SK Hynix Surges 7% as Memory Bid Widens Beyond NAND; Seagate Rallies 5%

The memory bid that opened in NAND has widened into the rest of the storage complex Friday afternoon, and the tape is showing exactly where the money went. The Roundhill Memory ETF (CBOE:DRAM) is up 5% to $59, while the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) is down 0.4% to $770. That gap flips a soft broad session into a clear sector event.

SK Hynix (NASDAQ:SKHY) stock is rallying 7% to $174.38, providing a clean read on the high-bandwidth memory and DRAM curve tied to AI accelerators. Meanwhile, Seagate Technology Holdings (NASDAQ:STX | STX Price Prediction) stock is climbing 5% to $837.23, a different technology serving a different customer set on a different cost curve.

Western Digital (NASDAQ:WDC) rounds out the listed hard-drive exposure alongside Seagate, and today’s tape doesn’t include a confirmed same-day print for the stock. Even so, storage and memory technologies moving together in one afternoon is a harder signal than two NAND names rising in tandem. WDC stock is up 4% today to $461.02.

Broad Memory Bid Extends Past NAND

There isn’t a fresh company-specific headline pushing SK Hynix higher today. The most recent preliminary quarterly report from the company showed revenue of KRW 79.32 trillion, up 256.8% year over year (YoY), with operating profit of KRW 60.54 trillion. HBM demand for AI infrastructure keeps delivering pricing power across both DRAM and NAND, which is why the American Depositary Share (ADS) is the market’s default proxy for the high-bandwidth cycle.

Seagate’s fiscal Q4 2026 report landed with revenue of $3.63 billion, up 48.5% YoY, and non-GAAP EPS of $5.71. CEO Dave Mosley pointed to “robust cloud data center demand and disciplined execution”, and Seagate guided fiscal Q1 2027 revenue to $4.1 billion, plus or minus $100 million. That guide underwrites the bid Seagate stock is drawing today.

Two Technologies, One Repricing

SK Hynix sells the HBM and DRAM parts that feed AI accelerators directly. Seagate sells hard drives, the cheaper mass-capacity tier that holds the exabytes AI workloads generate over time. Western Digital rounds out the pure-play HDD peer set after its Sandisk separation, and CEO Irving Tan noted on the recent call that “roughly 80% of data stored” in a hyperscale data center resides on hard drives.

Also, SK Hynix stock is up 22% over the past month, so today’s surge extends existing momentum. Seagate stock, for its part, entered the day off its recent highs, which explains part of the leverage on the intraday move.

What to Watch Next

The memory fund climbing hard while the broad tape softens puts SK Hynix, Seagate, and Western Digital in a leadership seat on an otherwise mixed session, and that reads as a sector event across storage broadly. Seagate stock is up 204% year to date (YTD) and Western Digital stock is up 168% YTD, extending a durable run into September. However, a cycle bid that broadens this fast can narrow just as fast, and none of the three announced anything today that changes their own fundamentals.

Investors sizing their exposure to SK Hynix, Seagate, or Western Digital shares can treat the move as a repricing of the memory cycle across the group (we reverse-engineered what the biggest chip winners looked like early in a free playbook here). Moreover, traders can watch for whether the DRAM memory ETF holds above $58 into next week and whether HDD names sustain the bid through the next round of hyperscaler capex commentary. Position sizing matters more than conviction when a whole complex reprices in one afternoon.

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