Gary Smith, chief executive officer and president of Ciena Corp., speaks during a Bloomberg Television interview in New York on June 14, 2013.
Scott Eells | Bloomberg | Getty Images
Networking hardware maker Ciena will join the S&P 500, returning to the benchmark after getting booted 17 years ago. The stock rose in extended trading.
Ciena is replacing human resources software company Dayforce, S&P Dow Jones Indices said in a statement on Wednesday. Private equity firm Thoma Bravo acquired Dayforce for $12.3 billion.
Ciena sells a variety of products for high-speed fiber optical networks. Nearly 18% of revenue in the 2025 fiscal year came from an unnamed cloud provider, and about 11% came from AT&T, according to the company’s annual report. Ciena’s market cap has almost tripled in the past year.
Shares of companies added to the S&P 500 often rise ahead of their inclusion in the index, as fund managers buy shares to match the benchmark. Technology companies AppLovin, Datadog, DoorDash and Robinhood entered the S&P 500 in 2025.
For Ciena, the entry marks a return. The company joined the index in 2001, boosted by the dot-com and telecom boom, and was removed in 2009, when it was replaced by Visa.
Investor excitement has returned due to soaring demand for data center infrastructure that can run generative artificial intelligence models. The opportunity represents “a major contributor to our 2026 expected growth rate,” Ciena CEO Gary Smith told analysts on a conference call in December.
At the time, the company called for revenue to grow about 24% during the 2026 fiscal year, which would mark the fastest rate of expansion since 2011.
On Tuesday, Ciena’s stock closed at the highest price since 2001. Network equipment giant Cisco recorded a new high on Tuesday as well.
As companies look to deliver additional AI capacity, components such as memory have become harder to find, driving up prices. Optical parts are also constrained, Marc Graff, Ciena’s finance chief, said on the December conference call.
“We’ve worked really closely with our key suppliers and I know who those are, to make sure that we can secure supply,” Graff said.
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