Why Memory and Storage Stocks Are Sinking While the Rest of the Market Climbs

Memory and storage stocks sold off on Tuesday afternoon even as the broader market and much of the chip sector traded higher. Seagate Technology (STX) fell about 9.5% to $802.97 and Western Digital (WDC) dropped about 7.4% to $408.89, while SK Hynix's U.S.-listed shares (SKHY) lost 6.2% and the Roundhill Memory ETF (DRAM) slid 2.6%. Three things are weighing on the group: a rival's plan to expand hard-drive output, caution ahead of Samsung's earnings, and the sheer size of this year's gains.

Prices are from afternoon trading on October 6, not closing figures.

Hard drives: the Toshiba overhang

The sharpest losses are in hard-drive makers. The trigger was not new on Tuesday: on Friday, Nikkei reported that Toshiba plans to spend about 60 billion yen, roughly $400 million, to double its hard-disk-drive capacity by fiscal 2027. Toshiba is the smallest of the three makers, with just over 10% of the market by capacity, and reportedly wants 30%. Seagate and Western Digital each fell roughly 10% on Friday, and Tuesday's drop extends that selloff. No new company-specific announcement was reported for Tuesday's move.

The concern is that more drives would end the tight supply that has let Seagate and Western Digital raise prices and widen margins. Both stocks had gained well over 140% to 200% this year even after Friday's drop, so investors are quick to take profits. Not everyone is convinced the threat is large. Citi analyst Asiya Merchant argued the market may be overstating it, because Toshiba relies on outside suppliers for key parts such as media and heads, which limits how fast it can add capacity.

Korea: caution before Samsung's report

In Seoul, Samsung Electronics fell about 1.5% to 1.8% and SK Hynix about 3.4% on Tuesday, pulling the KOSPI down roughly 1%. Samsung is due to release preliminary third-quarter results later this week, with analysts expecting a record operating profit of more than 100 trillion won, about $74 billion. SK Hynix reports later in October.

Even with strong numbers expected, investors cited several overhangs: a stronger won, which reduces overseas earnings when converted into the local currency; money set aside for bigger worker bonuses after a year of AI-fueled profits; and renewed worries about a slowdown in AI chip demand after reports of U.S. data-center delays. Last week's strong Micron report suggested AI demand held up through September, and Micron said memory supply should stay constrained for at least the next year. The pullback therefore looks more like pre-earnings de-risking than a change in the demand story.

After a huge run, little tolerance for supply news

The group has had an extraordinary year, which makes it sensitive to any headline about new supply. Memory and storage shares have repeatedly dropped sharply on single reports, even good earnings, since late June. With valuations elevated, news that capacity is coming online invites quick profit-taking, while the broader chip and AI-infrastructure names that don't carry this supply risk have kept rising on general AI spending.

What to watch

• Samsung's preliminary Q3 results (Thursday). A record profit that beats expectations could steady the group; a miss or cautious comments on pricing would hit it again.
• SK Hynix, Seagate and Western Digital earnings. All are due in late October, with hard-drive pricing and Toshiba's real timeline the key points.
• Memory price trackers. Contract DRAM and NAND price forecasts show whether the peak-cycle fears have any basis yet.