UnitedHealth remains largest US insurer by market cap after 40% hit in Q2 2025

UnitedHealth Group Inc. continued to be the largest US insurer by market capitalization during the second quarter, even as it experienced a historic tumble as investors balked at earnings figures.

In an analysis of the 20 largest US insurers by market cap, UnitedHealth had by far the largest decrease, falling 40.9% in the second quarter and 39.6% year over year. The managed care leader was beset by turmoil after it pulled its 2025 earnings guidance.

Of the eight market cap decreases of more than 5% in the analysis, four were by managed care insurers. Of the six increases, five were by property and casualty insurers.

Even with the sharp decline, UnitedHealth remained the largest US insurer by market cap, at $283 billion. There is a significant gap between UnitedHealth and the second-largest, The Progressive Corp., which had $156.44 billion in market cap.

Health insurers catch a chill

UnitedHealth has had a difficult time of late, beginning with the assassination of UnitedHealthcare CEO Brian Thompson on Dec. 4, 2024. This continued in May when Andrew Witty abruptly stepped down as UnitedHealth Group's CEO. UnitedHealth announced May 13 that former CEO Stephen Hemsley returned to that role and that it was pulling its 2025 guidance.

The subsequent stock market slide continued May 15 after The Wall Street Journal reported UnitedHealth was facing a US Department of Justice probe into possible Medicare fraud.

UnitedHealth did not respond to a request for comment regarding its second-quarter performance.

Fellow health insurers Centene Corp. and Elevance Health Inc. posted declines of more than 10% during the second quarter, with Centene down 10.3% and Elevance falling 10.8%. Humana Inc. and The Cigna Group decreased by a more modest 7.6% and 1%, respectively, during the same period.

The S&P 500 insurance index was up 19.55% year over year by the end of the second quarter, outpacing the broader market as the S&P 500 index rose 15.16% during the same period.

Managed care insurers also had a shaky start to the third quarter after Centene announced July 2 that it had pulled its 2025 earnings guidance, sending its stock plummeting 40.37% for the day. Other managed care insurers were impacted, too, including UnitedHealth and Elevance, which fell 5.7% and 11.5%, respectively.

President Donald Trump's legislative push, the One Big Beautiful Bill Act, appears poised to receive congressional approval and could cause millions of Americans to lose access to Medicaid, news of which sent the managed care space into another free fall during the first week of the third quarter. Medicaid generally involves private companies such as UnitedHealth and Centene administering health insurance plans using government funds.

Corebridge leads market cap growth

Corebridge Financial Inc. had the highest growth in market cap from the previous quarter among the 20 companies in the analysis. Corebridge, which recently announced it was removing a "headwind to earnings" through its reinsurance transaction that covers all variable annuities in its individual retirement business, increased its market cap by 11.2%, growing to $19.51 billion.

The company now ranks as the 19th largest public insurer by market cap in the US.

Markel Group Inc. reported the second-largest percentage increase in market cap with a gain of 6.1%. The insurer is sixth in year-over-year growth, increasing its market cap 23.7% by the end of the quarter.

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