The advertiser-funded ISBA Programmatic Supply Chain Transparency Study carried out by PwC, found that a lack of organisation and understanding in the supply chain has led to an "unknown delta" of adspend which could not be attributed.

As a result, publishers only receive 51% of advertising spend leaving a "big hole in the supply chain" with one third of adtech costs unattributed.

The study, carried out by PwC, collected data from 15 advertisers, eight agencies, five Demand Side Platforms (DSPs), six Supply Side Platforms SSPs) and 12 publishers for the study, representing approximately £0.1 billion of UK programmatic media spend.

PwC said there was a lack or organisation and understanding among ad tech suppliers in the supply chain around sharing data storage, and uniformity, particularly between SSPs and DSPs.

In response, ISBA has called for an immediate investigation into the "unknown delta", which will require industry collaboration and for standardisation across "a range" of contractual and technological areas.

Phil Smith, Director General of ISBA, said: “The publication of this study marks an important moment in our understanding of online advertising supply chains. It is the first time anywhere in the world that an attempt has been made to map a system which is not capable of being audited.

“This process has been led by our members, advertisers who proactively sought to understand a problem and find a way forward. The challenge now is for industry to come together, as they will in the new taskforce, to drive industry standards and create transparent supply chains, to allow companies and consumers to benefit properly from online advertising.”

Toby Bicknell, Commercial Product Director at TI Media commented: "This report really highlights the need for the programmatic market to mature. The key recommendation in standardising contracts and technology to facilitate data sharing is fundamental in enabling and driving a transparent supply chain. The sheer amount of challenges that were faced before a single piece of data could be analysed really highlights just how far we still have to go, especially when you consider the study represented some of the highest profiled advertisers, publishers, agencies and adtech businesses.

"Looking forward no one part of the chain can evolve without the other and I look forward to building on this to address some of those key recommendations."