G-SIB
From ACT Wiki
Global systemically important bank.
A G-SIB is a large bank whose potential failure would have widespread negative effects in the broader financial system.
For this reason, these banks are subject to more stringent regulation and capital adequacy requirements than other institutions.
As at November 2015, UK-headquartered G-SIBs included HSBC, Barclays, RBS and Standard Chartered Bank.