FINMA Supervisory Notice 01/2026 of 12 January 2026 organises the custody of crypto-based assets into three models and sends one of them definitively onto the balance sheet. The dividing line runs along the bank’s operational capacity to identify each client entitlement individually at any time. Internal accounting does not substitute for that allocation. Where it is absent, the institution loses segregability under Art. 16 para. 1bis BankG in conjunction with Art. 37d BankG and Art. 242a SchKG; off-balance-sheet treatment falls away with it — and, along with it, the exemption from full capital backing that applies only to segregable positions.

FINMA distinguishes three custody arrangements: individual custody per client; collective custody with client entitlements identifiable at any time and subject to an availability obligation; and pooled custody without clear allocation. The choice of model carries direct licensing consequences: collective custody with clearly booked client entitlements requires a FinTech authorisation (Art. 1b BankG); pooled custody without clear allocation constitutes acceptance of deposits from the public and triggers a full banking licence (Art. 1a/1b BankG in conjunction with Art. 5/5a BankV). Only the first two models survive the segregation test. The third — historically maintained through internal client accounts and balance-sheet booking — falls into the custodian’s insolvency estate. This is not a new rule; it has been in statute since the DLT omnibus legislation of 2021. What FINMA has now specified is where the allocation must be demonstrable: the Notice requires that client entitlements be identifiable at any time. Which means of proof suffice for that purpose will be settled by the audit cycle.

Where assets are not segregable, they enter the supervised institution’s balance sheet as claims against the custodian, subject to the standard capital backing. Off-balance-sheet treatment and the narrow operational-risk capital under Art. 4sexies BankG are reserved for demonstrably allocated assets. An internal ledger does not carry that proof; in the event of insolvency, the insolvency administrator would be expected to examine the on-chain record.

For foreign sub-custodians, the test doubles. The custodian must be prudentially supervised, and the insolvency regime of its jurisdiction must guarantee equivalent segregation. FINMA indicates that MiCA-regulated EU custodians are plausibly equivalent — without issuing a blanket certificate. Each Swiss institution bears the equivalence assessment for each individual custodian. Portfolio managers (Art. 24 FinIO) are subject to equivalent requirements; non-compliant existing arrangements may be maintained provisionally under documented client consent and full risk disclosure.

The legal position, the burden of proof, and the capital consequence are established. What remains open is the treatment of hybrid constructs: BIP-32 derivation from a master key, MPC schemes with pooled key shares where the allocation is cryptographically demonstrable but not implemented through separate wallet accounts. That question is likely to be resolved by the 2026 audit cycle: only the external audit reports on the 2026 annual accounts will show where FINMA accepts cryptographic allocation as segregation — and where it does not.