CTMX insider filing: Form 3 shows zero beneficial ownership

Rhea-AI Filing Summary

CytomX Therapeutics (CTMX) filed a Form 3 initial statement of beneficial ownership for its Chief Business Officer, Rachael Lester. The filing states that no securities are beneficially owned.

The reported event date is 10/20/2025. The form was signed by Christopher Ogden as attorney-in-fact, referencing Exhibit 24.1 (Power of Attorney).

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

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Accepted by SEC EDGAR 10/29/2025 - 04:49 PM Learn about SEC filing dates

FAQ

What did CTMX file?

CytomX Therapeutics filed a Form 3, the initial statement of beneficial ownership for an insider.

Who is the reporting person in the CTMX Form 3?

The reporting person is Rachael Lester, the company’s Chief Business Officer.

What holdings are reported in this CTMX Form 3?

The filing states that no securities are beneficially owned.

What is the event date on the CTMX Form 3?

The event date is 10/20/2025.

Who signed the CTMX Form 3?

It was signed by /s/ Christopher Ogden as attorney-in-fact for Rachael Lester, referencing Exhibit 24.1.

What is Form 3 used for?

Form 3 reports an insider’s initial beneficial ownership upon becoming subject to Section 16 reporting.

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^*

Lester Rachael

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC.

151 OYSTER POINT BLVD., SUITE 400

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/20/2025

3. Issuer Name and Ticker or Trading Symbol
CytomX Therapeutics, Inc. [ CTMX ]

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

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

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

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)

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

Explanation of Responses:

Remarks:

Exhibit 24.1 - Power of Attorney

No securities are beneficially owned.

	/s/ Christopher Ogden, as Attorney-in-Fact for Rachael Lester	10/29/2025
	** 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.