Two Boston private equity firms agreed to pay nearly $19 billion for broadcasting company Clear Channel Communications Inc. yesterday, in a deal that could change the nation's radio landscape.

Thomas H. Lee Partners and Bain Capital Partners, both of Boston, agreed to buy out Clear Channel, the country's largest radio broadcaster, for $37.60 a share, putting a value of about $19 billion on the company.

Lee and Bain will also assume $8 billion of San Antonio, Tex.-based Clear Channel's debt as part of the deal, bringing the total transaction to $26.7 billion.

Under the terms of the agreement, Clear Channel can pursue competing bids between Dec. 7, 2006 and Jan. 5, 2007.

Clear Channel also said it plans to sell off the 42 television stations it owns and 448 radio stations outside the top 100 markets.

None of the four local radio stations Clear Channel owns — JAM'N 94.5 (WJMN-FM), KISS 108 (WXKS-FM), WKOX-AM (1200 and 1430) and WXKS-AM (1430) — were listed as up for sale.

The bid from Bain and Lee comes at a time when a number of large public broadcasting companies are selling off individual stations to smaller private companies due to pressures from shareholders amid a weaker advertising market.

The sale of hundreds of radio stations could have a major impact on the country's media landscape. But most of the impact from the Clear Channel deal would likely be felt outside of Boston, said Scott Fybush, editor of NorthEast Radio Watch. "The impact in larger markets like Boston is going to be very minimal," he said. "There's not going to be that much of a change with KISS and with JAM'N."

Still, the ownership changes occuring at many radio stations are breeding anxiety within the industry, Fybush said. "It's a scary time to be working in radio right now," he said. "There's a sense of unease across the entire industry that is like nothing I've ever seen before."