Hi Community members, A solution to last week’s challenge can be found here. This challenge was submitted by our ACE Ippei Nakagawa, @gawa. Thank you, Gawa, for your submission! In this week’s challenge, your task is to detect transactions that may indicate money laundering. Money laundering schemes often follow a circular pattern, such as: * A sends money to B * B sends money to C * C sends the same money back to A These transactions form a loop, and your goal is to identify such suspicious loops in the dataset. To qualify as potential money laundering, a group of transactions must meet all the following criteria: * Consistent Amount: The same amount of money is transferred in each transaction forming a loop. * Cyclic Return: The money eventually returns to the original sender, forming a complete loop. * Chronological Order: Transactions within the loop occur in strictly ascending order of transaction date. * Minimum Hops: A valid loop must include at least two intermediary transactions (i.e., at least three participants in total, including the original sender). Once you have completed your challenge, include your solution file and a screenshot of your workflow as attachments to your comment. Good Luck! The Academy Team Source: Randomly generated dataset using Python. Challenge 490_start_file.yxzp Challenge 490_solution_file.yxzp

Complete!! Spoiler Challenge490_CK.yxzp

Challenge Completed Spoiler Challenge_490_Joe_Serpis.yxzp

solution Spoiler Challenge 490_start_file.yxzp

Challenge #490: Detecting Money Laundering

AYXAcademy

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Hi Community members,

A solution to last week’s challenge can be found here.

This challenge was submitted by our ACE Ippei Nakagawa, @gawa. Thank you, Gawa, for your submission!

In this week’s challenge, your task is to detect transactions that may indicate money laundering. Money laundering schemes often follow a circular pattern, such as:

A sends money to B
B sends money to C
C sends the same money back to A

These transactions form a loop, and your goal is to identify such suspicious loops in the dataset.

To qualify as potential money laundering, a group of transactions must meet all the following criteria:

Consistent Amount: The same amount of money is transferred in each transaction forming a loop.
Cyclic Return: The money eventually returns to the original sender, forming a complete loop.
Chronological Order: Transactions within the loop occur in strictly ascending order of transaction date.
Minimum Hops: A valid loop must include at least two intermediary transactions (i.e., at least three participants in total, including the original sender).

Once you have completed your challenge, include your solution file and a screenshot of your workflow as attachments to your comment.

Good Luck!

The Academy Team

Source: Randomly generated dataset using Python.

Challenge 490_start_file.yxzp

Challenge 490_solution_file.yxzp

Macros

Advanced

Difficult

Accepted answers

All comments

Erin

@AYXAcademy - When I click Download Start File, it brings up Cloud_Quest_25_Start.json. Is that right?

**Update**
Glad the input was fixed up. Here's my solution. Took me awhile to get there and I'm sure there's a more elegant solution, but I'm not elegant today.

challenge_490_submission_EM.yxzp

Pilsner

Tough challenge. I made the classic mistake and got a bit mixed up with all the different IDs, but got there in the end. Liked the use case too, great fun!

Spoiler

Workflow:

Macro:

490 (Money Laundering).yxzp

Hub119

Started doing this with a sequence of joins and filters (which got to the solution quickly enough) and then realized that wasn't very "dynamic" of me... so went back and built a quick macro. Fun challenge!

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Workflow

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Macro

Challenge 490 - CH Solved.yxzp

abacon

Really tough one but fun to figure out!

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Workflow

Macro

Challenge 490_abacon.yxzp

olga_strubbe

Thank you, Gawa @gawa.

This was a tough challenge but a really good one!

I leveraged the approach from @abacon - thanks much for sharing it. This approach seemed to me a fairly simple and straightforward one. I realized the trick was to use Receiver as Sender for iteration to work in the end as the money had to return to the sender in a loop.

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Workflow:

Iterative macro:

iterative macro.png

Challenge 490_OS.yxmd

IterativeMacro.yxmc

balajilolla3

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Solution Attached

Challenge 490_start_file.yxzp

alineruizcampos

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Challenge 490_Aline.yxzp

Bobbyt23

Really fun puzzle to solve, once I got my head round the logic.

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Weekly Challenge 490 11-09-25.yxzp

RolandSchubert

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challenge 490_solution_rsc.yxzp

alexnajm

Done

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Challenge 490_start_file_Alex Abi-Najm.yxzp

JBevan89

Spoiler

I did it without a macro, with the use of the multi-row formula tool.

A great challenge, as could be very useful in the real world.

With the answer, the two rows do have transactions after the date that the amount returned to it's original account ID. However, because we are looking at whole amounts instead of decimals there is a good probability of this. And we know that these are the fraudulent transaction because it has moved accounts at least three times and returned to the original account id.

Challenge 490_JB.yxmd

lwolfie

Nice challenge now that I've got the iterative macro.

Challenge 490_solution_LW.yxzp

Stosh

Cool challenge, I have really been enjoying the challenges involving iterative macros.

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The outer workflow requires that we create 2 fields on input 1, namely Hands Changed which is a count of if the receiver is the sender (should be 1 for each row), and original sender, so that the sender in transaction 1 is saved.

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t
The macro keeps looking to make chains where the receiver on one end of a transaction matches a sender on another, both in account_ID and amount. Once a chain involves 3 hands changed or more and the receiver is the original sender, the chain is sent out of the loop

Challenge 490_solution_stosh.yxmd

rmassambane

490

Challenge 490_start_file.yxzp

mattnason1

Had to do as a macro. But good practice.

Challenge 490_start_file.yxmd

MACRO!.yxmc

DaisukeTsuchiya

Congratulations, @gawa , It was an interesting challenge!

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Challenge 490_start_file_DT.yxzp

NatSnook

I admit i had to look at others to redirect myself after barking up the wrong tree for a bit thanks

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Challenge 490_NS.yxmd

Kenda

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c490 kenda.yxzp

AkimasaKajitani

My solution!

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Challenge 490_start_file_AK.yxzp

mmontgomery

C490.

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Flashes of AoC

c490.yxzp

Carolyn

That was really fun! It reminded me a bit of an Advent of Code challenge with tracking the paths of the money

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2025-09-15 11_00_20-Alteryx Designer x64 - Loop check.yxmc.png

Challenge 490_Carolyn.yxmd

wbasuki

My Solution

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Challenge 490_start_file_WB.yxzp

apmessner

I really struggled with this challenge, I think because I am not well-versed in macros.

Can you explain where the "Date Check" field comes from in your Iterative Macro? I don't see it in either of the inputs, and then it just sort of appears after the Join tool. I don't see it defined anywhere, like in the workflow constants, or in a formula tool.

Thanks!

dman2740

Spoiler

It was a bit difficult to do without an iterative macro where essentially the macro does the processing where it finds the transactions where the sender = receiver then ensures that the transaction amount was the same and the transactions where made on later days and the next transaction comes from the original sender.