A key group of creditors rejected iHeartMedia Inc.’s latest debt restructuring proposal and countered with their own deal, which requires the company to file for chapter 11, the company disclosed on Thursday, the Wall Street Journal reported yesterday. 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. A large group of bond and loan holders led by Franklin Resources rejected iHeart’s latest proposal even after the company increased the cut of equity offered to more than 87 percent in both the iHeart radio business and the company’s controlling stake in its Clear Channel Outdoor Holdings Inc. billboard unit, the company said. iHeartMedia has been trying to restructure $15.5 billion in debt since March, when it launched a public tender for a debt swap. The debt swap garnered little interest, and the company started engaging various creditor groups. It sweetened its offer in July in a bid to avoid bankruptcy.