A key group of creditors rejected iHeartMedia Inc.’s latest debt restructuring proposal, and countered with their own deal that may involve the company filing for chapter 11, the company disclosed on Thursday.

The latest development in long-running restructuring negotiations at iHeart, the largest radio network in the U.S. by number of stations, comes a day after Cumulus Media Inc., the second-largest, filed for bankruptcy, succumbing to billions of dollars of debt and competitive pressures from digital platforms.

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