Finishing the Build: Private Damages Class Action to Extend Competition Enforcement in Housebuilding Sector

The recent announcement of a proposed collective action for damages against housebuilders provides further evidence of a paradigm change in the competition law landscape in the United Kingdom ("UK"). This claim follows commitments accepted last year by the Competition and Markets Authority ("CMA") from certain householders. While public enforcement adapts to political calls for faster, 'growth-oriented' outcomes, shifting the associated risk calculus, private enforcement risk is increasing. Claimants stand ready to bring damages claims even without infringement decisions upon which to base "follow-on" actions. In this Legal Update, we set out key lessons to be learnt from this new potential claim and consider what this might mean for competition law enforcement in the UK going forward.

What happened?

This week, a consumer advocate has announced that in the coming weeks, he intends to file an opt‑out competition damages claim in the UK Competition Appeal Tribunal ("CAT") on behalf of UK homebuyers who purchased new‑build homes from major housebuilders. Although the exact parties involved and the amount of damages being claimed are not yet clear, the crux of this litigation is expected to be that the housebuilders allegedly exchanged competitively sensitive information in breach of competition law rules, and this led to inflated prices. The opt-out nature of the claim means that if certified, eligible homebuyers in the UK who bought new-build homes from the housebuilders during the relevant period will automatically be included unless they choose to opt out. The scale and public interest of the claim is therefore striking.

This development follows the CMA's acceptance of a commitments package in October 2025 from seven housebuilders, to close an investigation into anticompetitive behavior. This included a £100 million ex gratia payment to support affordable housing and compliance improvements to protect against the exchange of competitively sensitive information going forward. Crucially, the CMA's decision included no finding of an infringement of competition law due to the nature of commitment decisions.

Why does this matter?

The CMA's commitments-based resolution delivered swift, visible consumer benefits amid political pressure for speed and growth. The CMA's conclusions left the door open to private damages claims, but in the absence of a formal finding of infringement, the claimants must now bring standalone actions, requiring proof of breach and causation. While the CMA's commitments decision extends to nearly 50 pages, the claimants will need to rely upon a handful of pages setting out the nature of the allegedly problematic conduct. The practical utility of that to the claimants remains to be seen, although it will doubtless be the starting point in scoping any disclosure exercise. At the same time, claims need not be confined to the CMA's findings, potentially encompassing other housebuilders or behaviours, over a different time period etc.

The market context of this damages claim is especially significant given the value of the UK residential construction market (projected to be worth nearly £90 billion in 2025, with new-builds accounting for more than three-quarters of this) and the significant investment housing is for individual buyers. Furthermore, the construction market might be perceived as an environment in which information exchanges can have wide consumer impact and so potentially lends itself to collective redress.

The new claim underscores that competition commitments are now a target for private actions involving collective redress mechanisms, third-party funding, and specialist claimant firms actively pursuing damages. How successful this will be in the absence of an infringement finding is not yet clear: will the CAT be willing to find an infringement where the CMA was not? In any event, parties entering commitments in future will need to carefully weigh the pros and cons of such a course of conduct from a private litigation risk perspective.

The Evolving Antitrust Risk Picture for UK Businesses

News of this damages claim illustrates that private enforcement is becoming even more important as a complement and counterbalance to public enforcement in the current political climate. The UK Government's primary expectation is that the CMA will use its functions to drive economic growth and improve household prosperity, which might in some cases, steer the CMA away from a full investigation and infringement findings if behaviour change can be achieved more quickly for example via guidance or commitments. On the other hand, in terms of the private enforcement landscape:

• The CAT's collective actions regime (opt‑out) enables large‑scale consumer claims to mobilise quickly where market‑wide harm is alleged, particularly when bolstered by litigation funding. The recent UK Government consultation into the UK's opt-out competition damages regime closed in October 2025, with future proposals in 2026 expected to continue this trend; and
• The CMA's commitments, including sector‑wide guidance obligations, signal a compliance‑first emphasis, but companies should not view promises to comply as a litigation shield. 

Even as the transformed CMA pursues faster, outcome‑oriented resolutions, collective actions can test alleged anticompetitive conduct in court, particularly in sectors with identifiable consumer harm and indications of sensitive information exchanges. The result is a double layer of risk for businesses: reduced immediate fine exposure through commitments on the one hand, but increased exposure to standalone collective claims on the other.

Key Takeaways

• Private enforcement fills the gap: If the CMA continues to take action in sectors but not issue infringement decisions (e.g. by way of commitments, warning letters etc.), claimants may maintain the trend of increasing standalone opt‑out claims, backed by funding, to test alleged anticompetitive conduct.
• Commitments don't immunise: Remedies such as ex gratia payments and sector‑wide compliance obligations may resolve regulatory probes swiftly, but they do not remove exposure to collective damages claims.
• Prepare for litigation: Standalone collective claims will hinge on establishing infringement and harm. Defendants will need to be ready for rigorous scrutiny of pricing, incentives, sales and other financial data, as well as communication protocols and practices.