What is Sister Banks?
Different bank brands owned by the same parent company. Key UK groups: Lloyds/Halifax/Bank of Scotland (Lloyds Banking Group), NatWest/Royal Bank of Scotland/Ulster Bank (NatWest Group), HSBC/First Direct (HSBC Group). Switching between sister banks usually doesn't qualify for a bonus.
Sister banks are separate brands run by one parent company. The big UK examples: Lloyds, Halifax and Bank of Scotland all belong to Lloyds Banking Group; NatWest, Royal Bank of Scotland and Ulster Bank to NatWest Group; and First Direct is HSBC's phone-and-app brand. Each sister keeps its own accounts, apps and marketing, which makes the family ties easy to miss.
The ties bite in switch bonus terms. Eligibility is normally assessed at group level, so a switch from one sister to another doesn't qualify, and having recently held an account with any sister can trigger the group's cooling-off exclusion for all of them.
Sisters can also share a banking licence, in which case FSCS protection — £120,000 per person per licence — is spread across every account held with those brands combined rather than applying to each brand separately.