Oliver Bullough:

A decade ago, South Dakotan trust companies held $57.3bn in assets. By the end of 2020, that total will have risen to $355.2bn. Those hundreds of billions of dollars are being regulated by a state with a population smaller than Norfolk, a part-time legislature heavily lobbied by trust lawyers, and an administration committed to welcoming as much of the world’s money as it can. US politicians like to boast that their country is the best place in the world to get rich, but South Dakota has become something else: the best place in the world to stayrich.

At the heart of South Dakota’s business success is a crucial but overlooked fact: globalisation is incomplete. In our modern financial system, money travels where its owners like, but laws are still made at a local level. So money inevitably flows to the places where governments offer the lowest taxes and the highest security. Anyone who can afford the legal fees to profit from this mismatch is able to keep wealth that the rest of us would lose, which helps to explain why – all over the world – the rich have become so much richer and the rest of us have not.