As FTVLive first reported back in February, ratings company Nielsen is about to lose a very big client and it will have a big impact on their bottom line. 

Sinclair has sent a letter to their clients saying that they are going to dump Nielsen and mover over to comScore for their ratings. 

Fierce Cable writes that Sinclair has made no secret of its contempt for Nielsen, so a move away from the metrics firm would make sense.

Mark Aitken, vice president of advanced technology for Sinclair Broadcast Group, said that a big financial upside to deploying the ATSC 3.0 next-generation TV standard is the potential for collecting and analyzing viewership data.

“If we weren’t stuck with Nielsen and their reading of the tea leaves, we’d have tens of millions of extra dollars in our pocket,” Aitken told FierceBroadcasting, adding that the situation between broadcasters and Nielsen has been lopsided for a long time. He added that Nielsen’s numbers are “imprecise.”

Aitken said that Sinclair also used Rentrak, which he said in many ways offers a richer set of data. In 2015, comScore merged with Rentrak in an effort to bulk up for the fight against Nielsen for the audience measurement market.

Update: Nielsen released this statement to FTVLive:

“Our corporate policy prohibits us from discussing any client contracts or any ongoing negotiations. Sinclair is a longstanding and valued client, and we look forward to releasing our enhanced local measurement solution which will deliver best in class measurement and quality that all of our clients expect and rely on.”