Agios CCO vests 8,500 PSUs, sells shares

Agios Pharmaceuticals Chief Commercial Officer Tsveta Milanova reported a vesting and tax-related sale of shares.

Rhea-AI Filing Summary

Agios Pharmaceuticals Chief Commercial Officer Tsveta Milanova reported a vesting and tax-related sale of shares. On April 2, 2026, 8,500 performance share units were exercised into 8,500 shares of common stock at $0.00 per share, reflecting the vesting of performance-based equity compensation tied to a specified regulatory milestone.

On the same date, 3,262 shares of common stock were sold at $34.71 per share to cover tax withholding obligations, executed under durable automatic sale instructions consistent with Rule 10b5-1(c). After these transactions, Milanova directly owned 46,829 shares of Agios common stock.

Insider Trade Summary 10b5-1

Exercise and sale activity reported; no spread calculated

Exercise and Sale 3 txns

Insider Milanova Tsveta

Role Chief Commercial Officer

Sold 3,262 shs ($113K)

Approx. gross sale proceeds $113K

Approx. exercise cost $0.00

Type	Security	Shares	Price	Value
Exercise	Performance share units	8,500	$0.00	$0.00
Exercise	Common stock	8,500	$0.00	$0.00
Sale	Common stock	3,262	$34.71	$113K

Holdings After Transaction: Performance share units — 8,500 contracts (Direct); Common stock — 46,829 shares (Direct)

Footnotes (3)

1. F1. Shares sold to cover the tax withholding obligation in respect of vesting of the reporting person's performance share units. This transaction was effected pursuant to durable automatic sale instructions consistent with the affirmative defense to liability under Section 10(b) of the Securities Exchange Act of 1934 under Rule 10b5-1(c) promulgated under such Act. Such instructions were included in the reporting person's performance share unit agreement dated March 1, 2024.
2. F2. Each performance share unit represents a contingent right to receive one share of the issuer's common stock.
3. F3. The PSUs were granted on March 1, 2024. The PSUs vest as to 50% of the underlying shares upon the achievement of a specified regulatory milestone and as to the remaining 50% of the underlying shares upon the achievement of a specified commercial milestone. The performance criteria for the specified regulatory milestone was determined to have been met on April 2, 2026, resulting in the vesting of the PSUs as to 50% of the underlying shares. Vested shares will be delivered to the reporting person within three business days after such shares become vested.

Key Figures

PSUs exercised: 8,500 units Shares received: 8,500 shares Shares sold: 3,262 shares +4 more

7 metrics

PSUs exercised 8,500 units Performance share units converted to common stock on April 2, 2026

Shares received 8,500 shares Common stock received from PSU vesting and exercise

Shares sold 3,262 shares Common stock sold on April 2, 2026 to cover taxes

Sale price $34.71 per share Price for 3,262 shares of common stock sold

Shares held after 46,829 shares Direct common stock ownership after reported transactions

Exercise price $0.00 per share Conversion price for 8,500 performance share units

Regulatory milestone vesting 50% of PSUs Portion of PSUs vesting upon specified regulatory milestone on April 2, 2026

Key Terms

Performance share units, Rule 10b5-1(c), Section 10(b) of the Securities Exchange Act of 1934, regulatory milestone, +2 more

6 terms

Performance share units financial

"Shares sold to cover the tax withholding obligation in respect of vesting of the reporting person's performance share units."

Performance share units are a type of company stock award given to employees that depend on the company meeting specific goals or targets. If these goals are achieved, the employee receives shares or the value of shares; if not, they may receive little or no compensation. This aligns employees’ interests with the company's success and encourages performance that benefits investors.

Rule 10b5-1(c) regulatory

"durable automatic sale instructions consistent with the affirmative defense to liability under Section 10(b) ... under Rule 10b5-1(c)"

Rule 10b5-1(c) is an SEC guideline that lets company insiders set up a written, pre-planned schedule to buy or sell their company stock when they are not in possession of material, nonpublic information. For investors, it matters because such plans can reduce the appearance of insider trading by separating decisions from inside knowledge—like putting your trades on autopilot—while also requiring scrutiny since pre-planned trades can still affect market confidence and share value.

Section 10(b) of the Securities Exchange Act of 1934 regulatory

"affirmative defense to liability under Section 10(b) of the Securities Exchange Act of 1934 under Rule 10b5-1(c)"

regulatory milestone financial

"The PSUs vest as to 50% of the underlying shares upon the achievement of a specified regulatory milestone"

commercial milestone financial

"and as to the remaining 50% of the underlying shares upon the achievement of a specified commercial milestone."

performance share unit financial

"Such instructions were included in the reporting person's performance share unit agreement dated March 1, 2024."

A performance share unit (PSU) is a form of executive or employee pay that promises shares (or the cash value of shares) only if the company meets specific performance targets over a set period. Think of it like a bonus cheque that only arrives if the company hits agreed goals — it aligns managers’ rewards with business results and signals to investors how leadership is being incentivized to grow value over time.

FAQ

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

What insider transactions did AGIO Chief Commercial Officer Tsveta Milanova report?

Tsveta Milanova reported exercising 8,500 performance share units into common stock and selling 3,262 shares. The sale was made at $34.71 per share and was primarily to satisfy tax withholding obligations tied to the vesting of performance-based equity awards.

How many AGIO shares does Tsveta Milanova hold after the April 2, 2026 transactions?

Following the April 2, 2026 transactions, Tsveta Milanova directly owned 46,829 shares of Agios Pharmaceuticals common stock. This reflects the net position after receiving 8,500 vested shares from performance share units and selling 3,262 shares to cover related tax obligations.

Why did AGIO’s Tsveta Milanova sell 3,262 shares of common stock?

The 3,262 shares were sold to cover the tax withholding obligation arising from the vesting of performance share units. The sale was carried out under durable automatic sale instructions designed to comply with Rule 10b5-1(c), indicating a pre-established, formula-based transaction process.

What are performance share units (PSUs) in the AGIO Form 4 filing?

Agios performance share units represent a contingent right to receive one share of common stock per unit. Milanova’s PSUs were granted on March 1, 2024 and vest in two 50% tranches upon achieving specified regulatory and commercial milestones, with shares delivered within three business days after vesting.

What milestone triggered vesting of Tsveta Milanova’s AGIO performance share units?

The vesting was triggered when Agios determined that a specified regulatory milestone had been achieved on April 2, 2026. This determination caused 50% of the underlying shares subject to the performance share units to vest, resulting in delivery of 8,500 shares of common stock to Milanova.

Were Tsveta Milanova’s AGIO share sales made under a Rule 10b5-1 plan?

Yes. The sale to cover taxes followed durable automatic sale instructions included in Milanova’s March 1, 2024 performance share unit agreement. These instructions were structured to be consistent with the affirmative defense to liability under Section 10(b) via Rule 10b5-1(c).

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

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Accepted by SEC EDGAR 04/06/2026 - 04:07 PM Learn about SEC filing dates

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
Estimated average burden
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).

X

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^*

Milanova Tsveta

(Last) (First) (Middle)

C/O AGIOS PHARMACEUTICALS, INC.

88 SIDNEY STREET

(Street)

CAMBRIDGE MASSACHUSETTS 02139

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
AGIOS PHARMACEUTICALS, INC. [ AGIO ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/02/2026

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	04/02/2026		M		8,500	A	$0	50,091	D
Common stock	04/02/2026		S(1)		3,262	D	$34.71	46,829	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 share units	(2)	04/02/2026		M			8,500	(3)	(3)	Common stock	8,500	$0	8,500	D

Explanation of Responses:

1. Shares sold to cover the tax withholding obligation in respect of vesting of the reporting person's performance share units. This transaction was effected pursuant to durable automatic sale instructions consistent with the affirmative defense to liability under Section 10(b) of the Securities Exchange Act of 1934 under Rule 10b5-1(c) promulgated under such Act. Such instructions were included in the reporting person's performance share unit agreement dated March 1, 2024.

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

3. The PSUs were granted on March 1, 2024. The PSUs vest as to 50% of the underlying shares upon the achievement of a specified regulatory milestone and as to the remaining 50% of the underlying shares upon the achievement of a specified commercial milestone. The performance criteria for the specified regulatory milestone was determined to have been met on April 2, 2026, resulting in the vesting of the PSUs as to 50% of the underlying shares. Vested shares will be delivered to the reporting person within three business days after such shares become vested.

Remarks:

	/s/ William Cook, as Attorney in Fact for Tsveta Milanova	04/06/2026
	** 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)