Arms Index (TRIN)


Arms Index, also known as The Trading Index (TRIN), is a breadth oscillator that aids in the measurement of internal market strength or weakness.

How this indicator works

TRIN is a short-term trading tool that measures volatility in the stock market. TRIN represents the relationship between advancing and declining issues by measuring their volume flow. A rising TRIN depicts a weak market and a falling TRIN depicts a strong market. A moving average can be added to smooth the data.


Advancing Issues / Declining Issues
Advancing Volume / Declining Volume

The TRIN will read under 1.0 when advancing stocks are the major source of volume and above 1.0 when declining stocks are the predominant source of volume flow in the market.