The bookmaker William Hill could be fined after it emerged that it submitted incorrect data to the Gambling Commission. The information forced the regulator to tear up its analysis of the impact Covid-19 has had on betting habits. Responding to concern that successive lockdowns could drive people to bet too much online, the Gambling Commission has published regular updates since March 2020 on how much customers of big firms such as William Hill are losing. But in an update published on 23 December, the regulator said it had discovered that William Hill provided “incorrect datapoints” for the 16 months between March 2020 and September 2021. As a result, the commission said it would have to re-analyse all its data and would not be able to publish correct information until February. The regulator’s statistical bulletins during Covid-19, which rely on submissions from firms with 80% of the UK market, are seen as a key resource for academics and health workers trying to assess how the pandemic affected gambling-related harm. The commission said it was now “reviewing any regulatory consequences of William Hill’s failure to submit accurate data”. The regulator’s powers allow it to suspend or revoke gambling operators’ licence, although in practice it does so only in extreme cases. However, it frequently reaches financial settlements with companies that transgress the terms of their licence to offer gambling services in Great Britain. The risk of a penalty comes as William Hill’s UK operation is in the process of a £2.2bn sale, after London-listed 888 Holdings bought it from the US casino operator Caesars Entertainment. William Hill’s data error means it is one of two major operators braced for the possibility of a financial penalty in early 2022, just as the government is putting the finishing touches to a review of how gambling is regulated, with proposals set to be announced in the spring. The Guardian revealed in November that the online casino SkyVegas, owned by Flutter, had sent “free spin” promotions to thousands of people trying to recover from gambling addiction. The Guardian has approached William Hill for comment.