Fox is expected to finish second among viewers ages 18 to 49 and third overall.

"This was not our best year," Reilly conceded.

CBS, which averages nearly 12 million viewers a night, was the only broadcast network to maintain its audience. The network is on pace to finish atop the heap in total audience and among viewers ages 18 to 49. It would be the first time since 1991-92 that CBS has finished first in the key advertiser demographic.

Advertising insiders say CBS is in the strongest negotiating position. This month, CBS Corp. Chief Executive Leslie Moonves promised Wall Street that the network would negotiate ad rate increases of 7% to 12%.

NBC will probably finish third among viewers ages 18 to 49 but fourth overall. After a strong fall boosted by NFL football and "The Voice," the peacock lost its way in January. The network's audience slipped 6% compared with last season. But football begins this summer, and the network will benefit next season by broadcasting the Winter Olympics from Russia in February.

ABC is expected to finish in second place in overall viewers. The network has lost more than 6% of its audience compared with last season because its longtime hits, including the hospital drama "Grey's Anatomy," lost steam and the once-dominant "Dancing With the Stars" stumbled in the ratings.

Still, advertisers predict that the broadcasters should be able to maintain their premium ad rates.

"It's not a case of 'Your ratings are down so we're not going to buy you,'" Armando said. "There could be a shift in dollars to other sources, but the programming pipeline still is flowing one way. The networks are the ones creating the content that people want to watch — on TV and online. So this process remains critically important."