Fox News's years-long streak of weekly rating dominance has reportedly ended, with new data showing it ceding the top spot to its rival network, MSNBC.

Nielsen data regarding the week ending this past Sunday was shared on Twitter on Tuesday by A.J. Katz, a reporter specializing in the cable news business. According to the data, Fox's primetime 8 p.m. to 11 p.m. ET viewership averaged 1,504,429. The average viewership for the more left-leaning MSNBC over the same time frame averaged 1,520,857, narrowly beating out the conservative network that has long been a leader in cable news viewership.

As Katz noted in a tweet, the data from last week marks the end of a lengthy streak of rating dominance for Fox News.

"Barring a last-second data reporting change, Fox's 120-week-long winning streak in primetime appears to be over," Katz wrote.

This development comes as Fox News continues to bleed viewership after the abrupt firing of host Tucker Carlson, one of its biggest ratings draws, in late April. The network has yet to name a permanent replacement for its 8 p.m. ET primetime slot, opting in the meantime for a rotating cast of guest hosts for the hour. The timeslot has, according to Media Matters, seen viewership drop by half since Carlson departed, with viewership declining across its entire lineup as a whole.

The debate stage is prepared for the upcoming Democratic Presidential Debate hosted by MSNBC and The Washington Post at Tyler Perry Studios in Atlanta, Georgia, on November 19, 2019. Fox lost its rating winning streak to MSNBC after 120 weeks. Saul Loeb/AFP/Getty

The decline is also likely to have a negative impact on Fox News's ability to negotiate higher fees from cable providers, as it was hoping to do before firing Carlson.

The shift in ranking also comes amid a news cycle that, as Katz noted in a follow-up tweet, is more beneficial to MSNBC, which tends to see viewership increase when Trump's hardships escalate. Katz said that the networks have, however, been on "opposite ratings trajectories" owing to CNN bleeding viewers to MSNBC. He predicted that Fox will retake the crown this week, though by an ever-decreasing margin.

that time, Adweek reported that MSNBC had seen a surge in viewership over the course of that month, surpassing CNN in average daily viewers. However, while the month might have marked the last time Fox came second in weekly average viewers, the network still surpassed MSNBC in average monthly primetime viewership.

In its report, Adweek noted that the network's viewership in February 2021 was lifted by coverage of the second impeachment of Donald Trump, the ongoing COVID-19 pandemic, and the first weeks of Joe Biden's presidency. It also noted, conversely, that its February viewership was down from the prior month, which saw coverage of the January 6, 2021, Capital riots and their political aftermath.

The month also saw a surge in ratings at CNN, with the network occasionally besting Fox News. Fox itself also suffered in the wake of the firing of longtime host Lou Dobbs.

Newsweek reached out to MSNBC via email for comment.