SK Hynix Faces a Concrete Crisis on the Yongin Site Just as It Nails a 375-Layer NAND Milestone

Amid trucker strike, SK Hynix verifies 375-layer NAND design but Yongin cleanroom delay risk looms; stock up 217%.

South Korea’s largest memory maker is navigating two very different challenges this month. On one hand, a trucker strike has brought concrete deliveries to a standstill at its critical Yongin campus, threatening the timeline for a cleanroom that is supposed to open in early 2027. On the other, the company has just verified a 375-layer NAND design that could give it a clear edge in the market for high?density storage. The juxtaposition puts the stock’s meteoric year?to?date gain of 217% under a spotlight: the market is pricing in flawless execution, but the ground?level picture is more complicated.

The industrial action involves roughly 8,000 drivers who transport ready?mix concrete in the greater Seoul area. A tentative deal on higher freight rates was overwhelmingly rejected by almost 70% of union members, leaving the two sides back at the negotiating table. SK Hynix has responded by reshuffling work schedules on the Yongin site, pushing non?concrete tasks to the foreground. The company insists the direct damage remains limited for now, but construction firms warn that any prolonged halt in cement supplies will inevitably create real scheduling problems.

That matters because Yongin is at the heart of SK Hynix’s capacity expansion for AI memory chips. The first cleanroom there is slated to be operational by February 2027, a deadline that leaves little room for delays. The group reported first?quarter revenue of 52.6 trillion won and an operating profit of 37.6 trillion won, underscoring the financial firepower behind the build?out. Existing chip production lines are unaffected by the strike, but the new site is where the company plans to churn out the next generation of high?bandwidth memory and other advanced products.

While construction crews deal with the concrete impasse, SK Hynix’s technology team has been making progress on a different front. According to industry reports from TrendForce and Digital Citizen, the company has completed verification of a 375?layer 3D NAND device. The design was originally expected to reach the 400?layer mark, but the target was adjusted downward because of the manufacturing complexity involved in stacking that many layers. SK Hynix plans to begin mass production of the new NAND by the end of 2026, repurposing existing fab capacity for the ramp?up.

A notable engineering detail is the introduction of molybdenum into part of the word?line structure. As layers become thinner and more densely stacked, electrical resistance and signal delay rise; molybdenum helps mitigate both. The move puts SK Hynix well ahead of its rivals for now. Samsung started mass production of 286?layer NAND in April 2024, while Kioxia is still marketing 218?layer chips developed the year before. A 375?layer product would give SK Hynix a clear lead and edge it closer to the industry’s next threshold of 400 layers.

Investors have already rewarded the stock lavishly this year. The shares closed the week at 2,150,000 won, having gained roughly 218% since January. The 50?day moving average sits around 1.57 million won, meaning the current price trades almost 37% above that level. The relative strength index of 58.4 suggests the rally is not yet overstretched, but the annualised 30?day volatility of more than 100% hints at how sharply the stock can swing. From the all?time high of 2,407,000 won set in early June, the current level is about 10% lower.

For the stock to hold its valuation, the market needs to see both the NAND story and the Yongin construction stay on track. The NAND breakthrough broadens SK Hynix’s narrative beyond HBM and into a more comprehensive advanced?memory play, which could support the premium. But the concrete dispute is a reminder that even the best technology roadmap can be tripped up by logistics. The South Korean transport ministry is currently mediating between the union and the trucking industry. If a quick compromise is reached, the Yongin schedule can be salvaged. If the strike drags on, the company’s most important growth project will face hard delays – and the stock will have to justify its lofty multiple without the usual pace of execution.