PTC Therapeutics (PTCT) legal chief discloses planned stock sales

Q: Who reported insider transactions in PTC Therapeutics (PTCT) on this Form 4?

The reporting person is Mark Elliott Boulding , who serves as Executive Vice President and Chief Legal Officer of PTC Therapeutics, Inc.

Q: What type of PTC Therapeutics (PTCT) securities were involved in the Form 4?

The transactions involved PTC Therapeutics common stock , reported in Table I as non-derivative securities acquired, disposed of, or beneficially owned.

Q: When did the reported PTC Therapeutics (PTCT) insider sales occur and at what prices?

The sales occurred on January 8 and 9, 2026 . Examples include 2,482 shares sold at a weighted average price of $76.56 per share and 1,521 shares sold at a weighted average price of $77.46 per share, with other trades reported in the mid-to-high $70s.

Q: How many PTC Therapeutics (PTCT) shares did the insider hold after these transactions?

Following the reported sales, the filing shows that 111,312 shares of PTC Therapeutics common stock were beneficially owned directly after the final listed transaction.

Q: Were any of the PTC Therapeutics (PTCT) insider sales related to tax withholding on RSUs?

Yes. A sale of 1,286 shares is described as shares automatically sold under an irrevocable sell-to-cover election to satisfy tax withholding obligations tied to the vesting of 3,600 RSUs from a January 7, 2022 grant of 14,400 RSUs.

Q: How are the reported PTC Therapeutics (PTCT) sale prices described on the Form 4?

The per-share prices reported for several transactions are weighted average prices for multiple trades. Footnotes explain that the trades occurred within specified price ranges, and the reporting person undertakes to provide full trade-by-trade detail upon request.

Filing Impact

(Moderate)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

PTC Therapeutics executive Mark Elliott Boulding reported multiple open-market sales of company common stock. As Executive Vice President and Chief Legal Officer, he filed a Form 4 showing several sales on January 8 and 9, 2026 at per-share prices in the mid-to-high $70s. Individual transactions included sales such as 2,482 shares at a weighted average price of $76.56 and 1,521 shares at a weighted average price of $77.46, with all shares held directly.

After the reported sales, Boulding beneficially owned slightly more than 111,000 shares of PTC Therapeutics common stock. One block of 1,286 shares was automatically sold under an irrevocable “sell to cover” election to satisfy tax withholding tied to the vesting of 3,600 restricted stock units from a 2022 equity grant. The filing notes that the sales were carried out under a written Rule 10b5‑1 trading plan adopted on December 4, 2024, with several prices disclosed as weighted averages over narrow trading ranges.

Insider Trade Summary

Net Seller: 6,347 shares ($489,081)

Net Sell 6 txns

Insider Boulding Mark Elliott

Role EXEC. VP AND CLO

Sold 6,347 shs ($489K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,521	$77.46	$118K
Sale	Common Stock	686	$78.71	$54K
Sale	Common Stock	107	$79.52	$9K
Sale	Common Stock	2,482	$76.56	$190K
Sale	Common Stock	265	$77.07	$20K
Sale	Common Stock	1,286	$76.45	$98K

Holdings After Transaction: Common Stock — 112,105 shares (Direct)

Footnotes (1)

This transaction was effected pursuant to a written Rule 10b5-1 plan adopted by the Reporting Person on December 4, 2024. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $75.95 to $76.92 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $76.99 to $77.23 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. Represents shares automatically sold pursuant to an irrevocable sell to cover election to satisfy tax withholding obligations in connection with the vesting of 3,600 RSUs from a January 7, 2022 grant of 14,400 RSUs. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $77.12 to $78.08 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $78.23 to $79.21 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $79.35 to $79.60 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

Form 4 Insider Transactions: What Each Field Means →

01/12/2026 - 05:20 PM

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).

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^*

Boulding Mark Elliott

(Last)

(First)

(Middle)

C/O PTC THERAPEUTICS, INC.

500 WARREN CORPORATE CENTER DRIVE

(Street)

WARREN

07059

(City)

(State)

(Zip)

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

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

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	EXEC. VP AND CLO

3. Date of Earliest Transaction (Month/Day/Year)
01/08/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	01/08/2026		S⁽¹⁾		2,482	D	$76.56⁽²⁾	115,177	D
Common Stock	01/08/2026		S⁽¹⁾		265	D	$77.07⁽³⁾	114,912	D
Common Stock	01/08/2026		S		1,286⁽⁴⁾	D	$76.45	113,626	D
Common Stock	01/09/2026		S⁽¹⁾		1,521	D	$77.46⁽⁵⁾	112,105	D
Common Stock	01/09/2026		S⁽¹⁾		686	D	$78.71⁽⁶⁾	111,419	D
Common Stock	01/09/2026		S⁽¹⁾		107	D	$79.52⁽⁷⁾	111,312	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. This transaction was effected pursuant to a written Rule 10b5-1 plan adopted by the Reporting Person on December 4, 2024.

2. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $75.95 to $76.92 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

3. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $76.99 to $77.23 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

4. Represents shares automatically sold pursuant to an irrevocable sell to cover election to satisfy tax withholding obligations in connection with the vesting of 3,600 RSUs from a January 7, 2022 grant of 14,400 RSUs.

5. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $77.12 to $78.08 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

6. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $78.23 to $79.21 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

7. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $79.35 to $79.60 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

	/s/ Avraham S. Adler, Attorney-in-Fact	01/12/2026
	** 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.

Source: View Original Filing on SEC EDGAR

FAQ

Who reported insider transactions in PTC Therapeutics (PTCT) on this Form 4?

The reporting person is Mark Elliott Boulding, who serves as Executive Vice President and Chief Legal Officer of PTC Therapeutics, Inc.

What type of PTC Therapeutics (PTCT) securities were involved in the Form 4?

The transactions involved PTC Therapeutics common stock, reported in Table I as non-derivative securities acquired, disposed of, or beneficially owned.

When did the reported PTC Therapeutics (PTCT) insider sales occur and at what prices?

The sales occurred on January 8 and 9, 2026. Examples include 2,482 shares sold at a weighted average price of $76.56 per share and 1,521 shares sold at a weighted average price of $77.46 per share, with other trades reported in the mid-to-high $70s.

How many PTC Therapeutics (PTCT) shares did the insider hold after these transactions?

Following the reported sales, the filing shows that 111,312 shares of PTC Therapeutics common stock were beneficially owned directly after the final listed transaction.

Were the PTC Therapeutics (PTCT) insider trades executed under a Rule 10b5-1 trading plan?

According to the explanation of responses, one transaction was effected pursuant to a written Rule 10b5-1 plan adopted by the reporting person on December 4, 2024. The Form 4 also provides a checkbox reference for Rule 10b5-1(c) transactions.

How are the reported PTC Therapeutics (PTCT) sale prices described on the Form 4?

The per-share prices reported for several transactions are weighted average prices for multiple trades. Footnotes explain that the trades occurred within specified price ranges, and the reporting person undertakes to provide full trade-by-trade detail upon request.