If you establish a connection between your business and a U.S. state — known as ‘nexus’ — you must collect U.S. sales tax on the sales you make to buyers in that state, unless state rules say otherwise.
Businesses used to establish nexus in a state by having a physical presence within it, such as an office building or warehouse. However, since the 2018 Wayfair decision, which held that businesses with no physical presence in a state can be required to collect and remit U.S. sales tax on online orders, most U.S. states have passed laws that have changed the game for online sellers. These laws mean you could have nexus in a state even without a physical presence there.
Now, sellers not only have to follow the rules of the 45 states with U.S. sales tax laws, but somehow have to keep track of the rules and requirements of over 12,000 jurisdictions within those states. To make things harder, the rates vary and can frequently change. There is no national rule that applies in all states.
The complexity doesn’t stop there. Although marketplace facilitator laws require online marketplaces — such as Amazon — to collect U.S. sales tax on sales made by sellers on their platforms, this doesn’t mean you can forget about your U.S. sales tax obligations if you sell on a marketplace. A number of states may count the sales you make on marketplaces when calculating whether you’ve reached its nexus threshold or not. In some states, your total marketplace sales count towards the state nexus threshold, while others do not. Not keeping track of each state’s rules on whether to count marketplace sales in the nexus calculation could mean you fail to fulfil your obligations.
The rules — or more accurately, the lack of consistency in the rules — make it easy to establish nexus in a particular state without realising it, or misunderstand the threshold. As you’ve no doubt gathered, keeping up with ever-changing nexus rules in every state is near impossible.