Medpace Holdings Inc. (MEDP) experienced a significant after-hours plunge of 16.41% on Wednesday, despite reporting first-quarter revenue that exceeded analyst expectations.

The sharp decline appears to be driven by investor concerns following news that the company faces a lawsuit over alleged misleading book-to-bill guidance. According to the report, Medpace told investors cancellations were "well behaved" and that a 1.15 book-to-bill target remained achievable for the second half of 2025, but these statements are now being challenged in court.

This legal development overshadowed the company's positive quarterly results, which included a 26.5% year-over-year revenue increase and net new business awards growth of 23.7%. The lawsuit raises questions about the credibility of the company's future performance targets and guidance.