NEW YORK (Reuters) -UnitedHealth Group ( UNH ) investors, stunned by missteps at the once predictable healthcare giant, are warily expecting strategic changes in its Medicare Advantage health insurance business over the next year.

On Wednesday, the Wall Street Journal reported that UnitedHealth ( UNH ) was the subject of a criminal probe at the Justice Department, just one day after the company withdrew its financial outlook and said Group CEO Andrew Witty was leaving.

The blows are eroding the allure the healthcare behemoth once held for investors.

UnitedHealth ( UNH ) shares fell 14% in afternoon trading on Thursday to $274.35, near a five-year low. Shares had already plunged 18% on Tuesday, even as the company tried to assuage Wall Street concerns in a conference call. They are down 46% this year.

"Given that the investor call earlier this week was so brief and had a lack of detail, investors are on the lookout for another shoe to drop," said James Harlow, senior vice president at Novare Capital Management. The firm owns shares of UnitedHealth ( UNH ).

The DOJ criminal probe concerns the company's billing practices in its Medicare Advantage unit for older adults and people with disabilities, the Journal reported. UnitedHealth ( UNH ) has said in regulatory filings that investigations, audits and reviews by a dozen different government agencies are underway.

UnitedHealth ( UNH ) said in a Wednesday statement that it had not been notified of a criminal probe. "We stand by the integrity of our Medicare Advantage program," the company added.

Investors said they expect the company to turn around its profit outlook in 2026, at the earliest.

Exiting less profitable markets where it sells Medicare Advantage plans for people aged 65 and older and making health insurance plan design changes to offer access to lower-cost healthcare providers and a focus on cheaper generic drugs, rather than pricey branded ones, could be under consideration at UnitedHealth ( UNH ), said Jeff Jonas, a portfolio manager at Gabelli Funds.

Even after fixing plan issues, investors will likely need to price in a legal settlement that could cost the company over $1 billion, said Jonas.

And traditional cost-management measures that insurers have historically deployed, such as the use of prior authorizations and claim denials, have come under public and legislative criticism since the killing of UnitedHealthcare executive Brian Thompson last December, Jonas added.

In a first-quarter earnings call, the company noted that specialty care visits had generated higher costs after patients saw providers who are part of its Optum health services unit.

"Optum and OptumHealth are UnitedHealth's ( UNH ) supposed antidote to the low-margin business," said Kevin Gade, chief operating officer at Bahl & Gaynor. "The fact that OptumHealth is at the epicenter only magnifies this stock move."

Optum is too tightly integrated with the company's Medicare Advantage plans for investors to expect a breakup of the insurance business and other healthcare operations, Jonas said.

Harlow at Novare Capital Management said that without strategic details on a turnaround for its insurance business, a breakup would not assuage low morale from investors.

For investors planning to ride out the challenges, last year's difficulties in CVS Health's ( CVS ) Aetna insurance business come to mind. The company in 2024 missed earnings expectations for the first three quarters after facing rising healthcare costs and difficulty restructuring.

"There's no doubt UnitedHealth ( UNH ) got behind the pricing curve relative to peers for 2025," said Gade, who added the company still has value due to its average $20 billion in free cash after covering expenses.

"I don't think it's as existential as the stock price may appear."