Under U.S. tax law, the estates of foreign holders of U.S. assets, such as stocks, real estate, or valuables, are required to pay estate taxes on those assets after the death of the owner. There’s even a handy piece of IRS paperwork — form 706-NA — to help calculate the tax.
But one veteran Swiss banker tells CNBC that this rule is widely ignored around the world, and the U.S. government has no way to know how much money it is owed under its own laws.
The result, the banker said, is that the U.S. Treasury is likely being deprived of billions of dollars each year.