Few leadership changes in corporate America land with this much force: the CEO of the nation’s largest health insurer steps down, the company pulls its financial forecast, and a former chief takes the helm — all in one day. UnitedHealth Group’s abrupt May 13, 2025 announcement that Andrew Witty was out as CEO sent a clear signal that something deeper is shaking the $371.6 billion company.

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Resignation date: May 13, 2025 ·
Successor: Stephen Hemsley ·
Tenure as UnitedHealth Group CEO: 2021–2025 ·
Previous notable role: CEO of GlaxoSmithKline (2008–2017) ·
UnitedHealth Group 2024 revenue: $371.6 billion

Quick snapshot

1Confirmed facts
2What’s unclear
  • Exact reasons for exit — board pressure vs personal decision
  • Witty’s next career move
  • Long-term impact of Change Healthcare cyberattack on UnitedHealth’s operations
  • Timeline for UnitedHealth to restore full financial guidance
3Timeline signal
4What’s next
  • Hemsley returns to CEO role
  • Witty becomes senior adviser

Here are the key biographical details of Andrew Witty.

Six key facts about Andrew Witty and his tenure.
Field Value
Full name Sir Andrew Philip Witty
Born 22 August 1964
Nationality British
Education University of Nottingham (BA)
Knighted 2016
Net worth (estimated) $50–100 million

Why did Andrew Witty resign?

Board decision and immediate leadership change

Witty stepped down as CEO of UnitedHealth Group on Tuesday, May 13, 2025, for what the company described as personal reasons. The announcement came as a surprise to many industry observers. UnitedHealth said Stephen Hemsley, the company’s chairman and a former chief executive, would succeed Witty effective immediately. Hemsley had previously served as UnitedHealth CEO from 2006 to 2017, a period that saw the company expand into a dominant force in managed care.

The upshot

UnitedHealth’s board moved fast — within hours — to install someone who already knew the company’s inner workings. That speed suggests the resignation wasn’t a long-planned succession.

The resignation and immediate replacement underline the urgency of UnitedHealth’s situation.

Regulatory and financial pressures on UnitedHealth

Witty’s departure came amid a sharp downturn in UnitedHealth’s financial performance. Healthcare Dive reported that higher medical spending and unfavorable policy changes — especially around Medicare Advantage payment rates — were squeezing margins. At the same time, the company was facing a U.S. Department of Justice antitrust investigation and the fallout from the massive Change Healthcare cyberattack that disrupted billing systems nationwide in February 2024.

The pattern: a three-front crisis — regulatory, operational, and financial — all peaking simultaneously.

What happened to UnitedHealth Group CEO?

Sequence of events leading to resignation

On the morning of May 13, UnitedHealth’s board convened and accepted Witty’s resignation. By midday, the company had issued a press release confirming the change and announcing that it was suspending its 2025 earnings guidance. STAT described the move as unexpected, noting that the guidance withdrawal followed UnitedHealth’s first quarterly earnings miss in more than a decade.

Why this matters

When the country’s largest health insurer can’t predict its own profits, it signals deeper structural issues — not just a bad quarter — that could affect premiums and coverage for millions of members.

Impact on company stock and guidance

UnitedHealth’s stock dropped approximately 5% on the day of the announcement, erasing billions in market value. The company said it would not provide updated guidance until it had a clearer picture of medical cost trends and regulatory changes. CBS News reported that the decision to suspend guidance was directly tied to the earnings miss and rising medical expenses.

The implication: investors are now betting that UnitedHealth’s turbulence will take months — if not longer — to resolve.

What is Andrew Witty doing now?

Post-resignation plans and career

As of late May 2025, Witty has not announced a new role. In the company’s announcement, UnitedHealth said he would take on the position of senior adviser to the CEO, a transitional role that keeps him on the payroll but outside the day-to-day leadership. Speculation has emerged about a potential return to the UK — Witty holds a knighthood and has deep ties to British business and government circles — or advisory board seats with pharmaceutical and healthcare firms.

What this means: for now, Witty’s career path is a question mark. But with an estimated net worth between $50–100 million, he has no immediate financial pressure to make a quick decision.

Who is Andrew Witty?

Early career at GlaxoSmithKline

Born in 1964 and educated at the University of Nottingham, Andrew Philip Witty spent most of his career at GlaxoSmithKline (GSK), one of the world’s largest pharmaceutical companies. He joined GSK in 1985 and rose through the ranks, eventually becoming CEO in 2008. During his tenure, he oversaw major drug launches and navigated the company through patent expirations. In 2016, he was knighted for services to the UK economy and the pharmaceutical industry.

CEO tenure at GSK and knighthood

Witty served as GSK’s CEO from 2008 to 2017. Under his leadership, the company pushed into emerging markets and restructured its research and development operations. After stepping down from GSK, Witty moved into advisory roles before joining UnitedHealth Group in 2021 as CEO of Optum, the company’s fast-growing health services arm. Later that year, he succeeded David Wichmann as CEO of the parent company.

Move to UnitedHealth Group in 2021

Witty’s appointment as UnitedHealth CEO in 2021 was seen as a strategic bet on integrating healthcare delivery with insurance. He had led Optum for only a few months before taking the top job. Healthcare Dive noted that his background in pharmaceuticals brought a different perspective to the payer business, though critics questioned whether a drug-industry veteran understood the complexities of health insurance regulation.

The trade-off: Witty’s pharma experience gave him credibility on drug pricing and innovation, but UnitedHealth’s core business — managing medical costs for 152 million members — required a different expertise entirely.

Andrew Witty’s pharmaceutical background brought drug pricing credibility but did not insulate him from the operational pressures that ultimately led to his resignation.

Who replaced Andrew Witty as UnitedHealth CEO?

Stephen Hemsley’s background

Stephen Hemsley, 72, is a veteran of UnitedHealth Group who served as its CEO from 2006 to 2017. During that period, the company’s revenue grew from $71 billion to over $200 billion. Hemsley was the architect of the company’s aggressive expansion into technology and data analytics through Optum. CBS News reported that he had remained on the board as chairman after stepping down as CEO.

Previous tenure as CEO (2006–2021)

Hemsley is widely credited with building UnitedHealth into the healthcare behemoth it is today — a company with $371.6 billion in 2024 revenue. But his return also raises questions: if the company needs stability, bringing back a former CEO may signal that the current leadership pipeline is not ready. Healthcare Dive noted that Hemsley’s immediate assumption of the role suggests the board valued continuity over a search for fresh blood.

The catch

Hemsley built the company that now faces a DOJ investigation. Returning to the CEO role puts him at the center of the same structural challenges his own strategies helped create.

Hemsley’s comeback places the company’s past and present challenges squarely on his shoulders.

Stephen Hemsley’s return as CEO places him at the center of the same structural challenges his own strategies helped create, questioning whether stability or further turbulence awaits.

Timeline: Andrew Witty’s career and UnitedHealth’s crisis

  • 1964: Andrew Witty born in England.
  • 2008: Becomes CEO of GlaxoSmithKline.
  • 2016: Knighted for services to the UK economy.
  • 2017: Steps down as GSK CEO.
  • 2021: Appointed CEO of UnitedHealth Group.
  • February 2024: Change Healthcare cyberattack disrupts payments nationwide.
  • Early 2025: DOJ opens antitrust probe into UnitedHealth.
  • May 13, 2025: Resigns as UnitedHealth CEO; Stephen Hemsley takes over.

“UnitedHealth Group abruptly replaced CEO Andrew Witty on Tuesday, as the sweeping problems facing the company and industry deepened.”

— CBS News

“Witty is being replaced by Stephen Hemsley, the chairman of UnitedHealth’s board and a previous chief executive.”

— Healthcare Dive

“Inside the Downfall of UnitedHealth and Its CEO Andrew Witty”

— The Wall Street Journal

The timeline shows UnitedHealth’s troubles escalating quickly under Witty’s tenure.

Clarity section

Confirmed facts

  • Witty resigned on May 13, 2025.
  • Stephen Hemsley succeeded him as CEO.
  • Earnings guidance was suspended.
  • Change Healthcare cyberattack occurred in February 2024.
  • UnitedHealth faced a DOJ antitrust investigation.
  • Witty was CEO of GSK from 2008 to 2017.

What’s unclear

  • Exact reasons for resignation (board pressure vs personal decision).
  • Witty’s future career plans.
  • Full financial impact of the DOJ investigation.
  • Whether Hemsley will pursue structural changes or maintain Witty’s strategy.
  • Long-term operational impact of the Change Healthcare cyberattack.
  • Timeline for UnitedHealth to restore full financial guidance.

For the 152 million Americans who rely on UnitedHealth for coverage, the leadership change is more than a corporate story — it’s a signal that the nation’s largest health insurer is navigating its most turbulent period in a decade. The board has bet on a familiar hand, but the regulatory and financial pressures that forced Witty out haven’t disappeared. For patients and investors alike, the question is whether Hemsley’s return brings stability or simply extends the uncertainty.

Additional sources

homehealthcarenews.com, wuft.org, youtube.com

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Frequently asked questions

Did Andrew Witty resign or was he fired?

The company stated that Witty stepped down for personal reasons. However, the abrupt timing — combined with the simultaneous suspension of earnings guidance and the stock drop — has led many analysts to believe board pressure played a role.

What was Andrew Witty’s salary as UnitedHealth CEO?

Exact compensation figures for 2024 have not yet been fully disclosed, but his total compensation as CEO in prior years exceeded $20 million annually, including salary, stock awards, and bonuses.

How long was Andrew Witty CEO of UnitedHealth?

He served as CEO from 2021 until his resignation on May 13, 2025 — a tenure of approximately four years.

What is the Change Healthcare cyberattack?

In February 2024, a ransomware attack hit Change Healthcare, a subsidiary of UnitedHealth’s Optum division, causing massive disruptions to billing and payment systems across the U.S. healthcare system.

Is UnitedHealth Group under investigation?

Yes. The U.S. Department of Justice opened an antitrust investigation into UnitedHealth Group in early 2025, focusing on the company’s dominance in the health insurance and pharmacy benefit management markets.

Who is Stephen Hemsley?

Stephen Hemsley is UnitedHealth’s former CEO (2006–2017) and current chairman. He returned as CEO in May 2025 after Witty’s resignation.

What happens to UnitedHealth stock after Witty’s resignation?

The stock fell roughly 5% on the day of the announcement. As of late May 2025, it remains volatile as investors await a clearer financial outlook from the company.

These questions highlight the uncertainty surrounding the leadership change.