Key Highlights

● Coherent shares climbed on Tuesday, September 29, 2026, recovering after a drop on Monday, September 28.

● Citi forecast that the optical-switching market would be worth $11 billion by 2030, a day before the optics rebound.

● Lumentum rose strongly and management said the Demand signal for 2027 continues to be incredibly strong.

● Corning signed a multiyear fiber and cable Supply deal with AT&T worth more than $3 billion.

Coherent Corp. (NYSE:COHR) climbed on Tuesday, September 29, 2026, joining a broad rebound in optical-networking stocks. The shares rose solidly, recovering after a drop on Monday, September 28. The catalyst was sector-wide rather than specific to the company: the optics group bounced back a day after Citi forecast that the optical-switching market would be worth $11 billion by 2030.

Citi's Big Number

Optical switching refers to equipment that routes data as light, rather than converting it into electrical signals and back again. In AI data centers, where thousands of processors must exchange enormous volumes of data, optical switches can cut power use and delay. A forecast of an $11 billion market by 2030 signals that analysts expect the technology to move from niche to mainstream as AI clusters grow. Coherent is one of the major makers of optical components, including transceivers and lasers.

Peers Moved Together

Lumentum (NASDAQ:LITE) rose strongly in what was described as an optics selloff reversing a day after Citi's call, and Applied Optoelectronics also gained. Lumentum's management said the demand signal for 2027 continues to be incredibly strong.

Corning's Fiber Deal

Corning (NYSE:GLW) signed a multiyear fiber and cable supply deal with AT&T worth more than $3 billion. The agreement supports AT&T's plan to reach 60 million Americans with fiber by 2030. AT&T Chief Executive John Stankey said fiber remains the gold standard for superior internet connectivity. While the deal centers on telecom networks rather than data centers, it reinforced the sense that demand for optical technology is strong.

Chips Carry the Day

The optics bounce was part of a wider rebound in technology hardware. Semiconductors were among the best performers, with chip ETFs rising and the U.S. chip index higher. A leaked Anthropic IPO prospectus, as reported, showed $518 billion of planned compute and infrastructure obligations.

A Weaker Broader Market

The major indexes finished lower, with the S&P 500 down 12.85 points at 7,670.84 and the Dow Jones Industrial Average down 131.59 points at 51,349.92. The Nasdaq Composite ended nearly flat at 26,797.54. Long-term Treasury yields pressured stocks through the session, with the 30-year yield at its highest since 2002. The Conference Board's index of consumer confidence slid to 81.9, a 12-year low, from 88.6 the month before. Investors will watch for follow-up research on the optical-switching opportunity and for signs of how 2027 demand is shaping up across the optics supply chain.