Joel S. Marcus - 13 Oct 2026 Form 4 Insider Report for TRex Bio, Inc.

Reporting relationship: Director
Issuer ticker: N/A
Reported as of: 13 Oct 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 13 Oct 2026, 18:31:34 UTC
Prior SEC filing: 08 Oct 2026
Source filing: View source filing
Reporting owner signature: /s/ Brandon Hants, as attorney-in-fact

Key filing fact

Joel S. Marcus filed Form 4 for TRex Bio, Inc. on 13 Oct 2026.

Key facts

This page summarizes Joel S. Marcus's Form 4 filing for TRex Bio, Inc..
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 13 Oct 2026, 18:31.

Change

Previous filing in this sequence was filed on 08 Oct 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001216955 Primary reporting owner

MARCUS JOEL S

Relationship: Director
Address: C/O TREX BIO, INC., 269 EAST GRAND AVENUE, SUITE 300, SOUTH SAN FRANCISCO
Signature: /s/ Brandon Hants, as attorney-in-fact
Signature date: 13 Oct 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

No ticker transaction

Common Stock

Conversion of derivative security

Transaction value
Shares: +41,871
Change %
Price
Shares after: 41,871
Date: 13 Oct 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

No ticker transaction Derivative

Series B Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares: -161,828
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 13 Oct 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 41,871
Exercise price
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

On October 13, 2026, the shares of Series B Convertible Preferred Stock automatically converted into shares of Common Stock on a 3.8649-to-1 basis without payment of further consideration immediately prior to the closing of the Issuer's initial public offering. The shares have no expiration date.