Samsung, SK Hynix stocks sink 3% as a new risk hits the AI memory trade

Samsung Electronics and SK Hynix shares fell about 3% Wednesday as a fresh macro shock hit the AI-memory trade.

Samsung traded at 252,750 won in early Seoul dealings, down 3.16%, while SK Hynix dropped 3.6% to 1.632 million won.

The KOSPI opened 3.08% lower as renewed US-Iran fighting pushed oil prices higher and drove investors out of risk assets.

WTI crude moved above $90 a barrel and the US 10-year Treasury yield approached 4.8%.

The problem for chip investors is no longer demand alone, as higher rates can reduce what future AI profits are worth today.

Oil and yields are becoming an AI valuation problem

The selloff shows how quickly geopolitics can become a valuation issue for technology stocks.

Higher oil prices can keep inflation elevated, reducing the scope for central banks to ease policy and potentially forcing interest rates higher.

The US 10-year yield reached 4.8122% in Asian trading, its highest level in almost three years, after Wall Street's Nasdaq fell 1% overnight.

That matters for companies whose valuations depend heavily on earnings expected years into the future.

As bond yields rise, investors can demand a higher return for holding equities, putting pressure on the multiples they will pay for growth.

“The summer party for risk assets is over,” Coin Bureau founder and cross-asset analyst Nic Puckrin told Barron's on Tuesday.

He said investors were again beginning to incorporate the macroeconomic backdrop into equity valuations.

Strong memory demand cannot fully insulate the stocks

There is little evidence that Wednesday's decline reflects a collapse in semiconductor fundamentals.

South Korean chip exports remained strong in August, while demand for high-bandwidth memory and advanced DRAM continues to benefit from spending on AI infrastructure.

“August chip exports also confirmed the durability of semiconductor earnings,” Kiwoom Securities analyst Han Ji-young said.

Han's point separates today's market weakness from an industry downturn. Samsung and SK Hynix can continue posting stronger earnings while their shares fall if investors reduce the valuation multiples assigned to those profits.

That risk is particularly relevant after the 2026 rally in Korean semiconductor stocks. When expectations are already high, rising discount rates can hurt even companies with a healthy earnings outlook.

The tension is shifting from whether AI-memory demand can hold up to whether earnings can grow quickly enough to offset a tougher rates backdrop.

Buybacks provide support, not immunity

Both chipmakers have one important source of support: their own balance sheets.

Samsung and SK Hynix are conducting large share-repurchase programmes, helping absorb some selling from foreign and institutional investors.

Seoul Economic Daily reported that other corporate entities bought a net 3.3 trillion won of KOSPI shares over the previous two sessions, largely reflecting the chipmakers' buybacks.

Han estimates that, if the current pace continues, Samsung could keep purchasing shares until around October 8 and SK Hynix until roughly October 16.

That steady demand could cushion further declines, but it cannot eliminate the impact of a broad global repricing. Foreign and institutional investors were net sellers again as the KOSPI opened sharply lower Wednesday.