Retail Online & Mobile Banking — impact tolerance ≤ 4 hours — ITOL

Impact tolerance: ≤ 4 hours — during peak hours (7am–10pm local) with > 25% of active-session users affected (illustrative default — trace the derivation, then replace with your own harm analysis)

Definition: Digital channels for retail customers to view balances, transaction history, transfer funds, and manage account settings.

Why it is designated: This is the bank's primary customer-service channel. The UK Prudential Regulation Authority (PRA) uses balance visibility as the canonical important business service (IBS) in its challenger-bank example (SS1/21). Extended outages drive complaint spikes, deposit outflow risk, and regulatory attention.