Globally operating Systemically Important Financial Institution.
(Often written as 'Global systemically important financial institution'.)
Sometimes known as a Global SIFI.
A G-SIFI is a large institution whose potential failure would have widespread negative effects in the broader financial system.
For this reason, these institutions are subject to more stringent regulation and capital adequacy requirements than others.
Regulators in the FSB then identified similarly important non-bank institutions, for example insurance companies or large investors.