That puts it in the range of Internet radio leader Pandora, which had $638 million in revenue last year.
Pittman revealed the figure in an interview about the service reaching a milestone of 50 million registered users and 97 million visitors in May.
Clear Channel Communications Inc., iHeart Radio's parent, was taken private in 2008. It reports its financial results because of public debt, but has never broken out the financial health of its digital streams.
Pittman said iHeart Radio would be a valuable company on its own, but it's just part of Clear Channel, which owns radio stations and billboards. The company had $6.24 billion in revenue last year.
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