TRex Bio's Zarrin Ali reports holding 18,111 shares

The reported options have monthly vesting schedules, and vesting is subject to continued service through the applicable dates.

Rhea-AI Filing Summary

TRex Bio, Inc. Chief Scientific Officer Zarrin Ali reported direct ownership of 18,111 common shares and four stock-option positions covering 5,264, 20,913, 186,015 and 66,889 underlying shares, with exercise prices of $1.0900, $1.2400, $1.2400 and $1.2800, respectively. The options expire May 24, 2032; April 10 and September 30, 2035; and February 18, 2036. Vesting is subject to continued service, with monthly vesting schedules.

Insider Trade Summary

5 transactions reported

Mixed 5 txns

Insider Zarrin Ali

Role Chief Scientific Officer

Type	Security	Shares	Price	Value
holding	Stock Option (Right to Buy) F1	--	--	--
holding	Stock Option (Right to Buy) F2	--	--	--
holding	Stock Option (Right to Buy) F3	--	--	--
holding	Stock Option (Right to Buy) F4	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Stock Option (Right to Buy) — 279,081 contracts (Direct); Common Stock — 18,111 shares (Direct)

Footnotes (4)

1. F1. The option had a vesting start date of May 25, 2022. 25% of the options vested on May, 25, 2023, and vests as to the remaining shares in equal monthly installments over 36 months, subject to continued service through the applicable vesting dates.
2. F2. The option had a vesting start date of April 1, 2025 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.
3. F3. The option had a vesting start date of August 13, 2025 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.
4. F4. The option had a vesting start date of February 19, 2026 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

Key Figures

Common shares: 18,111 shares Stock option: 5,264 underlying shares; $1.0900 exercise price Stock option: 20,913 underlying shares; $1.2400 exercise price +2 more

5 metrics

Common shares 18,111 shares Directly held, reported October 8, 2026

Stock option 5,264 underlying shares; $1.0900 exercise price Expires May 24, 2032

Stock option 20,913 underlying shares; $1.2400 exercise price Expires April 10, 2035

Stock option 186,015 underlying shares; $1.2400 exercise price Expires September 30, 2035

Stock option 66,889 underlying shares; $1.2800 exercise price Expires February 18, 2036

Key Terms

Stock Option (Right to Buy), vesting start date, equal monthly installments

3 terms

Stock Option (Right to Buy) technical

"Stock Option (Right to Buy)"

vesting start date technical

"The option had a vesting start date"

equal monthly installments technical

"vests in equal monthly installments over 48 months"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many TRXB shares did Zarrin Ali report holding?

Zarrin Ali reported direct ownership of 18,111 common shares.

What are the exercise prices and expiration dates of Zarrin Ali's TRXB stock options?

The reported options cover 5,264 shares at $1.0900, expiring May 24, 2032; 20,913 shares at $1.2400, expiring April 10, 2035; 186,015 shares at $1.2400, expiring September 30, 2035; and 66,889 shares at $1.2800, expiring February 18, 2036.

How do Zarrin Ali's TRXB options vest?

The option with a May 25, 2022 vesting start date had 25% vest on May 25, 2023, with remaining shares vesting in equal monthly installments over 36 months. The options with start dates of April 1, 2025, August 13, 2025, and February 19, 2026 vest in equal monthly installments over 48 months. Each schedule is subject to continued service through applicable vesting dates.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/13/2026 - 08:15 PM EDT Accepted by SEC EDGAR 10/08/2026 - 09:43 PM EDT Learn about SEC filing dates

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Zarrin Ali

(Last) (First) (Middle)

C/O TREX BIO, INC.

269 EAST GRAND AVENUE, SUITE 300

(Street)

SOUTH SAN FRANCISCO CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
10/08/2026

3. Issuer Name and Ticker or Trading Symbol
TRex Bio, Inc. [ TRXB ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Scientific Officer

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	18,111	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	(1)	05/24/2032	Common Stock	5,264	$1.09	D
Stock Option (Right to Buy)	(2)	04/10/2035	Common Stock	20,913	$1.24	D
Stock Option (Right to Buy)	(3)	09/30/2035	Common Stock	186,015	$1.24	D
Stock Option (Right to Buy)	(4)	02/18/2036	Common Stock	66,889	$1.28	D

Explanation of Responses:

1. The option had a vesting start date of May 25, 2022. 25% of the options vested on May, 25, 2023, and vests as to the remaining shares in equal monthly installments over 36 months, subject to continued service through the applicable vesting dates.

2. The option had a vesting start date of April 1, 2025 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

3. The option had a vesting start date of August 13, 2025 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

4. The option had a vesting start date of February 19, 2026 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

Remarks:

Exhibit List: Exhibit 24 - Power of Attorney

	/s/ Brandon Hants, Attorney-in-Fact	10/08/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)