Automatic tax sale trims PTC Therapeutics (PTCT) CEO stake slightly

Rhea-AI Filing Summary

PTC Therapeutics, Inc. chief executive officer Matthew B. Klein reported an automatic sale of 2,850 shares of common stock at $70.91 per share. According to the filing, the shares were sold under an irrevocable sell-to-cover election to satisfy tax withholding obligations tied to the vesting of 6,500 RSUs from a prior 26,000-RSU grant. After this transaction, Klein directly holds 394,070 shares, indicating a small, tax-driven reduction in his overall stake.

Insider Trade Summary 10b5-1

Net Seller: 2,850 shares ($202,094)

Net Sell 1 txn

Insider Klein Matthew B.

Role CHIEF EXECUTIVE OFFICER

Sold 2,850 shs ($202K)

Type	Security	Shares	Price	Value
Sale	Common Stock	2,850	$70.91	$202K

Holdings After Transaction: Common Stock — 394,070 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 2,850 shares Sale price: $70.91 per share Shares held after sale: 394,070 shares +2 more

5 metrics

Shares sold 2,850 shares Automatic sale on 2026-04-21 to cover taxes

Sale price $70.91 per share Open-market sale price for common stock

Shares held after sale 394,070 shares Direct common stock ownership following transaction

RSUs vested 6,500 RSUs Portion vesting from April 18, 2023 grant

Original RSU grant 26,000 RSUs Grant dated April 18, 2023

Key Terms

irrevocable sell to cover election, RSUs, tax withholding obligations, open-market sale

4 terms

irrevocable sell to cover election financial

"Represents shares automatically sold pursuant to an irrevocable sell to cover election entered into upon acceptance of the grant"

RSUs financial

"to satisfy tax withholding obligations in connection with the vesting of 6,500 RSUs from an April 18, 2023 grant of 26,000 RSUs"

RSUs, or restricted stock units, are a form of company shares given to employees as part of their compensation. They are typically awarded with certain restrictions, such as a waiting period before they can be fully owned or sold, similar to earning a gift that becomes fully yours over time. For investors, RSUs can impact a company's stock offerings and reflect how much the company relies on stock-based incentives to attract and retain talent.

tax withholding obligations financial

"to satisfy tax withholding obligations in connection with the vesting of 6,500 RSUs"

open-market sale financial

"transaction_action": "open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Form 4 Insider Transactions: What Each Field Means →

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^*

Klein Matthew B.

(Last) (First) (Middle)

C/O PTC THERAPEUTICS, INC.

500 WARREN CORPORATE CENTER DRIVE

(Street)

WARREN NEW JERSEY 07059

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
PTC THERAPEUTICS, INC. [ PTCT ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF EXECUTIVE OFFICER

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/21/2026

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	04/21/2026		S		2,850(1)	D	$70.91	394,070	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. Represents shares automatically sold pursuant to an irrevocable sell to cover election entered into upon acceptance of the grant to satisfy tax withholding obligations in connection with the vesting of 6,500 RSUs from an April 18, 2023 grant of 26,000 RSUs.

	/s/ Avraham S. Adler, Attorney-in-Fact	04/23/2026
	** 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 insider transaction did PTC Therapeutics (PTCT) report for its CEO?

PTC Therapeutics reported that CEO Matthew B. Klein automatically sold 2,850 common shares at $70.91. The sale was triggered by an irrevocable sell-to-cover election to satisfy tax withholding obligations associated with restricted stock unit vesting.

Was the PTCT CEO’s April 2026 stock sale discretionary or tax-related?

The sale was tax-related, not discretionary. The 2,850 shares were automatically sold pursuant to an irrevocable sell-to-cover election to cover tax withholding obligations when 6,500 RSUs from an April 18, 2023 grant vested.

How many PTC Therapeutics shares does the CEO hold after this Form 4?

After the reported transaction, CEO Matthew B. Klein directly holds 394,070 shares of PTC Therapeutics common stock. This indicates the 2,850-share sale represented a small portion of his overall direct equity position in the company.

What RSU grant is linked to the PTC Therapeutics CEO’s tax-related share sale?

The tax-related sale is linked to an April 18, 2023 grant of 26,000 restricted stock units. From this grant, 6,500 RSUs vested, triggering automatic share sales to satisfy the associated tax withholding obligations under a sell-to-cover election.

Does the PTCT Form 4 indicate any remaining derivative or option positions for the CEO?

The filing’s derivative section shows no remaining derivative transactions or positions in this report. The activity disclosed relates solely to common stock and RSUs, with the sale tied to tax withholding on RSU vesting rather than option exercises.