Shares in Tribune Co. slid slightly Thursday after the company reported a big first quarter loss amid declining ad sales.

The Tribune Co. reported a first quarter loss of $16 million (-6 cents per share), a major falloff from a profit of $103 million (33 cents) for the same period a year earlier. The Chicago-based media company said declining ad revenue was the key factor.

Tribune, which owns the L.A. Times, Chicago Tribune, Newsday as well as more than 20 TV and radio stations and the Chicago Cubs, was recently sold to Chicago-based real-estate developer Sam Zell, who plans to take the company private.

Sales in the quarter fell more than 4 percent to $1.2 billion.

Tribune reported that operating revenues in its publishing sector fell 5 percent while expenses fell 3 percent. Overall advertising revenues fell 6 percent with classifieds dropping 14 percent, real estate ads off 15 percent, help wanted revenues down 14 percent and auto revenues down 16 percent.

However, one bright spot was interactive ad revenues, which climbed 17 percent for the quarter. Circulation revenues were also down 7 percent, Tribune said.

Despite the bad news, shares in Tribune were off just 4 cents to at $32.65 in afternoon trading Thursday on the New York Stock Exchange.