Global systemically important institutions (G-SIIs) and, subject to national discretion, other systemically important institutions (O-SIIs) must fulfil supplementary requirements concerning the amount of Common Equity Tier 1 capital they must hold as a buffer. These buffers aim to address the potential negative effects that these institutions may have on the international or domestic financial system.
The Capital Requirements Directive sets out “accumulation” rules for combining buffers for systemically important institutions with the systemic risk buffer. The European Banking Authority has drafted technical standards and guidelines for identifying G-SIIs and O-SIIs.