- UnitedHealth is the world’s largest public insurer by TTM revenue (~$435B), ahead of Cigna, Elevance, Centene, and Allianz.
- Despite double-digit revenue growth, UnitedHealth’s profitability has deteriorated as medical costs push its MCR toward ~90% and force sharply lower EPS guidance.
- Berkshire Hathaway’s ~$1.6B stake in UnitedHealth signals a value bet amid regulatory, pricing, and operational headwinds.
- Outside the U.S., Allianz remains a top revenue and earnings player, while insurers broadly face scrutiny over premium increases and affordability, especially in property & casualty.
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The insurance sector in 2025 is marked by divergent trends. On one hand, the size of the largest health insurers (particularly those offering Medicare Advantage, Medicaid, and private employer plans) continues to grow rapidly. UnitedHealth Group remains the dominant force globally by revenue, surpassing US$435B in trailing twelve months, far ahead of peers such as Cigna (~US$268B), Elevance (~US$195B), and Centene (~US$185B). This scale confers significant leverage, but introduces risks related to cost inflation, regulatory exposure, and reputational vulnerabilities.
UnitedHealth in particular reveals a case study in margin erosion. The company has faced steep medical cost inflation, mismatches in reimbursement expectations, underpricing of Medicare Advantage plans, and a high MCR (~89-90%) that has undermined adjusted EPS. Its Q2 2025 results saw revenue up ~13% YoY (~US$111.6B for the quarter), but operating margins plunged. Full year guidance for 2025 was cut, then reaffirmed at a lower base, projecting at least US$16.25 per share in adjusted earnings, down sharply from earlier forecasts. These dynamics signal that growth alone is insufficient without improved cost discipline, pricing strategy alignment, and favorable regulation.
The strategic move by Berkshire Hathaway—taking ~5.04 million shares (~US$1.57B) in UnitedHealth—indicates that value investors are seeing a long-term opportunity, likely betting on a recovery once cost and regulatory pressures stabilize. However, such a bet carries risk, given continuing governmental investigations into Medicare billing, scrutiny over pharmacy benefit manager practices, and pressure on health plan profitability.
Outside the U.S., giants like Allianz SE are expanding but show more stable margin profiles. Allianz reports ~US$160-162B in TTM revenue, with net income in the range of US$17-20B, and a diversified mix across property & casualty, life/health, and asset management. Property & casualty insurers in the U.S., in contrast, are facing both underwriting profits and rising political pressure over premium pricing and profit margins amid concerns about affordability.
In sum, the “biggest” insurance companies by revenue are under pressure to convert scale into sustainable profit. Key strategic levers include managing medical cost inflation (especially in health), aligning pricing with risk, navigating regulatory reforms (particularly in Medicare, PBM, affordability), and leveraging technology (e.g., AI, cost control) to improve operating efficiency.
Open questions remain whether Medicare Advantage reimbursement reforms, cost-sharing pressures, environmental/climate risk (for property & casualty), and regulatory cap proposals will erode profitability further. How insurers adapt—through pricing discipline, cost restraint, or product redesign—will likely determine winners and laggards.
Supporting Notes
- UnitedHealth posted TTM revenue of about US$435.15B, with other top insurers such as Cigna (~US$267.93B), Elevance (~US$194.82B), Centene (~US$185.85B), and Allianz (~US$161-162B) ranking closely behind in global insurance by revenue.
- UNH experienced a steep margin decline in Q2 2025: medical cost trend underpriced, operating margin at ~2.4% in its UnitedHealthcare segment vs ~6.2% in Q1, causing cuts to EPS guidance and a decline in investor confidence.
- Berkshire Hathaway acquired ~5.04 million shares of UnitedHealth in Q2 2025, a position worth ~US$1.57B, to capitalize on its depressed valuation despite significant regulatory and operational risk.
- Allianz SE in FY 2024 reported revenues of ~€179.8B (approximately US$160-162B depending on FX), operating income ~€16B, net income ~€10.5B, and ~156,000 employees; strong business volume in property, casualty, life, and health sectors.
- U.S. property & casualty insurers saw their highest underwriting profits in almost two decades during 2025, paired with sharp rate hikes and growing consumer/regulatory backlash over insurance affordability in regions especially prone to risk (e.g. natural disasters).
- UnitedHealth’s full-year guidance for 2025 was reaffirmed at a lowered EPS target of at least US$16-16.25, down from earlier guidance in the high US$20s, as the company absorbed ~$6.5B in unexpected medical costs and revised pricing for Medicare Advantage.