DMCC Act Ecommerce Rules: What CMA Fines Mean for UK Shopify Checkouts

The DMCC Act ecommerce rules stopped being theoretical in 2026. Since April, the Competition and Markets Authority has issued three fines under its new direct enforcement powers, including £720,000 against online electricals retailer Marks Electrical for pre-ticked add-ons at checkout. On 10 August, the government also brought the new subscription contract rules forward to January 2027.

For UK Shopify merchants, the message is clear. Checkout design, fee display and subscription flows are now enforcement priorities, and the CMA can fine without going to court first.

This guide explains what the Digital Markets, Competition and Consumers Act 2024 changed, what the 2026 cases reveal, and the checkout audit every UK store should run before peak trading.

What changed under the DMCC Act?

The consumer protection parts of the DMCC Act took effect in April 2025. The biggest shift is that the CMA can now decide that consumer law has been broken and impose penalties itself. According to Jones Day, fines can reach 10% of global turnover, plus up to £300,000 for directors or senior managers directly involved.

The CMA moved quickly. On 18 November 2025 it opened eight enforcement cases and sent around 100 advisory letters to businesses in 14 sectors, as TLT reported. Fashion and homeware retail were on the list, and three of the eight cases involved online homeware and appliance retailers: Wayfair, Appliances Direct and Marks Electrical.

What do the 2026 fines tell online retailers?

Three penalties have been issued so far, and each targets a practice that can easily appear in an ecommerce checkout.

Drip pricing

Drip pricing means showing a base price and adding unavoidable fees later in checkout. Under the DMCC Act it is one of the practices that are always unfair, whatever their effect. In the AA and BSM case, the original penalty was £7m before a 40% discount for settling early. HSF Kramer notes that the CMA opened three more drip pricing investigations on 19 August 2026, into Trainline, Virgin Atlantic and RED Driving School, and published price transparency guidance (CMA209) on 13 February 2026.

Pre-ticked add-ons

The Marks Electrical case is the closest to a typical online shop. According to TLT, customers buying appliances were automatically opted into paid recycling and packaging removal services through pre-ticked boxes. The lesson is simple: silence is not consent, and paid extras must be actively chosen.

Settlement matters

In both the AA and StubHub cases, early settlement cut penalties by 40%, TLT's StubHub analysis explains. It also notes that the CMA had published guidance before the infringements, which counted against the businesses.

What about reference prices and fake reviews?

Fake and misleading reviews are among the infringements the CMA has been able to pursue under its new powers since April 2025, according to the Jones Day analysis above. Pricing claims look like the next focus. On 9 August 2026, the government announced a consultation, expected to launch this autumn, on adding fake "was" prices, invented discounts and misleading RRPs to the list of practices that are always unfair. If adopted, that would directly affect sale pricing and compare-at prices in Shopify.

When do the new subscription rules start?

The subscription contracts regime is now expected to start in January 2027. TLT reports that the Prime Minister brought it forward from spring 2027 on 10 August 2026. Stephenson Harwood confirms the new timing, and that the substantive requirements have not changed. Secondary legislation and guidance are still outstanding.

For Shopify stores selling subscriptions, replenishment or memberships, the key requirements are:

• Key information up front, separate from full terms, with an express acknowledgement of the payment obligation at sign-up.
• Reminder notices, generally once every six months, plus extra notices for free or discounted trials and 12-month renewals.
• A new 14-day cooling-off period after relevant renewals, on top of the initial one.
• Easy exit. Customers who sign up online must be able to cancel online.

Where do Shopify stores typically go wrong?

Most UK Shopify stores are not deliberately hiding costs. Problems usually creep in through apps and settings added over time. Common risk areas include:

• Mandatory service or handling fees added at checkout through an app or a custom line item, rather than included in the product price.
• Upsell and protection apps that pre-select shipping insurance, extended warranties or carbon offsets.
• Bundled "free" gifts or donations that turn into a charge unless the customer removes them.
• Compare-at prices set once and never reviewed, so the "was" price no longer reflects a genuine previous price.
• Subscribe-and-save widgets that default to a subscription rather than a one-off purchase.

Each of these is easy to check, and most can be fixed in an afternoon.

How should UK Shopify stores audit their checkout?

Every store

1. Show all mandatory charges in the headline price. Any fee customers cannot avoid belongs in the price they see first. Check the CMA209 guidance on mandatory versus optional charges, including how delivery is shown.
2. Remove pre-ticked add-ons. Check checkout extensions, product page widgets and apps for protection plans, gift wrap, priority handling or donations that default to "on".
3. Review urgency tools. Countdown timers must reflect real deadlines, and "only 2 left" messages must be accurate.
4. Check reviews. Make sure your review app collects genuine reviews and does not hide negative ones.

Stores with sales and promotions

1. Document how every "was" price and compare-at price was set.
2. Avoid permanent or rolling "sales" that never end.
3. Watch for the government consultation on reference pricing this autumn.

Stores with subscriptions

1. Map your subscription app's sign-up, reminder and cancellation flows against the January 2027 rules.
2. Ask your app provider for its compliance roadmap and timeline.
3. Prepare templates for reminder and cooling-off notices now, so you are not rushing once guidance is final.

Because this is a legal area, it is sensible to have your final checkout and subscription flows reviewed by a consumer law adviser.

Conclusion

The CMA's first three DMCC fines all involve checkout practices that are common online: hidden mandatory fees and pre-ticked extras. With more investigations open, pricing claims under review and subscription rules arriving in January 2027, UK Shopify merchants should treat checkout compliance as an urgent job, not a future one.

The good news is that most fixes are configuration and design changes, and clearer pricing usually builds trust. If you need help auditing and rebuilding checkout, product page or subscription flows, ONEXT's Shopify development team can work with you as a trusted delivery partner.