Air America, the talk-radio network that helped boost the careers of liberals Al Franken and Rachel Maddow, said Thursday it was going out of business.

In a statement to employees of the New York-based network, Air America’s chairman, Charlie Kireker, wrote: “It is with the greatest regret, on behalf of our Board, that we must announce that Air America Media is ceasing its live programming operations as of this afternoon, and that the Company will file soon under Chapter 7 of the Bankruptcy Code to carry out an orderly winding-down of the business.

“The very difficult economic environment has had a significant impact on Air America’s business. This past year has seen a ‘perfect storm’ in the media industry generally. . . . In this climate, our painstaking search for new investors has come close several times right up into this week, but ultimately fell short of success.”

Air America launched in March 2004 and styled itself as a liberal alternative to conservative talk radio hosts such as Rush Limbaugh, Sean Hannity and Michael Savage. Although at one point its programming was heard on as many as 100 stations nationwide, it ran into financial trouble early. It filed for Chapter 11 bankruptcy protection in October 2006 and was sold to new investors for $4.25 million in early 2007.

Among its program hosts were Franken, who went on to win election to the U.S. Senate as a Democrat, and Maddow, who became the host of a prime-time program on MSNBC. The company also hired Ron Reagan Jr., rapper Chuck D and musician Steve Earle to host shows.