Key Highlights

● Coherent sank before the opening bell on Friday, October 30, 2026.

● Optical and AI-infrastructure stocks sold off in a wider tech slide.

● The move came with the sector rather than company news.

● The stock has fallen on concerns about indium phosphide substrate yields.

Shares of Coherent Corp. (NYSE:COHR) sank before the opening bell on Friday, October 30, 2026, according to market data 6:30 a.m. Eastern snapshot, as optical and AI-infrastructure stocks were hit by a widening technology selloff. The move came with the sector rather than on fresh company news.

Coherent makes lasers, optical networking components and materials used in data centers and communications equipment, including parts that carry data between AI servers. That exposure has tied the stock closely to sentiment about AI infrastructure spending.

The decline extended a difficult stretch. A brief from Market data said the stock has fallen steeply over the past 20 trading days on concerns about indium phosphide substrate yields, with analysts cutting price targets to $325. The brief did not name the firms.

Optical peers fell together

Coherent had company. Applied Optoelectronics fell in premarket trading without company-specific news, and Lumentum (NASDAQ:LITE) closed sharply lower amid the AI-infrastructure selloff and reported Acquisition talks with Marvell Technology (NASDAQ:MRVL), which also tumbled. Corning (NYSE:GLW) dropped before the bell as well. Those deal reports remain unconfirmed.

The chip sector was the center of the storm. Intel (NASDAQ:INTC)'s weak fourth-quarter outlook and cash-burn warning, issued after Thursday's close, set off a global rout. Intel guided fourth-quarter Revenue to $15 billion to $16 billion, well short of consensus, and its shares suffered their biggest one-day drop on record, according to market data. The Philadelphia Semiconductor index fell to 10,688.80.

AI spending under scrutiny

Amazon (NASDAQ:AMZN)'s results added to worries about the cost of artificial intelligence. The company's trailing 12-month free Cash Flow turned negative at $42.4 billion, and it held 2026 Capital spending at about $220 billion while signaling another increase next year. Alphabet (NASDAQ:GOOGL) suffered its worst day ever on Thursday after its free cash flow came in deeply negative.

A market analyst noted the scale of spending: "Together, Amazon, Google, Microsoft (NASDAQ:MSFT) and Meta (NASDAQ:META) spent more than $200bn in the third quarter alone," she said, adding that "the risk is that higher financing costs will absorb more of the cash generated,"

For suppliers like Coherent, heavy spending by the largest cloud companies has been a source of demand.

Broad market damage

The Nasdaq Composite fell 747.73 points to 25,437.00, its worst session since June. The S&P 500 lost 140.32 points to 7,580.07 and the Dow Jones Industrial Average dropped 572.25 points to 51,770.31. The equal-weight S&P 500 fell far less than the cap-weighted benchmark, a sign that losses were concentrated in megacap tech and chips. The Cboe (CBOE:CBOE) Volatility Index rose to 19.42 from 17.20 on Thursday, and new 52-week lows jumped to 448.

The Federal Reserve left its benchmark rate range unchanged earlier in the week, but two officials dissented in favor of a hike, and CME FedWatch data showed traders treating a December increase as likely. A senior market analyst said: "strong AI Demand is no longer enough on its own."

What to watch

Investors will watch for any update from Coherent on the substrate Yield issue cited by market data and for further changes to analysts' price targets. Developments in the reported Marvell-Lumentum talks could also affect sentiment across optical stocks.

Next week brings Apple (NASDAQ:AAPL)'s results on Monday, Nov. 2, the midterm elections on Tuesday, Nov. 3, and the October jobs report on Friday, Nov. 6, all of which will shape expectations for rates and for AI-related spending.