Why are Taiwan's optical stocks affected by U.S. earnings?

Taiwanese firms are deeply embedded in U.S. supply chains, so changes in demand forecasts directly impact orders.

Is this downturn temporary?

Long-term AI demand remains intact, but valuation corrections may require several months of adjustment.

Which Taiwan optical firms should be watched next?

Technologically strong, financially sound companies, especially those advancing 800G product development.

Optical Communication Stocks Hit Hard: Over 10 Stocks Hit Limit-Down Amid Lumentum and Coherent Slump

Published Jul 29, 2026 1:38 PM ・ Updated Jul 29, 2026 2:08 PM ・ 4 min read ・ Source: PR Times

Following weak financial forecasts from U.S. firms Lumentum and Coherent, Taiwan's optical communication stocks plunged, with over 10 stocks hitting limit-down, reflecting heightened market caution.

Ahead of the U.S. Federal Reserve's interest rate decision, semiconductor-related stocks declined broadly. Taiwan's stock market plunged over 2,000 points intraday on Wednesday (29th). Shares in Taiwan's optical communication sector opened sharply lower and continued to fall after Corning (GLW-US) issued disappointing guidance, while Lumentum (LITE-US) and Coherent Corp (COHR-US) suffered steep share price declines. More than 10 stocks, including high-priced favorites such as United Microelectronics (3081-TW) and Win Semiconductors (6442-TW), were heavily sold off and hit their daily trading limits on the downside.

Corning (GLW-US), a leading supplier of advanced optical fiber, cable, and connectivity products, reported second-quarter revenue and earnings per share that beat expectations. However, its current-quarter guidance fell significantly short of prior estimates, sending its stock tumbling 12.1%. This triggered a broad selloff in optical communication-related stocks, with Lumentum and Coherent plunging 8.43% and 10.31%, respectively, intensifying selling pressure on Taiwan-listed peers.

In addition to United Microelectronics and Win Semiconductors, other stocks including Lextar Electronics (3450-TW), Lide Optoelectronics-KY (7717-TW), Hwa Create (4979-TW), Suncom Technology (3363-TW), O-Net Communications (3234-TW), Tunic New Energy (6426-TW), Forward (4908-TW), and Jusda-KY (4977-TW) also hit limit-down during trading, turning the market landscape deeply red.

Institutional analysts note that the optical communication sector still holds significant long-term potential, with product demand expected to grow steadily, driven by AI development. However, many stocks were aggressively downgraded due to high price-to-earnings ratios, leading to widespread sell-offs. With several stocks already correcting below their yearly moving averages, a return to bullish momentum will likely depend on broader market stabilization and a shift to an overall upward trend.

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Source: PR Times
Category: News
Organizations: Lumentum / Coherent Corp

Optical Communication Stocks Hit Hard: Over 10 Stocks Hit Limit-Down Amid Lumentum and Coherent Slump

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