UnitedHealth Group (UNH) shares tumbled 5.65% in pre-market trading on Thursday following the release of its first-quarter earnings report and revised full-year guidance. The healthcare giant's performance fell short of expectations, sparking concerns among investors.

The company reported adjusted earnings per share of $7.20 for the first quarter, missing the analyst consensus estimate of $7.29. Revenue came in at $109.58 billion, also falling short of the expected $111.60 billion. Despite these figures representing increases from the same period last year, they failed to meet market projections.

Adding to investor worries, UnitedHealth significantly lowered its annual profit forecast. The company now expects 2025 adjusted earnings per share to be between $26 and $26.50, down from its previous guidance of $29.50 to $30 per share. This revision is primarily attributed to higher medical costs, as steady demand for healthcare services continues to impact the company's bottom line. The first quarter medical care ratio, a key metric measuring medical costs as a percentage of premiums, stood at 84.8%, indicating elevated healthcare utilization.