FTB-C000253 / Indicator

Arms Index

Arms Index compares the advance-decline issue ratio with the upside-downside volume ratio.

Also known asTRINTrading Index

Advanced Formula defined 1 linked topicPublished

Definitions

In plain terms

It combines issue participation and trading volume in a ratio of ratios commonly called TRIN.

Technical

Compute (A/D)/(UV/DV) from aligned counts and volumes, with explicit policies for zero denominators, universe, session, and feed revisions.

Scope

Its direction can feel inverted; a larger value does not simply mean more advancing participation.

Formula

TRIN = (A / D) / (UV / DV)
LaTeX: TRIN=\frac{A/D}{UV/DV}
SymbolMeaningUnit
Aadvancing issuesissues
Ddeclining issuesissues
UVup volumeshares or contracts
DVdown volumeshares or contracts

Output unit: ratio

Examples

  • A Fintech Builder lesson can compute or identify Arms Index only after declaring its inputs, timing, and edge-case rules.

Common misconceptions

  • Its direction can feel inverted; a larger value does not simply mean more advancing participation.

Concept relationships

Prerequisites

Related

Where this concept is used

Evidence and governance

  1. Arms Index (TRIN) StockCharts ChartSchool · secondary methodology

    Supports: preferred label, short definition, technical definition, formula

    Limits: Interpretive levels are market- and period-dependent; zero denominators and feed coverage require explicit policy.

Reviewed by
fintech-builder-batch-005
Last reviewed
2026-07-27
Next review
2027-07-27
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.