Les Moonves, chief executive of CBS Corp. (CBS), said Wednesday the improvements in advertising markets that he has been observing for several months are continuing in the third quarter.

At an investor conference in New York City, Moonves said third-quarter ad revenue from the so-called scatter market, where advertisers purchase spots during the TV season, is up 30% from the year-ago period.

Moonves added that scatter pricing is up "high single-digits" from last year's upfront season, where advertisers lock in large purchases in anticipation of the upcoming TV season.

He also said he was comfortable with the company's decision to hold more ad inventory from this year's upfront for the scatter market - a strategy adopted by many TV networks this year in hopes that an economic recovery will drive prices higher as the season progresses.

"When you have the ratings, the scatter market is a great place to be," said Moonves. "All our major ad categories are beginning to come back now."

Moonves also said he expects to take market share in the scatter market this year thanks to NBC's decision to launch Jay Leno's new comedy show in the 10 p.m. prime-time hour.

"There's no question that no matter how well Leno does, there's going to be more dollars available for others in the marketplace for the 10 o'clock hour," said Moonves.

He also said he noticed that Leno's audience ratings dropped sharply for the second night of his show after a successful debut.

-By Nat Worden, Dow Jones Newswires; (212) 416-2472; nat.worden@dowjones.com