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

Yes. Footnotes state that sales of 1,739 shares and 1,503 shares of PTC Therapeutics common stock were automatically executed under irrevocable “sell to cover” elections. These sales were made to satisfy tax withholding obligations associated with the vesting of restricted stock units from prior RSU grants.

PTC Therapeutics (PTCT) EVP Boulding logs option exercise and share sales

Q: What insider transactions did PTC Therapeutics (PTCT) report for Mark Elliott Boulding?

The filing reports that Mark Elliott Boulding , Executive VP and CLO of PTC Therapeutics , exercised stock options and sold common shares on January 6–7, 2026 . He exercised options for a total of 3,376 shares at an exercise price of $38.10 per share and sold several small blocks of PTCT common stock at prices generally in the high $70 s per share.

Q: Did the PTC Therapeutics executive use a Rule 10b5-1 trading plan for these trades?

According to the footnotes, certain transactions on January 7, 2026 were effected pursuant to a written Rule 10b5-1 plan adopted by Mark Elliott Boulding on December 4, 2024 . A Rule 10b5-1 plan is a pre-arranged trading program that schedules future trades of company stock.

Q: What prices were reported for the PTC Therapeutics stock sales on this Form 4?

The reported sales of PTC Therapeutics common stock occurred at weighted average prices such as $76.95 , $77.11 , $77.48 , $77.91 , $78.60 , $77.10 , $77.92 and $78.98 per share. Several of these prices are disclosed as weighted averages for multiple trades within specified price ranges.

Q: What stock options did the PTC Therapeutics executive exercise in this Form 4?

The Form 4 shows exercises of stock options (right to buy) with an exercise price of $38.10 per share. On January 7, 2026 , options covering 2,625 and 751 shares of PTC Therapeutics common stock were exercised, and the footnotes indicate these options were currently exercisable with an expiration date of January 6, 2032 .

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

PTC Therapeutics executive Mark Elliott Boulding, Executive VP and Chief Legal Officer, reported a series of stock option exercises and related share sales in PTCT common stock. On January 7, 2026 he exercised options for 3,376 shares at an exercise price of $38.10 per share and sold multiple small blocks of common stock at weighted average prices generally between $76.95 and $78.98 per share. Some sales on January 6–7, 2026 were automatic “sell-to-cover” transactions to satisfy tax withholding tied to vesting of restricted stock units, and other trades were carried out under a pre-arranged Rule 10b5-1 trading plan. Following these transactions, he directly owned 117,659 shares of PTC Therapeutics common stock.

Insights

Routine option exercise and tax-related sales; neutral signal.

The filing shows Mark Elliott Boulding, Executive VP and CLO of PTC Therapeutics, exercising stock options at an exercise price of $38.1 and selling portions of the resulting common shares around market prices in the high $70s. The option lines indicate currently exercisable awards converting into common stock, which is typical for long-term equity compensation.

Footnotes explain that the 1,739 and 1,503 share sales were automatically executed under irrevocable “sell to cover” elections to fund tax withholding on RSU vesting, while other January 7, 2026 trades were executed under a written Rule 10b5-1 plan adopted on December 4, 2024. These features frame the activity as largely pre-arranged and tax-driven rather than discretionary timing. After all reported trades, Boulding directly held 117,659 common shares, so he retains a substantial equity position.

Given the pre-set 10b5-1 plan and tax-withholding context, these transactions look like routine administration of equity awards rather than a change in outlook. The overall impact on PTC Therapeutics’ capital structure is very small relative to a typical public float, and the activity primarily affects the executive’s personal holdings.

Insider Trade Summary

Net Seller: 6,618 shares ($511,641)

Net Sell 12 txns

Insider Boulding Mark Elliott

Role EXEC. VP AND CLO

Sold 6,618 shs ($512K)

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy)	2,625	$0.00	--
Exercise	Stock Option (Right to Buy)	751	$0.00	--
Sale	Common Stock	1,503	$77.48	$116K
Exercise	Common Stock	2,625	$38.10	$100K
Sale	Common Stock	1,638	$77.11	$126K
Sale	Common Stock	949	$77.91	$74K
Sale	Common Stock	38	$78.60	$3K
Exercise	Common Stock	751	$38.10	$29K
Sale	Common Stock	471	$77.10	$36K
Sale	Common Stock	269	$77.92	$21K
Sale	Common Stock	11	$78.98	$868.78
Sale	Common Stock	1,739	$76.95	$134K

Holdings After Transaction: Stock Option (Right to Buy) — 751 shares (Direct); Common Stock — 117,659 shares (Direct)

Footnotes (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 4,500 RSUs from a January 3, 2025 grant of 18,000 RSUs. 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 4,250 RSUs from a January 5, 2023 grant of 17,000 RSUs. 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 $76.56 to $77.55 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 $77.58 to $78.54 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 $76.54 to $77.52 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 $77.54 to $78.47 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. Currently exercisable.

Form 4 Insider Transactions: What Each Field Means →

01/08/2026 - 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)
01/06/2026

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	01/06/2026		S		1,739⁽¹⁾	D	$76.95	119,162	D
Common Stock	01/07/2026		S		1,503⁽²⁾	D	$77.48	117,659	D
Common Stock	01/07/2026		M⁽³⁾		2,625	A	$38.1	120,284	D
Common Stock	01/07/2026		S⁽³⁾		1,638	D	$77.11⁽⁴⁾	118,646	D
Common Stock	01/07/2026		S⁽³⁾		949	D	$77.91⁽⁵⁾	117,697	D
Common Stock	01/07/2026		S⁽³⁾		38	D	$78.6	117,659	D
Common Stock	01/07/2026		M⁽³⁾		751	A	$38.1	118,410	D
Common Stock	01/07/2026		S⁽³⁾		471	D	$77.1⁽⁶⁾	117,939	D
Common Stock	01/07/2026		S⁽³⁾		269	D	$77.92⁽⁷⁾	117,670	D
Common Stock	01/07/2026		S⁽³⁾		11	D	$78.98	117,659	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)
Stock Option (Right to Buy)	$38.1	01/07/2026		M⁽³⁾			2,625	⁽⁸⁾	01/06/2032	Common Stock	2,627	$0	751	D
Stock Option (Right to Buy)	$38.1	01/07/2026		M⁽³⁾			751	⁽⁸⁾	01/06/2032	Common Stock	751	$0	0	D

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 4,500 RSUs from a January 3, 2025 grant of 18,000 RSUs.

2. 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 4,250 RSUs from a January 5, 2023 grant of 17,000 RSUs.

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

4. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $76.56 to $77.55 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.

5. This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $77.58 to $78.54 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 $76.54 to $77.52 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 $77.54 to $78.47 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.

8. Currently exercisable.

	/s/ Avraham S. Adler, Attorney-in-Fact	01/08/2026
	** 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

What insider transactions did PTC Therapeutics (PTCT) report for Mark Elliott Boulding?

The filing reports that Mark Elliott Boulding, Executive VP and CLO of PTC Therapeutics, exercised stock options and sold common shares on January 6–7, 2026. He exercised options for a total of 3,376 shares at an exercise price of $38.10 per share and sold several small blocks of PTCT common stock at prices generally in the high $70s per share.

How many PTC Therapeutics shares does the executive own after these Form 4 transactions?

After completing the reported option exercises and stock sales, Mark Elliott Boulding directly beneficially owned 117,659 shares of PTC Therapeutics common stock, as shown in the Form 4 tables.

Did the PTC Therapeutics executive use a Rule 10b5-1 trading plan for these trades?

According to the footnotes, certain transactions on January 7, 2026 were effected pursuant to a written Rule 10b5-1 plan adopted by Mark Elliott Boulding on December 4, 2024. A Rule 10b5-1 plan is a pre-arranged trading program that schedules future trades of company stock.

What prices were reported for the PTC Therapeutics stock sales on this Form 4?

The reported sales of PTC Therapeutics common stock occurred at weighted average prices such as $76.95, $77.11, $77.48, $77.91, $78.60, $77.10, $77.92 and $78.98 per share. Several of these prices are disclosed as weighted averages for multiple trades within specified price ranges.

What stock options did the PTC Therapeutics executive exercise in this Form 4?

The Form 4 shows exercises of stock options (right to buy) with an exercise price of $38.10 per share. On January 7, 2026, options covering 2,625 and 751 shares of PTC Therapeutics common stock were exercised, and the footnotes indicate these options were currently exercisable with an expiration date of January 6, 2032.