# Substack Compliance Archiving | FINRA Rule 2210 & SEC 17a-4

Substack newsletters from registered reps are retail communications under FINRA Rule 2210. Comma captures and archives them automatically into one tamper-proof, exam-ready archive.

Source: https://commacompliance.com/channels/substack-compliance
Last updated: 2026-07-14

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## The regulatory backdrop

A registered investment adviser publishing a Substack newsletter is generating written communications that must be retained under Rule 204-2 of the Investment Advisers Act. A registered representative doing the same is producing a retail communication under [FINRA Rule 2210](/regulations/finra-2210). Either way, the obligation follows the content, not the platform.

## The challenge

Most archiving vendors focus on messaging apps and leave publishing platforms like Substack outside the archive entirely. If an examiner requests all written communications for a given period, a Substack newsletter from that period is responsive — whether or not it was ever captured.

## How Comma closes it

Comma captures Substack newsletters automatically through an authenticated connection. Text, metadata, and publication date are written to [WORM-grade storage](/resources/worm-storage) in real time. No manual exports. No copy-paste workflows. No gaps.

[](/images/substack-compliance-scan-history.png)

## What's captured

Comma captures the full published record: newsletter issues from configured accounts, including content, timestamps, and author metadata. Each issue lands in the same archive and supervision queue as your other 40+ channels.