According to the legal website International Tax Blog, the number hovered around 500 a decade ago. Last year, it hit a record high of nearly 3,000.
This was not a gradual change. It was a sudden spike. It's a story of dominoes falling, one after another, leading to an unexpected outcome.
The first domino fell in 2008, when federal prosecutors accused the Swiss bank UBS of helping wealthy Americans hide their money tax-free in overseas accounts. It was a big case, leading to indictments, fines and prison time.