I can't find the detailed breakdown for 2025, but in 2024, they took in $308bn in premiums and paid out $264bn in medical costs. So even ignoring all of the downstream and systemic problems caused by insurance existing as a for-profit entity, they're taking 14% off the top just to exist as a middle-man.

https://www.unitedhealthgroup.com/content/dam/UHG/PDF/invest...

If you’ve had UHC you’d know very well that Optum is intimately tied to their insurance business. UHC just “administers the plan” while Optum controls plan decisions. So when there’s a problem, which there always is with every claim more complicated than a PCP visit, you get bounced between both companies for hours until you find someone willing to take responsibility for answering questions.