KOSPI jumps 2.41% as memory stocks rally on SanDisk outlook

SanDisk's investor-day margin guidance repriced the global memory complex and pulled South Korea's KOSPI out of a seven-week slide.

The KOSPI rose 2.41% to 6,977.34 on Friday, capping an 11.5% weekly gain that snapped a seven-week losing streak on a memory-chip rally.

"Risk appetite can hold for now because the immediate Fed hike risk has been repriced lower," said Charu Chanana, chief investment strategist at Saxo, noting softer oil is also helping. "But this is still a headline-driven rally rather than a clean risk-on regime."

SK Hynix jumped 3.26% to 1,645,000 won (about $1,160) and Samsung Electronics rose 2.43% to 274,500 won, while Japan's Nikkei 225 added 0.59% to 68,713.80. Kioxia gained 3.75% to 53,740 yen and SoftBank Group climbed 2.94% to 5,739 yen.

The move followed SanDisk's investor day Wednesday, where management guided to roughly 80% non-GAAP gross margins through 2030 and 100% of excess cash returned to shareholders. The stock closed Thursday at $1,528.11, up 13.7% and 544% year to date, resetting how the market values NAND cash flows.

SanDisk's framework rests on eight New Business Model long-term agreements covering about 50% of bits in fiscal 2027 and two-thirds in fiscal 2028, with an enterprise data-center flash total addressable market reaching 1.2 zettabytes by 2030. The read-through runs directly to Solidigm, SK Hynix's NAND arm, which is reportedly planning a Nasdaq listing at roughly a 50 trillion won valuation.

The nuance: both Samsung and SK Hynix are primarily DRAM and high-bandwidth memory businesses, with NAND a secondary line. The market is treating a NAND-specific datapoint as a memory-wide signal, while the Korean names' actual earnings leverage sits more in HBM. Supporting the rally, Samsung held the Q2 2026 NAND shipment crown, server-led enterprise SSDs reached 48% of NAND shipments, and top-five NAND suppliers' combined revenue rose 83.7% quarter over quarter in Q1 2026.

SK Group Chairman Chey Tae-won said Friday the company is considering building new memory chip plants through a joint-venture model to share high capital expenditure burdens, and warned tight memory supply could intensify further in 2027. If the supply-demand deficit widens, memory chip prices and corporate profitability may retain strong support.

Foreign capital has become a key driver of the rebound. Foreign investors net bought roughly $2 billion in South Korean stocks this week as of Thursday, versus cumulative net outflows exceeding $100 billion earlier this year. As leveraged positions accumulated in AI and semiconductor sectors unwound, previous volatility moderated, creating conditions for foreign capital to reallocate.

US peers rode the same move: Micron Technology closed up 4.2% and Western Digital up 7.3% Thursday, while the iShares MSCI South Korea ETF (EWY) gained 1.6% to $178.62, up 84% year to date. SK Hynix's US-listed ADS, which began trading around July 9, closed at $165.67, up 7.3%. The yen traded at 159.36 per dollar, hovering near the 160 level that traders believe could trigger another round of yen-buying from Tokyo.

At 6,977, the KOSPI remains well below its June 2026 peak above 9,000. The drawdown began in late June and worsened through July with back-to-back circuit breakers, while China's YMTC broke into the global top three NAND suppliers for the first time. Watch the US open in memory names Friday, as an extended rally could lift where the KOSPI begins trading next week.

This article is for informational purposes only and does not constitute investment advice.