Monthly Watchlist Scans for ThinkOrSwim (Free Download)

Overview

In this tutorial I build a monthly watchlist scan in ThinkOrSwim for the month of March. It combines two pieces: a seasonal filter from our Seasonal Analysis indicator that looks for stocks where March has been a strong month, and a trend filter from our Market Pulse indicator on both the daily and the weekly chart.

The result is what I call an obvious watchlist: stocks heading into a month that has been strong for them, with strong daily and weekly trends already in place. In the video the scan cut 606 stocks with weekly options down to 42, which I saved as a March 2024 watchlist to study on max-data charts. The same steps work for any month.

Key Takeaways

What the Monthly Watchlist Scan Finds

The monthly watchlist scan finds stocks and ETFs where the coming month has been a strong one and the trend is already strong on the daily and weekly charts. I call it an obvious watchlist: names with seasonality on their side and both trends pointing the same way as you head into the month.

The scan needs 4 conditions, which become 3 custom study filters in ThinkOrSwim:

Both source indicators are free. Our Seasonal Analysis indicator tracks how each month has performed on a chart, and our Market Pulse indicator sorts a chart into market stages. If you haven't added either study yet, start there, because the scan borrows their code.

Why the Scan Only Sees 3 Years of Data

The ThinkOrSwim Scan tab makes this process about 10 times faster than flipping through charts, but it limits how much history a study filter can read. Setting the seasonal filter to weekly bars pushes the history as far back as it goes, and that is still only about 3 years. The filter sees the past 3 Marches and no more.

With 3 Marches, "more than 80% up" means all 3 closed higher. Three years is a thin sample, so I treat the scan as the first cut and do the rest of the leg work by hand on a chart with max data, which on SPY goes back more than 20 years.

That's also why the other three conditions matter. A positive average March and 2 trend filters shrink the list to a size you can review chart by chart.

Weekly bars add one more wrinkle: a week that straddles the start or end of March shifts which open and close the code picks up. The scan's March numbers can differ a little from the same code on a daily chart, which is one more reason to confirm the names on the chart.

How to Build the Monthly Watchlist Scan in ThinkOrSwim

Building the monthly watchlist scan takes 3 custom study filters on a Weeklys scan. Each filter is a separate Study filter with its own aggregation. Have the Seasonal Analysis and Market Pulse studies on a chart first so you can copy their code.

1. Open the Scan tab and set Scan in to Weeklys, the list of stocks that have weekly options. You'll find it under the Public lists.
2. Click Add filter and choose Study. The new filter defaults to ADXCrossover. When I recorded the video, study filters only worked in the live-money version of ThinkOrSwim.
3. Go to the Charts tab, click the Studies icon, find the Seasonal Analysis indicator and click the scroll icon to open its code. Copy the March section.
4. Back in the Scan tab, click the pencil icon on the filter, open the thinkScript Editor and paste the March code. Add the plot signal line shown below, delete the AddLabel line, set the aggregation to W and click OK.
5. Add a second study filter, paste in the Market Pulse code, and edit it into the acceleration filter shown below. Leave the aggregation on D.
6. Add a third study filter, copy the code from the daily Market Pulse filter into it, and set its aggregation to W.
7. Click Scan.

Errors You'll See Along the Way

ThinkOrSwim throws two errors during the build in the video, and both come from code that works on a chart but not in a scan. The third row covers the live-money limit on study filters.

The Seasonal Filter Code

The seasonal filter is the March block from the Seasonal Analysis indicator plus one new line. The block works out, for every March on the chart, the move from March's first open to its last close. The full filter is on the Code tab. These are the lines that matter for the scan:

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The deleted AddLabel line is a handy reference: it already divides marUp by marTotalCount.

The plot signal line is what ThinkOrSwim scans for, and it needs both conditions to be true:

• marUp/marTotalCount > 0.8: March closed above its open more than 80% of the time. The ratio runs from 0 to 1, so 80% is written 0.8.
• marAvgDiff > 0: the average March move is positive, so March has been a positive month overall.

For the code behind each of those lines, see our seasonal analysis tutorial, which builds the January version step by step.

The Market Pulse Filter Code

The Market Pulse filter keeps the stocks that are in the acceleration stage, which is when the Market Pulse line on your chart turns green. The indicator's own label code spells out the condition: the bullish variable is true and the close is at or above the variable moving average.

In the Market Pulse code, bullish means the 8-bar volume-weighted moving average sits above the 21-bar, and the 21-bar above the 34-bar:

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To turn the indicator into a scan filter, keep everything through the distribution line and delete the label, color and bubble lines after it.

Then make two changes:

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The first line turns the VMA from a plot into a def, which clears the one-plot error. The second is the line the scan reads. The table shows all 4 Market Pulse stages from the indicator's code, and the scan keeps only the first.

The weekly filter is the same code with a weekly aggregation, so you can copy it straight from the daily filter instead of going back to the chart.

What the Scan Found in the Video

The monthly watchlist scan returned 42 results heading into March 2024. The Weeklys list was 606 stocks before the 3 custom filters, so the scan cut it to about 7% of the starting list.

I also had our Market Pulse Dashboard script loaded as columns in the scan results, which let me confirm double greens, daily and weekly, across the board. I sorted the results by volume and started with SPY.

On a SPY chart with max data, which goes back more than 20 years, the Seasonal Analysis label showed March as an up month more than 60% of the time. That longer history is the check the 3-year scan can't do.

Saving the Results as a Monthly Watchlist

Saving the results is the last step of the build. The watchlist is only useful if you can step through it quickly:

1. Save the scan itself as a scan query, or save the results as a manual watchlist. I named mine March 2024.
2. In the Charts tab, load the new watchlist in the left-hand panel. It shows up with your personal watchlists.
3. Link the watchlist and the chart with the same linking color and number.
4. Click a symbol, such as ACN, to load its daily chart with max data, then use your arrow keys to move through the list and pick the names to study further.

Checking the Seasonal Numbers With Chart Bubbles

ThinkOrSwim occasionally gives you a glitch in these calculations, which a fellow YouTube member found, and chart bubbles are the way to debug it. Add this line to the Seasonal Analysis indicator, under the March code:

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marDiff only has a value on the last bar of each March, so the chart stays clean. Each bubble shows one March's move as a percentage, in yellow at the close. Scroll back through them to see exactly which Marches feed the label. For another month, swap marDiff for that month's variable, such as aprDiff.

How I Use the Monthly Watchlist

The monthly watchlist is a starting list for research. The scan tells me which names have seasonality and both trends on their side, and the max-data chart tells me whether the seasonal pattern holds up over more than 3 years. From there I decide which ones to dig into.

A strong March in the past describes past Marches, and a green Market Pulse can turn. Before you trade a name from the list, decide where your stop goes and size the position so a stop-out costs a small, fixed share of your account. If you want a second trend read on the charts you review, our free Moving Average Clouds indicator is another trend tool.

The same idea works for other months and other watchlists. For another month, replace the March block with that month's block from the Seasonal Analysis indicator and change the mar variables in the plot line to match. For background on monthly patterns, read our research on stock market seasonality patterns.

How to Import the Shared Scan

The Monthly Watchlist Scan download is a .txt file with one ThinkOrSwim shared link to the scan. To load it:

1. In ThinkOrSwim, click Setup in the top right corner.
2. Choose Open shared item.
3. Paste in the link and save the scan.

The Code tab on this page shows the 3 filters as I write them in the video. The scan in the screenshot above is a different build: its seasonal filter starts with input selectedMonth = 3, where the video pastes the March block. Our guide on how to import into ThinkOrSwim covers shared items, and you'll find more free scans on the scans page.

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