CytomX (CTMX) Form 4: Executive Receives Options and Milestone PSUs

Rhea-AI Filing Summary

Marcia Belvin, SVP and Chief Scientific Officer of CytomX Therapeutics (CTMX), was granted equity awards on 09/26/2025. The filing reports a stock option to purchase 36,300 shares with an exercise price of $2.90 and 18,150 Performance Stock Units (PSUs) that convert to one share each upon vesting. The option vests monthly at 1/48th beginning on the Vesting Commencement Date of 09/26/2025, reaching full vesting on the fourth anniversary if service continues. The PSUs vest in three equal tranches upon achievement of specified clinical milestones, subject to continued service. The Form 4 was signed by an attorney-in-fact on 09/30/2025.

Positive

• Equity incentive granted: Reporting person received a stock option for 36,300 shares at an exercise price of $2.90.
• Performance linkage: 18,150 PSUs granted that vest upon achievement of three clinical milestones, aligning pay with development progress.
• Retention-focused vesting: Option vests monthly (1/48th) starting 09/26/2025, reaching full vesting on the fourth anniversary, encouraging continued service.

Negative

• None.

Insights

Compensation Analyst

TL;DR: Standard equity grant combining time-based options and milestone PSUs to align executive incentives with long-term performance.

The grant mixes a time-vested option and milestone-based PSUs, balancing retention with performance linkage. The option is sizeable at 36,300 shares with a low exercise price of $2.90, providing potential upside if the share price appreciates. Monthly vesting over four years is a common retention schedule. PSUs tied to clinical milestones directly link payout to R&D progress, which is typical for biotech senior scientists. There is no disclosure here of existing holdings, dilution impact, or grant valuation, so material financial impact on shareholders cannot be quantified from this filing alone.

Biotech Industry Analyst

TL;DR: Milestone PSUs focus compensation on clinical progress; timing indicates near-term program objectives matter.

The inclusion of 18,150 PSUs payable upon three clinical milestones emphasizes management's incentivization around development catalysts. This structure concentrates potential compensation payouts on successful trial or regulatory events rather than solely time served. The Form 4 provides no details on the specific milestones or their probabilities, so investors cannot assess the likelihood or timing of PSU realization. Overall, the award is a routine senior-executive grant with targeted R&D alignment.

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

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

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

1. Name and Address of Reporting Person^*

BELVIN MARCIA

(Last) (First) (Middle)

C/O CYTOMX THERAPEUTICS, INC.

151 OYSTER POINT BLVD., STE. 400

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

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)
	SVP, Chief Scientific Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/26/2025

4. 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 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

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
Stock Option (Right to Buy)	$2.9	09/26/2025		A		36,300		(1)	09/25/2035	Common Stock	36,300	$0	36,300	D
Performance Stock Units (PSUs)	(2)	09/26/2025		A		18,150		(2)	(2)	Common Stock	18,150	$0	18,150	D

Explanation of Responses:

1. 1/48th of the shares subject to the option vest on each monthly anniversary measured from September 26, 2025 (the "Vesting Commencement Date"), such that 100% of the shares subject to the option will be fully vested and exercisable on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continued service to the Issuer through each such date.

2. Each Performance Stock Unit ("PSU") represents a contingent right to receive one (1) share of Common Stock upon vesting. 1/3 of the PSUs vest upon the achievement of each of three clinical milestones, subject to the Reporting Person continuing as a service provider through each such date.

	/s/ Christopher Ogden, as Attorney-in-Fact for Marcia Belvin	09/30/2025
	** 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 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.
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FAQ

What awards did Marcia Belvin receive according to the CTMX Form 4?

The Form 4 reports a stock option to buy 36,300 shares at an exercise price of $2.90 and 18,150 Performance Stock Units (PSUs).

When do the awards vest for Marcia Belvin (CTMX)?

The option vests monthly at 1/48th beginning on the Vesting Commencement Date of 09/26/2025, fully vesting on the fourth anniversary if service continues. PSUs vest in three equal tranches upon achievement of specified clinical milestones, subject to continued service.

What is the exercise price of the option granted to Marcia Belvin?

The reported exercise price for the stock option is $2.90 per share.

How many shares would Marcia Belvin receive if all PSUs vest?

If all PSUs vest, Marcia Belvin would receive 18,150 shares of Common Stock (one share per PSU).

Who signed the Form 4 and when was it filed?

The Form 4 was signed by Christopher Ogden, as Attorney-in-Fact for Marcia Belvin on 09/30/2025.