Editorially reviewed September 8, 2026. This guide covers sales and use tax research; the state examples are limited to the jurisdictions cited. Confirm the applicable law and business facts before changing registration or collection.
Separate the questions before deciding where to collect
Nexus concerns the connection that can allow a state to impose tax obligations on a business. It does not, by itself, establish that every sale is taxable or that the seller must collect on every channel.
A useful review separates four decisions:
| Decision | Evidence to preserve |
|---|---|
| Nexus | Business locations, personnel, inventory, activities and the applicable economic threshold |
| Registration and filing | The state's requirements, exceptions, account type and relevant dates |
| Collection responsibility | Direct or marketplace channel, the responsible party and supporting documentation |
| Transaction treatment | Product, purchaser, exemption, sourcing and rate evidence |
An address or sales total can inform this analysis. Neither is a complete legal conclusion.
Physical presence and economic nexus require different facts
In South Dakota v. Wayfair, the Supreme Court rejected the physical-presence rule that had limited states' ability to require collection by out-of-state sellers. The decision did not eliminate physical presence as a relevant basis or establish one nationwide economic threshold. Supreme Court opinion.
For example, the Texas Comptroller distinguishes remote sellers from businesses with a Texas physical presence, including business locations, salespeople or representatives. Its remote-seller rules address economic nexus separately. Texas Comptroller: Remote Sellers.
For each state, record the current threshold, measurement period, included sales and effective date. Also review business activities that may matter independently of sales volume. A dashboard total should link to the underlying transactions and identify any missing channels or periods.
Terms such as affiliate or click-through nexus describe rules that require jurisdiction-specific research. Do not treat any referral relationship as an automatic nationwide registration trigger.
Marketplace collection is a separate responsibility
Selling through a marketplace is not a universal additional category of seller nexus. Marketplace laws can assign collection to a facilitator while leaving separate seller registration, recordkeeping or direct-sales questions.
Texas illustrates why those questions must stay separate: a qualifying remote seller selling only through a marketplace provider that certifies collection responsibility need not hold a Texas sales tax permit, while the Comptroller describes different permit requirements for a Texas seller. Texas Comptroller: Marketplace Providers and Sellers.
California likewise explains a general registration exception for marketplace sellers whose tangible merchandise is sold exclusively through a qualifying facilitator. This is a California rule with conditions, not a national marketplace exemption. CDTFA: Marketplace Facilitator Act.
Keep marketplace and direct sales identifiable. Preserve the provider's documentation and review the rule for each transaction period. Avoid both duplicate collection and an assumption that marketplace collection resolves every obligation.
Make the review usable by finance and operations
Maintain one record per state showing the facts reviewed, source authority, conclusion, reviewer, effective date and next action. Distinguish a completed review from a missing-data alert. A missing sales period should remain an unresolved input, not become a zero in the threshold calculation.
Before accepting a software demonstration, ask how it handles a newly discovered warehouse, a corrected sales import and a marketplace transaction that also appears in an accounting export. These are suggested evaluation cases, not reported customer results. The output should explain what changed and what still requires human review.
Use the Sales Tax Atlas to reach state-specific guidance. For the channel reconciliation test, see the marketplace software evaluation checklist. Compare reviewed workflows through the sales tax software overview. A software alert is a starting point for the review, not registration or filing authority.