Key Highlights

  • Sandisk shares traded between about $1,665 and $1,683 on October 6 with no company-specific news, as storage-sector selling spread.
  • The flash-memory maker's decline was far milder than the drops at Seagate and Western Digital the same day.
  • Toshiba's capacity expansion plans and a reported TDK bidding contest were the catalysts for the broader group's weakness.
  • Micron also slipped on the same day, while chip designers such as Marvell, AMD and Nvidia rallied to records.

Sandisk (NASDAQ:SNDK) slipped on Tuesday, trading between about $1,665 and $1,683 during the session, as the selling that hit hard-drive makers spread to other storage names in the S&P 500. The flash-memory company did not announce any news of its own. The weakness was tied to broader concerns about Toshiba's push for a bigger share of the storage market.

Sandisk's decline was far milder than the drops at Seagate (NASDAQ:STX) and Western Digital (NASDAQ:WDC), but it showed how quickly investors treated the storage group as a single trade on a day when most of technology was rallying.

What Happened to the Hard-Drive Makers

The trouble began with Toshiba. On October 2, the Japanese company announced plans to double its hard-drive output by 2027, aiming to take a much larger slice of a market long led by Seagate and Western Digital. On Tuesday, reports said Seagate and Toshiba are competing to buy TDK's magnetic-heads business, a unit valued at several billion dollars that supplies read-write heads to all three hard-drive makers.

Seagate tumbled and Western Digital sank as investors weighed the risk of more competition and possible shifts in component supply.

Why Sandisk Felt It

Sandisk makes NAND flash memory, which goes into solid-state drives, smartphones, memory cards and data-center storage, rather than spinning hard disks. Investors still tend to group it with the hard-drive makers because all of them sell into the same data-center storage market. Flash and hard drives compete for some of that Business and complement each other in other parts of it.

When one part of the storage chain stumbles, traders often trim exposure to the whole group, particularly after a strong run. Storage stocks have been among the market's big winners this year as AI applications drove Demand for capacity, leaving them sensitive to any hint of increased Supply or competition. Micron (NASDAQ:MU) also slipped, and South Korea's SK Hynix was reportedly under pressure.

A Record Day Elsewhere

The storage weakness stood apart from a buoyant session for the broader market. The S&P 500 rose 44.98 points to a record 7,818.93, and the Nasdaq Composite closed at a record just under 27,600. Chip designers led: Marvell (NASDAQ:MRVL) rallied after raising its Revenue outlook at its investor day, AMD (NASDAQ:AMD) climbed to a record and Nvidia (NASDAQ:NVDA) closed at an all-time high.

Treasury yields eased, with the 2-year yield slipping to about 4.791 and the 10-year to about 5.275, giving Growth Stocks some relief after a long stretch of rising borrowing costs. Utilities led the sectors after Constellation Energy's (NASDAQ:CEG) nuclear deal with Google (NASDAQ:GOOGL), while health care was the only sector to decline.

Watching Whether the Jitters Spread Further

For Sandisk, the main question is whether the hard-drive jitters stay contained or begin to shape views on pricing across the storage market. Investors will watch for any official word from Toshiba, Seagate or TDK on the heads business, and for more detail on Toshiba's expansion timeline.