Select Medical (SEM) shares tumbled 9.59% in pre-market trading on Friday, following the release of its first-quarter earnings report that fell short of analyst expectations. The healthcare company's performance and revised outlook have sparked concerns among investors, leading to a significant sell-off.

According to the report released late Thursday, Select Medical posted Q1 earnings from continuing operations of $0.44 per diluted share, up from $0.33 a year earlier but below the $0.46 expected by analysts polled by FactSet. Revenue for the quarter ended March 31 came in at $1.35 billion, missing the $1.39 billion forecast and only slightly higher than the $1.32 billion reported in the same period last year.

Adding to investor worries, Select Medical trimmed its annual revenue guidance for 2025 to a range of $5.3 billion to $5.5 billion, down from its previous forecast of $5.4 billion to $5.6 billion. This reduction, coupled with the earnings miss, appears to have triggered the sharp decline in the company's stock price. Despite the lowered revenue outlook, Select Medical reaffirmed its 2025 earnings guidance of $1.09 to $1.19 per diluted share, which is in line with analysts' expectations of $1.12.