OpenCorporates has a data-visualization tool for peering into the corporate tax-evasion structures of big corporations -- subsidiaries nested like Russian dolls made from Klein bottles:
In Hong Kong, there's a company called Goldman Sachs Structured Products (Asia) Limited. It's controlled by another company called Goldman Sachs (Asia) Finance, registered in Mauritius.
That's controlled by a company in Hong Kong, which is controlled by a company in New York, which is controlled by a company in Delaware, and that company is controlled by another company in Delaware called GS Holdings (Delaware) L.L.C. II.
...Which itself is a subsidiary of the only Goldman you're likely to have heard of, The Goldman Sachs Group in New York City.
That's only one of hundreds of such chains. All told, Goldman Sachs consists of more than 4000 separate corporate entities all over the world, some of which are around ten layers of control below the New York HQ.
Of those companies approximately a third are registered in nations that might be described as tax havens.Indeed, in the world of Goldman Sachs, the Cayman Islands are bigger than South America, and Mauritius is bigger than Africa.
Tim Harford's 2011 book Adapt proposes an ingenious regulatory solution to this problem, explaining how it might have been applied to companies like Lehman, whose complex structures drew out the post-bankruptcy mess for years and years. He suggested that if banks were stress-tested to determine how long they'd take to sort out after a bankruptcy, and then required to keep reserve capital necessary to run all operations through that whole period, they would be strongly incentivized to have the most simple, transparent corporate structures. Otherwise, they'd have to tie up billions of dollars in escrow to keep the doors open in the event that it all collapsed.