PTC Therapeutics holder plans sale of 40,000 shares

Section Six Partners, L.P., an affiliate of a PTCT director, files to sell 40,000 PTCT shares under Rule 144 after recent sales in the prior three months.

Rhea-AI Filing Summary

PTC Therapeutics, Inc. (PTCT) has a notice of proposed resale of its common stock filed on behalf of Section Six Partners, L.P., an affiliate of a director, under Rule 144. The notice covers 40,000 shares of common stock of PTCT, with an aggregate market value of $2,740,000 as of September 9, 2026. These shares were originally acquired on June 25, 2013 through an automatic conversion of preferred stock into common stock upon PTCT’s IPO, with the preferred stock purchased from the issuer for cash. In the prior three months, Section Six Partners, L.P. reported four separate sales of 12,500 shares each of PTCT common stock. Director Michael Schmertzler, a general and limited partner of Section Six Partners, L.P., disclaims beneficial ownership of the partnership’s shares except to the extent of his pecuniary interest.

Key Figures

Shares to be sold under Rule 144: 40,000 shares of common stock Aggregate market value of shares to be sold: $2,740,000 Shares outstanding: 83,460,802 shares +4 more

7 metrics

Shares to be sold under Rule 144 40,000 shares of common stock Maximum number of PTCT shares covered by the Form 144 notice

Aggregate market value of shares to be sold $2,740,000 Market value of 40,000 PTCT shares as of September 9, 2026

Shares outstanding 83,460,802 shares PTCT common shares outstanding used for Rule 144 calculations as of September 9, 2026

Shares sold on August 19, 2026 12,500 shares for $916,553.65 PTCT common stock sold by Section Six Partners, L.P. during prior three months

Shares sold on August 20, 2026 12,500 shares for $888,857.74 PTCT common stock sold by Section Six Partners, L.P. during prior three months

Shares sold on August 26, 2026 12,500 shares for $911,725.45 PTCT common stock sold by Section Six Partners, L.P. during prior three months

Shares sold on August 27, 2026 12,500 shares for $894,783.70 PTCT common stock sold by Section Six Partners, L.P. during prior three months

Key Terms

Rule 144, Automatic Conversion of Preferred Stock into Common Stock upon IPO, affiliate of Director, pecuniary interest

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Automatic Conversion of Preferred Stock into Common Stock upon IPO financial

"Automatic Conversion of Preferred Stock into Common Stock Upon IPO"

affiliate of Director regulatory

"Affiliate of Director"

pecuniary interest financial

"except to the extent of his pecuniary interest therein."

FAQ

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

What does the Form 144 filing mean for PTC Therapeutics, Inc. (PTCT)?

The filing reports that Section Six Partners, L.P., an affiliate of a PTCT director, intends to sell 40,000 shares of PTCT common stock under Rule 144. It is a notice of a potential resale by an existing holder, not an issuance of new shares by PTCT.

How many PTCT shares are covered by this Form 144 and what is their value?

The notice covers 40,000 shares of PTCT common stock with an aggregate market value of $2,740,000 as of September 9, 2026. The filing also lists 83,460,802 shares outstanding of PTCT common stock for context on the company’s equity base.

Who is selling PTCT shares in this Form 144 filing?

The seller is Section Six Partners, L.P., identified as an affiliate of a director of PTC Therapeutics, Inc. Director Michael Schmertzler is a general and limited partner of Section Six Partners, L.P. and signs the notice on its behalf.

What prior PTCT stock sales did Section Six Partners, L.P. report in the last three months?

The filing lists four prior sales of PTCT common stock by Section Six Partners, L.P.: 12,500 shares on August 19, 2026 for $916,553.65, 12,500 shares on August 20, 2026 for $888,857.74, 12,500 shares on August 26, 2026 for $911,725.45, and 12,500 shares on August 27, 2026 for $894,783.70.

How and when were the PTCT shares being sold originally acquired?

The 40,000 PTCT shares covered by the notice were acquired on June 25, 2013 through an Automatic Conversion of Preferred Stock into Common Stock upon IPO. The preferred stock had been acquired from PTC Therapeutics, Inc. for cash before being converted into common stock.

What does Michael Schmertzler’s beneficial ownership disclaimer in the PTCT Form 144 mean?

The filing states that Michael Schmertzler disclaims beneficial ownership of shares held by Section Six Partners, L.P., except to the extent of his pecuniary interest in them. This clarifies that only his economic stake in the partnership’s holdings is treated as his beneficial ownership.

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

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Available on EDGAR 09/09/2026 - 04:33 PM Accepted by SEC EDGAR 09/09/2026 - 04:32 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001288952
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	PTC THERAPEUTICS, INC.
SEC File Number
Address of Issuer	500 WARREN CORPORATE CENTER DRIVE Warren NEW JERSEY 07059
Phone	9082227000
Name of Person for Whose Account the Securities are To Be Sold	Section Six Partners, L.P.
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Affiliate of Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Merrill Lynch 225 Liberty Street Fl 39 New York NY 10281	40000	2740000	83460802	09/09/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	06/25/2013	Automatic Conversion of Preferred Stock into Common Stock Upon IPO	Issuer			40000	06/25/2013	Automatic Conversion of Preferred Stock into Common Stock upon IPO (Preferred Stock acquired from Issuer for cash)

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Section Six Partners, LP c/o PTC Therapeutics, Inc 500 Warren Corporate Center Drive Warren NJ 07059	Common	08/19/2026	12500	916553.65
Section Six Partners, LP c/o PTC Therapeutics, Inc 500 Warren Corporate Center Drive Warren NJ 07059	Common	08/20/2026	12500	888857.74
Section Six Partners, LP c/o PTC Therapeutics, Inc 500 Warren Corporate Center Drive Warren NJ 07059	Common	08/26/2026	12500	911725.45
Section Six Partners, LP c/o PTC Therapeutics, Inc 500 Warren Corporate Center Drive Warren NJ 07059	Common	08/27/2026	12500	894783.7

144: Remarks and Signature

Remarks	Michael Schmertzler is a member of the Board of Directors of the Issuer. He is also a general partner and limited partner of Section Six Partners, L.P. Mr. Schmertzler disclaims beneficial ownership of the shares held by Section Six Partners, L.P., except to the extent of his pecuniary interest therein.
Date of Notice	09/09/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	05/14/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	Michael Schmertzler, as President of S6 GP Holding, LLC, the General Partner of, and on behalf of, Section Six Partners, LP
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)