Optical Fiber Stocks Surge Up to 1,100% in a Month After Jensen Huang's GTC Remarks — Blind-Buying Warning Issued

After NVIDIA CEO Jensen Huang spotlighted optical communications as a critical infrastructure technology for AI data centers at GTC 2026 in March, South Korean small- and mid-cap optical fiber stocks surged as much as 1,100% within a single month. However, mounting concerns over a theme-driven rally with weak earnings fundamentals have triggered repeated overheating warnings from regulators and market observers.

Stock-by-Stock Surge Summary (Approx. 1 Month Post-GTC 2026)

The Catalyst: Jensen Huang's Pivotal Comments

In his GTC 2026 keynote, Jensen Huang explicitly named optical communications and silicon photonics as the key technologies to resolve high-speed data transmission bottlenecks in AI data centers. NVIDIA subsequently formalized partnerships with global optical component makers Lumentum and Coherent, committing approximately $2 billion (roughly ₩3 trillion) to each — a move that ignited the thematic rally in South Korean optical fiber equities.

Investor Frenzy Persists Despite Exchange Warnings

The Korea Exchange has issued a series of market alerts in response. Woori-ro (3/26), Bit & Electron (4/13), and Gwangjeonja (4/10 and 4/14) were subject to trading halts, while Daehan Optical Communications was designated an investment-warning stock on April 13. Yet investor enthusiasm has proven resilient — Bit & Electron hit the daily upper limit circuit immediately after its trading halt was lifted, underscoring how difficult it has been to cool market sentiment.

Valuation vs. Narrative

The core risk is valuation. Daehan Optical Communications traded at a price-to-book ratio (PBR) of 36.72x as of April 14 — more than 13 times the KOSDAQ average of 2.75x. While the structural growth potential of optical communications within the global AI infrastructure cycle is difficult to dismiss, most of the surging domestic names are small-caps with uncertain inclusion in NVIDIA's direct supply chain and low earnings visibility. The fact that Daehan Optical Communications fell more than 7% in early trading on the 16th, as profit-taking sellers flooded the market, is a clear signal of the limits of a narrative-driven rally.

Rather than chasing short-term momentum, investors should prioritize verifying each company's actual position in NVIDIA's supply chain, its order pipeline, and revenue growth trajectory. A theme can spark a fire — but without real earnings, all that's left is smoke.