Economic nexus — the rule that requires a business to collect and remit sales tax in a state once it crosses a certain amount of sales there, even without a physical presence — has existed since the 2018 Wayfair Supreme Court decision. What's changed by 2026 is how consistent the actual thresholds have become across states.
The convergence to $100,000
In the years right after Wayfair, states set wildly different thresholds — some used a transaction-count trigger (200 transactions) alongside a revenue number, creating confusing dual tests. Over time, most states have simplified down to a flat $100,000 in annual revenue as the trigger, dropping the separate transaction-count test entirely. That's made the rules meaningfully easier to track than they were even a few years ago.
Why sellers still miss it
Even with simpler, more consistent thresholds, the practical problem hasn't gone away: most sellers don't notice the moment they cross $100,000 in a given state until well after it happens. Revenue is usually tracked in aggregate, not broken out state by state in real time, so the actual crossing point tends to be discovered during a tax filing season, not the week it occurs.
What crossing the threshold actually requires
Once you cross a state's threshold, you're generally required to register for a sales tax permit in that state, then begin collecting and remitting sales tax on future sales there. This isn't retroactive in most cases, but the registration and collection obligation starts from the point of crossing — which is exactly why noticing quickly matters.
The practical fix
The only reliable way to catch this is tracking revenue against each state's threshold individually, not just watching total revenue. A seller doing meaningful business in a dozen states needs to know which of those dozen they've crossed in, not just that total sales are healthy.