CytomX (NASDAQ: CTMX) CFO sells 19,323 shares for tax withholding

Rhea-AI Filing Summary

CytomX Therapeutics, Inc. Chief Financial Officer Christopher Ogden sold 19,323 shares of common stock at an average price of $6.423 per share. The sale was made solely to satisfy tax and other government withholding obligations related to vesting restricted stock units. After this transaction, he directly holds 296,948 shares of common stock, which includes 173,082 restricted stock units.

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Ogden Christopher

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC.

151 OYSTER POINT BLVD., SUITE 400

(Street)

SOUTH SAN FRANCISCO CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/17/2026

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

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

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/17/2026		S(1)		19,323	D	$6.423	296,948(2)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The shares were sold solely to satisfy tax or other government withholding obligations in connection with the vesting of restricted stock units ("RSUs").

2. Includes 173,082 RSUs.

	/s/ Christopher Ogden	03/19/2026
	** 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 4 (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 4: SEC 1474 (03-26)

FAQ

What did CytomX (CTMX) CFO Christopher Ogden report in this Form 4?

CytomX CFO Christopher Ogden reported selling 19,323 shares of common stock. The sale was executed at an average price of $6.423 per share to cover tax and other government withholding obligations tied to vesting restricted stock units.

How many CytomX (CTMX) shares did the CFO sell and at what price?

The CFO sold 19,323 shares of CytomX common stock at an average price of $6.423 per share. This was an open-market sale recorded as an S-code transaction and linked to tax and government withholding obligations on RSU vesting.

Why did the CytomX (CTMX) CFO sell 19,323 shares?

The shares were sold solely to satisfy tax and other government withholding obligations connected to restricted stock unit vesting. This indicates the transaction was driven by tax requirements rather than a discretionary decision to reduce overall equity exposure.

How many CytomX (CTMX) shares does the CFO hold after the sale?

After the sale, the CFO directly holds 296,948 shares of CytomX common stock. This total includes 173,082 restricted stock units, which represent share-based awards that typically vest over time according to the company’s compensation arrangements.

Does the CytomX (CTMX) Form 4 indicate any derivative exercises by the CFO?

The Form 4 does not show any derivative exercises for this transaction. The filing reports only a non-derivative open-market sale of common stock and lists no remaining derivative positions in the derivative transaction summary section.

Are the CytomX (CTMX) CFO’s holdings direct or indirect after this transaction?

The holdings reported after the transaction are classified as direct ownership. The nature-of-ownership field does not reference any trusts or entities, and no footnote indicates indirect control or a lack of voting or investment authority over the reported shares.