Inspire Medical Systems' stock experienced a significant after-hours plunge of 14.30% on Monday, following the release of its first quarter 2026 financial results and updated annual guidance.

The company reported Q1 revenue of $204.6 million, which beat analyst estimates of $202 million, but represented only a modest 1.6% year-over-year growth. More concerning for investors was the Q1 GAAP diluted loss per share of $0.39 and a net loss of $11.3 million.

The primary driver behind the sharp decline appears to be the company's 2026 outlook. Inspire Medical Systems guided for full-year revenue between $825 million and $875 million, representing a decrease of 4% to 10% compared to 2025 levels. The company cited ongoing disruption from coding and reimbursement uncertainty, along with the impact of its WISeR program, as factors limiting revenue growth. Management anticipates this coding and reimbursement uncertainty will persist throughout 2026, negatively impacting results.