SK Hynix Sinks 4% as Foreign Funds Pull 1.04 Trillion Won and CXMT Rattles Memory Bulls

SK Hynix slid 4.0% to 1,613,000 KRW as foreigners sold a net 2.025 trillion Won of KOSPI blue chips, with 1.0431 trillion Won exiting the memory maker.

Seoul's chip complex took a hit on Tuesday as SK Hynix shares slid 4.0% to 1,613,000.00 KRW, dragged lower by a broad semiconductor retreat that rippled out from Wall Street. The decline came as trading resumed after South Korea's extended holiday weekend, with the benchmark KOSPI absorbing heavy selling from overseas accounts.

The scale of the exodus was striking. Foreign investors dumped a net 2.025 trillion Won worth of KOSPI-listed blue chips, and SK Hynix alone accounted for 1.0431 trillion Won of that outflow. The sustained withdrawal has pushed the overseas ownership share in the memory maker back below the 50% threshold for the first time in months — a symbolic marker of how quickly sentiment has cooled on what had been the market's favorite AI proxy.

A Chinese Blueprint, and a Reality Check

Part of the anxiety traces to Shanghai, where rival CXMT outlined plans to bring DDR5 server modules to market before the end of 2026, built on a novel 4F² cell architecture. The design promises roughly a 33% reduction in cell area versus today's industry standard — a leap that observers had penciled in for Samsung or SK Hynix only in later years.

Yet a working prototype and theoretical leakage gains from vertical transistors are a long way from volume production. Server DRAM demands punishing levels of reliability, round-the-clock endurance and compatibility, and CXMT has yet to substantiate either yields or firm delivery dates. The technological lead SK Hynix holds in high-complexity memory is unlikely to be erased overnight.

Samsung's Miss Adds to the Gloom

Domestic signals did little to calm nerves. Samsung Electronics undershot Visible Alpha consensus with its preliminary third-quarter operating profit, reigniting doubts about the medium-term growth trajectory of the entire AI complex. For many participants, that was reason enough to lock in profits across the tech sector.

Broader headwinds compounded the mood: soft US industry benchmarks, mounting caution ahead of upcoming US inflation prints, and a creeping skepticism about whether the semiconductor supercycle can run as long as bulls had assumed. After months of gains, global funds are increasingly questioning just how durable demand for advanced memory really is — and whether the lofty earnings expectations baked into AI names can be met in coming quarters.

Solidigm Chatter and a Local Discount

Analyst Kim Jun-young of iM Securities flagged Korea-specific factors weighing on SK Hynix relative to US peer Micron. Beyond the visible foreign outflows, he cited market concerns over a potential IPO of subsidiary Solidigm. A reversal could take shape, in his view, if SK Hynix pairs its late-October third-quarter report with fresh shareholder-return measures.

The operating picture, meanwhile, tells a different story than the tape. In the second quarter of 2026, SK Hynix booked an operating profit of 60.54 trillion Won on revenue of 79.32 trillion Won — an operating margin near 76%, pricing power that most industries can only envy. Mass production of HBM4 is already underway, and Goldman Sachs sees the company well positioned for the coming shift toward High-Bandwidth Flash in inference workloads, rating the stock a Buy.

Valuation Already Trimmed

With the shares now 46% below their 52-week high, a substantial chunk of the former valuation premium has already been surrendered. Even after the pullback, the stock is up 148% year-to-date — a gain that now hinges on the detailed quarterly results due at the end of October. Those figures will show how resilient the core business is against a global sector cooldown, and whether the current bout of nerves looks, in hindsight, like an overreaction to headlines rather than a genuine shift in the competitive landscape.