Executives on both sides, who spoke on the condition of anonymity because they did not want to be seen negotiating in public, agreed that the upfront market would be about 15 percent smaller than a year ago, when about $9 billion worth of deals were struck.
What is more, prices fell for the first time in eight years.
News Corp's Fox , Walt Disney Co's ABC, and CBS Corp's CBS agreed to deals at rates about 4 percent below those of a year ago, according to various media executives.
NBC, majority owned by General Electric and in last place in the prime-time ratings, struck deals at slightly deeper discounts.
An NBC spokeswoman confirmed that it had completed its dealmaking, but declined to comment on details about pricing or volume.
Tom Staggs, chief financial officer of Disney , said during a call last week he was "comfortable with the rates ABC has been achieving," although that network, too, declined to discuss specifics.
Jon Nesvig, president of sales at Fox, said in a prepared statement that the network had "achieved its primetime revenue goal" and that with "a broader economic recovery seeming to take hold, we are very comfortable in our marketplace positioning for next year."
Indeed, all of the broadcast networks appear to be banking on selling the remaining prime-time commercial inventory at higher prices in the so-called scatter market, the term used for last-minute sales.
CBS Chief Executive Les Moonves on Thursday said that "we have retained more inventory to sell in the scatter, and we like our position as the economy continues to improve." He "anticipates the scatter market will be stronger than the upfronts."
An executive at another network said: "We sold this upfront with the view that we were moving into a rising economy rather than a softening economy."
What's more, some key advertising categories, like auto, retail and financial services, are expected to have bigger advertising budgets in 2010, after buying about 20 percent less commercial time this around in the upfront market.
"We are looking at still a very uncertain period and I think that most advertisers are being more cautious," said Robin Diedrich, a media analyst with Edward Jones. She nonetheless said TV networks may be able to rebound from the depressed upfront market.
"When the advertising market was soft in 2002, the scatter market did actually stay up there and help make up for what had been a soft upfront." She added, however, "There are big risks on both sides."