Definitions
In plain terms
An existing member might remain unless it falls below a lower cutoff, while a new candidate must cross a higher entry threshold.
Technical
The rule requires ranking metric, entry and exit boundaries, tie handling, target size, capacity, review dates, point-in-time data, and deterministic conflict resolution.
Scope
A buffer limits turnover but does not eliminate methodology-driven changes or guarantee better performance.
Examples
- A governed index record identifies buffer rule with its applicable methodology version, effective time, source, and units.
Common misconceptions
- Buffer Rule does not have one universal implementation without the named index methodology, data cutoff, and governance context.
Concept relationships
Prerequisites
Where this concept is used
Evidence and governance
- FTSE Russell Index Policy and Methodology Library FTSE Russell, London Stock Exchange Group · first party methodology
Supports: preferred label, short definition, technical definition
Limits: The library links multiple documents with separate versions and applicability; the effective document must be identified.
- Fintech Builder Glossary Definition Contract The Fintech Builder · internal governed contract
Supports: variant distinction
Limits: Defines governed platform behavior rather than claiming these policies are universally prescribed by external McClellan methodology.
- Reviewed by
- fintech-builder-owner-approved
- Last reviewed
- 2026-07-27
- Next review
- 2027-07-27
- Record status
- published