One in 20 digital ad impressions sold as CTV are in fact lower value non-CTV inventory according to new 51Degrees research
New analysis of more than 11 million ad impressions has revealed that nearly 5% of inventory sold as CTV is incorrectly labelled, artificially inflating the value of lower priced digital ad space. Whether through fraud or accident, the findings mean that advertisers are overpaying for CTV inventory by nearly $2bn globally (Emarketer).
The research from precision data and technology business 51Degrees looked at 11.03 million OpenRTB ad impressions with a relevant device type ad signal between 15th-20th May 2026 and found that 4.92% of those that were labelled with the CTV signal were in fact lower value, non-CTV inventory. By comparison, just 0.18% of traffic with an Ad Signal present was CTV inventory wrongly labelled as not CTV.
The research used 51Degrees’ fast, accurate and efficient Device Detection capabilities to provide an independent classification of the device being used to consume the advertising impression and compared this with its OpenRTB specification label to verify its accuracy.
With CTV inventory commanding a significantly higher CPM than standard video, the mislabelling is inflating prices for advertisers whilst giving publishers who are misrepresenting their inventory a significant and revenue uplift.
James Rosewell, CEO of 51Degrees, said: “What is CTV? That is the question. 51Degrees believe it is a connected TV with an emphasis on the ‘TV’. Any device that is not a TV is not CTV. Advertisers are paying extra for the attention that content receives when its consumed on a TV, not on a phone or a laptop. Any advertiser or their agent that agrees are effectively overpaying for their CTV impressions by up to 5% based on the fact that they’re unknowingly buying a lot of lesser value inventory in their media buys.
“It would be helpful for the industry in definitions were tightened up so supply and demand side use a common vocabulary. Whether you’re a publisher, SSP or DSP its a simple matter to use Device Detection to accurately and cost-effectively identify the device on which advertising is being consumed, and with $2 billion on the table that investment will be more than justified.”
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