CBS Corp. (CBS) agreed to sell four radio stations in Portland, Ore., to a company run by former industry heavyweight Larry Wilson for $40 million.

The deal comes as CBS has been selling stations in mid-sized markets to concentrate the nation's biggest population centers while Wilson, who founded Citadel Communications (CTDB) and sold the company in 2001 for $2 billion, builds a Portland-based radio chain. Wilson recently bought Portland stations owned by Microsoft Inc. (MSFT) co-founder Paul Allen.

CBS' radio division has been struggling for years, a situation worsened by advertising woes affecting most media outlets. Radio revenue slumped 23% in the latest quarter while, profit plunged 43%.

CBS Radio Chief Executive Dan Mason said the sale - the company's third in eight months and involving a combined 12 stations - moves it closer to focusing primarily on the largest U.S. markets, "where we see the most long-term promise." The marketplace for station sales is improving, he said, "so we expect to make further progress on that goal going forward."

CBS has suffered from a steep downturn in ad revenue, slashing its dividend to save cash. Its shares were recently flat at $10.81. The stock is up 32% in 2009, but down by 35% from a year earlier.

-By Mike Barris, Dow Jones Newswires; 212-416-2330; mike.barris@dowjones.com