AI Stocks: Lumentum, Ciena Slide 10% in Optical Selloff

Lumentum and Ciena fell about 10% and Coherent 7% on Oct. 12 as profit-taking hit AI stocks tied to optical networking after a sharp multi-week rally.

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Shares of optical networking suppliers fell sharply on Monday, Oct. 12, as investors locked in gains from a multi-week rally. Lumentum (LITE) dropped about 10% to near $997 in midday trading. Ciena (CIEN) closed down 9.95% at $405.01, a loss of $44.76 on the session. Coherent (COHR) slid about 7% to roughly $289.68. Applied Optoelectronics (AAOI) also fell in the same session. The moves hit AI stocks that supply the fiber, lasers and transceivers linking data-center clusters.

What Happened to Optical Networking Stocks?

Optical names fell together on Monday with no earnings release, guidance change or analyst action behind the drop. The pattern points to rotation out of crowded positions rather than a change in company fundamentals.

Ciena had gained in five of the previous seven sessions, including a 14% jump on Oct. 6. Profit-taking had already started before Monday. On Oct. 8, Applied Optoelectronics fell about 9%, Coherent about 5% and Lumentum about 4%. Monday's selling was heavier and spread across the whole group.

Why Did the Selloff Hit These Stocks So Hard?

The group fell hardest because it had risen the most. Lumentum is up about 190% this year, and optical suppliers trade as high-beta parts of the AI infrastructure chain. Their shares tend to move more than the broader market in both directions.

The timing also coincided with the 2026 OCP Global Summit in San Jose. Companies there showed next-generation connectivity products, but investors had priced much of that into elevated valuations, and the event became a sell-the-news moment.

The wider market backdrop added pressure. Rising Treasury yields, higher crude oil prices and Federal Open Market Committee signals about possible rate increases have weighed on risk appetite. Higher rates reduce the present value of future earnings, which hits fast-growing, richly valued technology shares hardest.

Do Fundamentals Still Support the Optical Rally?

Demand data remain strong, and the selloff did not follow any deterioration in orders. Coherent's fiscal third-quarter 2026 revenue rose 21% from a year earlier to $1.8 billion. Revenue from its datacenter and communications segment rose 41%. Lumentum has reported an order book that is largely committed into early 2029, and 200G laser capacity is sold out.

That leaves valuation, not demand, as the main question. A stock priced for sold-out capacity has little room for error. Even a modest shift in sentiment can trigger double-digit single-day moves, as Monday showed. Ciena suffered a similar 14% drop after an earnings beat earlier this year, when investors worried that expectations had run ahead of results.

Strategic Context

Hyperscale cloud operators are building larger AI clusters. These need more optical links inside data centers and between sites, and that has made lasers, coherent optics and transport systems scarce. Suppliers with sold-out capacity have pricing power, which explains the size of the rally.

The same setup concentrates risk. Capital spending by a handful of large buyers drives demand across the group. Any sign that AI investment is slowing, or that financing conditions are tightening, tends to reach optical names first.

Outlook

Monday's session reset prices rather than the underlying order picture. Near-term direction for Lumentum, Ciena and Coherent will depend on Treasury yields, signals from the Federal Reserve and the next round of quarterly results. Those results will show whether sold-out capacity keeps translating into revenue growth. Until then, the group is likely to stay volatile.