Ciena's stock experienced a significant intraday plummet of 11.35% on Thursday, as investors reacted negatively to the company's forward-looking guidance despite reporting strong first-quarter financial results.

The networking equipment company reported adjusted earnings per share of $1.35 for its fiscal first quarter, beating analyst estimates of $1.17. Revenue for the quarter reached $1.43 billion, also surpassing the consensus estimate of $1.40 billion. Furthermore, Ciena raised its revenue guidance range for the full fiscal year 2026 to between $5.9 billion and $6.3 billion.

However, the company provided second-quarter revenue guidance of $1.5 billion, plus or minus $50 million, which appears to have fallen short of market expectations. This disappointment comes despite the strong quarterly performance and comes at a time when Ciena's stock had already risen approximately 47% year-to-date on strong demand for networking equipment from artificial intelligence data centers, indicating investor expectations were extremely high heading into the earnings report.