The Arms Index also goes by the acronym TRIN or TRading INdex. Richard W. Arms, Jr. developed the Arms Index in 1967. This ratio relies on the total number of advancing/declining stocks divided by advancing/declining volume. Most of the Arms Index advice from traders isn’t complex. A rising Arms Index gives a bearish indicator, while a falling Index typically signals a bullish short-term market.

The Arms Index is one of many technical indicators used by short-term swing traders, day traders and others using technical analysis. Understanding volume in relation to stocks advancing or declining is the core feature of this Index. When looking for Arms Index information, consider the following:

1. Look at free Arms Index charts providing daily, weekly or monthly indicators.

2. Gain added insights on how to use the Arms Index from several website providers.

3. Take individual training and read the book by Richard. W. Arms, Jr.

Action Steps
The best contacts and resources to help you get it done

Find free Arms Index charts for short and long term trends

Charts provide Arms Index information at a glance. Spot trends quickly with charts covering several different aspects of the Arms Index.

I recommend: Market Harmonics offers several updated charts. Scroll to the bottom and select Arms Index/TRIN, Market Participation Index, Eliades New TRIN, Relative Upside/Downside Volume Oscillator or NASDAQ Composite New TRIN among others. Click “$TRINQ” for the Nasdaq Composite Short-Term Trading Arms Index and “$TRIN” for the NYSE Short-Term Trading Arms Index at Trending123.com. Type “TRIN” in the SharpCharts dialog box and receive the daily Arms Index with interactive features at StockCharts.com.

Get good Arms Index information at these websites

These websites provide help with Arms Index through articles, overviews and charts. The theory behind the Index uses several parameters each day in a relatively easy formula.

I recommend: OnlineTradingConcepts.com offers an overview of the Arms Index that includes components, interpretation and fundamental problems. Read the tutorial article by Richard W. Arms on his methodology at TheStreet.com. Mr. Arms is a contributor for RealMoney at TheStreet.com. Go to ArmsInsider.com for “What is the TRIN?” and click “ARMS Index Overview” for further information.

Take a free tutorial or buy the book for Arms Index Training

Buy the book by Richard W. Arms, Jr., considered the best on the subject. It's like having Mr. Arms, the developer of the Index, as your personal Arms Index consultant. Also, check out the free online tutorial for hands-on insights.

I recommend: Read the book, "Arms Index (Trin Index): An Introduction to Volume Analysis," written by the person who developed it, Richard W. Arms, Jr. The new version is back in print with updated Arms Index information. Buy new at your favorite online bookseller such as Amazon.com, or buy used at AbeBooks. Take the free TRIN (Arms Index) tutorial at Highlight Investments Group.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Professional traders focus more on the Arms Index trend rather than looking at whether it's above or below the neutral number one on any given day. For example, a 20-day moving average of the advancing/declining issues divided by advancing/declining volume produces the trend.
• •  The best Arms Index consultant is your stockbroker. However, once you understand the Index, it's easy to look at the charts and see when the trend gives a buy or sell signal. Always use the Arms Index with other indicators for a complete picture of market activity.