Remote sellers establish sales tax nexus in a state when their activities meet the state's legal test for sufficient connection, shifting the duty to collect and remit sales tax from the buyer to the seller. The crucial shift in U.S. law replaced a strictly physical threshold with an economic presence standard, making online and out-of-state commerce subject to state sales tax rules.
Legal basis
The U.S. Supreme Court changed the controlling principle in an opinion authored by Chief Justice John G. Roberts Jr., U.S. Supreme Court, in South Dakota v. Wayfair Inc. That decision allowed states to require tax collection based on economic activity rather than physical location, provided the law does not place undue burdens on interstate commerce. States have interpreted that authority differently, creating a patchwork of standards and thresholds.
Practical triggers and consequences
Typical triggers include reaching a state-specific dollar sales threshold or a number of separate transactions within a rolling period. South Dakota’s statute, which motivated the Supreme Court case, used $100,000 in sales or 200 transactions as a bright-line test, while other states use different amounts or only a dollar threshold. The National Conference of State Legislatures tracks these variations and notes frequent legislative updates across states. Meeting a threshold establishes economic nexus, and the seller must register, collect applicable state and local sales taxes, file returns, and maintain compliance documentation. Smaller sellers may qualify for exemptions or de minimis thresholds, but rules vary and can change.
Beyond registration and collection, many states have enacted marketplace facilitator laws that shift collection responsibility to platforms such as online marketplaces, reducing compliance burdens for individual sellers but concentrating collection responsibilities with larger firms. The consequence of these rules affects business decisions about pricing, marketplace participation, and market entry strategies. For consumers and local governments, nexus rules influence the competitiveness of local retailers and the ability of states to capture tax revenues tied to remote consumption.
Human and territorial nuances appear in how states apply exemptions, tax holidays, or differentiated rates, and in how tribal jurisdictions and special economic zones interact with state rules. Compliance therefore requires ongoing monitoring of state statutes, administrative guidance, and court rulings. Consulting a tax professional or state revenue publications is prudent when revenue or transaction volumes approach common thresholds, since misreading nexus rules can result in back taxes, penalties, and interest.