Optical communication and optical semiconductor-related stocks fell across the board on the Korean stock market on the 13th. While the importance of optical communication technology is being highlighted amid the expansion of artificial intelligence (AI) infrastructure and data centers, selling pressure was seen across related stocks in the market that day.

■ Daehan Optical Communication, BitGwa Electronics, and Other Optical Communication Stocks Decline

As of the morning session on the 13th, Daehan Optical Communication traded at 14,850 won, down 870 won (5.53%) from the previous trading day. The stock showed large price swings, rising as high as 15,130 won intraday before falling back to 14,420 won, with a trading volume of 2,477,844 shares.

BitGwa Electronics fell 6.19% to 4,090 won, down 270 won, moving between an intraday high of 4,275 won and a low of 4,035 won on a volume of 3,580,058 shares. Bitsaem Electronics traded down 400 won (2.64%) at 14,750 won, and Kwang Electronics weakened 3.90% to 9,120 won, down 370 won.

The decline was not limited to a few companies. Korea Advanced Materials fell 35 won to 2,695 won (1.28%), Woorinet dropped 450 won to 10,000 won (4.31%), Lycom declined 235 won to 4,565 won (4.90%), and FiberPro fell 440 won to 11,950 won (3.55%).

■ RFHIC and RF Materials Fall More Than 6%... Equipment and Network Stocks Also Decline Together

A similar trend appeared in stocks holding optical communication equipment and network-related technologies. RFHIC traded 3,500 won lower at 53,800 won, down 6.11%, and RF Materials fell 3,300 won to 50,400 won, down 6.15%. Mercury dropped 180 won to 5,120 won (3.40%), and Jaram Technology recorded a decline of 810 won to 12,940 won (5.89%).

■ Hanmi Semiconductor Plunges 9.66%... AI Semiconductor Investment Sentiment Draws Attention

Among semiconductor-related stocks, Hanmi Semiconductor's decline stood out. Hanmi Semiconductor plunged 9.66%, trading 24,000 won lower at 224,500 won. It rose as high as 246,000 won intraday before retreating to 223,000 won.

Hanmi Semiconductor is a company highly related to semiconductor equipment used in the manufacturing process of high-bandwidth memory (HBM). Although its business area differs from that of optical communication equipment manufacturers, it is a stock drawing attention together under the common market interest in AI infrastructure investment. The steep fall that day draws attention to investment sentiment toward AI semiconductor-related stocks as well. However, it is difficult to attribute the decline of individual stocks to the same supply and demand factors.

■ Seoul Semiconductor and Other Optical Semiconductor Stocks Also Weak

Seoul Semiconductor, related to the optical semiconductor field, also fell. Seoul Semiconductor declined 4.28% to 9,400 won, down 420 won, with an intraday high of 9,750 won and a low of 9,360 won. Seoul Biosys weakened 3.23% to 7,790 won, down 260 won. That day, Sungho Electronics fell 650 won to 30,050 won (2.12%), LS dropped 13,000 won to 243,000 won (5.08%), and TMC weakened 790 won to 15,900 won (4.73%).

Optical semiconductor is a comprehensive concept covering semiconductor devices that generate or detect light, encompassing various technologies such as light-emitting diodes (LEDs), laser diodes, and photodetectors. However, not all companies related to optical semiconductors directly participate in the optical communication market. Optical semiconductors for lighting and displays and optical components for communications may have different major customers and sources of demand.

■ Short-Term Correction or Change in Investment Sentiment?

As related stocks fell in unison, market attention is focused on whether this movement will end as a short-term price correction or lead to a change in investment sentiment across the sector. In particular, with Daehan Optical Communication, BitGwa Electronics, RFHIC, and RF Materials falling 5-6% and Hanmi Semiconductor plunging more than 9%, volatility across related technology stocks is being highlighted.

■ Expansion of AI Data Centers as Background for Optical Communication Attention

Optical communication technology is one of the core infrastructures connecting AI data centers and ultra-high-speed communication networks. As AI services expand, the volume of data moving within and between data centers is also increasing. This is the backdrop for the growing importance of technology that quickly delivers data between servers performing large-scale computation and network equipment. In particular, optical transceivers that convert electrical signals into optical signals to transmit data, optical fibers, and optical communication components are cited as technologies necessary for building high-speed networks. Optical communication is advantageous for transmitting large volumes of data over long distances and also plays an important role in high-speed data center networks.

However, the industry's growth potential and the short-term stock price movements of related companies need to be distinguished. Even if AI data center investment expands, corporate performance may vary depending on which companies actually win orders and how product supply translates into revenue and profit. Moreover, while optical fibers and cables, optical transceivers, optical semiconductors, and communication equipment are interconnected industries, each company's technological competitiveness and profit structure are not identical.

■ Key Points to Watch Going Forward

The simultaneous decline of optical communication and optical semiconductor-related stocks that day shows that expectations for a growing industry and short-term stock market evaluations can move differently. Going forward, how much the expansion of AI data center investment is reflected in actual optical communication component demand and corporate performance is expected to be a key factor to watch. In the short term, it is necessary to examine not only the magnitude of stock price declines but also changes in trading volume, supply and demand by sector, and each company's new orders and earnings outlook. It is noteworthy that related stocks fell across the board that day, even as the mid- to long-term growth potential of the optical communication and optical semiconductor industries is being discussed.

[Optical communication and optical semiconductor-related stocks may show different price movements depending on their business structures and performance. This article is not a recommendation to invest in any specific stock, and investment decisions and responsibility rest with the investor. This article was written with the assistance of AI.]