The Gambling Commission (GC) has refrained from providing an estimate for the gross gambling yield (GGY) of the UK’s illegal gambling market, urging “caution” over other estimates by third parties.

The GC released its final report in a four-part series concerning the UK’s black market, entitled: “Illegal online gambling: Challenges of estimating the size of the illegal gambling market”.

Within the report, the GC evaluated the current methods used by third parties to estimate the size of the black market. 

The report highlighted the merits of the ‘dwell time’ approach, which converts data on engagement and ‘time-spent-on-site’ into expenditure estimates. 

The channelisation approach, which compares data on legal and illegal sources of engagement with gambling, and the survey-based approach, which relies on players providing details on their experiences through surveys collected, were also evaluated.

Although both the dwell time and channelisation approaches were deemed useful for the data-backed methodology, the report concluded that both methods relied too heavily on “multiple assumptions which, when combined, introduce significant margins for error”.

While the survey-based approach was lauded for being a cost-effective method of data collection, the GC noted that customer recall with regards to gambling expenditure can be “unreliable”.

Urge caution

The regulator concluded that “having examined different methodologies, we are not yet in a position to make a robust and reliable estimate of the size of this market”.

On outside attempts at calculating black market size, the GC said: “We recognise that several third parties have published estimates [on the size of the black market]. Whilst we welcome the focus on this issue, and recognise the concern stakeholders have about illegal gambling, we urge caution over use of estimates where the methodologies are not clear and levels of uncertainty are not set out. 

“Having examined different methodologies, we are not yet in a position to make a robust and reliable estimate of the size of this market. We have identified actions to be taken to address these limitations – creating a pathway towards developing an estimate of the size of this market which is fit for public use.

“We urge caution over any estimates presented by third parties or commentators which don’t have a transparent methodology, or which do not show how the challenges in this report have been considered, or that provide precise ‘point estimates’ without clarity of the associated margins for error and caveats.”

The GC went on to set out how it will work to provide more accurate estimates going forward. 

The statement continued: “Whilst we work to further improve our estimates, we will continue to collect data on illegal sites to prioritise our operational work to disrupt illegal websites, continue monitoring trends which help us to understand if market is growing, reducing, remaining stable, or experiencing seasonal fluctuations, use data to estimate the impact of disruption of illegal websites.  

“We will encourage others with data to come forward and help refine and improve assumptions, and further explore other areas of the illegal gambling market – such as gambling within social media Apps and land-based gambling.”

A Frontier Economics report, commissioned by the Betting and Gaming Council and released in September 2024, estimated that £4.3bn was staked on the UK black market each year, of which £2.7bn was online.

Research released by analyst firm Eilers & Krejcik Gaming in November 2024 estimated the black market to be worth £1.5bn.

While the GC report conceded that an estimate was currently out of reach, it was described as a “realistic goal” to work towards.

The report marked the fourth and final chapter of the GC’s research findings. The first covered consumer awareness and motivations,  the second explored engagement and trends, while the third report highlighted methods for disrupting the illegal market.

The second report found no evidence of persistent growth in the use of illegal sites, despite finding more than 1,000 to choose from over the research period of May 2024 to July 2025.

The post GC “not yet in a position” to accurately estimate size of the UK black market first appeared on EGR Intel.