“Before the 2008 purchase closed, there was a battle between the banks and private equity funds, who went to court to force the banks to complete the deal,” said Neil Begley, a Moody’s debt analyst. “While the equity holders would prefer an out-of-court restructuring, in this case they may not be able to come to terms with the banks.”

The company has $16 billion of bank debt, on which it pays variable rates, and $6 billion more of junior debt. The holders of the junior debt and the equity holders would absorb the first loss in the event of a bankruptcy, so the banks have some protection and less incentive to negotiate.

As advertiser spending plunges week by week, the likelihood grows that Clear Channel will fall out of compliance with one of its loan covenants by year’s end and be in technical default, several analysts said. The covenant requires that debt not exceed 9.5 times its cash flow. Lately, Clear Channel has been adding to its debt even as its cash flow is shrinking.

Image Scott Sperling, of Thomas H. Lee Partners, recently offered a reassuring assessment of Clear Channels finances. Credit... Brendan McDermid/Reuters

Media companies of all types are suffering from the recession while consumer appetites are shifting in the digital revolution. Those laden with debt may buckle, with the biggest so far being the Tribune Company, thrown into bankruptcy after Sam Zell borrowed heavily to pay $8.2 billion for the company and assume $5 billion more of its existing debt. When Bain and Thomas H. Lee finally completed the Clear Channel acquisition in July after two years of struggle, they paid $18 billion and assumed $5 billion in outstanding debt. Today, there are few buyers for broadcast assets. Should the market rebound, the company could be worth about $12 billion, Mr. Begley of Moody’s said.

Mr. Cheen estimates its market value today at less than $6.3 billion. “The market has gone from irrational exuberance to excessive awfulness,” he said.

Though many companies acquired by private equity firms at the end of the bubble are in trouble, critics say the Clear Channel deal was ill advised from the start. The acquirers raised their bids several times to win over the previous shareholders even as the economy weakened.