Definitions
In plain terms
Squaring gives larger shares more influence, so the value rises as the distribution becomes more concentrated.
Technical
For normalized fractional shares, compute sum(s_i^2); record whether shares use fractions or percentages before interpreting the scale.
Scope
Its antitrust thresholds must not be transferred automatically to financial index concentration.
Formula
HHI = sum(s_i^2)HHI=\sum_i s_i^2| Symbol | Meaning | Unit |
|---|---|---|
s_i | normalized nonnegative share of member i | ratio |
Output unit: squared-share index
Examples
- A Fintech Builder lesson can compute or identify Herfindahl-Hirschman Index only after declaring its inputs, timing, and edge-case rules.
Common misconceptions
- Its antitrust thresholds must not be transferred automatically to financial index concentration.
Concept relationships
Where this concept is used
Evidence and governance
- Herfindahl-Hirschman Index U.S. Department of Justice · official standard
Supports: preferred label, short definition, technical definition, formula
Limits: Antitrust concentration thresholds do not automatically apply to index-constituent concentration; this glossary reuses only the mathematics.
- Reviewed by
- fintech-builder-batch-005
- Last reviewed
- 2026-07-27
- Next review
- 2027-07-27
- Record status
- evidence reviewed
This record is evidence-reviewed and readable, but not yet promoted to published — it is served noindex,follow and excluded from the sitemap.