According to BusinessWeek (and other sources) --- In 1966 Congress allowed the NFL to qualify for 501(c) tax exempt status. Ever since then, while the NFL now generates $9.5 billion in annual revenue, they pay no federal taxes. The NFL's league office calls itself a trade association "promoting the interests" of its 32 teams. This is a bit like McDonalds calling itself a trade association and "promoting the interests" of its 14,000 U.S. restaurants.
What's even just as jaw-dropping --- a conservative Republican (U.S. Senator Tom Coburn) has introduced the PRO Sports Act, which would amend the tax code to prohibit professional sports organizations (such as the NFL, NBA, and PGA) with annual revenues over $10 million from enjoying the same tax-exempt status as industry trade associations (lobbyists) and public interest groups (political groups like the Tea Party).
Major League Baseball gave up its exempt status in 2007. That's good to hear, because these days they're not even paying their bat boys the minimum wage.
Some NFL owners inherited teams from their wealthy families. Some are lifetime businessmen who bought a franchise as a midlife vanity project. One is married to a Walmart heiress. Yet on the whole, NFL owners have one thing in common: their relative anonymity. That's because, for years, they've had a hired hand to do their dirty work --- from federal investigations to millions in political donations --- it's all in a day's work for football's money men.
* Now there's a petition at Change.Org