Why Ciena Sank Today

Shares of Ciena (NYSE: CIEN) plummeted 18.6% on Thursday as of 1:05 p.m. EDT.

As a leader in optical networking hardware and software platforms, Ciena's share price has skyrocketed with the advent of generative AI and the associated infrastructure build-out. The stock, even with today's sell-off, is up a whopping 271% over the past year alone.

That may be why Ciena's fiscal first-quarter earnings report, which showed both a strong revenue and earnings beat, didn't lead to a positive outcome for the stock.

Ciena's growth accelerates, but it's not enough for its now-lofty valuation

In the fiscal first quarter ending at the end of January, Ciena saw growth rise 33.1% to $1.43 billion, while adjusted (non-GAAP) earnings per share rallied 111%. Both figures handily beat analyst expectations. Management also raised full-year guidance to a range of $5.9 billion to $6.3 billion, up from a prior range of $5.7 billion to $6.1 billion, and above the consensus estimates of $5.96 billion. Ciena also raised its gross margin guidance to 44% at the midpoint, up from prior guidance of 43%.

CEO Gary Smith noted in the release:

Our record fiscal fourth-quarter and full-year performance reinforce our position as the global leader in high-speed connectivity, with an expanding role in the AI ecosystem... Looking ahead, we are confident in our growth trajectory over the coming years, driven by durable demand from our cloud and service provider customers and a growing set of opportunities inside and around the data center.

Image source: Getty Images.

Ciena investors are selling the good news

To be honest, it's really hard to come away with any negatives in this earnings release. It should be noted that many AI and semiconductor-related stocks were down on Thursday amid fears over supply chain disruptions from the U.S.-Iran war, which caused a pullback in the sector.

Still, Ciena was down by even more. That likely means investors might have been hoping for an even bigger guidance raise. Of note, the full-year outlook would imply a 28% growth rate over fiscal 2025, which would mark a deceleration from first-quarter results and second-quarter guidance of 33% growth. The guidance therefore implies a significant deceleration in the back half of the year. So despite the guidance raise, investors might have been looking for even more, given the strong first quarter.

Yet that may also be management playing things conservatively. Ciena has a recent history of regularly beating guidance, so it may be the case that management is merely managing expectations. Shares came into the day trading at 77 times this year's earnings estimates, so investors may merely be locking in substantial gains, with the stock price already reflecting much good news.

Billy Duberstein and/or his clients have no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Ciena. The Motley Fool has a disclosure policy.