MCKESSON CORP

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 (Amendment No. )

McKESSON CORPORATION

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Focus on People and Culture

At McKesson, our purpose is Advancing Health Outcomes for All®

What sets McKesson apart as an exceptional place is our people. Our employees understand that together, unified by our global I²CARE values (Integrity, Inclusion, Customer-First, Accountability, Respect, Excellence), we fulfill our mission and uphold our reputation as a trusted partner to our customers and their patients. Our I²CARE values are foundational to all that we do and who we are as a company.

At McKesson, everyone is a leader. ILEAD (Inspire, Leverage, Execute, Advance, Develop) is our common definition and shared commitment to leadership. By embracing this commitment, we bring out the best in ourselves and position McKesson to continue to drive better health – for our company, our customers and the patients we impact for years to come.

A Letter From Our Independent Chair

“We value the trust you place in us through your investment in McKesson and remain focused on driving the long-term growth of the company.”Donald R. KnaussIndependent Chair

June 20, 2025

Dear Fellow Shareholders,

On behalf of our entire Board of Directors, thank you for your continued support of McKesson. As directors, we play a key role in guiding McKesson's culture and strategy, all in support of our purpose of Advancing Health Outcomes for All®.

McKesson’s Annual Meeting is an important opportunity to share how we are delivering on our strategic priorities, provide insight into key governance matters and to connect with our shareholders regarding the Board’s activities over the last year. As we approach the Annual Meeting, I would like to highlight several key areas of focus for the Board.

Delivering on our Strategic Priorities

We are proud of the progress McKesson has made in executing against our strategic priorities with focus and unwavering dedication. This commitment has enabled us to expand our differentiated capabilities, drive operational efficiencies and create real value for our partners and shareholders. In fiscal year (FY) 2025, McKesson made meaningful strides across our four strategic priorities: focus on people and culture, strengthen our North American pharmaceutical distribution, modernize and accelerate our portfolio, and enhance oncology and biopharma services platforms.

•Grounded in our I 2 CARE and ILEAD values, McKesson delivered disciplined execution across the business in FY 2025, resulting in a 25% increase in our stock price.

•In December, we completed the divestiture of our Canada-based Rexall and Well.ca businesses, sharpening our focus on strategic capital deployment that prioritizes investments in our oncology and biopharma services platforms.

•We also successfully onboarded several new customers and expanded a key pharmaceutical distribution relationship with a strategic customer in FY 2025, further demonstrating our differentiated distribution and sourcing capabilities, including our strong customer value proposition.

•We launched a comprehensive digital enablement and digital mindset training program across the enterprise to foster a cultural shift towards embracing digital tools and emerging technologies, including artificial intelligence (AI), ensuring that our leadership and employees are equipped to navigate and leverage the digital landscape effectively to increase efficiency and drive value. This initiative underscores our commitment to fostering a digital-first culture and equipping our workforce with the skills and mindset necessary to thrive in an increasingly digital world by reimagining how we work.

•By setting the tone at the top, we continue to play a key role in overseeing McKesson's commitment to regulatory excellence and compliance with applicable laws.

A Letter From Our Independent Chair

Enhancing our Technology and AI

McKesson is integrating technology and AI to drive efficiency and enable smarter decision-making, improving our ability to deliver better health outcomes. We believe that by accelerating the use of AI across our portfolio, we can unlock the potential to improve the customer experience and increase productivity. Our Board is focused on managing AI-related risks as well as overseeing our AI strategy. McKesson has established a strong governance structure to balance considerations related to our AI strategy. We are excited to be recognized as one of America's Most Innovative Companies in 2025 by Fortune and will continue to strengthen our innovative culture to help drive McKesson's strategy and efforts to become the best place to work in healthcare.

Focusing on Governance

On behalf of the Board, thank you to our shareholders for your ongoing engagement and valuable feedback. Over the past year, we have had insightful conversations with many of you about important topics including: Board composition and refreshment; AI and cybersecurity; human capital management; and the structure of our executive compensation program.

Our Board is composed of a group of committed and highly qualified individuals who care deeply about McKesson and its future. We routinely evaluate the composition of the Board and strategically refresh our membership to ensure we have a balanced mix of expertise across disciplines to guide McKesson and support our strategic priorities. Since our last Annual Meeting, we have appointed two new members to our Board, Lynne M. Doughtie and Julie L. Gerberding, M.D., M.P.H. Ms. Doughtie brings to the Board a deep background in accounting and finance, and she serves on our Audit Committee and Finance Committee. Dr. Gerberding brings extensive executive experience in the healthcare industry and in federal health policy, and she serves on our Compliance Committee and Compensation and Talent Committee. The Board is excited about the appointment of these two new directors and looks forward to incorporating their expertise as we work together to continue to drive growth for McKesson. Additionally, Richard Carmona, M.D., who has reached the retirement age under our Corporate Governance Guidelines, will not be renominated to the McKesson Board. We would like to thank him for his dedicated service on the Board and the valuable insights he has provided over the years.

Thank You

Your Board members appreciate the opportunity to serve McKesson on your behalf. We value the trust you place in us through your investment in McKesson and remain focused on driving the long-term growth of the company.

Your vote is very important to us. We strongly encourage you to review both our proxy statement and annual report in their entirety ahead of the Annual Meeting on July 30, 2025, and respectfully request your support of our voting recommendations.

Donald R. Knauss

Independent Chair of the Board

Notice of 2025 Annual Meeting of Shareholders To Be Held on July 30, 2025

We also will conduct such other business as may properly be brought before the meeting.

You will be able to attend the Annual Meeting online, vote and submit questions during the meeting by visitingwww.virtualshareholdermeeting.com/MCK2025 and entering the 16-digit control number included in our Notice Regarding the Availability of Proxy Materials, voting instructions form or proxy card. Online access to the audio webcast will open approximately 15 minutes prior to the start of the Annual Meeting to allow time for you to log in and test the computer audio system.

On or about June 20, 2025, we began delivering proxy materials to all shareholders of record at the close of business on June 4, 2025. The mailing address of our principal executive offices is McKesson Corporation, 6555 State Highway 161, Irving, Texas 75039.

June 20, 2025

By Order of the Board of Directors

Saralisa C. Brau

Corporate Secretary

VOTING METHODS

Important Notice Regarding the Availability of Proxy Materials for the 2025 Annual Meeting of Shareholders to be held on July 30, 2025. Our 2025 proxy statement and annual report are available free of charge at proxyvote.com.