Corning’s AI-driven rally revives an old risk as it expands fiber output

A familiar boom-and-bust pattern

The rally has been volatile. Corning shares rose nearly 200% in the first half of 2026, then fell 50% in July as investors questioned the company’s valuation and whether AI had become a bubble.

Corning has seen a boom turn before. In the early 2000s, after spending $10 billion on acquisitions, it faced a sharp drop in orders as the telecom bubble collapsed. Its stock fell from $113 to $1.10 in less than two years.

That history gives the current expansion a sharper edge: this time, Weeks is also trying to reduce the company’s reliance on any single market.

Fiber is still doing most of the work

In the first half of the year, fiber-optic products generated 45% of Corning’s $8.6 billion in revenue. Other businesses are growing, but remain smaller: solar sales nearly doubled to $808 million.

The diversification effort spans several markets:

Corning plans to spend about $1 billion on research and development in 2026, or 7% of revenue. Analysts expect 2026 revenue to reach $19.3 billion and profit to double.

Diversification is not the same as insulation

I think the key question is whether these newer businesses can become large enough to soften a downturn in fiber demand. The company’s plans cover distinct markets, but the figures show that fiber remains the biggest contributor, while even a near-doubling in solar sales has brought that business to $808 million.

The $40 billion target makes that gap consequential. Corning is investing in a broader portfolio, but its near-term growth still rests heavily on demand tied to AI infrastructure. The company’s past does not prove the current boom will end the same way; it does make the pace of diversification matter as much as the headline revenue target.