Entercom Communications Corp. (ETM) is the fourth largest radio broadcasting company in the U.S. based on net revenue. Entercom operates more than 100 radio stations in 23 markets in the country. The company's portfolio of radio stations is geographically diverse and offers a wide variety of programming formats. Entercom derives its revenue primarily from the sale of broadcasting time to local and national advertisers. In 2006, Entercom generated a little more than 77% of its net revenue from local advertising and 20% from net national spot advertising. The balance of its revenue is generated principally from network compensation, radio station events, and rental income from tower sites.