Optical communications theme stocks that surged on expectations of expanding artificial intelligence infrastructure have quickly moved into a sharp correction, with volatility rising and investor sentiment cooling as recent gains are erased.
According to the Korea Exchange on Wednesday, major optical communications-related shares have shown a clear downtrend since forming peaks in mid-April. Optical Electronics, which makes optical sensors and related products, jumped from 2,080 won on March 17 to 17,780 won on April 15, then slid to close at 10,110 won on Wednesday after a pullback.
Daehan Optical Communication topped 20,000 won, hitting 20,150 won on April 14, but closed Wednesday at 15,150 won, down about 24.8%. Wooriro, which had risen more than 1,000% since the start of the year, fell about 41.2% from 14,200 won on April 16 to 8,350 won on Wednesday, giving back a large share of its gains.
Other names also extended losses: Bitsam Electronics fell about 48.8% from 23,650 won to 12,110 won; Lycom dropped about 38.0% from 8,400 won to 5,210 won. Bitgwang Electronics slid about 22.1% from 6,520 won to 5,080 won, and Gigalane fell about 27.5% from 2,855 won to 2,070 won, reflecting broad declines across the sector.
Optical communications transmits data using light rather than electrical signals, enabling ultrafast, high-capacity networks over fiber optics and is widely viewed as next-generation infrastructure. As AI services spread and require real-time processing of massive data, demand has been rising for uses such as links between data centers and internal server networks, supporting longer-term growth expectations for the industry.
The rally appeared to be sparked by comments from Nvidia CEO Jensen Huang. Speaking at "GTC 2026" on March 17 local time, he cited optical communications as a core technology for next-generation AI infrastructure, drawing market attention. Related shares then posted gains of several hundred percent through mid-April in a rapid run-up.
More recently, however, prices have reversed and quickly surrendered gains. Market participants have described the move as typical theme-stock trading, with profit-taking accelerating after expectations were priced in. Some analysts said volatility could persist depending on whether earnings visibility improves and industry conditions are confirmed.
* This article has been translated by AI.
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