A record 54 companies in the Standard & Poors 500 Index of leading U.S. firms are now at least partially exempt from the corporate income tax. Thats more than twice the number four years ago.

President Barack Obama says U.S. corporations that adopt foreign addresses to avoid taxes are unpatriotic. His own administration helped one $20 billion American company do just that.

Washington is buzzing this summer about inversions, and the chatter has nothing to do with the weather.