Why Samsung and SK Hynix stock are falling today

Samsung Electronics and SK Hynix fell on Monday even as South Korea prepared to unveil one of the biggest AI and chip investment drives in its history.

That is the irony worrying investors. A spending plan that could reach as much as 2,000 trillion won, or about $1.3 trillion, would normally look bullish for the country’s two memory-chip giants.

Instead, Samsung dropped more than 4%, while SK Hynix lost over 3%, as traders focused on the cost of staying ahead in the AI race.

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President Lee Jae Myung is set to unveil his “Three Mega Projects for the Great Leap Forward” initiative on Monday, with semiconductors, AI data centres and robotics at its centre.

Local media reports say Samsung Group and SK Group could together announce as much as 2,000 trillion won in investment over the next decade.

The money is expected to fund new semiconductor fabs, AI data centres, advanced packaging plants and other infrastructure needed to keep South Korea at the heart of the global AI supply chain.

Samsung is reportedly preparing a plan worth around 1,000 trillion won, including chip factories, data-centre investment and regional expansion beyond the Seoul metropolitan area.

SK Group is expected to outline a similar long-term push, led by SK Hynix’s memory and AI-chip ambitions.

On paper, this seems like good news. AI demand is still booming, high-bandwidth memory remains tight, and South Korea already dominates the most important parts of the global memory market.

But investors are also asking how much capital Samsung and SK Hynix must spend to defend that growth, and whether the next upcycle risks becoming too expensive.

Samsung: Spending big to catch up

For Samsung, the investment plan involves closing the AI-memory gap.

SK Hynix recently overtook Samsung Electronics to become South Korea’s most valuable listed company.

The reason was high-bandwidth memory, or HBM, the specialised memory used alongside AI processors from companies such as Nvidia.

SK Hynix moved faster in HBM, becoming the market leader. Samsung, long the world’s dominant memory name, has been playing catch-up.

Reuters quoted Kim Sunwoo, senior analyst at Meritz Securities, as saying that customised AI memory has “fundamentally changed the industry’s economics” and helped SK Hynix establish itself as the leader.

That is the problem Samsung is trying to fix.

Its reported spending plans include new fabs, possible Gwangju semiconductor capacity, AI data centres in Asan and advanced packaging investment.

SK Hynix: Defending its AI crown

SK Hynix is in a stronger position, but the company has become the defining memory winner of the AI boom.

Its HBM chips are central to Nvidia’s AI systems, and that leadership has helped drive a historic rally in the stock.

Now the question is whether it can defend that crown without overspending.

SK Hynix is already raising capital through a planned US listing and has committed heavily to new fabs, advanced packaging and EUV equipment.

The logic seems straightforward: if AI customers want more HBM, SK Hynix must build more capacity.

The risk is the classic chip-market trap. Neither Samsung nor SK Hynix can afford to fall behind, so both keep spending.

But if both spend aggressively at the same time, the industry can eventually end up with too much supply.