Stacked Moving Average Scans for ThinkOrSwim (Free Download)

ScanFreeBeginner8 min video28 lines of codeJun 25, 2023Updated Oct 21, 2026

Two free stacked moving average scans for ThinkOrSwim that find stocks where the 8, 21, 34 EMAs and 50, 200 SMAs stacked on the latest bar.

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Overview

In this tutorial I turn our Stacked Moving Averages indicator into two stacked moving average scans for ThinkOrSwim. The bullish scan finds stocks where the 8, 21 and 34-period EMAs and the 50 and 200-period SMAs went into a bullish stack on the current bar, and the bearish scan finds the first bar of a bearish stack.

The work is editing: a scan accepts exactly one plot, so every other plot becomes a def and the formatting lines come out. It's for traders who like the stack arrows on a chart and want a list of every stock where one printed on the latest bar.

Key Takeaways

The stacked moving average scans find stocks where the moving averages went into a stack on the current bar: the 8 EMA above the 21 EMA, the 21 EMA above the 34 EMA and the 50 SMA above the 200 SMA for bullish, all 3 reversed for bearish.
Both scans are built from our Stacked Moving Averages indicator code. Every plot except one becomes a def and the formatting lines come out, because a ThinkOrSwim scan accepts exactly one plot.
In the video, the daily bullish scan on all optionable symbols returned 73 results. Adding an ask price filter above $10 cut that to about 56.
Stanley Black & Decker (SWK) was one bullish result: its 50 SMA had newly crossed above its 200 SMA. Disney (DIS) was at the top of the bearish list.
The finished bullish and bearish scans are also saved as 2 ThinkOrSwim shared links (tos.mx links) in our Stacked Moving Average Scans file.

What the Stacked Moving Average Scans Find

The stacked moving average scans are two ThinkOrSwim stock scans that look for the first bar of a moving average stack. On a chart, our Stacked Moving Averages indicator marks that bar with an arrow. The scans search a list of symbols, all optionable stocks in the video, for the same arrow on the current bar, so you don't have to flip through charts to find it.

The indicator page covers the moving averages, the colors and how the arrow logic works. This page covers turning that code into a scan. The table shows what each scan checks.

Check	Bullish scan	Bearish scan
8 EMA vs 21 EMA	Above	Below
21 EMA vs 34 EMA	Above	Below
50 SMA vs 200 SMA	Above	Below
Previous bar	Not a bullish stack	Not a bearish stack
The one plot left in the code	`bullStackedPlot`	`bearStackedPlot`

All of the checks have to be true on the current bar, and the stack must not have been true on the bar before. That's what makes it the first bar of the stack instead of any bar inside one.

Why a Scan Needs Exactly One Plot

A ThinkOrSwim scan filter accepts exactly one plot. That's the whole idea of a scan: you give it one thing to look for, and it goes and finds wherever that's happening.

The Stacked Moving Averages indicator has 7 plots: 5 moving averages and 2 arrows. Paste it into a scan as is and ThinkOrSwim refuses it. The edits come down to this:

What you see	Why	Fix
At least one plot should be defined	The editor is empty after you delete the ADXCrossover code	Paste in the indicator code
Exactly one plot expected	The indicator code has 7 plot variables	Change every plot except one to def
Errors on the formatting lines	You can't apply formatting to a def	Delete the setDefaultColor, setStyle, setPaintingStrategy and setLineWeight lines

Delete the formatting even on the plot you keep. Scans don't use it, it tends to cause more errors than anything, and even with only one plot I found it affects the scan's performance. The goal is clean code.

How to Build the Bullish Scan in ThinkOrSwim

Building the bullish stacked moving average scan starts from the indicator code. Copy all of it from the indicator's Code tab or the downloaded file first.

Open the Scan tab. If it already has custom scripts, you may want to remove them.
Click Add filter and choose Study. By default the filter loads the ADXCrossover study.
Click the pencil icon on the right of the filter to open the editing panel, and select thinkScript Editor.
Delete the ADXCrossover code and paste in the Stacked Moving Averages code.
Change plot to def on the 8, 21 and 34 EMAs and the 50 and 200 SMAs, and delete their color and style lines.
Delete the arrow formatting lines, then change plot bearStackedPlot to def. bullStackedPlot is the one plot left.
Leave the aggregation period on daily and click OK.
Run the scan in all optionable symbols and click Scan.

Here's what the first moving average looks like before and after the edit. In the indicator: