Producers on some Fox programs have been told to monitor Newsmax's guest bookings and throw some sand in Newsmax's gears by encouraging guests who appear on both channels to stop saying yes to the upstart.

According to Fox sources, producers were told to avoid some regular guests if they kept showing up on Newsmax after being encouraged to stop. Management's goal: to remind guests who's boss in the right-wing media world.

And Fox News is still boss, with five times the audience of Newsmax at any given time of day. A Fox spokesperson said there was no directive about guest bookings.

But it's clear that Fox is feeling pressure from the right like never before. Fox hosts and producers are on edge about the ratings race, a number of staffers told CNN Business. The staffers also said that the competitive dynamic is having an impact on some of Fox's programming choices.

Newsmax TV's ratings boom

Until election day, Newsmax barely had a pulse on Nielsen's TV ratings reports, which showed that the channel only averaged 34,000 viewers at any given time in August and September. A slight uptick in October became a groundswell of viewership after November 3. One of the obvious causes was Fox's projection that President Trump would lose the state of Arizona, drastically narrowing his path to re-election. Newsmax criticized Fox and gave viewers false hope about Trump's chances.

This tactic continued when Fox and all the other major networks called the election for President-elect Biden on November 7. Newsmax insisted that the race wasn't over and that the major networks were acting irresponsibly, when in fact Newsmax was the irrational actor. A subset of the Fox audience flocked to Newsmax for shows that hyped voter fraud allegations and harangued the rest of the media.

Greg Kelly, the 7 p.m. host on Newsmax, was the biggest beneficiary: His show averaged 80,000 viewers in the run-up to election day and topped 800,000 on the first weekday after Biden was projected as president-elect.

Sources at Fox derided Newsmax as "far-right" and "fringe" and they singled out Kelly for particular criticism. But there has been a noticeable shift in the way they talk about Newsmax.

Earlier this year, while working on a book about Fox News and Trump, I spoke with some of the same staffers, and when I brought up Newsmax and another wannabe rival, One America News, they usually scoffed or cracked a joke. The channels were dismissed like the fleas on an elephant's back.

But the Fox staffers are not joking anymore. They are paying close attention to the daily ratings spreadsheets that show Newsmax's performance alongside Fox News, Fox Business and other channels.

Overall, CNN has made the biggest gains in the post-election period; CNN has been beating Fox News in the key 25- to 54-year-old demographic for nearly three weeks. But Fox has also been losing share to Newsmax, particularly in the early evening hours, according to a close reading of the Nielsen data.

On Monday evening, for example, Kelly averaged 188,000 viewers between the ages of 25 and 54, while Fox's "The Story" averaged 288,000 viewers in that demographic at that hour.

Before the election, Kelly was garnering about 30,000 viewers in the demo, while Fox was getting more than 500,000 in the demo.

Some of Fox's audience erosion is due to predictable post-election fatigue; Fox also fell into a slump after Mitt Romney lost to Barack Obama in 2012.

If history is any guide, the audience will gradually "come home," in the words of one Fox executive, who pointed out that the network remains dominant among conservative viewers. On Monday Fox had 1.4 million viewers at any given time of day, and more than 2 million during prime time, while Newsmax had 300,000 at any given time of day.

Competition in the right-wing media landscape

No one quite knows what to expect in this new competitive landscape. In recent days, Newsmax has come off its immediate post-election highs. Kelly averaged 600,000 viewers on Tuesday, down from 1.1 million last Thursday.

And Newsmax is one of many Fox challengers. One America News is not rated by Nielsen, which is normally a sign that a channel is very small, but the channel's owners say that their internal metrics show big post-election gains. Google searches for both Newsmax and One America News both spiked after Election Day.

Charles Herring, the president of OANN, said Friday that "a massive wave of former Fox News viewers have abandoned Fox and have found a home at OAN."

He said some former Fox viewers "believe new pro left voices have infiltrated the network."

Other right-wing outlets include two streaming services: BlazeTV, with Glenn Beck and Mark Levin among the hosts, and The First TV, with Bill O'Reilly. One throughline of most of Fox's rivals: They employ former Fox talent.

Trump, despite being closely aligned with Fox during his time in office, has been taking advantage of the competition and promoting Newsmax on his Twitter feed.

On Tuesday night Trump tweeted out the results of an unscientific poll, "Should President Trump concede to Biden?," that was shown multiple times on Newsmax TV.

The results were meaningless, except to show that Newsmax is still catering to Trump fans who don't want the election to be over.

Some of Fox's talk shows have indulged election denialism, too, but they have been contradicted by the newscasts that air at other times of day. And this is a source of tension internally, some of the Fox sources said. Last Sunday the vociferously pro-Trump host Maria Bartiromo delievered a scathing criticism of an election technology company called Dominion Voting Systems. Then she told viewers to tune in later in the day when a spokesperson for Dominion would be interviewed by Fox News anchor Eric Shawn. She even read a list of questions that she said Shawn should ask.

Inside Fox, staffers cringed at the awkward contrast between Bartiromo's conspiratorial programming and Shawn's straightforward interview, which rebuked the conspiracy theories.

Many Fox viewers prefer the conspiracy theories however -- Bartiromo's show had more than 1.9 million viewers while Shawn's newscast barely averaged 1 million.

"Our audience has absolutely been radicalized," one longtime on-air staffer at Fox said.

Multiple staffers pointed to programming adjustments, like the airing of Mark Levin's right-wing talk show on both Saturday and Sunday nights, that are
meant to appeal to the Fox base. Levin's show used to air just on Sundays. Last Saturday, however, Fox aired a six-day-old episode of the show, full of out-of-date claims about Trump's legal challenges.

The staffers said the frequent re-airing of clips from "Tucker Carlson Tonight" during the day was another noticeable attempt to appease viewers.

When asked about the apparent booking drama between Fox and Newsmax, Chris Ruddy, the CEO of Newsmax, said Fox is committing an "anti-competitive violation" by trying to block guests. Two of the Fox sources shrugged at that suggestion. "Welcome to the big leagues," one said.