A term used by APRA to classify larger, more complex financial institutions like major banks or large insurers. To be considered an SFI, the entity must be non-foreign, and its total assets must be larger than the designated limits depending on the institution type (e.g. $20 billion for ADIs/Banks (to be increased to $30 billion), $10 billion for general insurers and $3 billion for private health insurers). SFIs are subject to stricter regulatory rules, such as those under CPS511, because their failure could harm the wider economy.