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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934

 

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PTC Therapeutics, Inc.
100 Corporate Court
South Plainfield, New Jersey 07080

April 28, 2014

Dear Stockholder:

        You are cordially invited to attend the 2014 Annual Meeting of Stockholders of PTC Therapeutics, Inc. on Tuesday, June 10, 2014 at 10:00 a.m., Eastern time. The Annual Meeting will be held at the Embassy Suites, located at 121 Centennial Ave in Piscataway Township, New Jersey.

        The attached Notice of the Annual Meeting and proxy statement provide important information about the Annual Meeting and will serve as your guide to the business to be conducted at the meeting. Your vote is very important to us. We urge you to read the accompanying materials regarding the matters to be voted on at the Annual Meeting and to submit your voting instructions by proxy. Our Board of Directors recommends that you vote "for" each of the proposals listed on the attached Notice.

        You may submit your proxy by Internet, by telephone or by requesting a printed copy of the proxy materials and using the enclosed proxy card. If you submit your proxy before the meeting but later decide to attend the Annual Meeting in person, you may still vote in person at the Annual Meeting.

        On behalf of our Board of Directors, management and all of our employees, I thank you for your continuing support and confidence.

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PTC Therapeutics, Inc.
100 Corporate Court
South Plainfield, New Jersey 07080

Notice of Annual Meeting of Stockholders
To Be Held on June 10, 2014

        This proxy statement contains information about the 2014 Annual Meeting of Stockholders of PTC Therapeutics, Inc., which we refer to as the Annual Meeting. The Annual Meeting will be held on Tuesday, June 10, 2014 at 10:00 a.m., Eastern time, at the Embassy Suites, located at 121 Centennial Avenue in Piscataway Township, New Jersey. At the Annual Meeting, stockholders will consider and act upon the following matters:

1.

To elect the three Class I director nominees nominated by our Board of Directors and named in the proxy statement, each to serve for a term ending in 2017, or until his successor has been duly elected and qualified;



2.

To ratify the appointment of Ernst & Young LLP, a registered public accounting firm, as our independent registered public accounting firm for the fiscal year ending December 31, 2014; and



3.

To transact such other business as may properly come before the Annual Meeting or any adjournment or postponement thereof.

        Instead of mailing a printed copy of our proxy materials to all of our stockholders, we provide access to these materials via the Internet. This reduces the amount of paper necessary to produce these materials as well as the costs associated with mailing these materials to all stockholders. Accordingly, on or about April 28, 2014, we will begin mailing a Notice of Internet Availability of Proxy Materials, or Notice, to stockholders of record at the close of business on April 15, 2014, the record date for the Annual Meeting, and will post our proxy materials on the website referenced in the Notice. As more fully described in the Notice, stockholders may choose to access our proxy materials on the website referred to in the Notice or may request to receive a printed set of our proxy materials.

        If you are a stockholder of record, we encourage you to vote in one of the following ways:

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Vote over the Internet, by going to http://www.proxyvote.com (have your Notice or proxy card in hand when you access the website);



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Vote by Telephone, by calling the toll-free number (800) 690-6903 (have your Notice or proxy card in hand when you call); or



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Vote by Mail, if you received (or requested and received) a printed copy of the proxy materials, by returning the enclosed proxy card (signed and dated) in the envelope provided.

        If your shares are held in "street name," meaning that they are held for your account by a broker or other nominee, you will receive instructions from the holder of record that you must follow for your shares to be voted.

        Whether or not you plan to attend the Annual Meeting in person, we urge you to take the time to vote your shares.

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PTC Therapeutics, Inc.
100 Corporate Court
South Plainfield, New Jersey 07080

Proxy Statement for the Annual Meeting of Stockholders
To Be Held on June 10, 2014

        These proxy materials are being furnished in connection with the solicitation of proxies by our Board of Directors for use at the 2014 Annual Meeting to be held on Tuesday, June 10, 2014 at 10:00 a.m., Eastern time, at the Embassy Suites, located at 121 Centennial Ave in Piscataway Township, New Jersey, and at any adjournment or postponement thereof.

        All proxies will be voted in accordance with the instructions contained in those proxies. If no choice is specified, the proxies will be voted "for" each of the director nominees and "for" the proposals set forth in the accompanying Notice of Annual Meeting of Stockholders. You may revoke your proxy at any time before it is exercised at the meeting by giving our Secretary written notice to that effect.

        The Notice of Annual Meeting and proxy statement are first being mailed and/or made available to stockholders on or about April 28, 2014 in conjunction with the delivery of our 2013 Annual Report to Stockholders.

        In this proxy statement, unless expressly stated otherwise or the context otherwise requires, the use of "PTC," "the company," "our," "we" or "us" refers to PTC Therapeutics, Inc. and its subsidiaries. Certain information contained in this proxy statement relating to the occupations and security holdings of our directors and officers is based upon information received from the individual directors and officers.

        Whether or not you expect to attend the Annual Meeting in person, please vote as promptly as possible to ensure that your representation and the presence of a quorum at the Annual Meeting. You may vote your shares on the Internet by visiting www.proxyvote.com or by telephone by calling 1-800-690-6903 and following the recorded instructions, by requesting a printed copy of the proxy materials and using the enclosed proxy card or by voting in person at the Annual Meeting. Your proxy is revocable in accordance with the procedures set forth in this proxy statement.

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EXPLANATORY NOTE

        We are an "emerging growth company" under applicable federal securities laws and therefore permitted to take advantage of certain reduced public company reporting requirements. As an emerging growth company, we provide in this proxy statement the scaled disclosure permitted under the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, including the compensation disclosures required of a "smaller reporting company," as that term is defined in Rule 12b-2 promulgated under the Securities Exchange Act of 1934, as amended. In addition, as an emerging growth company, we are not required to conduct votes seeking approval, on an advisory basis, of the compensation of our named executive officers or the frequency with which such votes must be conducted. We may remain an emerging growth company until December 31, 2018, provided that, if the market value of our common stock that is held by non-affiliates exceeds $700 million as of any June 30 before that time or if we have annual gross revenues of $1 billion or more in any fiscal year, we would cease to be an emerging growth company as of December 31 of the applicable year.

IMPORTANT INFORMATION ABOUT THE ANNUAL MEETING AND VOTING

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CORPORATE GOVERNANCE

        Our Board believes that good corporate governance is important to ensure that our company is managed for the long-term benefit of our stockholders. This section describes key corporate governance guidelines and practices that we have adopted to further this goal. Complete copies of the committee charters and code of business conduct and ethics described below are available on the Corporate Governance page of the Investor Relations section of our website, www.ptcbio.com. Alternatively, you can request a copy of any of these documents by writing to our Director, Corporate Communications, PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, New Jersey 07080.

Code of Business Conduct and Ethics

        We have adopted a written Code of Business Conduct and Ethics, which is a code of ethics that applies to our directors, officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. We have posted a current copy of the Code of Business Conduct and Ethics on the Corporate Governance page of the Investor Relations section of our website, www.ptcbio.com. In addition, we intend to post on our website all disclosures that are required by law or NASDAQ's listing standards concerning any amendments to, or waivers from, any provision of the Code of Business Conduct and Ethics.

Corporate Governance Guidelines

        Our Board has adopted Corporate Governance Guidelines to assist it in the exercise of its duties and responsibilities and to serve the best interests of our company and our stockholders. These principles, which provide a framework for the conduct of our Board's business, provide that:

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the principal responsibility of the directors is to oversee our management and to hold our management accountable for the pursuit of our corporate objectives;



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a majority of the members of our Board shall be independent directors;



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the independent directors meet regularly in executive session;



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directors have full and free access to management and, as necessary and appropriate, independent advisors;



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new directors participate in an orientation program and all directors are encouraged to attend director education programs; and



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at least annually, our Board and its committees will conduct a self-evaluation to determine whether they are functioning effectively.

Director Independence

        Rule 5605 of the NASDAQ Stock Market Rules requires a majority of a listed company's board of directors to be comprised of independent directors within one year of listing. Under applicable NASDAQ rules, a director will only qualify as an "independent director" if, in the opinion of our Board, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director.

        Our Board has determined that all of our directors and director nominees, other than Dr. Peltz, our Chief Executive Officer, are independent as defined under applicable NASDAQ rules. In making such determination, our Board considered the relationships that each such person has with our company and all other facts and circumstances that our Board deemed relevant in determining independence, including beneficial ownership of our common stock by our non-employee directors. In considering the independence of our directors, our Board considered the association of certain of our

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directors with the holders of more than 5% of our common stock as well as the effect of each of the transactions described under the heading "Related Person Transactions" below.

Director Nominations

Process

        Our Nominating and Corporate Governance Committee is responsible for identifying individuals qualified to serve as directors, consistent with criteria approved by our Board, and recommending the persons to be nominated for election as directors, except where we are legally required by contract, law or otherwise to provide third parties with the right to nominate.

        The process followed by our Nominating and Corporate Governance Committee to identify and evaluate director candidates includes requests to members of our Board and others for recommendations, meetings from time to time to evaluate biographical information and background material relating to potential candidates and interviews of selected candidates by members of our Nominating and Corporate Governance Committee and our Board.

Criteria and Diversity

        In considering whether to recommend any particular candidate for inclusion in our Board's slate of recommended director nominees, our Nominating and Corporate Governance Committee applies the criteria specified in our Corporate Governance Guidelines. These criteria include the candidate's integrity, business acumen, knowledge of our business and industry, experience, diligence, conflicts of interest with us, and ability to act in the interests of stockholders. Our Nominating and Corporate Governance Committee does not assign specific weight to particular criteria and no particular criterion is a prerequisite for any prospective director nominee.

        Our Board does not have a formal policy with respect to diversity, but our Corporate Governance Guidelines provide that an objective of Board composition is to bring to our company a variety of perspectives and skills derived from high quality business and professional experience. Our Board recognizes its responsibility to ensure that director nominees possess appropriate qualifications and reflect a reasonable diversity of personal and professional experience, skills, backgrounds and perspectives, including those backgrounds and perspectives with respect to age, gender, culture, race and national origin. We believe that the backgrounds and qualifications of our directors, considered as a group, should provide a composite mix of experience, knowledge and abilities that will allow our Board to promote our strategic objectives and to fulfill its responsibilities to our stockholders.

        The director biographies presented under "Proposal 1—Election of Directors" indicate each director nominee's experience, qualifications, attributes and skills that led our Board to conclude that he should be nominated to serve as a member of our Board. Our Board believes that each of the director nominees has had substantial achievement in his professional and personal pursuits, and possesses the background, talents and experience that our Board desires and that will contribute to the best interests of our company and to long-term stockholder value.

Stockholder Nominations

        Stockholders may recommend individuals to our Nominating and Corporate Governance Committee for consideration as potential director candidates by submitting their names, together with appropriate biographical information and background materials as of the date such recommendation is made, to our Nominating and Corporate Governance Committee, c/o Secretary, PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, New Jersey 07080. Assuming that appropriate biographical and background material has been provided on a timely basis, our Nominating and Corporate Governance Committee will evaluate stockholder-recommended candidates by following

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substantially the same process, and applying substantially the same criteria, as it follows for candidates submitted by others.

        Stockholders also have the right under our amended and restated bylaws, or bylaws, to directly nominate director candidates, without any action or recommendation on the part of our Nominating and Corporate Governance Committee or our Board, by following the procedures set forth under "Stockholder Proposals for 2015 Annual Meeting." If our Board determines to nominate a stockholder-recommended candidate and recommends his or her election, then his or her name will be included in our proxy statement and proxy card for the next annual meeting. Otherwise, candidates nominated by stockholders in accordance with the procedures set forth in the bylaws will not be included in our proxy statement and proxy card for the next annual meeting.

Board Meetings and Attendance

        Our Board met 16 times during the fiscal year ended December 31, 2013, or fiscal 2013, either in person or by teleconference. During fiscal 2013, each of our directors attended at least 75% of the Board meetings and the meetings of the committees on which he then served.

Director Attendance at Annual Meeting of Stockholders

        Our Corporate Governance Guidelines provide that our directors are expected to attend the Annual Meeting. We did not hold an annual meeting of stockholders in 2013.

Board Leadership Structure

        The positions of Chair of the Board and Chief Executive Officer are separated. Mr. Schmertzler serves as our Chair of the Board and Dr. Peltz serves as our Chief Executive Officer. This leadership structure allows our Chief Executive Officer to focus on our day-to-day business and allows our Chair of the Board to lead our Board in its fundamental role of providing advice to and independent oversight of management. Our Board recognizes the time, effort and energy that our Chief Executive Officer must devote to his position, as well as the commitment required by Mr. Schmertzler to serve as our Chair of the Board, particularly as our Board's oversight responsibilities continue to grow. Our Board also believes that this structure ensures a greater role for the independent directors in the oversight of our company and active participation of the independent directors in setting agendas and establishing priorities and procedures for the work of our Board.

        Our bylaws do not require the position of Chair of our Board and Chief Executive Officer to be separate. Our Board believes that its leadership structure demonstrates our commitment to good corporate governance, and is appropriate because it strikes an effective balance between strategy development, independent leadership and management oversight. Our Board believes its leadership structure positively affects its administration of its risk oversight function.

Board Committees

        Our Board has established three standing committees: our Audit Committee, our Compensation Committee and our Nominating and Corporate Governance Committee. Each of these committees operates under a charter that has been approved by our Board. Each committee's charter is posted on the Corporate Governance page of the Investor Relations section of our website, www.ptcbio.com.

        Our Board has determined that all of the members of each of its three committees are independent as defined under applicable NASDAQ rules, including, in the case of all members of our Audit Committee, the independence requirements contemplated by Rule 10A-3 under the Securities Exchange Act of 1934, as amended, or the Exchange Act, and, in the case of all members of our

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Compensation Committee, the independence requirements contemplated by Rule 10C-1 under the Exchange Act.

Audit Committee

        The members of our Audit Committee are Messrs. Bolte, Kranda and Southwell. Mr. Kranda chairs our Audit Committee. Our Audit Committee's responsibilities include:

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appointing, approving the compensation of, and assessing the independence of our registered public accounting firm;



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overseeing the work of our independent registered public accounting firm, including through the receipt and consideration of reports from such firm;



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reviewing and discussing with management and our independent registered public accounting firm our annual and quarterly financial statements and related disclosures;



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monitoring our internal control over financial reporting, disclosure controls and procedures and code of business conduct and ethics;



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overseeing our internal audit function;



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overseeing our risk assessment and risk management policies;



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establishing policies regarding hiring employees from our independent registered public accounting firm and procedures for the receipt and retention of accounting related complaints and concerns;



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meeting independently with our internal auditing staff, our independent registered public accounting firm and management;



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reviewing and approving or ratifying any related person transactions; and



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preparing the audit committee report required by Securities and Exchange Commission, or SEC, rules.

        Our Board has determined that Mr. Southwell is an "audit committee financial expert" as defined in applicable SEC rules.

Compensation Committee

        The members of our Compensation Committee are Messrs. Aldrich, Schmertzler and Southwell. Mr. Southwell chairs our Compensation Committee. Our Compensation Committee's responsibilities include:

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reviewing and approving, or making recommendations to our Board with respect to, the compensation of our Chief Executive Officer and our other executive officers;



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overseeing an evaluation of our senior executives;



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overseeing and administering our cash and equity incentive plans; and



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reviewing and making recommendations to our Board with respect to director compensation.

Compensation Processes and Procedures

        Our Compensation Committee makes all compensation decisions regarding our executive officers and our Chief Executive Officer, including salary, annual cash incentive compensation and long-term equity compensation (or, when the Committee deems it appropriate, makes recommendations concerning such matters to our Board). If the Compensation Committee deems it appropriate, it may

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delegate any of its responsibilities to one or more Compensation Committee members or subcommittees.

        Our Compensation Committee relies on management for legal, tax, compliance, finance and human resource recommendations, data and analysis for the design and administration of the compensation, benefits and perquisite programs for our executive officers. As a result, our Chief Executive Officer, Chief Financial Officer, Senior Vice President, Human Resources, and Executive Vice President, Chief Legal Officer and Corporate Secretary generally attend Compensation Committee meetings upon the invitation of the Committee.

        On an annual basis our Chief Executive Officer meets with those executive officers who report directly to him to discuss the company's accomplishments as well as the individual executive officer's performance and contributions over the year. Based on these discussions and input from others within our company, our Chief Executive Officer, with respect to each executive officer other than himself, prepares an evaluation of the executive as to the level of contribution made to the management and success of our company. In addition, our Chief Executive Officer, with the participation of other members of senior management, prepares information concerning the company's achievements and our performance against corporate goals during the fiscal year.

        The Compensation Committee is presented with this information and the Chief Executive Officer's recommendations with respect to each executive officer, other than himself, as to the appropriateness of salary levels, the amount of annual cash incentive compensation earned, if any, and the long-term equity awards, if any, to be granted. The Chief Executive Officer's recommendations, information concerning the company's performance over the applicable fiscal period, and advice from its independent compensation consultant are all taken into account by the Compensation Committee when it makes a final determination on executive compensation.

        Our Chief Executive Officer's performance and salary, annual cash incentive compensation and long-term equity compensation are discussed by the Compensation Committee in executive session, with advice and participation from the Compensation Committee's independent compensation consultant as requested by the Compensation Committee. Our Chief Executive Officer does not participate in decisions regarding his own compensation.

        The Compensation Committee also establishes, with input from the Chief Executive Officer and other members of the executive team, the corporate goals applicable to our annual cash incentive awards. For 2013, these goals primarily related to financial, operational and strategic items, such as the successful completion of our initial public offering, the achievement of project milestones for certain clinical pipeline products, and the development of new organizational capabilities as a public company.

Role of Compensation Consultants

        Our Compensation Committee may, in its sole discretion, retain or obtain the advice of one or more compensation consultants. In 2013, our Compensation Committee engaged Radford, an AON Hewitt Company, as its independent compensation consultant, to provide comparative data on executive compensation practices in our industry and to advise on our executive compensation program generally. The Committee also engaged Radford for recommendations and review of non-employee director compensation in 2013.

        Although our Compensation Committee considers the advice and recommendations of Radford as to our executive compensation program, our Compensation Committee ultimately makes their own decisions about these matters. In the future, we expect that our Compensation Committee will continue to engage independent compensation consultants to provide additional guidance on our executive compensation programs and to conduct further competitive benchmarking against a peer group of publicly traded companies.

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        In 2013, the Compensation Committee reviewed information regarding the independence and potential conflicts of interest of Radford, taking into account, among other things, the factors set forth in the NASDAQ listing standards. Based on such review, the Committee concluded that the engagement of Radford did not raise any conflict of interest. Outside of services provided for the Compensation Committee, the compensation consultant provided nominal additional services to the company in 2013 related to benchmarking data with respect to certain non-executive positions in an effort to ensure that our compensation is competitive so that we can attract, reward, motivate and retain all employees. The total amount paid to Radford in connection with these additional engagements was less than $120,000 in 2013.

Nominating and Corporate Governance Committee

        The members of our Nominating and Corporate Governance Committee are Drs. Jacobson and Koppel and Mr. Schmertzler. Mr. Schmertzler chairs our Nominating and Corporate Governance Committee. Our Nominating and Corporate Governance Committee's responsibilities include:

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identifying individuals qualified to become members of our Board;



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recommending to our Board the persons to be nominated for election as directors and to each of our Board's committees;



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reviewing and making recommendations to our Board with respect to our board leadership structure;



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reviewing and making recommendations to our Board with respect to management succession planning;



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developing and recommending to our Board corporate governance principles; and



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overseeing a periodic evaluation of our Board.

Risk Oversight

        Risk is inherent with every business and how well a business manages risk can ultimately determine its success. We face a number of risks, including those described under "Risk Factors" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2013. Our Board is actively involved in oversight of risks that could affect us.

Role of Our Board in Management of Risk

        Our Board administers its risk oversight function directly and through its Audit Committee and receives regular reports from members of senior management, including our Chief Executive Officer, Chief Financial Officer and Chief Legal Officer, on areas of material risk to our company, including operational, financial, legal and regulatory, and strategic and reputational risks and has direct access to our Senior Vice President of Quality and Vice President of Regulatory Affairs. As part of its charter, our Audit Committee regularly discusses with management our major risk exposures, their potential financial impact on our company and the steps we take to manage them. Our Board believes that full and open communication between our management and our Board is essential for effective risk management and oversight.

        In addition, our Compensation Committee assists our Board in fulfilling its oversight responsibilities with respect to the management and risks arising from our compensation policies and programs. Our Nominating and Corporate Governance Committee assists our Board in fulfilling its oversight responsibilities with respect to the management of risks associated with board organization, membership and structure, succession planning for our directors and executive officers and corporate governance.

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Communicating with our Independent Directors

        Our Board will give appropriate attention to written communications that are submitted by stockholders, and will respond if and as appropriate. Our Chair of the Board and the Chair of our Nominating and Corporate Governance Committee, with the assistance of our Chief Legal Officer and Secretary and Director, Corporate Communications, are primarily responsible for monitoring communications from stockholders and for providing copies or summaries to the other directors as they consider appropriate.

        Communications are forwarded to all directors if they relate to important substantive matters. In general, communications relating to corporate governance and corporate strategy are more likely to be forwarded than communications relating to ordinary business affairs, personal grievances and matters that are duplicative communications. Items that are unrelated to the duties and responsibilities of the Board may be excluded or redirected, as appropriate, such as business solicitations, job inquiries or advertisements, mass mailings, new product suggestions, or communications that have no rational relevance to our business or operations. In addition, material that is unduly hostile, threatening or similarly unsuitable will be excluded; however, any communication will be made available to any director upon his request.

        Stockholders who wish to send communications on any topic to our Board should address such communications to the Board of Directors c/o PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, New Jersey 07080, Attn: Secretary.

Compensation Committee Interlocks and Insider Participation

        Messrs. Aldrich, Bolte, Schmertzler and Southwell served as the members of our Compensation Committee in 2013. Mr. Bolte previously chaired our Compensation Committee and transitioned off the Compensation Committee in May 2013.

        None of our executive officers serves as a member of the board of directors or compensation committee, or other committee serving an equivalent function, of any other entity that has one or more of its executive officers serving as a member of our Board or our Compensation Committee. None of the members of our Compensation Committee is, or has ever been, an officer or employee of our company.

Related Person Transactions

        Since January 1, 2013, we have engaged in the following transactions with our directors, executive officers and holders of more than 5% of our voting securities, and affiliates of our directors, executive officers and holders of more than 5% of our voting securities. We believe that all of these transactions were on terms as favorable to us as could have been obtained from unrelated third parties.

Participation in our February 2014 Public Offering

        In our public offering that we completed in February 2014, certain existing stockholders of ours agreed to purchase an aggregate of 660,551 shares of our common stock and were named in the prospectus for that offering. Each of those purchases was made through the underwriters at the public offering price of $24.50 per share. The following table sets forth the aggregate number of shares of our

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common stock that these stockholders purchased in this public offering in which the amount involved in the transaction exceeded $120,000:

Participation in our June 2013 Initial Public Offering

        In our initial public offering that we completed in June 2013, certain of our directors, executive officers, 5% stockholders, and their affiliates purchased an aggregate of 3,856,528 shares of our common stock. Each of those purchases was made through the underwriters at the initial public offering price of $15.00 per share. The following table sets forth the aggregate number of shares of our common stock that these directors, executive officers, 5% stockholders, and their affiliates purchased in our initial public offering in which the amount involved in the transaction exceeded $120,000:

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Series Four Senior Preferred Stock Financing and Reclassification of Outstanding Preferred Stock

        In March 2013, we issued and sold an aggregate of 4,497,035 shares of our series four senior preferred stock, at a price per share of $12.00, for an aggregate purchase price of $53,964,420. In addition, we issued an aggregate of 502,919 shares of our series four senior preferred stock upon conversion of the convertible promissory notes described below that we originally issued in January and February 2013. The following table sets forth the number of shares of our series four senior preferred stock purchased by our directors, executive officers and 5% stockholders and their affiliates and the number of shares of our series four senior preferred stock that we issued to our directors, executive officers and 5% stockholders and their affiliates upon conversion of the convertible promissory notes described below.

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        In connection with the series four senior preferred stock financing, we effected a one-for-120 reverse stock split of our common stock and a reclassification of our previously outstanding preferred stock into an aggregate of 6,700,487 shares of series five junior preferred stock. In addition, we issued an aggregate of 2,095,515 shares of our series five junior preferred stock upon the automatic exercise of the preferred stock warrants described below that we originally issued in January 2013. The following table sets forth the number of shares of our series five junior preferred stock that we issued to our directors, executive officers and 5% stockholders and their affiliates upon the reclassification of our previously outstanding preferred stock and the number of shares of our series five junior preferred

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stock that we issued to our directors, executive officers and 5% stockholders and their affiliates upon the automatic exercise of the preferred stock warrants described below.

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Bridge Financing

        In January and February 2013, we issued convertible promissory notes in an aggregate principal amount of $6,000,000. In connection with this bridge financing, we also issued to the holders of the promissory notes warrants to purchase an aggregate of 515,186 shares of our series one preferred stock, at an exercise price of $0.01 per share, and warrants to purchase an aggregate of 2,012,489 shares of our series two preferred stock, an exercise price of $0.01 per share. The following table sets forth the principal amount of the promissory notes and the number of series two warrants and series three warrants that we issued to our directors, executive officers and 5% stockholders and their affiliates.

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        In connection with the series four senior preferred stock financing, the outstanding convertible promissory notes converted into an aggregate of 502,919 shares of series four senior preferred stock and the outstanding warrants for series one preferred stock and series two preferred stock were automatically exercised for an aggregate of 2,095,515 shares of series five junior preferred stock.

Placement Agent Fees

        In connection with our series four preferred stock financing, including our issuance of an additional 375,000 shares of our series four senior preferred stock in May 2013, we paid Credit Suisse Securities (USA) LLC an aggregate fee of $2,386,951 for its service as a placement agent for the transaction. Credit Suisse Securities (USA) LLC is an affiliate of Credit Suisse First Boston Equity Partners, L.P. and affiliated funds, which together hold more than 5% of our voting securities. In its capacity as one of several underwriters of the issuance and sale of our common stock, Credit Suisse Securities (USA) LLC also received underwriters discounts and commissions pursuant to the terms of an underwriting agreement between us and the underwriters in connection with our initial public offering of our common stock in June 2013 and our follow-on public offering of our common stock in February 2014.

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Familial Relationship

        Ellen Welch, Ph.D., the domestic partner of Stuart W. Peltz, our Chief Executive Officer, is employed by us as a Senior Director, Biology. In 2014, Dr. Welch received a performance bonus of $49,214 and we granted her an option to purchase 4,900 shares of our common stock at an exercise price of $27.05 per share. In 2013, Dr. Welch received an annual base salary of $170,883 and a performance bonus of $24,729, and we granted her an option to purchase 3,900 shares of our common stock at an exercise price of $10.85 per share in May 2013, a restricted stock award of 9,753 shares of our common stock in March 2013 and a restricted stock award of 7,800 shares of our common stock in May 2013.

        Dr. Peltz does not participate in the supervision of or compensation decisions regarding Dr. Welch, and we believe her compensation is fair and commensurate with what her compensation would be if she had no relationship to Dr. Peltz.

Registration Rights

        We entered into a second amended and restated investors' rights agreement, dated March 7, 2013, which we refer to as the investors' rights agreement, with the holders of our preferred stock prior to the closing of our initial public offering. Holders of a total of 7,653,885 shares of our common stock as of April 9, 2014, including shares issued upon conversion of our preferred stock, have the right, subject to certain limitations, to require us to register these shares under the Securities Act of 1933, as amended, or Securities Act, and to participate in future registrations of securities by us, under the circumstances described below. After registration pursuant to these rights, these shares will become freely tradable without restriction under the Securities Act. If not otherwise exercised, the rights described below will expire three years after the closing of our initial public offering, which occurred on June 25, 2013.

Demand Registration Rights

        Subject to specified limitations set forth in the investors' rights agreement, at any time, the holders of 20% of the then-outstanding shares having rights under the investors' rights agreement, which we refer to as registrable shares, may at any time demand in writing that we register all or a portion of the registrable shares under the Securities Act if the total amount of registrable shares registered have an aggregate offering price of at least $10 million (net of selling expenses). We are not obligated to file a registration statement pursuant to this provision on more than two occasions, and we are not obligated to file a registration statement pursuant to this provision within 60 days before or 180 days after the effective date of any other registration statement that we may file or if we determine in good faith that it would be seriously detrimental to us or our stockholders.

Form S-3 Registration Rights

        In addition, at any time after we become eligible to file a registration statement on Form S-3, subject to specified limitations set forth in the investors' rights agreement, the holders of registrable shares may demand in writing that we register on Form S-3 all or a portion of the registrable shares so long as the total amount of registrable shares being registered have an aggregate offering price of at least $5 million (net of selling expenses). We are not obligated to file a Form S-3 pursuant to this provision on more than four occasions, and we are not obligated to file a registration statement pursuant to this provision within 30 days before or 90 days after the effective date of any other registration statement that we may file or if we determine in good faith that it would be seriously detrimental to us or our stockholders.

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Incidental Registration Rights

        If we propose to file a registration statement under the Securities Act, other than pursuant to the demand registration rights described above, the holders of registrable shares will be entitled to notice of the registration and, subject to specified exceptions, including market conditions, have the right to require us to register all or a portion of the registrable shares then held by them.

        In the event that any registration in which the holders of registrable shares elect to participate pursuant to our investors' rights agreement is intended to be an underwritten public offering, we have agreed to enter into an underwriting agreement containing customary representation and warranties and covenants, including without limitation customary provisions with respect to indemnification of the underwriters of such offering. Holders of registrable securities must agree to any such underwriting agreement as a condition to participation in the offering.

Expenses

        Pursuant to the investors' rights agreement, we are required to pay all registration expenses, including registration and filing fees, exchange listing fees, printing expenses and accounting fees and the fees and expenses of one counsel to represent the selling stockholders, in addition to any underwriting discounts and commissions, that are related to any demand or incidental registration described above. The registration rights agreement contains customary cross-indemnification provisions, pursuant to which we are obligated to indemnify the selling stockholders in the event of material misstatements or omissions in the registration statement attributable to us, and they are obligated to indemnify us for material misstatements or omissions in the registration statement attributable to them.

Indemnification Agreements

        Our restated certificate of incorporation, or certificate of incorporation, provides that we will indemnify our directors and officers to the fullest extent permitted by Delaware law. In addition, we have entered into indemnification agreements with our directors and executive officers. These indemnification agreements may require us, among other things, to indemnify each such director and executive officer for some expenses, including attorneys' fees, judgments, fines and settlement amounts incurred by him in any action or proceeding arising out of his or her service as one of our directors and/or executive officers. Certain of our non-employee directors may, through their relationships with their employers, be insured and/or indemnified against certain liabilities incurred in their capacity as members of our Board.

Policies and Procedures for Related Person Transactions

        Our Board has adopted written policies and procedures for the review of any transaction, arrangement or relationship in which our company is a participant, the amount involved exceeds $120,000 and one of our executive officers, directors, director nominees or 5% stockholders, or their immediate family members, each of whom we refer to as a "related person," has a direct or indirect material interest.

        If a related person proposes to enter into such a transaction, arrangement or relationship, which we refer to as a "related person transaction," the related person must report the proposed related person transaction to our Chief Legal Officer. The policy calls for the proposed related person transaction to be reviewed and, if deemed appropriate, approved by our Audit Committee. Whenever practicable, the reporting, review and approval will occur prior to entry into the transaction. If advance review and approval is not practicable, the Audit Committee will review, and, in its discretion, may ratify the related person transaction. The policy also permits the Chair of our Audit Committee to review and, if deemed appropriate, approve proposed related person transactions that arise between

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Audit Committee meetings, subject to ratification by the Audit Committee at its next meeting. Any related person transactions that are ongoing in nature will be reviewed annually.

        A related person transaction reviewed under the policy will be considered approved or ratified if it is authorized by our Audit Committee after full disclosure of the related person's interest in the transaction. As appropriate for the circumstances, the Audit Committee will review and consider:

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the related person's interest in the related person transaction;



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the approximate dollar value of the amount involved in the related person transaction;



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the approximate dollar value of the amount of the related person's interest in the transaction without regard to the amount of any profit or loss;



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whether the transaction was undertaken in the ordinary course of our business;



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whether the terms of the transaction are no less favorable to us than terms that could have been reached with an unrelated third party;



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the purpose of, and the potential benefits to us of, the transaction; and



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any other information regarding the related person transaction or the related person in the context of the proposed transaction that would be material to investors in light of the circumstances of the particular transaction.

        Our Audit Committee may approve or ratify the transaction only if the Audit Committee determines that, under all of the circumstances, the transaction is in our best interests. The Audit Committee may impose any conditions on the related person transaction that it deems appropriate.

        In addition to the transactions that are excluded by the instructions to the SEC's related person transaction disclosure rule, our Board has determined that the following transactions do not create a material direct or indirect interest on behalf of related persons and, therefore, are not related person transactions for purposes of this policy:

•

interests arising solely from the related person's position as an executive officer of another entity (whether or not the person is also a director of such entity) that is a participant in the transaction, where (a) the related person and all other related persons own in the aggregate less than a 10% equity interest in such entity, (b) the related person and his or her immediate family members are not involved in the negotiation of the terms of the transaction and do not receive any special benefits as a result of the transaction and (c) the amount involved in the transaction is less than the greater of $200,000 or 5% of the annual gross revenues of our company receiving payment under the transaction; and



•

a transaction that is specifically contemplated by provisions of our certificate of incorporation or our bylaws.

        The policy provides that transactions involving compensation of executive officers shall be reviewed and approved by our Compensation Committee in the manner specified in its charter.

        With respect to related person transactions prior to our initial public offering, it was the practice of our Board to consider the nature of and business reason for such transactions, how the terms of such transactions compared to those which might be obtained from unaffiliated third parties and whether such transactions were otherwise fair to and in the best interests of, or not contrary to, our best interests. In addition, all related person transactions required prior approval, or later ratification, by our Board.

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PRINCIPAL STOCKHOLDERS

        The following table sets forth information, to the extent known by us or ascertainable from public filings, with respect to the beneficial ownership of our common stock as of April 15, 2014, except as otherwise indicated in the table below, by each of our directors; each of our named executive officers; all of our directors and executive officers as a group; and each person, or group of affiliated persons, who is known by us to beneficially own more than 5% of our common stock.

        The column entitled "Percentage of shares beneficially owned" is based on a total of 30,076,773 shares of our common stock outstanding as of April 15, 2014.

        Beneficial ownership is determined in accordance with the rules and regulations of the SEC and includes voting or investment power with respect to our common stock. Shares of our common stock subject to options or warrants that are currently exercisable or exercisable within 60 days of April 15, 2014 are considered outstanding and beneficially owned by the person holding the options or warrants for the purpose of calculating the percentage ownership of that person but not for the purpose of calculating the percentage ownership of any other person. Except as otherwise noted, the persons and entities in this table have sole voting and investing power with respect to all of the shares of our common stock beneficially owned by them, subject to community property laws, where applicable.

        Except as otherwise indicated in the table below, addresses of named beneficial owners are in care of PTC Therapeutics Inc., 100 Corporate Court, South Plainfield, New Jersey 07080.

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SECTION 16(A) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

        Section 16(a) of the Exchange Act requires our directors and executive officers and beneficial owners of more than 10% of our common stock to file reports of ownership and changes of ownership with the SEC on Forms 3, 4 and 5. The SEC has designated specific deadlines for these reports and we must identify in this proxy statement those persons who did not file these reports when due.

        We believe that, during fiscal 2013, our directors, executive officers and beneficial owners of more than 10% of our common stock timely complied with all applicable filing requirements, with the exception of the late filing of a Form 3 by Vulcan Ventures Inc., the late filing of a Form 3 by HBM Healthcare Investments (Cayman) Ltd., or HBM, the late filing of a Form 4 by HBM reporting the conversion of series four and series five Senior preferred stock and the purchase of our common stock by HBM, the late reporting on Form 3 of an option award granted to Dr. Koppel, and the late filing of a Form 4 by Dr. Koppel reporting the conversion of series four senior preferred stock and the purchase of our common stock by Brookside Capital Partners Fund, L.P. In making these disclosures, we relied solely on a review of copies of such reports filed with the SEC and furnished to us and written representations that no other reports were required.

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PROPOSAL 1: ELECTION OF DIRECTORS

Information Regarding Directors and Director Nominees

Board Composition

        Our Board currently consists of ten directors, each of whom was elected as a director prior to our initial public offering. Our certificate of incorporation provides for the classification of our Board into three classes, each having as nearly an equal number of directors as possible. The terms of service of the three classes are staggered so that the term of one class expires each year. At each annual meeting of stockholders, directors are elected for a full term of three years to continue in office or to succeed those directors whose terms are expiring. Our directors hold office until their successors have been elected and qualified, or until the earlier of their resignation or removal.

        At the Annual Meeting, stockholders will be asked to consider the election of Stuart W. Peltz, Ph.D., Jerome B. Zeldis, M.D., Ph.D., and Ronald C. Renaud, Jr. Mr. Renaud is being nominated for election as director for the first time and was originally proposed to us as a director nominee by CTPartners, a third-party search firm engaged by our Nominating and Corporate Governance Committee to identify potential director candidates. Upon the recommendation of our Nominating and Corporate Governance Committee, our Board has nominated Drs. Peltz and Zeldis and Mr. Renaud for election at the Annual Meeting as Class I directors, each to serve until 2017.

        Each of the director nominees has indicated his willingness to serve on our Board, if elected. If any director nominee should be unable to serve, the person acting under the proxy may vote the proxy for a substitute director nominee designated by our Board. We do not contemplate that any of the director nominees will be unable to serve if elected.

        Unless otherwise instructed in the proxy, all proxies will be voted "FOR" the election of each of the director nominees identified above to a three-year term ending in 2017, each such director nominee to hold office until his successor has been duly elected and qualified.

        A plurality of the voting power of the shares of common stock present in person or represented by proxy at the Annual Meeting and entitled to vote is required to elect each director nominee as a director.

Our Board Recommends that You Vote "FOR" the Election of

Stuart W. Peltz, Ph.D., Jerome B. Zeldis, M.D., Ph.D., and Ronald C. Renaud, Jr.

Biographical Information

        The following table and biographical descriptions provide information as of April 15, 2014 relating to each director nominee and each director continuing in office, including his age and period of service as a director of our company; his committee memberships; his business experience during the past five years, including directorships at other public companies; his community activities; and the other experience, qualifications, attributes or skills that led our Board to conclude he should serve as a director of our company.

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        There are no family relationships between or among any of our directors or director nominees. The principal occupation and employment during the past five years of each of our directors and director nominees was carried on, in each case except as specifically identified above, with a corporation or organization that is not a parent, subsidiary or other affiliate of us. There is no arrangement or understanding between any of our directors or director nominees and any other person or persons pursuant to which he was or is to be selected as a director or director nominee.

        Our certificate of incorporation and bylaws provide that the authorized number of directors may be changed only by resolution of our Board; that our directors may be removed only for cause by the affirmative vote of the holders of at least 75% of the votes entitled to be cast in an annual election of directors; and that any vacancy on our Board, including a vacancy resulting from an enlargement of our Board, may be filled only by vote of a majority of our directors then in office.

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PROPOSAL 2: RATIFICATION OF SELECTION OF
INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

        Our Audit Committee has appointed the firm of Ernst & Young LLP, an independent registered public accounting firm, to audit our books, records and accounts for the fiscal year ended December 31, 2014, or fiscal 2014. This appointment is being presented to the stockholders for ratification at the Annual Meeting.

        Ernst & Young LLP was our independent registered public accounting firm for fiscal 2013 and for the fiscal year ended December 31, 2012, or fiscal 2012. Ernst & Young LLP has no direct or indirect material financial interest in our company or our subsidiaries. Representatives of Ernst & Young LLP are expected to be present at the Annual Meeting and will be given the opportunity to make a statement on the firm's behalf if they so desire. The representatives also will be available to respond to appropriate questions.

        Our Audit Committee is solely responsible for selecting our independent registered public accounting firm for fiscal 2014. Although we are not required to submit the appointment to a vote of the stockholders, our Board believes that it is appropriate as a matter of good corporate governance to request that the stockholders ratify the appointment of Ernst & Young LLP as our independent registered public accounting firm.

        If the stockholders do not ratify the appointment, our Audit Committee will investigate the reasons for stockholder rejection and may reconsider its appointment of Ernst & Young LLP as our independent registered public accounting firm for fiscal 2014 and may appoint another independent registered public accounting firm. Even if the appointment is ratified, our Audit Committee in their discretion may direct the appointment of a different independent registered public accounting firm at any time during the year if they determine that such a change would be in the best interests of our company and our stockholders.

        A majority of the voting power of the shares of common stock cast on this matter is required to approve this proposal. Unless otherwise instructed in the proxy, all proxies will be voted "FOR" the ratification of Ernst & Young LLP.

        Our Board Recommends that You Vote "FOR" the Ratification of Ernst & Young LLP as our Independent Registered Public Accounting Firm for the Fiscal Year Ending December 31, 2014.

Fees Paid to Independent Registered Public Accounting Firm

        The following table sets forth the fees that we paid to Ernst & Young LLP during fiscal 2012 and 2013:

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        Our Audit Committee determined that the provision of the non-audit services by Ernst & Young LLP described above is compatible with maintaining Ernst & Young LLP's independence.

Audit Committee Pre-Approval Policy and Procedures

        Our Audit Committee as a whole, or through its Chair, pre-approves all audit and non-audit services (including fees) to be provided by the independent registered public accounting firm. Our Audit Committee has delegated to the Chair of our Audit Committee the authority to pre-approve non-audit services not prohibited by law to be performed by Ernst & Young LLP and associated fees, provided that the Chair of our Audit Committee reports any decisions to pre-approve such services and fees to the full Audit Committee at its next regular meeting. All services provided by Ernst & Young LLP during 2012 and 2013were pre-approved by the Audit Committee.

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REPORT OF THE AUDIT COMMITTEE OF THE BOARD OF DIRECTORS

        The Audit Committee has reviewed and discussed the audited financial statements of PTC Therapeutics, Inc. for the fiscal year ended December 31, 2013 with management.

        The Audit Committee has discussed with Ernst & Young LLP, our independent registered public accounting firm, the matters required to be discussed by Auditing Standard No. 16, as modified or supplemented (communication with audit committees), as adopted by the Public Company Accounting Oversight Board.

        The Audit Committee has received the written disclosures and the letter from Ernst & Young LLP required by applicable requirements of the Public Company Accounting Oversight Board regarding Ernst & Young LLP's communications with the Audit Committee concerning independence, and has discussed Ernst & Young LLP's independence from us with Ernst & Young LLP.

        Based on the review and discussions referred to in the foregoing paragraphs, the Audit Committee recommended to the Board that the audited financial statements for the fiscal year ended December 31, 2013 be included in the company's Annual Report on Form 10-K for the fiscal year ended December 31, 2013.

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EXECUTIVE OFFICERS

        The following table and biographical descriptions provide information as of April 15, 2014 relating to each of our executive officers, other than Dr. Peltz, who also serves as a director of the company. Dr. Peltz's biographical information is presented above in this proxy statement under the heading "Item 1—Election of Directors—Biographical Information."

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        There are no family relationships between or among any of our executive officers. There is no arrangement or understanding between any of our executive officers and any other person or persons pursuant to which he and she was or is to be selected as an executive officer.

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EXECUTIVE COMPENSATION

        This section describes the material elements of compensation awarded to, earned by or paid to each of our named executive officers in 2013 and 2012. Our "named executive officers" for 2013 are Stuart W. Peltz, our Chief Executive Officer, Claudia Hirawat, our President, and Mark A. Rothera, our Chief Commercial Officer. This section also provides qualitative information regarding the manner and context in which compensation is awarded to and earned by our executive officers and is intended to place in perspective the data presented in the tables and narrative that follow.

Summary Compensation Table

        The following table sets forth information regarding compensation awarded to, earned by or paid to our named executive officers during 2013 and 2012:

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Narrative Disclosure to Summary Compensation Table

        In 2013, we paid base salaries of $460,753 to Dr. Peltz, $316,209 to Ms. Hirawat and $400,000 to Mr. Rothera, and in 2012, we paid base salaries of $446,250 to Dr. Peltz and $281,039 to Ms. Hirawat. Mr. Rothera has served as our Chief Commercial Officer since April 2013 and was not employed by us before that date. Base salaries are used to recognize the experience, skills, knowledge and responsibilities required of all our employees, including our named executive officers. None of our named executive officers is currently party to an employment agreement or other agreement or arrangement that provides for automatic or scheduled increases in base salary. In addition, for 2013, we paid cash amounts under our annual cash incentive plan of $290,000 to Dr. Peltz, $195,840 to Ms. Hirawat and $211,200 to Mr. Rothera, and for 2012, we paid cash amounts under our annual cash incentive plan of $204,829 to Dr. Peltz and $83,609 to Ms. Hirawat.

        Although we do not have a formal policy with respect to the grant of equity incentive awards to our executive officers, or any formal equity ownership guidelines applicable to them, we believe that equity grants provide our executives with a strong link to our long-term performance, create an ownership culture and help to align the interests of our executives and our stockholders. In addition, we believe that equity grants with a time-based vesting feature promote executive retention because this feature incents our executive officers to remain in our employment during the vesting period. Accordingly, our Board periodically reviews the equity incentive compensation of our named executive officers and from time to time may grant equity incentive awards to them in the form of stock options. In 2013, based upon our overall performance, we granted to Dr. Peltz 188,803 shares of restricted stock and options to purchase an aggregate of 571,000 shares of our common stock, to Ms. Hirawat 50,057 shares of restricted stock and options to purchase an aggregate of 135,000 shares of our common stock, and to Mr. Rothera options to purchase an aggregate of 165,000 shares of our common stock. In 2012, based upon our overall performance, we granted to Dr. Peltz an option to purchase 416 shares of our common stock and to Ms. Hirawat an option to purchase 191 shares of our common stock.

Outstanding Equity Awards at December 31, 2013

        The following table sets forth information regarding outstanding stock options and restricted stock awards held by our named executive officers as of December 31, 2013:

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        In January 2014, our Board granted stock options to our executive officers, including our named executive officers, pursuant to our 2013 long term incentive plan, or the 2013 public company plan, as follows:

Additional Narrative Disclosure

Employment Agreements with Executive Officers

        In May 2013, we entered into employment agreements with our executive officers serving at that time. These agreements amended and restated existing employment agreements that we had previously entered into with Dr. Peltz, Ms. Hirawat and Messrs. Boulding and Almstead. Effective as of January 23, 2014, we entered into an employment agreement with Dr. Spiegel in connection with his appointment as our Chief Medical Officer on a full-time basis in January 2014.

        Each of our existing employment agreements with our executive officers provides that employment will continue until either we or the executive officer provides written notice of termination in accordance with the terms of the agreement. In addition, each of these agreements prohibits our executive officers from disclosing confidential information and competing with us during the term of their employment and for a specified time thereafter.

        Pursuant to their respective employment agreements, prior to the consummation of our initial public offering, each of our executive officers was entitled to receive an annual base salary as follows: Dr. Peltz: $460,000; Ms. Hirawat: $289,470; Mr. Boulding: $312,998; Mr. Rothera: $400,000; Mr. Almstead: $273,156; and Mr. Kovacs: $335,000. From and after the consummation of our initial public offering, each of our executive officers is entitled to receive an annual base salary as follows: Dr. Peltz: $460,000; Ms. Hirawat: $340,000; Mr. Boulding: $330,000; Mr. Rothera: $400,000; Mr. Almstead: $295,000; and Mr. Kovacs: $335,000. Dr. Spiegel is entitled to an annual base salary of $350,000.

        In addition, each of our executive officers is eligible to receive an annual cash incentive award, which is based on the percentage achievement of all corporate, individual and functional performance objectives in aggregate and calculated as a percentage of the executive's annual base salary, and which will be determined by our Board, in its sole discretion. For 2013, Dr. Peltz's target annual cash incentive award was 50% of his annual base salary, and the target annual cash incentive award for each of our other executive officers was 40% of his or her annual base salary, and for 2014, Dr. Peltz's target annual cash incentive award was 50% of his annual base salary, and the target annual cash incentive award for each of our other executive officers was 40% of his or her annual base salary.

        Upon execution and effectiveness of a release of claims, each of our executive officers will be entitled to severance payments if his or her employment is terminated under specified circumstances.

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Potential payments upon termination or change in control

        Dr. Peltz.    If we terminate Dr. Peltz's employment without cause or if Dr. Peltz terminates his employment with us for good reason, each as defined in his employment agreement, absent a change in control, or "corporate change", as defined in his employment agreement, we are obligated to: pay Dr. Peltz a lump sum amount equal to his base salary for 18 months; accelerate 25% of Dr. Peltz's outstanding unvested equity awards granted on or prior to May 15, 2013 other than the restricted stock awards granted in March 2013, which unvested restricted stock awards will accelerate in full; extend the exercise period of certain of Dr. Peltz's option awards, subject to specified limitations; and, to the extent allowed by applicable law and the applicable plan documents, continue to provide Dr. Peltz and certain of his dependents with group health insurance for a period of 18 months.

        If we terminate Dr. Peltz's employment without cause or if Dr. Peltz terminates his employment with us for good reason, in each case within six months prior to or 18 months following a corporate change, we are obligated to: pay Dr. Peltz a lump sum amount equal to his base salary for 24 months; accelerate in full the vesting of all of Dr. Peltz's outstanding equity awards; extend the exercise period of certain of Dr. Peltz's option awards, subject to specified limitations; pay Dr. Peltz his target annual bonus for the year in which he is terminated; and, to the extent allowed by applicable law and the applicable plan documents, continue to provide Dr. Peltz and certain of his dependents with group health insurance for a period of 24 months.

        If under any circumstances we terminate Dr. Peltz's employment without cause or if Dr. Peltz terminates his employment with us for good reason, we are obligated to: engage Dr. Peltz as a consultant for up to 24 months, at his per-diem base salary rate immediately before termination of his employment plus reimbursement of reasonable out-of-pocket expenses, in order to transition Dr. Peltz's responsibilities as our Chief Executive Officer to his successor; and, subject to specified limitations, permit Dr. Peltz to continue to purchase coverage under our group health insurance plan following the expiration of any benefits continuation provided by us as described above until such time as he is eligible for Medicare.

        In the event of a corporate change, regardless of whether Dr. Peltz's employment with us is terminated, we are obligated to accelerate 50% of Dr. Peltz's outstanding unvested option awards granted in May 2013 and 100% of Dr. Peltz's unvested restricted stock awards granted in March 2013.

        Other executive officers.    For our executive officers other than Dr. Peltz, if we terminate an executive officer's employment without cause or if an executive officer terminates his or her employment with us for good reason, each as defined in such executive officer's employment agreement, in each case absent a change in control, or "corporate change", as defined the employment agreement, we are obligated to: pay such executive officer's base salary for a period of 12 months; to the extent allowed by applicable law and the applicable plan documents, continue to provide to such executive officer and certain of his or her dependents with group health insurance for a period of 12 months; and, upon a termination without cause only, accelerate in full the vesting of each executive officer's outstanding unvested restricted stock awards granted in March 2013.

        If we terminate any such executive officer's employment without cause or if such executive officer terminates his or her employment with us for good reason, in each case within three months prior to or 12 months following a corporate change, we are obligated to: pay such executive officer a lump sum amount equal to his or her base salary for 12 months; to the extent allowed by applicable law and the applicable plan documents, continue to provide to such executive officer and certain of his or her dependents with group health insurance for a period of 12 months; accelerate in full the vesting of all outstanding equity awards held by such executive officer; and pay each such executive officer his or her target annual bonus for the year in which he or she is terminated.

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        In the event of a corporate change, regardless of whether any executive officer's employment with us is terminated, we are obligated to accelerate 50% of each such executive officer's outstanding unvested option awards granted in May 2013 and 100% of each executive officer's outstanding unvested restricted stock awards granted in March 2013.

        Indemnification.    In addition, we have agreed to indemnify Dr. Peltz and each of our other executive officers in any action or proceeding arising out of his service to us, unless he initiates such action or proceeding. These indemnification obligations may require us, among other things, to indemnify such executive for certain expenses, including attorneys' fees, that are incurred by him or her, and to advance to the executive such expenses upon request.

        Taxation.    To the extent that any severance or other compensation payment to any of our executive officers pursuant to an employment agreement or any other agreement constitutes an "excess parachute payment" within the meaning of Sections 280G and 4999 of the Internal Revenue Code of 1986, as amended, then such executive officer will receive the full amount of such severance and other payments, or a reduced amount intended to avoid the application of Sections 280G and 4999, whichever provides the executive with the highest amount on an after-tax basis.

401(k) Retirement Plan

        We maintain a 401(k) retirement plan that is intended to be a tax-qualified defined contribution plan under Section 401(k) of the Internal Revenue Code. In general, all of our employees are eligible to participate, beginning on the first day of the month following commencement of their employment. The 401(k) plan includes a salary deferral arrangement pursuant to which participants may elect to reduce their current compensation by up to the statutorily prescribed limit, equal to $17,500 in 2014, and have the amount of the reduction contributed to the 401(k) plan. During fiscal 2013, we provided a 20% matching contribution for up to the first 5% of each contributing employee's base salary contributions.

Rule 10b5-1 Sales Plans

        Our directors and executive officers may adopt written plans, known as Rule 10b5-1 plans, in which they will contract with a broker to buy or sell shares of our common stock on a periodic basis. Under a Rule 10b5-1 plan, a broker executes trades pursuant to parameters established by the director or officer when entering into the plan, without further direction from the director or officer. The director or officer may amend or terminate the plan in some circumstances. Our directors and executive officers may also buy or sell additional shares outside of a Rule 10b5-1 plan when they are not in possession of material, nonpublic information.

EQUITY COMPENSATION PLAN INFORMATION

        The four equity incentive plans discussed in this section are the 1998 employee, director and consultant stock option plan, as amended and restated, or the 1998 plan, the 2009 equity and long term incentive plan, as amended, or the 2009 plan, the 2013 stock incentive plan, or the 2013 plan, and the 2013 long-term incentive plan, or the 2013 public company plan.

        Prior to the closing of our initial public offering, we granted awards to eligible participants under the 1998 plan, the 2009 plan and the 2013 plan. Awards granted under these plans prior to our initial public offering remain outstanding under the applicable plan. Any shares of common stock subject to awards under the 2013 plan or 2009 plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased without having been fully exercised or resulting in any common stock being issued will be available for grant under the 2013 public company plan up to a specified number of shares.

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        Since the closing of our initial public offering in June 2013, we have granted awards to eligible participants under the 2013 public company plan only.

        The following table sets forth information as of December 31, 2013 with respect to compensation plans under which shares of our common stock are authorized for issuance:

2013 Long Term Incentive Plan

        In May 2013, our Board adopted, and our stockholders subsequently approved, the 2013 public company plan, which became effective immediately prior to the closing of our initial public offering in June 2013. The 2013 public company plan provides for the grant of incentive stock options, nonstatutory stock options, restricted stock awards and other stock-based awards.

        Our employees, officers, directors, consultants and advisors are eligible to receive awards under the 2013 public company plan. However, incentive stock options may only be granted to our employees.

        Pursuant to the terms of the 2013 public company plan, our Board has delegated the administration of the plan to our Compensation Committee. Subject to any limitations in the plan, the Compensation Committee selects the recipients of awards and determines:

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the number of shares of our common stock covered by options and the dates upon which the options become exercisable;



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the type of options to be granted;



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the duration of options, which may not be in excess of ten years;

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the exercise price of options, which must be at least equal to the fair market value of our common stock on the date of grant; and



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the number of shares of our common stock subject to and the terms of any stock appreciation rights, restricted stock awards, restricted stock units or other stock-based awards and the terms and conditions of such awards, including conditions for repurchase, issue price and repurchase price.

        In accordance with the terms of the 2013 public company plan, the Compensation Committee has delegated limited authority to our Chief Executive Officer to grant stock options to certain non-executive employees. Our Compensation Committee has fixed the terms of the awards to be granted by such executive officer, including the exercise price of such awards, and the maximum number of shares that may be granted.

        Upon a merger or other reorganization event, our Board may, in its sole discretion, take any one or more of the following actions pursuant to the 2013 public company plan as to some or all outstanding awards other than restricted stock:

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provide that all outstanding awards shall be assumed, or substantially equivalent awards shall be substituted, by the acquiring or successor corporation (or an affiliate thereof);



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upon written notice to a participant, provide that all of the participant's unexercised awards will terminate immediately prior to the consummation of such reorganization event unless exercised by the participant;



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provide that outstanding awards shall become exercisable, realizable or deliverable, or restrictions applicable to an award shall lapse, in whole or in part, prior to or upon such reorganization event;



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in the event of a reorganization event pursuant to which holders of shares of our common stock will receive a cash payment for each share surrendered in the reorganization event, make or provide for a cash payment to the participants with respect to each award held by a participant equal to (1) the number of shares of our common stock subject to the vested portion of the award (after giving effect to any acceleration of vesting that occurs upon or immediately prior to such reorganization event) multiplied by (2) the excess, if any, of the cash payment for each share surrendered in the reorganization event over the exercise, measurement or purchase price of such award and any applicable tax withholdings, in exchange for the termination of such award; and/or



•

provide that, in connection with a liquidation or dissolution, awards shall convert into the right to receive liquidation proceeds.

        Our Board does not need to take the same action with respect to all awards and may take different actions with respect to portions of the same award.

        Upon the occurrence of a reorganization event other than a liquidation or dissolution, the repurchase and other rights with respect to outstanding restricted stock awards will continue for the benefit of the successor company and will, unless our Board may otherwise determine, apply to the cash, securities or other property into which shares of our common stock are converted or exchanged pursuant to the reorganization event. Upon the occurrence of a reorganization event involving a liquidation or dissolution, all restrictions and conditions on each outstanding restricted stock award will automatically be deemed terminated or satisfied, unless otherwise provided in the agreement evidencing the restricted stock award.

        At any time, our Board may, in its sole discretion, provide that any award under the 2013 public company plan will become immediately exercisable in full or in part, free of some or all restrictions or conditions, or otherwise realizable in full or in part.

        No award may be granted under the 2013 public company plan on or after June 3, 2023. Our Board may amend, suspend or terminate the 2013 public company plan at any time, except that stockholder approval may be required to comply with applicable law or stock market requirements.

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DIRECTOR COMPENSATION

        The following table sets forth information regarding compensation awarded to, earned by or paid to our directors, other than Dr. Peltz, during 2013:

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Narrative to Director Compensation Table

        In May 2013, in connection with our initial public offering, our Board approved a new compensation policy for our non-employee directors. This policy provides for the following compensation for our non-employee directors, effective upon the closing of our initial public offering:

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an annual retainer for board service of $35,000;



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for any newly elected non-employee director, an option grant to purchase 20,000 shares of our common stock, which option vests annually over three years;



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an annual option grant to purchase 10,000 shares of our common stock, which option vests in full on the first anniversary of the date of grant;



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for our Chair of the Board, an additional annual option grant to purchase 10,000 shares of our common stock, which option vests in full on the first anniversary of the date of grant;



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for members of our Audit Committee, an additional annual retainer of $8,000 ($16,000 for the Chair);



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for members of our Compensation Committee, an additional annual retainer of $5,000 ($10,000 for the Chair); and



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for members of our Nominating and Corporate Governance Committee, an additional annual retainer of $3,000 ($6,000 for the Chair).

        The stock options granted to our non-employee directors have an exercise price equal to the fair market value of our common stock on the date of grant and expire ten years after the date of grant, subject to the director's continued service to us.

        Each member of our Board is also entitled to reimbursement for reasonable travel and other expenses incurred in connection with attending meetings of the Board and any committee on which he serves.

        Prior to the closing of our initial public offering in June 2013, our non-employee directors were generally compensated for their services on our Board in the form of option grants. The option grants reported in the Director Compensation table were awarded prior our initial public offering. In addition, in March 2013, as reported in the Director Compensation table, certain directors were granted a restricted stock award. Half of each restricted stock award vested in March 2014 and the remaining half of each award will vest in March 2015.

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STOCKHOLDER PROPOSALS AND NOMINATIONS FOR DIRECTOR

Stockholder Proposals to be Included in the 2015 Proxy Statement

        To be considered for inclusion in the proxy statement relating to the annual meeting of stockholders to be held in 2015, we must receive stockholder proposals no later than December 29, 2014, which is a date no less than 120 calendar days before the date on which our proxy statement was released to stockholders in connection with this year's Annual Meeting. If the date of next year's annual meeting is changed by more than 30 days from the anniversary date of this year's annual meeting on June 10, 2014, then the deadline is a reasonable time before we begin to print and mail proxy materials. Upon receipt of any such proposal, we will determine whether or not to include such proposal in the proxy statement and proxy in accordance with the rules and regulations governing the solicitation of proxies.

Stockholder Proposals to be Brought Before the 2015 Annual Meeting (not included in the proxy statement)

        Our bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of stockholders, including proposed nominations of persons for election to our Board. Stockholders at an annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of our Board or by a stockholder of record on the record date for the meeting, who is entitled to vote at the meeting and who has delivered timely notice of the stockholder's intention to bring such business before the meeting in proper form.

        We must receive written notice of stockholder proposals (including director nominations) intended to be presented at the 2015 annual meeting of stockholders but that will not be included in the proxy statement by February 10, 2015, but not before March 12, 2015, which is not less than 90 days nor more than 120 days prior to the first anniversary of this year's annual meeting. However, in the event that the date of next year's annual meeting is advanced by more than 20 days, or delayed by more than 60 days, from the first anniversary of this year's annual meeting, we must receive written notice of stockholder proposals no earlier than the 120th day prior to such annual meeting and not later than the close of business on the later of (A) the 90th day prior to such annual meeting and (B) the tenth day following the day on which notice of the date of such annual meeting was mailed or public disclosure of the date of such annual meeting was made, whichever first occurs.

        Any proposals we do not receive in accordance with the above standards will not be voted on at the 2015 annual meeting. The foregoing time limits also apply to determining whether notice is timely for purposes of rules adopted by the SEC relating to the exercise of discretionary voting authority. These rules are separate from and in addition to the requirements a stockholder must meet to have a proposal included in our proxy statement. In addition, stockholders are required to comply with any applicable requirements of the Exchange Act and the rules and regulations thereunder.

Content of Notices of Stockholder Proposals to be Brought Before the Annual Meeting

        Each stockholder's notice for a proposal must be timely given to our Secretary at the address of our principal executive offices. The requirements for a stockholder notice are more fully set forth in Sections 1.10 and 1.11 of our bylaws, and the following summary is qualified by reference to the applicable sections of our bylaws.

        Each notice generally is required to set forth certain information as to each matter proposed to be brought before an annual meeting and must meet other requirements specified in our bylaws, as determined by us, including, but not limited to, (1) a brief description of the business the stockholder desires to bring before the meeting (including the exact text of any resolutions proposed for

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consideration) and the reasons for conducting such business at the meeting, (2) the name and address, as they appear on our stock transfer books, of the stockholder proposing such business, (3) the class and number of shares beneficially owned by the stockholder making the proposal, (4) the names and addresses of the beneficial owners of any of our capital stock registered in such stockholder's name, and the class and number of our shares so owned, (5) the names and addresses of other stockholders known by the stockholder proposing such business to support such proposal, and the class and number of our shares beneficially owned by such other stockholders, and (6) any material interest of the stockholder proposing to bring such business before such meeting (or any other stockholders known to be supporting such proposal) in such proposal.

        For director nominations, a stockholder's notice to the Secretary generally must set forth further information specified in our bylaws, as determined by us, as to each person proposed to be nominated, including, but not limited to, (1) the name, age, business and residence address of such person, (2) the principal occupation of such person, (3) the class and number of our shares which are beneficially owned by such person on the date of such stockholder notice, and (4) the consent of each director nominee to serve as a director if elected. The notice must also set forth as to the stockholder giving the notice a description of all arrangements or understandings between such stockholder and each director nominee and any other person or persons (naming such person or persons) pursuant to which the nomination(s) are to be made by such stockholder.

HOUSEHOLDING OF PROXIES

        The SEC has adopted rules that permit companies and intermediaries such as brokers to satisfy delivery requirements for annual reports and proxy statements with respect to two or more stockholders sharing the same address by delivering a single annual report and/or proxy statement addressed to those stockholders. This process, which is commonly referred to as "householding," potentially provides extra convenience for stockholders and cost savings for companies. We and some brokers household proxy materials, delivering a single annual report and/or proxy statement to multiple stockholders sharing an address unless contrary instructions have been received from the affected stockholders. Once you have received notice from your broker or us that they or we will be householding materials to your address, householding will continue until you are notified otherwise or until you revoke your consent. If, at any time, (1) you no longer wish to participate in householding and would prefer to receive a separate set of proxy materials in the future or (2) you and another stockholder sharing the same address wish to participate in householding and prefer to receive a single copy of our proxy materials, please notify your broker if your shares are held in a brokerage account or us if you hold registered shares. You can notify us by sending a written request to Director, Corporate Communications, PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, New Jersey 07080 or via e-mail at irpr@ptcbio.com.

OTHER MATTERS

        As of the date of this proxy statement, we know of no matter not specifically referred to above as to which any action is expected to be taken at the Annual Meeting. The persons named as proxies will vote the proxies, insofar as they are not otherwise instructed, regarding such other matters and the transaction of such other business as may be properly brought before the meeting, as seems to them to be in the best interest of our company and our stockholders.

        Your vote is important. Please vote your proxy promptly so your shares are represented, even if you plan to attend the Annual Meeting. You may vote by Internet, by telephone, by requesting a printed copy of the proxy materials and using the enclosed proxy card or in person at the Annual Meeting. Your cooperation in giving this your immediate attention will be appreciated.

        You may obtain a copy of our Annual Report on Form 10-K for fiscal 2013, as filed with the SEC, except exhibits, without charge upon written request to Director, Corporate Communications, PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, New Jersey 07080.

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