In a 5-4 decision with major implications for e-commerce retailers, the Supreme Court has closed the “online sales tax loophole” by holding that a state may collect sales tax from out-of-state sellers that do not maintain a physical presence in the state. The decision, South Dakota v. Wayfair, Inc. et al., No. 17-494, 585 U.S. __ (2018), overturns two prior Supreme Court cases holding that an out-of-state seller’s duty to collect and remit tax to a consumer’s home state depended on whether the seller had a physical presence in that state. The Court found that this “Physical Presence Rule” was inconsistent with “the present realities of the interstate marketplace” and was costing states an estimated $8 to $33 billion in revenue each year. The Court also was persuaded by the notoriously low rate of consumer compliance with use taxes, and by the fact that the state law in question afforded small merchants a “reasonable degree of protection” by applying only to sellers that annually delivered more than $100,000 of goods or services or engaged in 2,000 or more separate transactions for the delivery of goods or services into the state. The dissenting opinion by Chief Justice Roberts insists that Congress, not the courts, should have undertaken the task to overturn the Physical Presence Rule and that the burden of this new tax regime will fall disproportionately on start-ups and small businesses.