A settlement layer has a different job from a commercial bank. Its purpose is to move value reliably between institutions, not to lend, take risk or earn a spread on maturity transformation. That difference in purpose points towards a narrow-bank design: a balance sheet that does not lend, holds reliable short-term assets and focuses on settlement rather than credit. For a layer that others depend on, that restraint is a feature.

What a narrow bank does

A narrow-bank model keeps the institution's function close to settlement and payment. Rather than running a loan book, it holds high-quality, short-term assets and central-bank reserves where available, so the funds backing settlement are not exposed to credit or duration risk. The model is narrower and, for a settlement role, safer: there is less to go wrong and less to unwind.

Why it suits a hub

A hub concentrates flows from many participants. If that layer also took credit risk, its failures would propagate directly into the institutions depending on it. A non-lending balance sheet removes the most dangerous transmission channel. The hub's job is validation, netting, routing and settlement — activities that demand reliability, not leverage.

The phased route

This is a destination, not a starting point. SUPA is not yet a bank; before a banking licence it does not take deposits or hold client money in its own name, and balances sit with licensed partners. Only in a later phase does the network hold its own banking licence, at which point the narrow-bank shape becomes the natural form of the hub. ClearBank is a useful reference point for the narrow-bank model in practice.

What to watch

The design must be matched by operational and liquidity resilience — a settlement layer that becomes systemically relevant must be able to withstand stress, not merely avoid credit risk.

In short

  • A settlement layer's job differs from a lending bank's.
  • A narrow bank avoids credit and duration risk on the assets backing settlement.
  • Non-lending balance sheets stop failures propagating into participants.
  • The banking licence arrives in a later phase; today balances sit with licensed partners.
  • Reliability must be paired with real operational resilience.

See how the layers are designed at /protocol/.