The 24-hour trap: Why the UK’s new crypto rules could catch some firms off guard

The U.K.’s Financial Conduct Authority (FCA) is proposing crypto rules that could quietly expand the definition of custody, potentially sweeping in platforms and software providers that don’t consider themselves custodians.

The FCA published its Cryptoasset Perimeter Guidance on Wednesday, which includes a few technical traps for firms handling clients' crypto assets.

The rules draw a red line at the 24-hour mark for custody. Any firm or crypto platform or app holding client assets for longer than a day during trade settlement will likely fall under the regulated custodian classification, which triggers a requirement for a full safeguarding-license.

Validators and node operators also need to proceed with caution. The regulator warned those involved in those activities will lose their pure tech exemption the moment they provide “added value” features. That includes things like user dashboards, yields or reward-compounding tools. In those cases, they must seek full approval for arranging staking.

“Our new perimeter gives us the tools to strengthen protections for consumers and support fair, transparent and orderly markets as the sector matures,” the FCA stated in the paper.

Also noteworthy is that for the first time, the FC has addressed the “shadow custody” issue. The financial watchdog made it clear that if a crypto service provider allows it to theoretically override a client’s authority, it is officially a custodian even if it guarantees it will never exert that power.

“The fact that an arrangement involves smart contracts, public blockchains or some elements of decentralisation does not determine the perimeter position or place the arrangement outside of regulation,” the document noted.

For stablecoin issuers, the mandate is equally blunt as it considers issuance legal only if the issuer is established in the United Kingdom and manages the entire lifecycle. That includes everything from the initial offering to redemption and reserve maintenance.

The FCA requested views on these proposals until the consultation closes on June 3, 2026, it said in a separate statement Wednesday. The regulator intends to publish finalized rules in policy statements this summer, followed by the final perimeter guidance in September.

The roadmap forces all entities providing crypto services to transition from the current money-laundering registrations systems to a more strict approval regime under the U.K.’s Financial Services and Markets Act (FSMA).

Firms intending to continue in business under the new regulations face a five-month application window from Sept. 30 of this year to Feb. 28, 2027. Missing this deadline exposes them to potential fines and suspensions as well as permanent closures.

Only those who apply during the application period will benefit from the so-called “savings provisions” that allow them to keep operating while the regulator deliberates.