UnitedHealth Group announced a dramatic shakeup, with former CEO and current chairman Stephen Hemsley stepping back into the top job following the abrupt resignation of Andrew Witty.

Witty, who led UnitedHealth since 2021, is stepping down effective immediately for “personal reasons,” the company said Tuesday.

The move comes at a time of escalating crises for the healthcare giant — including the recent fatal shooting of Brian Thompson, the CEO of UnitedHealthcare, UnitedHealth’s insurance subsidiary.

Luigi Mangione, 27, faces the death penalty after he was indicted on federal charges in connection with Thompson’s killing.

UnitedHealth Group is facing a shareholder lawsuit accusing the healthcare giant of concealing the financial consequences of consumer backlash following Thompson’s murder.

The proposed class action, filed last week in federal court in Manhattan, claims that UnitedHealth misled investors about how the company’s strategic shift — made in response to outrage over Thompson’s death — was impacting its bottom line.

The shareholders allege in the lawsuit that after the Dec. 4 shooting, UnitedHealth began quietly moving away from aggressive claim denial practices that had previously bolstered profits, without informing shareholders of the financial risk.

This undisclosed pivot left the company vulnerable, culminating in a steep selloff after UnitedHealth slashed its 2025 earnings forecast, it was alleged.

UnitedHealth shares have lost more than $190 billion in market value, having fallen more than 35% since early this year. That includes a stunning 22% plunge in a single day last month. The shares fell 18% to $311.38 on Tuesday.

“The company has tremendous opportunities to grow as we continue to help improve health care and to perform to our potential,” said Hemsley in a statement.

“In so doing, we aim to return to our long-term growth objective of 13 to 16 percent.”

UnitedHealth was not immediately available for further comment.

In addition to the slaying of Thompson, UnitedHealth has faced a devastating cyberattack that crippled its tech unit and heightened regulatory scrutiny including multiple Justice Department investigations.

UnitedHealth also announced it is suspending its revised 2025 earnings outlook, issued on April 17, citing unexpectedly high medical costs from new Medicare enrollees and broader care utilization trends.

The company had slashed full-year adjusted earnings guidance to a range of $26 to $26.50 per share — down sharply from its previous forecast of $29.50 to $30.00.

It did not issue a replacement projection.

Witty had attempted to calm investor fears during the April earnings call, blaming the downturn on federal reimbursement changes and promising operational fixes.

But Wall Street responded swiftly and negatively, sending shares into a historic one-day freefall.

Since then, the stock has shed another 17%, translating to roughly $70 billion in lost value.

UnitedHealth now finds itself isolated, as competitors like CVS Health and Humana have not reported similar Medicare Advantage cost pressures in recent months.

Under Hemsley’s prior tenure as CEO — from 2006 to 2017 — UnitedHealth was transformed from a traditional insurer into a sprawling $400 billion healthcare conglomerate, integrating pharmacy benefit management, physician groups and data services.

Investors frequently rewarded the strategy, and his return is being viewed as a stabilizing move amid a string of crises.

“Hemsley brings a combination of strategic vision and deep operational focus that are highly valuable to our company,” said Michele Hooper, lead independent director on UnitedHealth’s board.

“We’re confident in his ability to guide the company through this period.”

Witty will stay on as a senior adviser during the transition.