TRIN Indicator (Arms Index): Free TradeStation Download

The TRIN indicator is one of our free indicators for TradeStation. This page showcases the Better TRIN Indicator, the Better TRIN Oscillator and, new for the site’s 20th anniversary, the Better TRIN System: a swing trading system built in 2007, now with real-world results with 20 years of Emini data.

Use the links above to jump to the TRIN indicator topics that interest you.

How is the TRIN formula calculated?

TRIN = (Advancing Issues / Declining Issues) / (Advancing Volume / Declining Volume)

“Issues” is the number of stocks rising or falling on the day. “Volume” is the volume traded in those rising or falling stocks. Richard Arms published the index in 1967, and it was revolutionary: for the first time, a trader could see whether a rally was broad, with volume flowing into most stocks, or narrow, with a few names dragging the index up while the rest of the market sold off.

Here is how to read the TRIN ratio:

TRIN reading	What it means	Market condition
Below 0.5	Volume heavily concentrated in advancing stocks	Euphoria, often near a short-term top
0.5 to 1.0	More volume in advancers than decliners	Healthy buying
1.0	Volume evenly split	Neutral
1.0 to 2.0	More volume in decliners	Selling pressure
Above 2.0	Volume heavily concentrated in declining stocks	Panic, often near a short-term low

Both the NYSE TRIN and the Nasdaq TRIN are available as data symbols in TradeStation ($TRIN and $TRINQ). The Better TRIN indicators below use both, because a market where NYSE and Nasdaq breadth agree is a stronger signal than either alone.

How do you read a TRIN chart?

A raw TRIN chart is hard to read, and the chart above shows why. Buying days sit squashed between 0.5 and 1.0. Selling days spike to 2, 3, sometimes 5. Your eye is drawn to the sell spikes and misses the buying, so most traders only ever use TRIN for one thing: spotting a panic low when the reading goes above 2 or 3.

That is a legitimate use. A TRIN print above 3 on a down day is capitulation, and the market usually bounces within a few sessions. But it leaves most of the information on the table. The four fixes below turn TRIN into an indicator you can read every day, not just on crash days.

Why doesn’t the raw TRIN work as a trading indicator?

There are three problems with the TRIN index as published:

1. The TRIN is not intuitive. Values above 1 indicate selling, and values below 1 indicate buying. Every other indicator you use goes up when the market is strong. TRIN goes down.
2. TRIN values are unbalanced. If stocks are bought and sold at equal rates the TRIN is 1. After a day of heavy buying, the TRIN might be 0.4. After a day of equally heavy selling it could be 3. A 0.6 move one way and a 2.0 move the other, for the same amount of pressure.
3. Averaging the TRIN doesn’t work. The traditional fix is a 10-day moving average of TRIN. Because the data is unbalanced, the average is dragged around by the big selling values and tells you little about buying pressure.

How to make a Better TRIN Indicator in 4 steps

The Better TRIN Indicator fixes all three problems with four lines of maths:

1. Take the Log of the NYSE TRIN value. Log(2.0) is +0.69 and Log(0.5) is -0.69, so the data is now balanced around zero.
2. Invert it, so buying is positive and selling is negative.
3. Multiply by 100 so the numbers are readable.
4. Repeat for the Nasdaq TRIN and add the two readings.

The result ranges roughly between -100 and +100, with zero as the neutral point. Positive readings indicate buying pressure and go with up moves. Negative readings are selling pressure and go with down moves. Now the indicator behaves like every other indicator on your chart, so you can average it, build an oscillator from it, and trade it systematically.

TRIN indicator divergence patterns

A divergence occurs when the market makes a new low, but the Better TRIN reading is less negative than at the previous low: price is still falling, but the selling pressure behind it is drying up. The reverse at tops. The Better TRIN Indicator has a built-in divergence warning (the Diverg input) that colors the bar when one of these patterns sets up. These are daily chart patterns and do not apply intraday.

What is the Better TRIN Oscillator?

The Better TRIN Indicator measures buying and selling pressure at a point in time. The Better TRIN Oscillator shows the waves of buying and selling. It is built by cumulating the daily Better TRIN readings into a running total, like on-balance volume but built from breadth, then measuring how far that total has moved from its own 10-day average. A stochastic and a Fisher transform sharpen the turning points. The oscillator swings between -100 and +100, and zero means buying and selling pressure are at their recent norm.

Divergence patterns on the oscillator are stronger than on the indicator. A bullish divergence is the oscillator making a higher low while price makes a lower low. A bearish divergence is the oscillator making a lower high while price makes a higher high.

The oscillator also works on intraday charts. The chart above is the Better TRIN Oscillator on 5-minute Emini bars. The waves of buying and selling pressure during the day line up with the swings in the Emini, and the turns in the oscillator lead the turns in price more often than not.

Does a TRIN trading system work? 20 years of Better TRIN System signals

I first coded a trading system on the Better TRIN Oscillator in December 2007. It had five entry variations, long and short, and it tested really well. So well, in fact, that I sold it on the website for some years. Then I moved on and forgot all about it!

For the site’s 20th anniversary, I went back to it with 20 years of daily Emini data (December 2006 to October 2026) and asked a simpler question: did the system still work? The answer is yes, but only long (shorts were break-even).

The Better TRIN System buys when selling pressure resumes after a failed bounce. In plain English: the oscillator is below zero; it rallies but peaks before it gets back to neutral, then falls for one to three days running. That’s when amateurs hoping for a rally give up and sell. The system buys the close of that down day. It sells when the oscillator peaks above zero and rolls over, marking the first day buying pressure fades.

Price never enters the calculation. The system is built entirely on who is being forced to sell, which is why it works on the long side and not on the short side: capitulation lows are sharp and V-shaped, euphoric tops are slow and rounded.

The backtest: 1 contract of ES, four signals, no Martingale double-up or compounding, no optimisation of the oscillator settings since 2007:

Metric	Long trades only
Trades	318
Percent profitable	72%
Profit factor	3.31
Average trade	$1,750 (ES) $175 (MES)
Max drawdown	$56,000 (ES) $5,600 (MES)
Time in market	22%

The code is included in the download with every line commented, so you can see exactly what the system does and change it. Two inputs are worth knowing about. DoubleUp doubles the trade size after a losing trade (Martingale money management). Compound grows the number of contracts with closed equity, one contract per $50,000 ($5,000 MES). Both default to off. Run it plain first.

Hypothetical performance results have inherent limitations. Simulated trades were not executed; results may not reflect the impact of market factors such as liquidity, and systems designed with hindsight may not perform the same in the future. Past performance is not indicative of future results.

TRIN vs TICK: which market breadth indicator should you use?

TICK and TRIN are the two market breadth indicators most Emini day traders have on their screens, and they answer different questions. TICK counts how many NYSE stocks last traded on an uptick minus how many last traded on a downtick. It is instant and noisy, and it is a day trading tool. TRIN compares the volume flowing into advancing stocks against declining stocks, so it tells you whether the money agrees with the price. It is slower and better for swing trading.

Use TICK for intraday extremes (readings beyond +1000 or -1000). Use the Better TRIN Oscillator for the swings that last days to weeks, and for intraday turns on a 5-minute chart if you want a breadth confirmation that is less twitchy than TICK. Neither replaces volume analysis on the Emini itself, where professionals show their hand first.

Download the free Better TRIN Indicator, Oscillator and System

The Better TRIN indicators and system are free to download and use. TradeStation only, because the code needs the $TRIN and $TRINQ data streams on the same chart, and TradeStation supplies them.

What’s included in the download:

• _Better TRIN Indicator - balanced TRIN reading with divergence warning
• _Better TRIN Oscillator - swing oscillator, daily/intraday, with divergence warning
• _Better TRIN System (20 year anniversary version) - the long-only swing trading system with DoubleUp and Compound inputs
• PDF EasyLanguage source code for all indicators and system, fully commented

Installation note: Build a daily chart with three data streams: your Emini contract as Data1, $TRIN as Data2 and $TRINQ as Data3. In TradeStation, you need both NYSE and Nasdaq Level 1 data for the TRIN symbols. Apply the indicators to that chart. To run the system, set Initial Capital in Strategy Properties to match the StartingCapital input (default $50,000).

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