CBS is considering ending its longstanding contract with TV ratings provider Nielsen as it looks for new ways to measure audiences in the multiplatform universe.

The nation’s most-watched TV network is prepared to drop Nielsen’s measurement services if the two sides can’t come to an agreement by the end of this month, according to a person familiar with the matter. CBS’ current contract with Nielsen – valued at more than $100 million a year — expires at year’s end, the source said.

CBS senior executives have informed CBS O&O stations and various other business units to prepare in case a deal with Nielsen cannot be reached, this person said. Chances of a breakdown are “not remote,” this person said. CBS is seeking “a competitive rate” from Nielsen given that there are more measurement alternatives available for a marketplace that has moved well past the linear TV ratings that Nielsen has delivered for decades.

A CBS spokesperson declined to comment. A Nielsen rep indicated that CBS’ threat to drop the service was posturing amid tough contract talks.

“We expect to arrive at a mutually beneficial agreement well in advance of Dec. 31,” a Nielsen spokesman said.

At issue is a long-running complaint from TV networks that Nielsen isn’t measuring the many different audiences for their programming as well as it should. As smartphones, mobile tablets and broadband-connected TV’s gain more consumer acceptance, audiences are increasingly able to stream their TV favorites in on-demand fashion, making the task of counting them exponentially more difficult. TV networks have long based their advertising rates on Nielsen’s measure of linear TV audiences, which have slipped as consumers embraced Netflix, Hulu, Amazon Prime and other streaming and on-demand options.

In this environment, TV networks believe Nielsen’s overnight ratings are no longer as reliable a barometer of viewership as they once were.

CBS has begun to invest more money in hiring other measurement services, such as Comscore, and even in its own proprietary capabilities. CBS recently unveiled an offering called “DNA” which “allows advertisers to buy specific audience segments, so our advertisers can target people who like to eat out and drive SUVs rather than just buy the broad demographic of adults between the ages of 25 and 54,” as Joseph Ianniello, CBS’ acting CEO, explained during a recent investor call. Nielsen is involved in that project, according to a person familiar with the matter.

“At the same time, we are also aggressively pursuing partnerships in set-top boxes and smart TVs to sell highly targeted, addressable ads. And we are using the data we collect from our direct relationship with the viewers on our OTT platforms to optimize our dynamic ad insertion capability. So as consumer habits change and technology advances, we’re finding new ways to monetize our audiences, and it’s becoming more valuable all the time,” Ianniello said during the Nov. 1 call.

In truth, CBS may be hard-pressed to abandon Nielsen entirely. The company has long been the standard of measurement in the media industry, and has worked in recent years to start measuring viewers who watch TV in new ways. Nielsen has also involved itself in new consumer-counting ventures, such as “Open A.P.,” a consortium made up of Fox Networks Group, Viacom. Turner, NBCUniversal and Univision that aims to help advertisers measure specific kinds of audiences, such as first-time car buyers or early adopters of technology. ESPN has worked with Nielsen to count viewers who watch its sporting events in bars and hotels – places that have previously been hard to quantify.

Many industry executives, however, continue to have serious issues with Nielsen as they see ad dollars dwindle and audiences migrate to less measurement-friendly platforms. CBS would not be the first media company to loosen its ties to Nielsen. In 2015, NBCU’s CNBC stopped using Nielsen to measure its daytime programming, driven by the theory that a good chunk of its audience watches from offices and trading floors rather than on living room TV sets that still comprise the bulk of Nielsen’s sample. CNBC has cut deals with advertisers using data from Cogent, a marketing research firm that surveyed 1,000 investors and financial advisers on their media habits.

The CBS-Nielsen contract showdown comes after Nielsen recently installed a new CEO. David Kenny is a veteran of the advertising world and a co-founder of Digitas, the digital-advertising company that was sold to France’s Publicis Groupe. Since that time, Kenny has logged stints as chairman and CEO of Weather Company, one-time owner of cable’s Weather Channel. He had most recently worked in a senior role at IBM.

One person close to the negotiations portrayed the talks as ongoing. “There have never been any issues with CBS,” this person said. “They’ve always been progressive-minded measurement partners that have helped to develop important industry innovations that are used across the market today.”

Even so, the once-unthinkable prospect of CBS ending its Nielsen relationship can’t be welcome news for Kenny. If the two sides can’t reach a deal, CBS’ stance could embolden other media giants to put more pressure on Nielsen.