Meet our Leaders.

David Wichmann became chief executive officer, UnitedHealth Group, on September 1, 2017. He is responsible for the strategic direction and overall performance of the enterprise and its long-term growth agenda. He is also a member of the board of directors. Previously, Wichmann served as president, UnitedHealth Group, beginning in November 2014, with oversight responsibility for all of UnitedHealthcare's domestic and international businesses, and for overall UnitedHealth Group performance. Wichmann also served as chief financial officer of the enterprise from 2011 until mid-2016. He previously held positions as president, UnitedHealthcare; president and chief executive officer, Specialized Care Services (now OptumHealth); and senior vice president, Corporate Development. Prior to joining UnitedHealth Group in 1998, Wichmann was a partner with Arthur Andersen.    

Larry Renfro was named vice chairman, UnitedHealth Group, in November 2014. Renfro has oversight responsibility for all enterprise strategic relationships, key client relationships and companywide business growth efforts. He also is managing partner of Optum Ventures investment funds, helping accelerate innovation at Optum and across the enterprise through early stage investments in emerging and advanced technology, data and analytics and health care services companies with transformative capabilities. Renfro joined the company in January 2009 and has served as chief executive officer, Optum, and CEO, Public and Senior Markets Group. He was formerly a senior executive officer at Fidelity Investments and a member of the Fidelity Executive Committee. Renfro was president and chief executive officer, AARP Services, Inc., before he rejoined Fidelity in 2008. Renfro has also held senior executive positions at NewRiver, Inc.; State Street Bank & Trust; and Allmerica Financial.

Sir Andrew Witty was named president, UnitedHealth Group, in November 2019, in addition to his role as chief executive officer of Optum. As UnitedHealth Group president, Sir Andrew is responsible for enterprise business strategy formulation, enterprise business development and partnerships, and oversight of enterprise research and development and clinical capacities. Witty was named executive vice president, UnitedHealth Group, and chief executive officer, Optum, in March 2018. He is also a member of the Office of the Chief Executive and previously served as a UnitedHealth Group company director. Witty is former chancellor of the University of Nottingham, a British public research university, and serves on the Singapore Prime Minister’s Research, Innovation and Enterprise Council. He is an advisor to 8VC and Hatteras Venture Partners, as well as to the Bill and Melinda Gates Foundation. Witty was knighted in 2012 for services to the U.K. economy. In 2017, he was named an Honorary Citizen by Singapore for his contributions to the country’s growth and development. Witty recently took a leave of absence from his current role as president, UnitedHealth Group, and CEO of Optum, to co-lead the World Health Organization COVID-19 vaccine program.

Dirk McMahon was named chief executive officer, UnitedHealthcare, in June 2019. Prior to this role, McMahon was president and chief operating officer, Optum, with responsibility for driving Optum's enterprise performance overall and directly overseeing OptumInsight, Optum Technology, Operations, Optum Administration and business and corporate strategy. In 2017, McMahon was named to the Office of the Chief Executive. Previously, he was executive vice president, Enterprise Operations, UnitedHealth Group. McMahon has served in a number of leadership positions across the enterprise since joining the company in 2003, including chief executive officer, OptumRx, overseeing UnitedHealth Group's pharmacy benefit management programs, along with various management positions in information technology, operations and finance. Before joining UnitedHealth Group, McMahon was head of airport operations worldwide for Northwest Airlines.

Cory Alexander was appointed executive vice president, Corporate Affairs, UnitedHealth Group, and named to the Office of the Chief Executive in 2018. Alexander provides executive leadership for marketing, communications, research, international relations, U.S. external affairs, social responsibility and United Health Foundation activities. From 2014 to 2018, Alexander led External Affairs, with responsibility for enterprise government and public affairs, international relations, and social responsibility activities. Alexander joined UnitedHealth Group in 2009, serving in various Government Affairs leadership roles. Prior to joining UnitedHealth Group, Alexander held a senior role in Government Relations for Fannie Mae and previously served as chief of staff for House Democratic Whip Steny Hoyer (D-MD).

As chief scientific officer, Ken Ehlert leads UnitedHealth Group’s Research & Development function, an innovation engine intended to positively impact patient health on a global scale. UnitedHealth Group’s R&D efforts are driven by math, data and clinical science, but also focus on the human connections required to understand, manage and prevent the chronic diseases that afflict nearly half of the world’s population. Ehlert has worked with UnitedHealth Group since 2004, became the chief scientific officer in 2017 and joined the Office of the Chief Executive in 2019. Previously the co-founder and CEO of Savvysherpa, Ehlert has spent his career building products and businesses that improve the health care system.

Patricia Lewis was appointed executive vice president and chief human resources officer, UnitedHealth Group, and was named a member of the Office of the Chief Executive in October 2019. She is responsible for overseeing all aspects of human capital, including compensation and benefits, talent management, leadership and employee development, rewards and recognition and organization development. Lewis joins UnitedHealth Group from Lockheed Martin, where she was senior vice president and chief human resources officer, leading a large global team to deploy a human capital strategy in support of a diverse global workforce in more than 50 countries. She has successfully led human capital teams within complex and highly regulated industries spanning aerospace, defense, energy, cybersecurity, data analytics, biometrics, technology and chemicals. Prior to joining Lockheed Martin in 2011, Lewis held various positions in Human Resources at IBM and DuPont.

In 2013, Richard Migliori, M.D., was appointed executive vice president, Medical Affairs, and chief medical officer, UnitedHealth Group. Dr. Migliori works with businesses across the enterprise to help improve health care quality, access and affordability. He was appointed to the Office of the Chief Executive in 2019. Previously, as executive vice president, Health Services, Dr. Migliori was responsible for the ongoing development, design, and adaptation of market leading clinical innovations aimed at ensuring clinical excellence, improving clinical and economic outcomes, and delivering robust business performance on behalf of UnitedHealth Group's largest public and private sector clients.

John Rex was appointed executive vice president and chief financial officer, UnitedHealth Group, and a member of the Office of the Chief Executive in 2016. In 2012, Rex joined Optum, UnitedHealth Group’s health services business, as executive vice president, chief financial officer, Optum. In his prior roles, Rex was a leading equity research analyst, served as a strategy and operational consultant and practiced as a certified public accountant across diverse health care sectors.

Dan Schumacher was named president and chief operating officer, Optum, in June 2019. In this role, he is responsible for driving Optum's enterprise performance overall and directly overseeing OptumInsight, as well as Optum Technology, global operations and enterprise clinical capabilities. Schumacher was named to the Office of the Chief Executive for UnitedHealth Group in September 2017. Prior to his role at Optum, he had oversight responsibility for U.S. and global commercial markets including the UnitedHealthcare Employer & Individual business and the clinical, network, operations and technology groups for all of UnitedHealthcare's domestic teams as president and chief operating officer. Previously, Schumacher served as chief financial officer and controller, UnitedHealthcare. He also served as chief financial officer, Group Insurance Division, Specialized Care Services (now OptumHealth); director of Finance, Specialized Care Services, and director, UnitedHealth Group Corporate Development, in enterprisewide merger and acquisition activity.

Marianne Short was appointed executive vice president and chief legal officer, UnitedHealth Group, in January 2013, and was named to the Office of the Chief Executive in November 2014. She is responsible for overseeing legal, regulatory and compliance matters across the enterprise. Prior to joining the company, Short was the managing partner at Dorsey & Whitney LLP for six years, a partner in the Trial department, co-chair of the firm's Appellate and Health Litigation practice groups and a member of the American College of Trial Lawyers and the American Academy of Appellate Lawyers. From 1988-2000, she was a judge on the Minnesota Court of Appeals, authoring more than 900 opinions in virtually every area of civil and criminal law. She has more than 35 years of courtroom experience from her work on the court, the Dorsey firm and the Minnesota Attorney General's Office.

Ellen Wilson serves as executive vice president in the Office of the Chief Executive, UnitedHealth Group, focusing on strategic enterprise initiatives. Previously, Wilson served as executive vice president and chief human resources officer, UnitedHealth Group, where she oversaw all aspects of human resources from June 2013 until November 2019. Prior to joining UnitedHealth Group she served for 17 years at Fidelity Investments, concluding her tenure there as head of Human Resources. Wilson earned a Bachelor of Science in Business Administration from Bryant University and a Master in Business Administration from Babson College. She currently serves on the board of the Walker Art Center, Boston Ballet and Bryant University.

Terry Clark was appointed senior vice president and chief marketing officer, UnitedHealth Group, in 2014. Clark oversees branding, marketing and advertising for UnitedHealth Group and its two operating platforms, UnitedHealthcare and Optum, with responsibility for helping positively shape the customer experience. Previously, Clark served as chief marketing officer, UnitedHealthcare Medicare & Retirement, where he led marketing and direct-to-consumer engagement efforts focused on seniors. Clark joined UnitedHealthcare in 2006 from InterActiveCorp, a consumer technology company comprised of leading digital brands, where he served as executive vice president, sales and marketing, for the Entertainment Publications division.

Brett Manderfeld was named senior vice president for UnitedHealth Group’s Capital Markets Communications area in June 2019. Manderfeld joined the company’s Capital Markets Communications area as vice president in May 2007. Previously, he served as a senior stock analyst at Piper Jaffray following technology and business service companies.

Richard Mattera was named chief development officer of UnitedHealth Group in 2020. He leads corporate development efforts enterprise-wide, both legal and financial oversight, as well as strategic integration plan development, performance accountability and measurement responsibilities, fostering continued expansion of established and emerging businesses directly aligned with the social mission and growth strategy of the company. Previously, Mattera was the chief legal officer at Optum and has led the M&A legal function across UnitedHealth Group for nearly a decade. Prior to joining UnitedHealth Group in 2011, Mattera was a partner at the international law firm of Hogan Lovells, where he represented publicly and privately held companies in a variety of matters, including in the areas of mergers and acquisitions, joint ventures, securities, corporate finance and corporate governance.

Tom Roos was appointed chief accounting officer for the enterprise in August 2015. He is responsible for SEC reporting, accounting policy, tax and enterprise risk management. Previously, Roos was a partner at Deloitte & Touche LLP for eight years, where he worked closely with Deloitte & Touche's national office and industry leaders on emerging technical accounting and reporting matters in the health insurance industry, with experience in company mergers and acquisitions and initial public offerings.