FTB-C000001 / Financial concept

Market Breadth

Market breadth describes how widely a market movement is shared across its eligible securities.

Also known asmarket participation breadth

Foundation 9 linked topicsPublished

Definitions

In plain terms

Instead of looking only at whether a headline index rose or fell, market breadth asks how many securities participated and how strongly activity was distributed across them.

Technical

Market breadth is a family of cross-sectional measures derived from a declared security universe, such as advancing-minus-declining issue counts or up-minus-down allocated volume.

Scope

This concept covers participation measures and not a claim that breadth predicts prices, causes returns, or supplies a universal trading signal.

Examples

  • A rising index accompanied by many more advances than declines has broad issue participation.

Common misconceptions

  • Market breadth is not the same thing as the return of a capitalization-weighted index.

Concept relationships

Narrower concepts

Related

Required by

Where this concept is used

Tutorials planned

These catalogued topics use this concept, but their complete build has not shipped yet.

  • D04-F01-A01 Prerequisite
  • D04-F01-A02 Prerequisite
  • D04-F01-A03 Prerequisite
  • D04-F01-A04 Prerequisite
  • D04-F01-A05 Prerequisite
  • D04-F02-A01 Prerequisite

Evidence and governance

  1. A-D definition Nasdaq, Inc. · official exchange

    Supports: preferred label, short definition, technical definition

    Limits: Does not prescribe universe membership, revision handling, volume allocation, EMA initialization, or software behavior.

  2. Daily Market Summary Data Fields and Definitions Nasdaq, Inc. · official exchange

    Supports: technical definition, variant distinction

    Limits: Does not define the pilot's exhaustive partition, causal cutoff, revision lineage, EMA policy, or normalized breadth formula.

Reviewed by
Last reviewed
2026-07-26
Next review
2027-07-26
Record status
published
Written by

Fintech engineer building market-data and financial systems, and the author of every article, glossary record, and reference implementation on The Fintech Builder.