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Cracking cartels: Implications of the CMA’s latest boom in whistleblowing and leniency
Cracking cartels: Implications of the CMA’s latest boom in whistleblowing and leniency
8 October 2026
Series
Blogs
8 October 2026
The CMA has recorded a sharp rise in whistleblowing for suspected cartel conduct for 2025-2026, compared with all previous years on record. Its recent statistics show 48 whistleblowing disclosures in 2025-26 - a 50% increase on 2024-25, which in turn was 88% up on 2023-24 – and a striking reversal of the 70% fall in cartel whistleblowing reported between 2017 and 2022.
This rise coincides with a push in the UK to encourage reporting of anticompetitive collusion - illustrated mostly recently by CMA guidance (released 2 October 2026) clarifying (i) how to make a whistleblowing report, and (ii) how to report a cartel - but also its updated 2025 leniency guidance and the UK government’s proposal to provide Type A (first-in) leniency applicants with full immunity from private damages claims.
This article looks at the impact of these developments for cartel detection and enforcement going forward - and what it means for businesses.
Whistleblowing is central to cartel detection, given the difficulty in uncovering evidence (as cartels are generally conducted in secret). Whistleblower evidence can underpin an investigation, without requiring a leniency application from the cartelists. Since raising the financial reward for whistleblowing from £100,000 to £250,000 in 2023, the CMA has increasingly encouraged reporting, including through its "Cheating or Competing?" public awareness campaign.
There has been a global push to incentivise whistleblowing, including the US DOJ’s revamp of a Whistleblower Rewards Program (July 2025), in partnership with the US Postal Service, which now offers whistleblowers a presumptive 15-30% share of a resulting criminal fine (for fines of at least $1 million). The DOJ’s first reward under the program in January 2026 paid $1 million for a whistleblower tip that led to a $3.28 million bid-rigging fine. This early success has prompted calls for higher financial incentives in the UK too. Elsewhere in Europe, Italy’s whistleblowing platform has proved increasingly effective, with over 200 reports in 2024, while the European Commission’s whistleblower tool reportedly received around 500 tips in 2025.
Leniency applications are another key plank in cartel detection, incentivising cartelists to self-report in exchange for immunity or a reduction in the fine. Since the issue of its previous leniency guidance over 12 years ago, the CMA has received nearly 250 applications, resulting in over £355 million in fines and 24 director disqualifications. Successful UK applicants also gain immunity from director disqualification and criminal prosecution, provided they cooperate effectively.
But the CMA (like other authorities – including in Spain, Portugal, Brazil and Korea) is also focusing on diversifying its detection tools beyond conventional reporting methods. It has dedicated in-house technology, data science and AI capability to scan markets for signs of collusion - including algorithmic collusion. The CMA has also called for the UK government to deploy the CMA’s “cutting-edge” Bid Rigging Intelligence Tool to public procurement data, which would “bring the UK in line with international counterparts”.
The CMA made two significant revisions to its leniency guidance in October 2025:
The CMA (like other regulators) has seen leniency applications stall in recent years. Type A applications to the CMA decreased from an average of 21 per year between 2014-2016 to only eight per year between 2022-2024. The risk of private enforcement (driven by the introduction and rapid growth of the UK’s opt-out collective actions regime) is likely, at least in part, to explain this trend.
The CMA’s revised guidance aims to strengthen the incentive for leniency applications prior to an investigation being opened - even while internal fact-finding is ongoing, and before a company is ready to admit an infringement. Additionally, the UK Government is consulting on a proposal (supported by the CMA) to provide Type A applicants with full immunity from private litigation in the UK.
Given that CMA antitrust investigations take 37 months on average to conclude, it is too early to say whether its recent efforts will translate into increased cartel investigations and enforcement action.
Some commentators remain concerned that higher financial incentives could encourage exaggerated or unreliable whistleblowing (a factor which both authorities and businesses should bear in mind when assessing the credibility of information submitted by whistleblowers).
Nevertheless, the CMA had only five ongoing competition enforcement investigations as of 31 March 2026. And although there has been a global increase in antitrust enforcement post-Covid, OECD data across more than 65 jurisdictions show cartel investigations still fell by around a third between 2015-2024, with the EC opening only six cartel investigations between 2020-2024.
The CMA is also increasing its use of warning and advisory letters (in place of a full investigation) to flag concerns and prompt self-assessment, with potential binding commitments on future conduct (in place of a formal decision) – though perhaps less likely in cases involving the most egregious forms of cartels, such as price-fixing.
Looking ahead, the CMA is likely to prioritise cartel enforcement in sectors with the greatest impact on public spending (e.g. bid-rigging in public procurement), where anticompetitive conduct is most likely to inhibit economic growth or where it directly harms consumers facing cost-of-living pressures, as well as potentially novel forms of anticompetitive conduct - such as algorithmic/AI-based collusion between competitors.
The consequences of anticompetitive collusion remain severe and increasingly varied. Beyond fines (of up to 10% of worldwide turnover), individuals can face up to five years' imprisonment and director disqualification for up to 15 years. Businesses also face growing exposure to follow-on damages claims and debarment from public procurement contracts.
Increased incentives for whistleblowing and leniency mean businesses need a more pro-active strategy for detecting potential anticompetitive conduct in-house, so they can weigh their options before a rival or the authority uncovers a cartel first. This should include robust internal reporting channels, competition law training for staff in commercially sensitive roles, and prompt escalation to legal advisers to preserve the option of leniency or immunity.
Litigation, Arbitration & Investigations Partner, London
United Kingdom
Litigation, Arbitration & Investigations Partner, London
United Kingdom
Litigation, Arbitration & Investigations Senior Counsel, London
United Kingdom
Partner and Head of UK Antitrust and Foreign Investment Group, London
United Kingdom
Antitrust & Foreign Investment Partner, London
United Kingdom
Antitrust & Foreign Investment Partner, London
United Kingdom
Antitrust & Foreign Investment Partner, UK Technology Sector Leader, and Games and Interactive Entertainment Sector Leader, London
United Kingdom
Antitrust & Foreign Investment Partner, London / Dublin
United Kingdom