The Supreme Court says states can force online shoppers to pay sales tax. The 5-4 ruling Thursday is a win for states, who said they were losing out on billions of dollars annually under two decades-old Supreme Court decisions that impacted online sales tax collection.

The high court ruled Thursday to overturn those decisions. They had resulted in some companies not collecting sales tax on every online purchase. The cases the court overturned said that if a business was shipping a product to a state where it didn't have a physical presence such as a warehouse or office, the business didn't have to collect the state's sales tax. Customers were generally supposed to pay the tax to the state themselves if they don't get charged it, but the vast majority didn't. Justice Anthony Kennedy wrote that the previous decisions were flawed.

"Each year the physical presence rule becomes further removed from economic reality and results in significant revenue losses to the States. These critiques underscore that the physical presence rule, both as first formulated and as applied today, is an incorrect interpretation of the Commerce Clause," he wrote.

In addition to being a win for states, the ruling is also a win for large retailers, who argued the physical presence rule was unfair. Retailers including Apple, Macy's, Target and Walmart, which have brick-and-mortar stores nationwide, generally collect sales tax from their customers who buy online. That's because they typically have a physical store in whatever state the purchase is being shipped to. Amazon.com, with its network of warehouses, also collects sales tax in every state that charges it, though third party sellers who use the site to sell goods don't have to.

But sellers that only have a physical presence in a single state or a few states could avoid charging customers sales tax when they're shipping to addresses outside those states. Online sellers that don't charge sales tax on goods shipped to every state range from jewelry website Blue Nile to pet products site Chewy.com to clothing retailer L.L. Bean. Sellers who use eBay and Etsy, which provide platforms for smaller sellers, also aren't required to collect sales tax nationwide.