Chances are you’ve done business with a company operating out of the Ugland House; 121 South Church Street, George Town, Cayman Islands, is the registered address for as many as 18,857 companies. For the low cost of a Caymanian mailbox, each company is able to save tens, even hundreds of thousands of dollars in taxes — to the tune of more than $100 billion in lost federal revenue annually. In 2016, US multinational corporations reported 43% of their foreign earnings in Bermuda, Ireland, Luxembourg, the Netherlands, and Switzerland — despite maintaining, on average, only 4% of their foreign workplaces and 7% of their foreign investments in these small countries.

The same scheme plays out in tax havens around the world. Famous ones include vacation destinations like the Cayman Islands and British Virgin Islands, microstates like Luxembourg and Malta, and financial hubs like Switzerland and Hong Kong. And yet the tax haven with the second-greatest number of registered companies is none other than the United States itself.

The American equivalent of the infamous Ugland House is the Corporation Trust Center, located at 1209 North Orange Street in Wilmington, Delaware, a two-story building that 285,000 businesses — 15% of all US companies — call home. Corporations take advantage of the so-called Delaware loophole, which, like all the best tax havens, enables them to avoid paying income tax in the state where they actually earn their revenue. Delaware allows corporations to cloak themselves in secrecy by permitting anonymous registration, making it difficult to know who is operating there — and intangible assets like trademarks and naming rights (to which companies can hitch an enormous amount of revenue) are exempt from taxation entirely. In addition to who knows what else, the shady corporate underground in Delaware no doubt includes businesses owned by Russian oligarchs, just as it once hosted several American outposts of the infamous Viktor Bout’s global arms dealership.