Economist Gabriel Zucman investigates the wealth stored in tax havens (2019)

I have edited the title to make it less editorialized. I find Zucman's work very interesting – on his website there is more information about this book, and his wider work. Zucman was a student of Thomas Piketty's (perhaps best known for his book Capital in the 21st Century).

The book basically provides essential data about tax havens. Some of the results (from the book), all emphasis mine

The main conclusion of my investigation is that, despite some progress in curtailing it in recent years, tax evasion is doing just fine. There has, in fact, never been as much wealth in tax havens as today. On a global scale, 8% of the financial wealth of households is held in tax havens. According to the latest available information, in the spring of 2015 foreign wealth held in Switzerland reached $2.3 trillion. Since April 2009, when countries of the G20 held a summit in London and decreed the “end of banking secrecy,” the amount of money in Switzerland has increased by 18%. For all the world’s tax havens combined, the increase is even higher, close to 25%. And we are only talking about individuals here.

Corporations also use tax havens. Corporate filings show that US companies are shifting profits to Bermuda, Luxembourg, and similar countries on a massive and growing scale. Fifty-five percent of all the foreign profits of US firms are now kept in such havens. Since multinationals usually try to operate within the letter—if not the spirit—of the law, this profit shifting is better described as “tax avoidance” rather than outright fraud. But **its cost is enormous—$130 billion a year for US firms alone—**and since equity ownership is very concentrated, it essentially benefits only the wealthiest among us.