Some companies were acquired by larger rivals. Others are simply no longer in business.
For the better part of two decades, Caribbean countries such as Bermuda and the Cayman Islands were hot spots for reincorporation.
That started to change in 2004 when Congress said American companies could relocate overseas if foreign shareholders owned 20 per cent of their stock.
Europe became a natural choice because many companies had an established presence there and tax rates were generally lower than the United States, especially in Ireland and, more recently, Britain.
Now Democratic lawmakers want to up that stock threshold to 50 per cent to make it harder for firms to hightail it out of the country. That push to change tax policy is gaining momentum in Washington and may factor into midterm congressional elections.
In the meantime, here is a look at some of the firms that have inverted. The list is far from exhaustive, but offers a glimpse into a practice that some say is robbing the US of billions of dollars in tax revenue.
Click here for the list of American companies that have incorporated overseas.