in missed notices and unexpected liabilities.
Recordkeeping is essential. Retain sales records, exemption certificates, and filed returns for at least four years. If you’re audited, the state will ask for documentation supporting every sale you claimed as exempt. Missing exemption certificates can turn a tax-free sale into a taxable one, with you on the hook for the tax.
Finally, if you stop selling into a state, you must formally close your permit. Do not simply stop filing. An inactive permit with unfiled returns will eventually trigger delinquency notices and potential penalties. Contact the state’s revenue department and follow their process to close the account.
Why Spencer Accounting Group Is the Right Partner for Compliance Resolution
Multi-state sales tax compliance is not a one-time task. It’s an ongoing obligation that grows more complex as your business expands into new states, adds sales channels, or changes its operational footprint. The stakes are high: back taxes, penalties, interest, and personal liability can threaten everything you’ve built.
Spencer Accounting Group works with business owners to cut through the confusion. We help you determine exactly where you need to register, handle voluntary disclosures for past non-compliance, and set up filing systems that keep you current going forward. Our clients include e-commerce operators, service providers, and growing companies that are entering new states and discovering obligations they didn’t know they had.
If you’re unsure whether your business is registered in all the right states, contact Spencer Accounting Group today for a compliance review. We’ll help you get right with the states, before they come to you.