Market themes: optical and memory stocks lead Monday selloff
Ciena, Lumentum and other optical networking stocks fell about 8% to 10% on Monday, while memory shares also slid. What drove the AI-infrastructure selloff.
NEW YORK — The sharpest losses in Monday’s market came from the companies that supply the networking and memory hardware behind artificial intelligence data centers. Among the market themes of the week, valuation worry in AI infrastructure is now the one to watch.
The moves
According to 24/7 Wall St., Ciena fell 10.49%, Lumentum 9.8% and Applied Optoelectronics 8.1%. Benzinga’s midday tally showed Lumentum down about 9.1%, TTM Technologies down about 9.8% and Sandisk down about 6%, and IonQ lower by roughly 8.6% after announcing an all-stock acquisition of cybersecurity firm Elisity valued at up to $1.3 billion.
Benzinga said the optical and networking moves appeared sector-wide, with no company-specific news behind the declines in Ciena or TTM Technologies.
Memory in focus
The pressure was not limited to U.S. shares. Benzinga reported that Samsung and SK Hynix each fell more than 4% and that South Korea’s Kospi dropped 3.6%. Yahoo Finance linked part of the memory weakness to an announcement by Chinese memory maker CXMT of progress on a new memory-cell design, noting that Micron and SK Hynix fell more than 3%. Benzinga tied Sandisk’s drop to the slide in Samsung and SK Hynix.
Benzinga’s sector data showed the semiconductor fund down about 1.5% at midday and the technology sector fund down about 1.0%, while the Nasdaq Composite closed down roughly 0.4% to 0.5%.
Reading the theme
Two ideas run through the day’s coverage. The first is valuation: Yahoo Finance cited concerns over an AI bubble, and 24/7 Wall St. described money rotating out of tech as blue-chip industrials and financials advanced. The second is competition in memory, where a rival’s technical progress is enough to move prices for established suppliers.
A day does not make a trend, and the broader S&P 500 fell only about 0.1%. But concentration is the issue for index investors, since the tech sector’s run has done much of the lifting for the index.
What to watch
Earnings season starts in earnest this week with major banks reporting Tuesday, and the September CPI on Wednesday could shift rate expectations that bear on high-multiple stocks. Watch whether optical and memory names recover their losses or extend them, and whether buyers return to semiconductors.
Prepared with AI assistance from public sources and reviewed under our editorial policy. Not investment advice.
