Nielsen Holdings filed a lawsuit Friday seeking to block rival ComScore from offering a new service, Extended TV, that will provide TV audience data.

Nielsen alleges that the ComScore service will make use of Nielsen’s own People Meter data, violating an agreement between the two companies. Nielsen is seeking an injunction that would bar ComScore from launching the service.

The litigation marks an escalation of the bitter rivalry between the two audience measurement firms.

The groundwork for the dispute was laid back in 2013, when Nielsen acquired Arbitron. In order to preserve competition in the audience measurement business, the Federal Trade Commission approved a consent agreement requiring Nielsen to license People Meter data to ComScore, for the purpose of creating a “cross-platform” measurement service. Such a service would have to measure both TV and online viewership, Nielsen contends.

Nielsen alleges that ComScore’s new service, called Extended TV, violates that agreement. On a February investor call, ComScore CEO Gian Fulgoni said the new service provides “a TV-centric view of the world,” and contrasted it with its existing cross-platform service.

“In almost all circumstances. Extended TV will provide a linear television audience measurement with requisite demographics for broadcast daypart/program, but will fail to provide any material online audience measurement (instead reporting an online measurement of “zero” for almost all dayparts, programs, and episodes),” Nielsen alleges.

Nielsen objected to ComScore executives, arguing that ComScore is improperly using Nielsen’s own People Meter data to compete with it.

In an Aug. 8 letter, ComScore’s attorneys countered that Extended TV meets the definition of a “cross-platform service.”

“Extended TV is not limited to linear TV estimates as it measures content across multiple platforms, including but not limited to television, online, mobile, tablets, etc.,” the letter states.

Nielsen alleges that ComScore is seeking to offer Extended TV at a lower price than Nielsen’s service, thereby cutting into Nielsen’s client base. Nielsen’s attorneys claim that TV networks are already beta-testing Extended TV, and that one client has already announced its intention to switch to Extended TV.

“Given that comScore plans to launch Extended TV in the next few months, with the intention of having the product available at the end of 2017, it is possible that Nielsen will lose other clients, particularly given that Nielsen has several large client contracts up for renewal,” Nielsen states.

Nielsen filed for arbitration on Friday to resolve the dispute, while also seeking an injunction in New York federal court to block ComScore from releasing Extended TV.

In a statement, a ComScore spokesperson says, “We can confirm that there is a dispute regarding interpretation of the 2013 FTC consent decree, which resulted from Nielsen’s acquisition of Arbitron, that provides comScore with access to certain Nielsen data. The dispute is being addressed through binding arbitration. Due to the pending nature of these legal proceedings, we have no further comment at this time.”

Nielsen Comscore Suit by gmaddaus on Scribd