The price represents a multiple of the $71m Gore and his partners paid in 2004, according to a 2008 regulatory filing, for the channel that became Current TV.
Gore, chairman, and Joel Hyatt, co-founder and CEO, announced the sale without providing financial terms.
While the purchase gives Al Jazeera access to the biggest US pay-TV carriers for the first time, it will have to improve on Current TV’s viewership to have staying power.
Time Warner Cable, the second-biggest US cable carrier, is dropping Current TV as it seeks to eliminate low-rated channels. The network averaged about 42,000 prime-time viewers last quarter, according to Horizon Media.
“It’s a pretty risky deal for them,” said Derek Baine, an SNL Kagan cable analyst in Monterey, California. The $500m price paid by Al Jazeera “sounds high”.
Current TV’s owners raised a total of $153m including debt, according to a report from PrivCo, a New York-based researcher covering closely held companies.
While Al Jazeera’s English network, started in 2006, reaches 250m homes in 130 countries, the US represents only a small fraction of that audience.
Al Jazeera said it will replace Current TV’s shows with its own this year, doubling its US staff to 300, with headquarters in New York.
In the US, Al Jazeera’s English-language network is carried on seven pay-TV providers.