April 3, 2023

Dear Fellow Shareholder:

You are cordially invited to attend the 2023 Annual Meeting of Shareholders of Koppers Holdings Inc. (Koppers). The meeting will be held via live virtual meeting webcast on Thursday, May 4, 2023, beginning at 10:00 a.m. Eastern Daylight Time.

Purpose of Our Meeting

The purpose of the meeting will be to elect nine directors, to hold an advisory vote on named executive officer compensation, to hold an advisory vote on the frequency of future advisory votes on named executive officer compensation and to ratify the audit committee’s appointment of KPMG LLP as our independent registered public accounting firm for fiscal year 2023.

This booklet includes the Notice of Annual Meeting and Proxy Statement. The proxy statement describes the business we will conduct at the meeting and provides information about Koppers that you should consider when you vote your shares. Also enclosed is our Annual Report, which includes our consolidated financial statements for 2022.

Your Vote is Important

Your vote is important regardless of how many shares you own and I urge you to vote your shares. Whether or not you plan to attend the annual meeting, please provide your proxy via Internet, telephone or sign, date and return the proxy card in the enclosed envelope to make sure that your shares are voted at the meeting. Voting your shares by proxy does not limit your right to be present at the virtual meeting and vote your shares electronically during the virtual annual meeting.

I appreciate your continued confidence in Koppers.

There will be no in-person annual meeting. The meeting will be held virtually over the Internet and you will be able to attend and participate in the annual meeting online, vote your shares electronically and submit your questions prior to and during the meeting by visiting meetnow.global/M24GAKH. The meeting will begin promptly at 10:00 a.m. Eastern Daylight Time and online access will open 15 minutes prior to allow time to log-in. Please follow these instructions to attend and participate in the annual meeting online:

Registered Shareholders:

If your shares are registered in your name with our transfer agent and you wish to attend the online-only virtual meeting, please use the website set forth above and the voter control number that is located on your proxy card to log-in to the meeting at the date and time set forth above.

Beneficial Shareholders (those holding shares through a brokerage account or by a bank or other holder of record):

If you hold your shares through an intermediary, such as a bank, broker or other holder of record, there are two ways to attend the online-only virtual annual meeting:

Please note, however, that this option is intended to be provided as a convenience to beneficial shareholders and will not be available to all beneficial shareholders because only certain intermediaries provide a voter control number along with the voting instruction form. The inability to provide this option to any or all beneficial shareholders in no way impacts the validity of the virtual annual meeting. All beneficial shareholders, including those who do not receive a voter control number from an intermediary, may choose to obtain a legal proxy as set forth below.

Requests for registration must be labeled as “Legal Proxy” and be received no later than 5:00 p.m. Eastern Daylight Time on Monday, May 1, 2023. You will receive a confirmation of your registration by email with a voter control number after we receive your valid registration materials. In order to attend the online-only virtual meeting, please use the website set forth above and the voter control number that you receive to log-in to the meeting at the date and time set forth above. Requests for registration should be directed to us by forwarding the email from your broker granting you a legal proxy, or attaching a legible photograph of your legal proxy, to legalproxy@computershare.com.

We have designed the virtual meeting to provide similar opportunities to participate as you would have at an in-person meeting. In order to maintain the interactive nature of the virtual meeting, virtual attendees are able to:

Record Date:

You can vote if you were a shareholder of record on March 20, 2023.

If the annual meeting is adjourned because of the absence of a quorum, those shareholders entitled to vote who attend the adjourned annual meeting, although constituting less than a quorum as provided herein, shall nevertheless constitute a quorum for the purpose of electing directors. If the annual meeting is adjourned for one or more periods aggregating at least fifteen (15) days because of the absence of a quorum, those shareholders entitled to vote who attend the reconvened annual meeting, if less than a quorum as determined under applicable law, shall nevertheless constitute a quorum for the purpose of acting upon any matter set forth in this Notice of Annual Meeting of Shareholders.

Admission to the Meeting:

You will not be able to attend the annual meeting in person. To attend the virtual annual meeting, please follow the instructions above.

By Order of the Board of Directors

Stephanie L. Apostolou

General Counsel and Secretary

April 3, 2023

TABLE OF CONTENTS

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General

We are asking shareholders to elect the nine nominees named in this proxy statement to serve on the board of directors of Koppers Holdings Inc. (the “company,” “Koppers,” “we” or “us”) until the 2024 Annual Meeting of Shareholders or until their successors have been duly elected and qualified.

On March 20, 2023, we increased the size of our board of directors from eight to nine directors and elected Andrew D. Sandifer as a director of the company.

Each nominee currently serves on our board of directors and has been nominated for election by our nominating and corporate governance committee and approved by our board. The board has nominated Leroy M. Ball, Xudong Feng, Ph.D., Traci L. Jensen, David L. Motley, Albert J. Neupaver, Andrew D. Sandifer, Louis L. Testoni, Stephen R. Tritch and Sonja M. Wilkerson for election.

Each nominee who is elected as a director will hold office for the length of their term or until the director’s death, resignation, incapacity or until the director’s successor shall be elected and shall qualify. Vacancies on the board of directors, including vacancies resulting from an increase in the number of directors, will be filled by a majority vote of the directors then in office, even if less than a quorum.

As set forth in our corporate governance guidelines, all directors, other than our CEO, who are first elected to the board of directors after August 2, 2017, will have a term limit of 15 years, unless the board approves an exception to this limit, which the board has the authority to do on a case-by-case basis. In addition, a director will not be eligible to stand for re-election as a director where he or she has reached the age of 75 before the date of election, unless the board approves an exception to this guideline, which the board has the authority to do on a case-by-case basis.

Vote Required

In any uncontested election of directors, each director will be elected if more votes are cast “for” the director’s election than are cast “against” the director’s election, with abstentions and broker non-votes not being counted as a vote cast either “for” or “against” the director’s election. A plurality standard will apply in any contested election of directors, which is an election in which the number of nominees for director exceeds the number of directors to be elected.

If any incumbent director fails to receive a majority of the votes cast in any uncontested election, the director will be required to tender his or her resignation to the board of directors within ten days following certification of the election results. The nominating and corporate governance committee of the board of directors, or such other committee as the board may designate, will then recommend to the board whether to accept or reject such director’s resignation, or whether other action should be taken. The nominating and corporate governance committee may consider any factors it considers appropriate or relevant in considering whether to accept or reject a director’s resignation, or whether other action should be taken. The board will act on the nominating and corporate governance committee’s recommendation and publicly disclose its decision within 120 days following the date of the certification of the election results. If the tendered resignation is accepted by the board, the board may fill the resulting vacancy or decrease the number of directors comprising the board in accordance with our bylaws.

Your proxy will be voted “FOR” the election of the nominees set forth in the proxy card, unless you vote against, or abstain from voting for or against, one or more of them. If any nominee is unable or unwilling to stand for election, your proxy authorizes us to vote for a replacement nominee if the board names one.

Director Qualifications

There are no specific minimum qualifications a nominee must meet in order to be recommended for the board. However, our nominating and corporate governance committee seeks to establish, as required by the committee’s charter, a board that consists of individuals from diverse educational and professional experiences and backgrounds, that, when taken as a whole, provide meaningful counsel to management. Board candidates are considered based upon various criteria, such as their broad-based business skills and experiences, prominence and reputation in their profession, global business perspective, concern for the long-term interests of our shareholders and personal integrity, values and judgment — all in the context of an assessment of the perceived needs of the board. In addition, directors must have significant time available to devote to board activities and to enhance their knowledge of our business. Although we do not have a

PROXY ITEM 1 — PROPOSAL FOR ELECTION OF DIRECTORS

formal policy with respect to diversity, our nominating and corporate governance committee considers the diversity of our board as a whole, including the skills, background and experience of our directors.

Our nominating and corporate governance committee believes each member of our board of directors possesses the individual qualities necessary to serve on the company’s board of directors, including high personal and professional ethical standards and integrity, honesty and good values. Our directors are highly educated and have diverse backgrounds and extensive track records of success in what we believe are highly relevant positions with large international companies, firms and major private and public institutions. They have each demonstrated an ability to exercise sound judgment and have exhibited a commitment of service to the company and to the board, and each of our directors possesses strong communication skills. In addition, we believe that each director brings the skills, experience and perspective that, when combined, creates a board that possesses the requirements necessary to oversee the company’s business. Each nominee’s particular experience, qualifications, attributes and skills that led the board to conclude that such nominee should serve as a director for the company are set forth below. The committee reviews the board membership criteria and modifies them as necessary each year.

Board Composition and Diversity

The board recommends a vote “FOR” the election of all nine nominees.

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Board Skills and Characteristics Summary

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Biographical Summaries of Nominees

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Board Meetings and Committees

Board Meetings

Our corporate governance guidelines provide that our directors are expected to attend the meetings of the board, the board committees on which they serve and the annual meeting of shareholders. All directors then in office typically attend all committee meetings. All directors then in office attended our 2022 annual meeting of shareholders.

During 2022, the board held nine meetings. Each incumbent director attended at least 75 percent of the aggregate number of meetings of our board and of the committees on which he or she sat, and the cumulative attendance at meetings of our board and committees of our board during 2022 was 100 percent.

Board Committees

Our board of directors currently has five standing committees: an audit committee, a management development and compensation committee, a nominating and corporate governance committee, a strategy and risk committee and a sustainability committee. Descriptions of these committees are set forth below. Each of our committees operates under a charter adopted by our board of directors. The charters of our committees are available on our website at www.koppers.com. You may also request a printed copy of any committee charter at no cost by writing to our corporate secretary at Koppers Holdings Inc., Attention: Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219.

Our shares of common stock are listed on the New York Stock Exchange, or NYSE. We are subject to the NYSE corporate governance rules and certain rules of the Securities and Exchange Commission, which we refer to as the SEC, including the rules relating to independent members on certain of our board committees. NYSE rules require that all of the members of our audit, nominating and corporate governance, and management development and compensation committees be independent. Certain SEC independence rules also apply to members of our audit committee. All of the members of our audit, nominating and corporate governance, and management development and compensation committees are independent as required by applicable NYSE and SEC rules.

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Audit Committee

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Management Development and Compensation Committee

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Nominating and Corporate Governance Committee

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Strategy and Risk Committee

Sustainability Committee

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Corporate Governance Guidelines

Our board of directors has adopted corporate governance guidelines to ensure we are fully compliant with the law and engaging in corporate governance “best practices,” which promote the long-term interests of shareholders and strengthen board and management accountability.

Our corporate governance guidelines address matters such as:

A copy of our corporate governance guidelines is available on our website at www.koppers.com. You may also request a printed copy at no cost by writing to our corporate secretary at Koppers Holdings Inc., Attention: Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219.

Director Independence

For a director to qualify as independent, our board must affirmatively determine that a director does not have a material relationship with the company (either directly or as a partner, shareholder or officer of an organization that has a material relationship with the company). Our board has established its own guidelines for what constitutes independence for directors (which are included in our corporate governance guidelines available on our website at www.koppers.com) which either conform to, or are more exacting than, the independence requirements of the NYSE. In making its independence determinations, the board reviewed the independence guidelines that are part of our corporate governance guidelines, the corporate governance rules of the NYSE and the individual circumstances of each director.

Our Guidelines on Independence

The following is a summary of the guidelines established by our board in our corporate governance guidelines and which are used by the board to help determine the independence of each director. In general, the board will determine that a director will not be independent if, within the preceding three years:

In addition, the board will determine that a director is not independent if:

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When the board reviews the independence of its members, the board considers the following commercial or charitable relationships to be material relationships that would impair a director’s independence:

Each independent director is required to notify the chair of the nominating and corporate governance committee of any event, situation or condition that may affect the board’s evaluation of the director’s independence.

Our Board’s Independence Determinations

Our board of directors reviewed the independence of each of our current directors and nominees, in accordance with our corporate governance guidelines and NYSE rules. Based on its review, the board of directors determined that a majority of our current directors and nominees have no material relationship with us (either directly or as a partner, shareholder or an officer of an organization that has a relationship with us) and are independent under the independence criteria for directors established by the NYSE and in accordance with our corporate governance guidelines. Based on this evaluation, our board has determined that Dr. Feng, Ms. Jensen, Mr. Motley, Mr. Neupaver, Mr. Sandifer, Mr. Testoni, Mr. Tritch and Ms. Wilkerson each satisfy the independence standards. In addition, based on its evaluation, the board determined that Mr. Ball is not independent.

Board Leadership Structure

Our current policy and practice is that the roles of the chairman of the board and the chief executive officer should be separate because our board believes separating the roles allows the chairman to serve as a check on the chief executive officer and to independently assess the overall performance of the company on behalf of the shareholders. In addition, our board believes it is important to separate the roles of the chief executive officer and the chairman of the board due to the differences between the two roles and the time-intensive responsibilities of each. Our chief executive officer is the officer through whom the board delegates authority to corporate management. He is responsible for setting our strategic direction and the day-to-day leadership and performance of the company, while ensuring that all orders and resolutions of the board are carried into effect. The chairman of the board, on the other hand, provides guidance to our chief executive officer, presides over meetings of the full board, calls meetings of the board and board committees when he deems them necessary and performs all duties assigned to him by the board. Our chairman of the board is also responsible for acting as chairman at all meetings of our shareholders. Mr. Tritch, one of our independent directors, is currently the chairman of our board.

Executive Sessions

Our independent directors meet at regularly scheduled executive sessions without management. Our corporate governance guidelines provide that when the roles of the chairman of the board of directors and the chief executive officer are separate and the chairman of the board of directors is not an employee, then the chairman of the board of directors also serves as the independent Presiding Director. If the chairman of the board of directors is not an independent director, the responsibilities of the Presiding Director set forth in our corporate governance guidelines would be determined by the independent directors on a meeting-by-meeting basis with respect to all separate meetings of the independent directors. If the roles of the chairman of the board of directors and the chief executive officer are combined in the future (or if such roles are separate but both roles are filled by employees), the chair of the nominating and corporate governance committee (an independent director) would serve as the Presiding Director.

The independent Presiding Director presides over the executive sessions of the independent directors and, together with the members of the nominating and corporate governance committee, develops the agendas for the executive sessions and periodically reviews and proposes revisions to the board’s procedures and the corporate governance guidelines. The independent Presiding Director is also responsible for communicating the board’s annual evaluation of the chief executive officer.

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Risk Oversight

Our board as a whole has an active role in overseeing the company’s management of risks. Our board regularly assesses the major risks facing the company and reviews options for their mitigation by reviewing information regarding accounting, operational, legal and regulatory, and strategic and reputational risks based on reports from senior management, including by our director of compliance, who reports to our general counsel and secretary, and our independent auditor.

In addition, our board has established a formal risk management process that involves regular and systematic identification and evaluation of risks. As part of this process, we conduct an enterprise risk assessment at least biennially to review and update the risks to the company in view of changing conditions. Once our key risks are identified and inventoried, our leadership council, which consists of all direct reports to the chief executive officer and certain others appointed by the chief executive officer, conducts a risk prioritization. The initial prioritization of these risks is based on impact and likelihood criteria, after which the risks are divided into four tiers, with tier 1 consisting of the most severe risks. When conducting the risk prioritization, our leadership council considers, among other things, aggregate impact of the risk, timing of probable onset, velocity and duration. The risks are then re-prioritized based on the effectiveness of the risk management/mitigation responses, including controls. Our final risk inventory, which includes a list of prioritized risks, is presented annually to the strategy and risk committee of the board of directors, highlighting risks that have been added or removed, or any significant changes in status for tier 1 risks. The strategy and risk committee also receives a quarterly update on changes and highlights of specific risks, which may include specifics of mitigation plans. Our board delegates the oversight of specific risk areas to board committees as follows:

Code of Conduct and Code of Ethics

Our board of directors has adopted a Code of Conduct for all directors, officers and employees and a Code of Ethics Applicable to Senior Officers. A copy of each code is available on our website at www.koppers.com. You may also request a written copy at no cost by writing to our corporate secretary at Koppers Holdings Inc., Attention: Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219. The Code of Conduct covers such matters as conflicts of interest, insider trading, misuse of confidential information, compliance with laws and protection and proper use of corporate assets. Directors are expected to comply with the Code of Conduct and report any violations of the code, including any potential conflicts of interest, as outlined in the code. All directors must remove themselves from any discussion or decision affecting their business or personal interests. We intend to post on our website all disclosures that are required by law, the SEC rules or the NYSE rules concerning any amendments to, or waivers from, any provision of our codes.

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Sustainability

Koppers aspires to be a leader in sustainability through the ways we operate our business, care for our communities and secure success for all our stakeholders. Sustainability is a journey we undertake with a steadfast commitment to—and belief in—our ability to create positive change.

At Koppers, we are guided by our purpose of Protecting What Matters and Preserving The Future. We strive to place the care and protection of people, the environment, and communities first while providing responsible solutions essential to global infrastructure and our modern world. Our sustainability pillars reflect our values of People, Planet, and Performance, and serve as guideposts for how we work with one another, conduct business, and interact with our stakeholders. We believe that success happens when all three values are in balance and pursued with enthusiasm by every team member, in every location, every day. Koppers is fully committed to securing our future by taking care of our employees, being a good steward of the environment, creating value for our stakeholders, and contributing beneficial products to society for generations to come.

Our shareholders, employees, customers, regulators and other stakeholders are all increasingly focused on the importance of effective engagement and action on environmental, social, and governance topics. Corporate social responsibility, which we view as our obligation to people and the environment and our commitment to maintaining good corporate governance processes, has been a part of our culture for many years. We believe this culture, supported by a spirit of collaboration and innovation, allows us to decrease our impact on the environment and create value for all of our stakeholders. We believe this commitment is reflected in our improving safety culture and our trend of greenhouse gas and energy usage reductions.

We have established a governance structure to support and develop our sustainability practices. The sustainability committee of the board of directors provides oversight of our programs and serves to assist the board in its assessment of the company’s policies, programs and performance in accordance with our vision and commitment to environmental and social responsibility and sustainability principles. Management provides direction through its leadership council, which is chaired by the CEO. Our chief sustainability officer position, reporting directly to the CEO and sitting on the leadership council, ensures that the company’s strategy, policies and practices are consistent with its sustainability goals. Our sustainability steering committee, chaired by our chief sustainability officer, provides guidance on goals and programs designed to improve our performance against expectations.

Our full annual disclosure of sustainability performance can be found in our most recent Sustainability Report on the company’s website at www.koppers.com. Our historical Sustainability Reports dating to 2015 are also available on www.koppers.com. Our sustainability reporting referenced in this proxy statement, including, without limitation, our most recent and historical Sustainability Reports, and the information on, or accessible through, our websites are not part of or incorporated by reference into this proxy statement.

Environmental

The circular nature of our business starts with our raw materials, the majority of which are by-products generated by other industries (including scrap copper and coal tar) and renewable resources (trees). We purchase approximately 32 million pounds of scrap copper per year which is post-consumer or post-industrial in nature. We believe this places Koppers in the center of what is known as the “circular economy” that emphasizes the “reduce, reuse, recycle” mentality that continues to frame global conservation efforts. Our wood-treatment solutions, while supporting an important role in our global infrastructure across multiple industries, also support an important role in the carbon cycle. Treating wood significantly increases its useful lifespan, allowing the carbon stored within the wood to be immobilized for up to 50 years, keeping it out of the atmosphere and limiting its impact on the environment. In addition, we have businesses which have product life cycle management capabilities to help solve our customers’ challenge of responsibly disposing of end-of-life crossties and utility poles by repurposing used wood products, including as a fuel source. This reduces the end-of-life impact of our ties and poles, contributing to greater product sustainability.

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Social

Our ability to positively affect our communities starts with investing in our people. We put the health, safety and well-being of our employees at the forefront of everything we do as part of our Zero Harm culture. Our people-focused strategy considers all aspects of the employee experience, from hiring practices and onboarding to health and wellness and talent management. We seek to create and foster an inclusive and welcoming culture where all employees feel empowered and can directly impact and share in the organization’s success. Key to this effort is delivering a consistent onboarding experience, as well as communications and safety training in all of our facilities across the globe.

Our talented employees are a critical element to make our business successful, so it is essential that we position them for success. It is also important that we continue attracting top talent to our workforce. Our Culture and Engagement team leads these efforts to attract, retain and develop our employees and has created various programs to enhance the skill set of our workforce. Recognizing the importance of a consistent and comprehensive onboarding and safety training experience for new hires across our facility footprint, we have a web-based training program to ensure every employee receives a consistent message from the start of their employment. The program includes videos detailing the company and its primary business lines as well as a new hire information packet filled with information on employee programs, services, benefits and more.

We also have a toolkit to help managers guide new employees for success and we conduct regular new hire surveys to solicit feedback and identify opportunities for improvement. We continue to evaluate and employ methods to identify at-risk behaviors during the hiring process to place prospective employees in appropriately suited positions where they can be successful and workplace injuries can be avoided. This behavioral data also enables us to tailor training and onboarding based on the opportunities it highlights.

To ensure our employees have the best opportunity for success, our performance development process includes periodic meetings between employees and managers to discuss their goals and strategies to achieve them. We no longer conduct traditional annual reviews and instead opt for these more frequent two-way discussions focused on fostering ideas that will enable employee success. Each manager is expected to meet one-on-one at least monthly with their employees to discuss tailored strategies to encourage employee success like additional training, attendance at conferences or establishing connections to others within our company. These monthly meetings also help managers gauge employee engagement and develop approaches to increase and sustain positive engagement.

We also have a New Hire Mentoring Program as another component of our development process. The program provides both hourly and salaried employees an extra opportunity to receive support from experienced employees and discuss any ideas they may have for improving our operations or their work experience. Prior to participating, mentors and mentees receive training on getting the most out of the program.

As a part of our people-focused approach to our operations, we are committed to helping our employees thrive in their roles and grow both personally and professionally. A major component of this plan is our commitment to providing each employee with the training and education they need to be successful. Under the umbrella of our Koppers College, we provide leadership development training to our front-line employees to expand their growth opportunities within the organization. We also foster innovation and develop our next wave of high-potential employees through our leadership forum, an intensive nine-month program conducted in partnership with a university local to our corporate headquarters. Approximately ten to twelve employees from across the world are chosen annually for each cohort. Selected participants travel to our corporate headquarters to take part in workshops facilitated by university professors and business leaders. We also offer our employees a tuition reimbursement program to help them pursue degrees and certifications related to relevant skills they utilize for their positions to further personal and company success.

We believe a robust wellness program that encourages employee participation is key to promoting healthy lifestyles and decision-making. Our wellness screening program for our U.S.-based employees provides them the opportunity to learn more about their health and daily routines. As part of this program, employees can earn financial incentives for completing a variety of wellness initiatives. Recognizing the importance of supporting our employees in all aspects of their lives, we provide an Employee Assistance Program with a full range of supportive resources including financial wellness, mental health and family services. For our U.S.-based employees, we also offer four weeks of paid time-off for mothers and fathers who have a birth or adoption as part of our parental bonding leave program. Additionally, we offer work schedule flexibility including the opportunity to work remotely when conditions allow.

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We encourage employee participation in our benefit programs for saving for retirement through robust defined contribution and employee stock purchase programs. The U.S. 401(k) program includes both traditional matching and an additional non-elective company contribution based on organizational performance. When the company achieves the established performance target, employees share in this success through an automatic contribution to their 401(k) accounts. We also offer our employees the option to acquire Koppers stock through an employee stock purchase program. The program gives our employees the opportunity to buy shares at a discount through payroll deductions during defined quarterly offering periods.

We work with a Zero Harm approach to every employee’s health and safety. Zero Harm includes policies that guide our safety practices and procedures throughout all of our facilities, a focus on leading activities that prevent accidents and a leadership culture that insists the health and safety of our employees comes ahead of everything we do.

We support an inclusive and diverse work environment across our company through a range of strategic programs. Our internal processes and programs target inclusion and diversity as a key area of importance and externally we place emphasis on the topic during philanthropic activities. Our global inclusion and diversity initiative focuses on supporting our strategy to be an employer of choice, and helps to ensure that all employees feel they are heard and valued to harness the power of an engaged workforce. Our employee resource groups, LINKWomen, which was launched in 2018, and LINKParents, which was launched in 2021, provide an important development forum for employees and serve as a model for future initiatives. Additionally, the 2022 Women on Boards Gender Diversity Index ranks Koppers as a 3+ Company with three or more women on our board of directors.

We are committed to proactively evaluating and addressing community needs in the areas where we operate. Many of our locations have made strong connections with local community members, allowing our representatives to share facility information and address any questions, observations, concerns and ideas. Our community impact is demonstrated through our employees’ volunteer commitments and a corporate philanthropy program. Employees worldwide volunteer their time to, among other things, mentor students, enhance local education initiatives, take care of the elderly, assist at homeless shelters and provide hands-on help to those affected by natural disasters.

Communication across our global footprint drives our efforts. All Koppers employees are given the opportunity to provide direct feedback to leadership as part of the company’s annual engagement survey. Our leadership reviews this feedback in detail and, in conjunction with our Culture and Engagement team, develops responsive action plans for improvement.

Governance

We believe our corporate governance structure is designed to assure accountability to our stakeholders and to make certain that we conduct business in a responsible, ethical way. We maintain a comprehensive Code of Conduct that details the expectations and requirements we have as an organization for our employees. This Code of Conduct applies to all employees, whether we are engaging in peer-to-peer interactions, working to comply with complex regulations, marketing our products, purchasing materials, creating new products, managing our finances or interacting with our communities.

Training employees on the Code of Conduct is a key aspect of our approach to ethics. We require every Koppers employee to complete training on the Code of Conduct annually. We also conduct focused trainings on specific topics that are relevant to employees with particular responsibilities.

We encourage our employees who have questions regarding the Code of Conduct and other ethics issues to seek guidance. Similarly, if an employee recognizes a potential ethics violation, they are empowered and encouraged to notify the appropriate management personnel so that Koppers can investigate and take appropriate corrective action. Employees can also utilize the Koppers Compliance Line, a free confidential resource available 24 hours a day, seven days a week, to ask questions or raise concerns. Another option for anonymous reporting is our third-party email reporting system.

Our board of directors is broadly responsible for contributing to the strategic direction and oversight of the company. Among its duties and responsibilities, the board oversees management’s direction of the legal, ethical and socially responsible behavior of the company, such as developing effective performance measurement systems, reviewing the company’s long-term strategy and overseeing risk management processes. Our leadership council is responsible for directing the development and implementation of the company’s strategic plan and business operations around the globe. These executive leaders establish and maintain our commitment to ethics, integrity, fiscal responsibility, growth and sustainability.

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Communications with the Board

The board of directors welcomes the input and suggestions of shareholders and other interested parties. Shareholders and other interested parties wishing to contact the chairman of the board, the non-management directors as a group or specified individual directors may do so by sending a written communication to the attention of the chairman of the board, c/o Koppers Holdings Inc., Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219. Issues or complaints regarding questionable accounting practices, internal accounting controls or auditing matters may be sent in writing to the attention of the audit committee chairman, c/o Koppers Holdings Inc., Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219. Our corporate secretary will forward all written communications to the director or directors to whom it is addressed. Alternatively, you may place an anonymous, confidential, toll-free call in the United States to our Compliance Line at 800-385-4406.

Nomination Procedures

The nominating and corporate governance committee will consider nominees for director recommended by the committee, other directors, employees and shareholders and evaluate such nominees against the same criteria used to evaluate all candidates for director. Any shareholder wishing to recommend a candidate for director to the nominating and corporate governance committee should submit the recommendation in writing to our corporate secretary at Koppers Holdings Inc., Attention: Corporate Secretary’s Office, 436 Seventh Avenue, Pittsburgh, Pennsylvania 15219.

Pursuant to our bylaws, in order to recommend a nominee for election at our annual meeting a shareholder must provide advance notice of such nomination (1) if the meeting is to be held on a date that is within 30 days before or 30 days after the anniversary date of the prior annual meeting, not less than 120 days nor more than 150 days prior to such annual meeting, or (2) if the meeting is to be held on a date that is not within 30 days before or 30 days after the prior annual meeting, not later than the tenth day following the day on which notice of the date of the meeting was mailed or the first public disclosure of the date of such meeting was made, whichever occurs first. In the case of a special meeting to elect directors, notice must be received no later than the tenth day following the earlier of the day on which notice was mailed or the first public disclosure of the date of such meeting. Any such notice must set forth, among other things: (1) the name, age, address and principal occupation of the nominee; (2) a representation that the notifying shareholder intends to appear in person or by proxy to nominate the nominee; (3) the class and number of shares beneficially owned by the nominee; (4) the number of shares to be voted by the notifying shareholder for the nominee; (5) a description of all arrangements between the notifying shareholder and the nominee and other persons pursuant to which the nomination is to be made; (6) all information about the nominee that would be required to be disclosed in a proxy statement (including a written consent to serving as director); and (7) a written representation and agreement, (i) disclosing, and providing that if elected that he or she will disclose, any agreement with any person as to how such nominee will act or vote, (ii) disclosing, and providing that if elected that he or she will disclose, any other commitments that could interfere with his or her fiduciary duties, (iii) disclosing, and providing that if elected that he or she will disclose, any agreement with any person with respect to direct or indirect compensation or indemnification for services as director, and (iv) providing that if elected that he or she will comply with all applicable corporate governance, conflict of interest, stock ownership, trading, and other policies and guidelines.

As to the shareholder giving notice, any beneficial owner on whose behalf the nomination is made, and any person controlled by or controlling such shareholder and beneficial owners, such notice must set forth: (1) their name and address; (2) class and number of shares beneficially owned and of record and any other positions owned, including derivatives, hedges and any other economic or voting interest in the company; (3) a representation whether such person intends to be part of a group which intends to deliver a proxy statement or otherwise solicit proxies from shareholders; (4) whether hedging or other transactions have been made to mitigate a loss of such person; and (5) any other information relating to each party that would be required to be disclosed in a proxy statement.

All notices provided must be updated so that the information provided is true and correct as of the record date and as of the date that is ten business days prior to the meeting.

The company may also require any nominee to submit to background checks and an in-person interview and furnish such other information as reasonably required to determine the eligibility of the nominee to serve as an independent director or that could be material to the understanding of independence.

Under our bylaws, no nominations may now be made by shareholders for the 2023 annual meeting.

CORPORATE GOVERNANCE MATTERS

Committee Reports to Shareholders

Audit Committee Report

As set forth in our charter, management is responsible for the preparation, presentation and integrity of our financial statements, and for maintaining appropriate accounting and financial reporting principles and policies and internal controls and procedures designed to provide reasonable assurance of compliance with accounting standards and related laws and regulations. Our internal auditors are responsible for providing reliable and timely information to the board of directors and senior management concerning the quality and effectiveness of, and the level of adherence to, our control and compliance procedures and risk management systems. Our independent auditor is responsible for planning and carrying out an integrated audit of our consolidated annual financial statements and the effectiveness of internal control over financial reporting in accordance with the standards of the Public Company Accounting Oversight Board (the “PCAOB”), reviewing our annual report on Form 10-K prior to the filing of such report with the SEC, and reviewing our quarterly financial statements prior to the filing of each of our quarterly reports on Form 10-Q with the SEC.

In the performance of its oversight function, the audit committee has reviewed and discussed the audited financial statements for the year ended December 31, 2022, with management and with KPMG LLP, our independent auditor for 2022. The audit committee has discussed with our independent auditor the matters required to be discussed by the applicable requirements of the PCAOB. The audit committee has received the written disclosures and the letter from the independent auditor required by the applicable requirements of the PCAOB regarding the independent auditor’s communications with the audit committee concerning independence and has discussed with the independent auditor its independence. Also, in the performance of its oversight function, during 2022 the audit committee received frequent reports from our director of internal audit.

At various times the audit committee has considered whether the provision of non-audit services by the independent auditor to us is compatible with maintaining the independent auditor’s independence and has discussed with KPMG LLP their independence. The audit committee or its chairman (acting pursuant to delegated authority) pre-approves all new non-audit services (as defined in the Sarbanes-Oxley Act of 2002) proposed to be performed by our independent auditor.

Based upon the review and discussions described in this report, and subject to the limitations on the role and responsibilities of the audit committee referred to above and in its charter, the audit committee recommended to the board of directors that the audited financial statements be included in our Annual Report on Form 10-K for the year ended December 31, 2022, for filing with the SEC.

The audit committee of the board of directors presents the foregoing report.

Management Development and Compensation Committee Report

The management development and compensation committee has reviewed and discussed the Compensation Discussion and Analysis with our management. Based on our review and discussions, the committee has recommended to our board of directors that the Compensation Discussion and Analysis be included in this proxy statement.

The management development and compensation committee of the board of directors presents the foregoing report.

COMMON STOCK OWNERSHIP

Director and Executive Officer Stock Ownership

Set forth below is certain information with respect to the beneficial ownership of shares of our common stock as of March 20, 2023, by directors, the NEOs, who are included in the Summary Compensation Table, and all directors and executive officers as a group. Except as otherwise indicated, sole voting power and sole investment power with respect to the shares shown in the table are held either by the individual alone or by the individual together with his or her spouse.

COMMON STOCK OWNERSHIP

Beneficial Owners of More Than Five Percent

The following table shows shareholders whom we know were beneficial owners of more than five percent of our common stock as of March 20, 2023.

EXECUTIVE AND DIRECTOR COMPENSATION

Compensation Discussion and Analysis

Executive Compensation Program Principles

The committee considers the following principles when it makes compensation decisions:

EXECUTIVE AND DIRECTOR COMPENSATION

Executive Compensation Objectives

Consistent with these overall principles, the committee has established the following objectives for its executive compensation programs, which are critical to our long-term success:

Key Components of Our Compensation Program

The key compensation objectives for our NEOs are achieved through the following mix of components of target direct compensation for our CEO and other NEOs, respectively, which are discussed in more detail later in this Compensation Discussion and Analysis.

In addition to the components outlined above, our compensation program also provides our executives with certain severance and retirement benefits and certain perquisites. While we do not consider these benefits key components of our compensation program, they do assist in achieving our compensation objectives of attracting and retaining talented executives.

EXECUTIVE AND DIRECTOR COMPENSATION

2022 Say-on-Pay Vote

We value our shareholders’ opinions and feedback and are committed to maintaining an active dialogue to understand the priorities and concerns of our shareholders. We believe that ongoing engagement builds mutual trust and alignment with our shareholders and is essential to our long-term success. We received strong support for our executive compensation program in the annual “say on pay” vote with over 98% approval at the 2022 annual meeting. The committee believes these results reflect our shareholders’ affirmation of our executive compensation program. Nevertheless, the committee regularly reviews and adjusts the program as needed to ensure it remains competitive and aligned with the best interests of the company and its stakeholders.

Our Compensation-Setting Process

Through the course of our compensation-setting process:

The fiscal year 2022 compensation decisions for our NEOs were made in three steps.

The committee may use its judgment to supplement, reduce or modify at any time the compensation intended to be paid or awarded to the NEOs. The committee believes that it is in the best interest of the company and its shareholders that the committee have sufficient latitude to recognize and reward superior performance, which is important to attract and retain talented executives, and to adjust awards to reflect the quality of the company’s financial performance. The committee did not exercise any such positive discretion this year.

Overview of 2022 NEO Compensation. Our 2022 actual NEO compensation includes both short- and long-term incentives established using financial metrics. In addition to base salary, this structure, shown graphically below, includes cash incentives and long-term equity incentives, comprised of PSUs, stock options and RSUs.

For our CEO, Mr. Ball, approximately 84 percent of 2022 direct compensation is pay-at-risk, which is payable over time or determined based upon financial goals or performance achievements. For our other NEOs, on average approximately 70 percent of 2022 direct compensation is pay-at-risk.

EXECUTIVE AND DIRECTOR COMPENSATION

The following represents the total actual compensation to our NEOs for 2022, computed in accordance with SEC regulations for purposes of the Summary Compensation Table disclosed below.

Please see our Summary Compensation Table on page 34 which also reports amounts for Changes in Pension Value, Nonqualified Deferred Compensation Earnings and All Other Compensation.

2020, 2021 and 2022 Total Realized Compensation as a Percentage of Target

CEO

2022 Total Realized Compensation

Below is a comparison of 2022 target compensation to total realized compensation for our NEOs. Total realized compensation is based on the actual dollar value of cash and vested equity delivered to our NEOs in any given year. This measure further demonstrates our ongoing commitment to compensating our leadership based on the company’s performance and placing a significant portion of senior executive compensation at risk. Total realized compensation was lower than target for our NEOs in 2022 because none of our NEOs exercised previously-granted stock options in 2022.

Total realized compensation is calculated as follows:

EXECUTIVE AND DIRECTOR COMPENSATION

2022 Compensation Decisions and Performance

Base Salary. As part of setting pay mix and structure for 2022, the committee evaluated NEO base salaries. Annual salary increases are neither automatic nor guaranteed, but determined by the committee after taking into consideration each NEO’s position with the company, their respective responsibilities and experience and peer company information for similar positions. Based on this evaluation, the following 2022 base salary increases for the NEOs were approved by the committee and ratified by the independent members of the board. All increases were effective April 1, 2022. A base salary increase of 4.7% was awarded to Mr. Sullivan and a base salary increase of 9.1% was awarded to Ms. Apostolou in order to be more competitive with market.

Annual Cash Incentives. In early 2022, the committee approved and the board ratified our annual incentive plan, which served as the company’s main annual incentive plan for salaried employees. The annual cash incentive payouts under the annual incentive plan are based upon: (1) each participant’s target total annual incentive (115% of salary for Mr. Ball, 80% of salary for Mr. Sullivan and 60% of salary for Mses. Smith, Apostolou and Hyde) and (2) the company’s performance in relation to the plan’s adjusted EBITDA targets. Adjusted EBITDA, as measured under the annual incentive plan, is defined as earnings before interest, taxes, depreciation and amortization, as adjusted by the committee in its discretion to account for certain items, as set forth on Appendix A hereto. Mr. Sullivan’s target total annual incentive increased from 75% of salary in 2021 to 80% of salary in 2022 in order to move his target annual incentive opportunity closer to market median. Target total annual incentive as a percentage of salary did not change between 2021 and 2022 for our other NEOs.

Taking all of these elements together, the committee’s framework for determining annual cash incentives for the NEOs can be expressed as follows:

The committee established a target corporate adjusted EBITDA performance level of $230.0 million along with a range of incentive payouts at threshold, target and maximum performance levels (with linear interpolation for performance in between such levels), as set forth below.

EXECUTIVE AND DIRECTOR COMPENSATION

For 2022, the company achieved adjusted EBITDA performance of $228.1 million, as calculated for purposes of the annual cash incentives. This corresponded to achievement of 99% of target adjusted EBITDA performance and a 98% payout level, which resulted in the following annual cash incentive payments to our NEOs:

Long-Term Equity Incentives. In 2022, each NEO received his or her long-term incentive award in three primary forms (with the applicable weighting determined as described below): PSUs (50%), which measure our performance over a three-year period, stock options (30% for Mr. Ball and 25% for our other NEOs) and RSUs (20% for Mr. Ball and 25% for our other NEOs), which vest in annual installments of 25% over four years. Equity awards are granted under our shareholder-approved 2020 Long Term Incentive Plan, as amended, or a predecessor plan (the “LTIP”). The table below summarizes the material terms and conditions of the 2022 long-term incentive awards.

PSU performance is based on a range of relative TSR achieved in each of the relevant performance periods as set forth in the following table:

EXECUTIVE AND DIRECTOR COMPENSATION

The percentage vesting is interpolated on a straight-line basis for performance between levels above the threshold.

We grant equity awards to executives on an annual basis using a grant date that occurs in the first quarter of each year. We also periodically grant equity awards in connection with certain management events, such as the hiring or promotion of an executive or the achievement by an executive of extraordinary personal performance objectives. Each equity award granted to our executives has a grant date that was on or after the date on which the committee approved the award. It is possible that the committee may possess material nonpublic information when it approves awards. However, awards are granted only at certain pre-designated times of the year or in connection with certain management events, and the committee does not try to achieve more advantageous grant dates in connection with the timing of the release of material nonpublic information.

The target dollar value of all equity awards to each NEO is determined based upon a multiplier of base salary. Once the total dollar value of the awards is determined for each NEO, the actual number of PSUs, stock options and RSUs is determined for each NEO as follows: 50 percent of the total dollar value is allocated to the PSU portion of the award (assuming target achievement), 30 percent of the total dollar value for Mr. Ball and 25 percent of the total dollar value for our other NEOs is allocated to the stock option portion of the award and 20 percent of the total dollar value for Mr. Ball and 25 percent of the total dollar value for our other NEOs is allocated to the RSU portion of the award. The committee then uses the closing price of our common stock on the NYSE on the grant date to determine the number of PSUs (assuming target achievement) and RSUs awarded. To determine the number of stock options awarded, the committee divides the total dollar value attributed to the stock option by the estimated fair value of the stock options on the date of grant, which is determined in accordance with the Black-Scholes valuation method by an independent valuation consultant.

The granting of a combination of stock options, RSUs and PSUs has historically fallen within the range of peer group practices and has had a strong performance orientation. Based on data provided by our compensation consultant, the long-term incentive portion of our NEOs’ total direct compensation is slightly ahead of peer group average practice.

Results of Performance-Based Restricted Stock Units. The table below summarizes the results of our outstanding PSUs as of December 31, 2022. Our total shareholder return was measured against that of the S&P Small Cap 600 Materials Index (as described above) over the applicable three-year period, two-year period or one-year period as set forth below. Our percentile ranking on this performance measure determined the percentage of target shares (if any) that were earned for each tranche. If the company’s TSR is negative over the three-year performance period, then the cumulative number of units that may vest for such three-year period will be capped at 150% of target.

Changes to Long-Term Equity Incentives for 2023. On December 7, 2022, we approved the following changes for 2023 grants of equity compensation to eligible employees, including our NEOs, under the LTIP:

EXECUTIVE AND DIRECTOR COMPENSATION

We believe that these changes better align our long-term compensation with the company’s strategic plan and remain consistent and competitive with peer group practices.

NEO Retirement Benefits. We maintain a 401(k) plan that permits U.S. salaried employees, including the NEOs, to contribute up to 60 percent of pay, subject to applicable limits for 401(k) plans. We match 100 percent of salaried employee contributions to the 401(k) plan on the first three percent of an employee’s salary contributed to the plan and match 50 percent on the next two percent of an employee’s salary contributed to the plan. In order to remain competitive in the market for senior executive talent, we also maintain a supplemental benefit plan, which we refer to as the Benefit Restoration Plan, to restore employer non-elective contributions lost by certain U.S. highly-paid employees, including the NEOs, in our 401(k) plan under U.S. tax law. Under both plans, we make employer non-elective contributions tied to our financial performance. Employer contributions have not yet been made for 2022; however, we have assumed such contributions will be paid for 2022 and the corresponding amounts are included in the tables below.

Ms. Hyde is covered by the Retirement Plan of Koppers Inc. and Subsidiaries for Salaried Employees, a tax-qualified pension plan that we refer to as the salaried plan, and the Supplemental Executive Retirement Plan, a non-qualified excess defined benefit plan that we refer to as SERP II. No other NEOs participate in either the salaried plan or SERP II. Ms. Hyde is also covered under our Survivor Benefit Plan, which makes her eligible for a post-retirement survivor benefit. No other NEOs are covered under our Survivor Benefit Plan. More information on the salaried plan, SERP II and the Survivor Benefit Plan can be found under 2022 Pension Benefits on pages 40 and 41.

Perquisites and Other Benefits. We provide a limited number of perquisites and other benefits to certain of our NEOs, which include club dues, parking and executive physicals. Additional details of the perquisites and other benefits we provide are more fully described in the footnotes to the “All Other Compensation” column of the Summary Compensation Table below.

We provide these perquisites and other benefits to promote a healthy work/life balance and provide opportunities for developing business relationships. We believe they are important to our ability to attract and retain top-quality executive talent and are consistent with those provided to executives at other companies comparable to us. The costs associated with providing these benefits for our NEOs are reflected in the “All Other Compensation” column of the Summary Compensation Table below on page 34.

Our NEOs also participate in the same standard salaried benefit plans as our other U.S. salaried employees. This includes a basic welfare benefits package consisting of medical, dental, vision, life and disability insurance and accident insurance plans, as well as flexible spending arrangements for health care, dependent care and transportation expenses.

Our NEOs are provided certain protections in the event of their termination of employment under specified circumstances, including in connection with a change in control of the company. We believe that these protections serve our retention objectives by permitting our NEOs to maintain continued focus and dedication to their responsibilities in order to maximize shareholder value, including in the event of a transaction that could result in a change in control of the company.

Compensation Policies and Practices

Compensation and Risk. The committee has concluded that the company’s compensation policies and practices do not create risks that are reasonably likely to have a material adverse effect on the company. The committee has designed a total compensation package with features that it believes will mitigate the risks associated with compensation policies and practices including:

EXECUTIVE AND DIRECTOR COMPENSATION

Role of Consultants. In accordance with its authority to retain advisors, in late 2021, the committee engaged Meridian Compensation Partners, LLC (“Meridian”) as outside consultants to advise the committee with respect to 2022 compensation design decisions.

Meridian does not advise our management or receive any other compensation from us, except for performing valuations of PSUs. In its role as independent advisor to the committee, Meridian provided advice to the committee from time to time on various executive compensation matters, including conducting an annual competitive compensation analysis, which Meridian prepared for the committee in late 2021.

In compliance with the SEC and the NYSE disclosure requirements regarding the independence of compensation consultants, Meridian provided the committee with a completed questionnaire addressing each of the six independence factors enumerated in the SEC requirements. Their responses affirm the independence of Meridian and the partners, consultants, and employees who service the committee on executive compensation matters and governance issues.

Companies Used for Defining Competitive Compensation. As stated above, one of the committee’s principles is to target the compensation of our NEOs within a range of the market median of our peer companies that were selected based on comparability in terms of industry, revenue and complexity. The revenue range for our 2022 peer group was $727 million to $4.873 billion, with the peer group consisting of companies in multiple related industries, including building products (GICS code 20102010), commodity chemicals (GICS code 15101010), forest products (GICS code 15105010) and specialty chemicals (GICS code 15101050). In advance of its decisions regarding 2022 compensation, the committee reviewed with Meridian the 2021 peer group and, taking into account Meridian’s advice, made the following changes to the peer group for purposes of 2022 compensation decisions:

Accordingly, for purposes of 2022 compensation decisions, the peer group selected by the committee, in consultation with Meridian, consisted of the following:

Statistical regression was not used to adjust peer compensation data based on our revenue positioning relative to the peer group.

Through its competitive assessment, Meridian determined that the aggregate target cash and target total compensation for the majority of our executives fell at or below the market median competitive range, primarily due to base salaries (which drive target annual incentives and long-term incentives) that are generally below market.

EXECUTIVE AND DIRECTOR COMPENSATION

In advance of its decisions regarding 2023 compensation, the committee again reviewed with Meridian the peer group companies listed above and confirmed that it continues to generally constitute an appropriate peer group for benchmarking our executive compensation programs with four recommended changes. Accordingly, taking into account Meridian’s advice, the committee made the following changes to the peer group for purposes of 2023 compensation decisions: