Phathom CEO Reports 90,000 Vested Shares; Tax Withholding via 48,375 Share Surrender

Rhea-AI Filing Summary

Steven L. Basta, President and CEO and a director of Phathom Pharmaceuticals, Inc. (PHAT), reported stock and derivative transactions on Form 4. On 09/25/2025 he acquired 90,000 shares of common stock upon vesting of performance stock units granted 04/03/2025; those 90,000 shares were reported as acquired at $0 and increased his direct beneficial ownership to 90,000 shares. The filing also shows the surrender of 48,375 shares to the issuer to cover tax withholding at a price of $11.66 per share, leaving 41,625 shares after that disposition. The reporting person holds 270,000 shares underlying performance stock units after the reported vesting event, reflecting a grant of 360,000 PSUs on 04/03/2025 of which 90,000 vested due to achievement of a stock-price hurdle. The remaining PSUs vest upon future stock-price hurdles through four years from the grant, subject to continued service.

Positive

• 90,000 performance stock units vested due to achievement of a stock-price hurdle, aligning executive pay with performance
• Reporting person retains 270,000 PSUs outstanding, indicating continued incentive alignment for future performance hurdles

Negative

• 48,375 shares were surrendered to satisfy tax withholding, reducing net share receipt from the vested 90,000
• Remaining PSUs vest only upon future stock-price hurdles, so value realization is contingent on future performance

Insights

Corporate Governance Expert

TL;DR: Insider received vested PSUs and used shares to satisfy tax withholding; this is routine executive compensation activity.

The filing documents a common executive compensation mechanics: 90,000 performance stock units vested when a specified stock-price hurdle was met, converting into shares delivered to the reporting person. A portion of shares (48,375) were surrendered to satisfy tax-withholding obligations at $11.66 per share. The remaining disclosed direct ownership includes 90,000 vested shares and 270,000 shares underlying unvested performance units, indicating material outstanding equity-based awards but not an open-market purchase or sale by the insider. This transaction is governance-normal and consistent with incentive alignment between management and shareholders; it does not by itself change control or indicate atypical insider trading patterns.

Compensation & Equity Specialist

TL;DR: Vesting achieved a stock-price hurdle; share surrender for tax withholding is typical and reduces net share receipt.

The report shows a PSU grant of 360,000 on April 3, 2025 with stepped vesting tied to stock-price hurdles over four years. On 09/25/2025, 90,000 PSUs vested and converted to shares with zero cash exercise price, consistent with performance-contingent equity awards. The reporting person surrendered 48,375 shares to satisfy tax withholding at $11.66 per share, reducing delivered shares to 41,625 from the gross 90,000. The filing clarifies the remaining 270,000 PSUs continue to be contingent, which is important for dilution and future expense recognition but is routine for executive compensation programs.

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).

1. Name and Address of Reporting Person^*

Basta Steven L

(Last) (First) (Middle)

C/O PHATHOM PHARMACEUTICALS, INC.

100 CAMPUS DRIVE, SUITE 102

(Street)

FLORHAM PARK 07932

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Phathom Pharmaceuticals, Inc. [ PHAT ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

3. Date of Earliest Transaction (Month/Day/Year)
09/25/2025

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
Common Stock	09/25/2025		M		90,000	A	$0	90,000	D
Common Stock	09/25/2025		F(1)		48,375	D	$11.66	41,625	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
Performance Shares	$0(2)	09/25/2025		M			90,000	(3)	(3)	Common Stock	90,000	$0	270,000	D

Explanation of Responses:

1. Represents shares underlying the performance stock units that were surrendered by the reporting person to the Issuer in satisfaction of the Issuer's tax withholding obligation.

2. Each performance stock unit represents a contingent right to receive one share of common stock of the Issuer.

3. On April 3, 2025, the reporting person was granted 360,000 performance stock units, of which 90,000 vested on September 25, 2025 due to the achievement of the applicable stock price hurdle. The remaining performance stock units will vest based on the achievement of stock price hurdles over a period of four years following the grant date, subject to the reporting person's continued service through the date each such stock price hurdle is achieved.

	/s/ Steven L. Basta	09/26/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What did Steven L. Basta report on Form 4 for PHAT?

The report shows 90,000 shares acquired on 09/25/2025 upon vesting of performance stock units and 48,375 shares surrendered for tax withholding at $11.66 per share.

How many performance stock units were originally granted to Basta and how many remain?

On 04/03/2025 he was granted 360,000 PSUs; after 90,000 vested, 270,000 PSUs remain outstanding contingent on future stock-price hurdles.

What was the tax-withholding action reported?

The filing shows 48,375 shares were surrendered to the issuer to satisfy tax withholding at a reported price of $11.66 per share.

Did the filing report any open-market purchases or sales by the insider?

No. The transactions relate to vesting of PSUs and share surrender for tax withholding, not open-market trades.

What conditions remain for the unvested PSUs to convert to shares?

The remaining PSUs vest based on achievement of specified stock-price hurdles over four years from the grant date and continued service by the reporting person.