Key Highlights

● Optical and storage stocks were among Monday's biggest winners.

● Coherent traded at $227.36 in the afternoon.

● Lumentum and Ciena jumped sharply.

● Brent fell $5.75 to $92.57, easing Inflation worries.

Every AI model needs two things beyond processing power: fast connections to move data between chips and huge drives to hold it. That makes optical-networking and storage companies the plumbing of the AI boom. On Monday, November 9, 2026, the plumbing was where the action was.

Coherent (NYSE:COHR), which makes lasers and optical components, rocketed and ranked among the S&P 500's top performers, according to news reports. Market data had it trading at $227.36 in the afternoon. Lumentum (NASDAQ:LITE) and Ciena (NYSE:CIEN) jumped sharply, and storage makers Seagate Technology (NASDAQ:STX) and Western Digital (NASDAQ:WDC) soared, reports said.

Bouncing from the bottom

Much of the move was a rebound. Coherent had reported strong fiscal first-quarter results on November 4, yet the stock tumbled the next day as the AI trade buckled, according to market coverage. Market data tied Monday's surge to that rebound plus AI-driven interest in optical components.

Seagate's story was similar. Market data said the shares had plunged four days earlier, when incoming Democratic senators called for slowing AI data-center development. On Monday Seagate traded around $510.73 in the afternoon, according to market reports. Western Digital moved with the storage group, with no company-specific news found.

Memory giant Micron Technology (NASDAQ:MU), whose chips sit alongside processors in AI servers, closed up $43.15 at $733.15, according to market data, on Volume of 31.9 million shares, above its 27.9 million average. Market data found no company-specific news.

Photonics gets a boost

There was at least one fresh product headline in the optical space. Keysight Technologies (NYSE:KEYS) certified its ADS Photonic Designer software for Tower Semiconductor's PH18 silicon-photonics process design kits. The company said the tools are "intended to shorten development cycles and accelerate deployment," according to news reports, and its shares climbed.

Connector and networking names joined the move. Amphenol (NYSE:APH) and Arista Networks (NYSE:ANET) both closed sharply higher, according to market coverage. No company-specific news was found for either; both moved with the broader AI-hardware and networking rebound.

The bigger picture

The backdrop was one of the strongest sessions of the year. The S&P 500 jumped 173.08 points to 7,549.94, its best day since April 8, and the PHLX Semiconductor index rocketed to 10,033.93. Falling oil, with Brent down $5.75 to $92.57, eased inflation worries, and strategists pointed to cleaned-out positioning after last week's rout.

Some caution applies to the numbers.

The gains also came despite Nvidia (NASDAQ:NVDA) sliding amid an independent review by its board involving CEO Jensen Huang. Investors appeared to separate that company-specific issue from Demand for the broader AI Supply chain. Advanced Micro Devices (NASDAQ:AMD) and Broadcom (NASDAQ:AVGO) surged, and the semiconductor index's gains came even with Nvidia as its only decliner, reports said.

AI Plumbing Demand Under Watch

The key question is whether AI spending plans hold up. This week's reports from CoreWeave and Nebius, both big buyers of networking and storage gear, will offer clues, as will Cisco's results. Nvidia's November 17 report could set the tone for the entire hardware chain. Investors will also track Washington: any concrete push from the new Congress to slow data-center construction would hit these suppliers first. Tuesday's October inflation data matters, too, for a group whose valuations are sensitive to interest rates.