Affiliate nexus is a sales tax rule that can require your out-of-state business to collect a state’s sales tax because a related company or a contracted referral partner is active in that state on your behalf. You don’t need employees, a warehouse, or an office in the state yourself. If a sister company accepts your returns at its local store, a subsidiary services your products there, or in-state websites earn commissions steering buyers to you, the state can attribute that presence to you and require you to register and collect.
What Triggers Affiliate Nexus Through a Related Company
The core idea is attribution. When an in-state business helps a remote seller build or keep customers in the state, the state treats the seller as operating there through a proxy. Corporate structures are the most common source. If your out-of-state entity and an in-state entity share a parent, or one owns a stake in the other, states often treat the two as a connected enterprise for sales tax purposes.
No two states define the relationship identically, but the triggering activities cluster around a few patterns:
- An affiliated local store accepts returns or exchanges for products the out-of-state seller shipped.
- The businesses share trademarks, logos, or trade names, so customers see them as one operation.
- An in-state affiliate performs warranty work, repairs, or installation on the remote seller’s products.
- The remote seller’s inventory sits in an affiliate’s local warehouse or distribution center.
The connecting thread is competitive advantage. If the remote seller benefits from the local affiliate’s physical footprint in a way that helps it sell to in-state customers, the state has a strong argument for nexus. A business with subsidiaries or sister companies in several states should map which entity performs which activity in which state, because a single overlooked connection can create a collection obligation that reaches back to the date the affiliate relationship began.
Click-Through Nexus Through In-State Referral Partners
Click-through nexus is a related doctrine aimed at commission-based referrals rather than corporate affiliates. The typical setup: an out-of-state retailer pays in-state website owners, bloggers, or influencers a commission for sending customers through tracking links. About 15 states maintain active click-through nexus laws, and each defines the triggers differently.
Two conditions generally have to be met. The in-state partner has to actively solicit sales rather than passively display an ad, and the cumulative sales generated through those referrals have to exceed a dollar threshold over a 12-month period. Once your network of local referrers drives enough revenue, the state treats you as having a sales force operating within its borders.
These laws predate the Supreme Court’s 2018 decision in South Dakota v. Wayfair, Inc., and many sellers that click-through nexus was written to reach now also cross the economic nexus thresholds most states adopted after Wayfair.1Supreme Court of the United States. South Dakota v. Wayfair, Inc. For smaller sellers who sit below the economic threshold but rely on aggressive referral networks, click-through nexus can still be the rule that creates the filing obligation.
How Affiliate Nexus Fits With Economic Nexus and Marketplaces
After Wayfair, every state with a sales tax adopted economic nexus, which creates a collection obligation based purely on sales volume into the state. The South Dakota law the Court upheld set the bar at $100,000 in annual sales or 200 separate transactions.1Supreme Court of the United States. South Dakota v. Wayfair, Inc. Most states adopted a $100,000 threshold, though some set theirs higher, and the trend since 2019 has been to drop the transaction-count test.
Affiliate nexus wasn’t replaced by economic nexus. It sits alongside it. The same seller can have affiliate nexus in a state because a parent company operates a warehouse there, and independently have economic nexus because online sales into that state cross the dollar threshold. Either one creates a duty to register and collect. The distinction matters when you’re figuring out when the obligation began: affiliate nexus can reach back to the date the affiliate relationship started, while economic nexus begins only once you cross the sales threshold.
Marketplace facilitator laws are a separate track that changes who does the collecting, not whether you have nexus. Nearly all states with a sales tax now require the marketplace itself, Amazon, Etsy, Walmart Marketplace, and others, to collect and remit tax on the third-party sales it processes. That’s real relief, but it only covers sales made through the platform. If you also sell through your own website, at trade shows, or through any other channel, you still owe collection on those sales in every state where you have nexus. Affiliate nexus from a related entity’s in-state activity applies to those direct sales even when the marketplace is handling tax on your platform sales.
What To Do Once You Have Affiliate Nexus
Once you conclude that an affiliate relationship has created nexus in a state, register with that state’s tax authority before you start collecting. Most states run an online portal through their department of revenue. The application asks for your federal Employer Identification Number, the legal name of your business, information about your officers, and the date you first met the nexus threshold.2Internal Revenue Service. Employer Identification Number Registration is free in most states; about a dozen charge fees from $5 to $100. Processing usually takes two to three weeks, and the state issues a sales tax permit that authorizes you to collect.
Pinpointing the exact date your nexus obligation began is one of the harder parts. If the affiliate relationship has existed for years and you’re only now registering, the state may treat you as out of compliance since the relationship started. That retroactive exposure is why businesses with complex corporate structures should evaluate affiliate nexus before an audit forces the question.
Voluntary Disclosure If You’re Already Late
If you find you’ve had affiliate nexus for months or years without collecting, voluntary disclosure is usually a better route than waiting for the state to find you. Most states offer voluntary disclosure agreements that let you come forward, register, and pay back taxes in exchange for a limited lookback period and a waiver of penalties. The catch: you must not already have been contacted by the state about the tax you’re disclosing.
The Multistate Tax Commission runs a centralized voluntary disclosure program through its National Nexus Program, which lets you apply to multiple states at once. The process stays anonymous until you sign an agreement with each state.3Multistate Tax Commission. Multistate Voluntary Disclosure Program Lookback periods typically run three to four years depending on the state, so you’d file returns and pay tax for that window rather than the full period of non-compliance.4Multistate Tax Commission. Lookback Periods for States Participating in National Nexus Program The MTC won’t process applications where estimated tax owed to a state is under $500.
Personal Liability for Owners and Officers
Sales tax exposure doesn’t always stop at the corporate level. Most states have responsible-person statutes that let tax authorities pursue individual officers, directors, or managers for uncollected or unremitted sales tax. Liability typically falls on whoever had the authority or duty to see that the company collected and paid it, which can include CEOs, CFOs, controllers, and in some cases anyone who signs the company’s tax returns.
The exposure is broader than many owners realize. In some states, personal liability attaches even when the company never collected the tax in the first place, not only when it collected and failed to remit. The responsible person owes the full amount the company should have collected, plus penalties and interest. Corporate dissolution doesn’t erase the debt. If your business has affiliate nexus in states where it isn’t registered, the personal liability clock is already running for whoever controls the finances.