Kirby : 2024 Proxy Statement

TABLE OF CONTENTS

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

Dear Fellow Stockholders:

You have the right to receive this notice and vote at the Annual Meeting if you were a stockholder of record at the close of business on February 28, 2024. Please remember that your shares cannot be voted unless you sign and return a paper proxy card, vote during the Annual Meeting, or vote your shares via the phone or internet. All participants who attend the Annual Meeting will be allowed to ask questions to management during the meeting.

Important Notice Regarding the Availability of Proxy Materials for Our 2024 Annual Meeting of Stockholders

We are pleased to take advantage of Securities and Exchange Commission (the "SEC") rules that allow us to furnish our proxy materials, including this Proxy Statement, a proxy card or voting instruction form, and our Annual Report on Form 10-K (collectively, the "Proxy Materials"), over the Internet. As a result, we are mailing to most of our stockholders a Notice of Internet Availability of Proxy Materials (the "Notice") instead of paper copies of the Proxy Materials. The Notice contains instructions on how to access those documents over the Internet and how to submit your proxy via the Internet. The Notice also contains instructions on how to request a paper copy of the Proxy Materials. All stockholders who do not receive the Notice will receive a paper copy of the Proxy Materials by mail or an electronic copy of the Proxy Materials by e-mail. This process allows us to provide our stockholders with the information they need in a timelier manner, while reducing the environmental impact and lowering the costs of printing and distributing the Proxy Materials. The Notice is first being sent to stockholders and the Proxy Materials are first being made available to stockholders at www.proxydocs.com/KEX on or about March 12, 2024.

Your Vote Is Important

Your vote is important. Whether you intend to attend the meeting or not, please ensure that your shares will be represented by completing, signing, and returning your proxy card, or by voting via the phone or internet.

Sincerely,

AMY D. HUSTED

Vice President, General Counsel and Secretary

BOARD COMPOSITION & EXPERIENCE

The following matrix displays the most significant skills and qualifications that each Director, who is either nominated for election or continuing in office, possesses. The Environmental, Social and Governance ("ESG") and Nominating Committee reviews the composition of the Board as a whole periodically to ensure that the Board maintains a balance of knowledge and experience and to assess the skills and characteristics that the Board may find valuable in the future and in the long-term interest of stockholders. The Board considers longevity of service and experience of great value given the breadth of our business and its long-term investment horizons. The Board's approach to diversity and board refreshment ensures it benefits from fresh ideas and perspectives.

Rocky B. Dewbre and Joseph H. Pyne will conclude their board service at the 2024 Annual Meeting, and thus their information is not reflected in the above.

The ESG and Nominating Committee recommends to the Board the qualifications for Board membership and for identifying, assessing and recommending qualified Director candidates for the Board's consideration. Directors should have the following attributes:

• A commitment to building stockholder value;
• Business acumen and broad experience and expertise in the skills, qualifications and experience represented in the above skills matrix;
• Sufficient time to effectively carry out duties as a Director; and
• Independence (at least a majority of the Board must consist of Independent Directors, as defined by the New York Stock Exchange ("NYSE") Corporate Governance Standards).

2023 FINANCIAL SUMMARY

Consolidated revenues increased 11% in 2023 to $3.1 billion. The year-over-year improvement was driven by improved pricing and increased demand in the KMT business and improved demand and activity levels in the D&S segment. Net earnings attributable to Kirby were $222.9 million or $3.72 per share in 2023.

KMT revenues increased 6% to $1.7 billion during 2023. The strong growth was primarily due to an 11% increase in inland marine revenues driven by strong demand, increased term and spot contract pricing and higher barge utilization. Inland market conditions steadily improved throughout 2023 despite seasonal weather challenges and other headwinds. The first quarter was impacted by poor navigation conditions due to high wind and heavy fog resulting in significant delay days. In the second quarter, inland market conditions improved significantly with sequential increases in spot market prices and strong utilization. In the third quarter, despite the Illinois River locks closure, inland marine experienced strong market conditions with a sequential increase in spot market prices and high-teens operating margins. Weather challenges impacted the fourth quarter, but strong pricing and utilization mostly offset this allowing for inland marine margins to conclude the year with operating margins in the high teens on average. The inland market is expected to remain strong in 2024, driven by steady customer demand, and improved pricing as a result of minimal new barge construction and a heavy year for industry maintenance.

In coastal marine, market conditions improved throughout the year. However, revenues decreased 10% year-over-year due to planned shipyard maintenance and ballast water treatment installations on some vessels. In the first quarter, we experienced high barge utilization levels driven by solid customer demand and limited availability of vessels. During the second quarter, continued customer demand and limited capacity availability resulted in significant price increases year-over- year on term contract renewals and spot prices. In the third quarter, improvements in market fundamentals accelerated, but our third quarter revenues and operating margins were impacted due to planned shipyard maintenance. In the fourth quarter, strong customer demand and high barge utilization continued but was partially offset by planned maintenance and ballast water treatment installations. As a result, the coastal business was able to finish the year with operating margins in the low single digits in the fourth quarter.

In D&S, revenues increased 17% year-over-year, led by strong demand across our markets with higher levels of service work and deliveries. In the commercial and industrial market, overall demand remained solid across our business units, with growth coming from the marine repair, power generation, and on-highway sectors. In addition, demand for Thermo King refrigeration equipment remained positive throughout the year. In the oil and gas market, revenues and operating income improved from 2022 as our manufacturing business received new orders for Kirby's environmentally friendly pressure pumping equipment and power generation solutions for electric fracturing. However, throughout the year operations were challenged by supply chain delays and extended lead times. D&S concluded the year with operating margins improving to the high single digits.

From a cash flow and balance sheet perspective, Kirby generated $540 million in cash flow from operations in 2023 which was used to fund capital expenditures, pay down debt and buy back shares. Capital expenditures were higher compared to 2022 due to increased marine maintenance and growth capital spending in both segments. Throughout the year, the Company remained committed to reducing debt and repaid over $63 million. At the end of 2023, Kirby's total long-term debt had declined to $1.0 billion, with the debt-to-capitalization ratio improving to 24.2%. During the year, Kirby also returned capital to shareholders by buying back 1.5 million shares at an average price of $75.95.

CORPORATE GOVERNANCE

The Board represents the stockholders' interest and is responsible for overseeing Company management, which includes monitoring the effectiveness of management practices and decisions, corporate performance, the integrity of the Company's financial controls, and the effectiveness of its enterprise risk management programs. To that end, the Board has established governance practices including the guidelines and charters described below which are reviewed by the Board at least annually and changes are made as necessary.

Risk Oversight

The full Board is responsible for the oversight of key risks to Kirby's business and reviews with management the Company's business, including identified risk factors. The Board periodically visits Kirby operations sites. These visits enable the directors to observe and provide input on practices, performance, technology, industry and corporate standards. The Board oversees a broad spectrum of interrelated risks with assistance from its committees. The Board has designated the Audit Committee, the Compensation Committee, and the ESG and Nominating Committee certain responsibilities to provide assistance in fulfilling the Board's responsibilities. A particular risk will be monitored and evaluated by the Board committee with primary responsibility in the area of the subject matter involved. For example, the Compensation Committee reviews the risks related to the Company's compensation policies and practices and the Audit Committee receives regular reports and updates on cybersecurity issues. See page 24 for further detail on risk oversight by the Board and its committees.

Business Ethics Guidelines

The Board has adopted Business Ethics Guidelines that apply to all directors, officers, and employees of the Company, including the Company's chief executive officer, chief financial officer, chief accounting officer or controller, or persons performing similar functions. A copy of the Business Ethics Guidelines is available on the Company's website at www.kirbycorp.com in the Investor Relations section under Governance/Governance Documents. The Company is required to make prompt disclosure of any amendment to or waiver of any provision of its Business Ethics Guidelines that applies to any director or executive officer including its chief executive officer, chief financial officer, chief accounting officer or controller, or persons performing similar functions. The Company will make any such disclosure that may be necessary by posting the disclosure on its website at www.kirbycorp.com in the Investor Relations section under Governance/Governance Documents.

Corporate Governance Guidelines

The Board has adopted Corporate Governance Guidelines. A copy of the guidelines is available on the Company's website at www.kirbycorp.com in the Investor Relations section under Governance/Governance Documents.

Communication with Directors

Interested parties, including stockholders, may communicate with the full Board or any individual director, including the Chairmen of the Audit, Compensation, and Governance Committees, the Chairman of the Board, the lead independent director, if any, or the non-management or independent directors as a group, by writing to them c/o Kirby Corporation, P.O. Box 1745, Houston, Texas 77251-1745. The Company will refer the communication to the appropriate addressee(s). Complaints about internal controls and accounting or auditing matters should be directed to the Chairman of the Audit Committee at the same address. All communications will be forwarded to the person(s) to whom they are addressed.

Website Disclosures

The following documents and information are available on the Company's website at www.kirbycorp.com in the Investor Relations section under Governance/Governance Documents:

• Audit Committee Charter
• Compensation Committee Charter
• ESG and Nominating Committee Charter
• Criteria for the Selection of Directors
• Business Ethics Guidelines
• Corporate Governance Guidelines
• Communication with Directors
• Clawback Policy
• Insider Trading Policy