From https://www.forbes.com/2008/05/14/clear-channel-buyout-marke...:
"Thomas H. Lee Partners and Bain Capital, agreed to a lower sale price of $17.9 billion or $36.00 per share of the radio company"
Wait, maybe the name "Bain Capital" rings a bell? That's because their leveraged buyout of Toys R Us saddled the company with so much debt they went completely out of business.
https://nypost.com/2017/09/21/bain-capital-has-now-plunged-t...
Also see https://dealbook.nytimes.com/2012/02/29/sorting-through-the-...
There's really no reason for iHeartMedia to have all this debt other than Bain Capital did their thing.