Ciena shares rise 5.47% premarket after rejoining S&P 500, driven by AI demand and 24% revenue growth guidance.

Ciena surged 5.47% in premarket trading following confirmation of its rejoining the S&P 500 on February 9, 2026, a move attributed to surging AI infrastructure demand and record orders. The stock’s inclusion in the benchmark index, replacing Dayforce, validates its transformation into a critical supplier for hyperscalers, with CEO Gary Smith highlighting "massive and accelerating" AI-driven network expansion. Recent wins with hyperscalers for "scale-across" training architectures and a 197% surge in share price over the past year underscore investor confidence in Ciena’s role in the AI era. The premarket rally aligns with broader market optimism around AI infrastructure beneficiaries and the anticipated influx of index fund capital post-inclusion.