Taiwan's copper-clad laminate (CCL) stocks got hammered on a rumor that co-packaged optics (CPO) will make high-end board materials unnecessary — bad news for shareholders short-term, but the industry says the story is wrong.

• The rumor: once chips send signals out as light (CPO), motherboards only need to carry slow control signals, so cheaper M4-grade CCL would do, breaking the "better material = higher prices" growth story.
• Taiwan's three big CCL makers — EMC, Taiwan Union Technology, and ITEQ — all fell sharply, with ITEQ hitting limit-down, and PCB stocks were dragged down too.
• The industry pushes back: every new motherboard generation still needs more layers, higher voltage tolerance, lower signal loss, and stable power, so upgrades won't stop.
• PCB makers add that optical modules actually demand even stricter, ultra-low-loss materials, not cheaper ones.
• Short sellers have been targeting hot AI stocks with unverified rumors about spec changes or lost orders — Kinsus-linked names, Largan, and Wiwynn were hit the same way this week.

Outlook: CCL makers and rivals in China and Korea keep pouring money into high-end capacity for AI servers and 800G switches, so the upgrade trend looks intact even if rumor-driven selloffs keep rattling the sector.