The Kospi’s first-half gain was led by Samsung Electronics, whose share price surged 183% since January, according to the Guardian analysis. SK Hynix stock rose 310% over the same period. Both companies have reported increased demand from artificial-intelligence data center operators competing for high-bandwidth memory chips.
U.S. memory-chip makers posted even larger percentage gains. Sandisk rose 780% in 2026 and has increased 4,510% over the past 12 months, the Guardian reported. Western Digital gained 240% this year, Micron Technology rose 296%, and Seagate Technology climbed 226%, with two trading days remaining until the second half.
Dan Coatsworth, head of markets at the investment platform AJ Bell, described the moves as “the kind of gains in six months you might normally expect over decades with investing.” He said demand driven by constrained supply led to surging memory chip prices and explosive earnings growth for suppliers.
The rally in memory-chip stocks has put pressure on downstream electronics manufacturers. Apple blamed rising memory chip costs for price increases on its iPads and MacBooks last week, according to the Guardian. The company is also reportedly seeking clearance from the Trump administration to buy memory chips from CXMT, a Chinese company blacklisted by the Pentagon.
Some large software companies saw their shares fall as investors rotated from software into hardware stocks. Microsoft shares are down 24% during 2026 and hit a one-year low last week, the Guardian said, reflecting concern about the huge spending plans of leading AI companies.
There have been signs in recent days that the chip stock rally is faltering, with shares pulling back from highs as investors rotated into other sectors. Chris Beauchamp, chief market analyst at IG Group, said: “Having piled in to AI and tech since the end of March, there is a desire to protect profits, and investors continue to be in a mood to sell first and ask questions later.”
Broader stock markets also posted gains. Japan’s Nikkei climbed 38% in the first half. The U.K.’s FTSE 100 gained 5.8%, though it fell back from a record high at the end of February as the Iran conflict hit share prices. Brent crude oil began the year at $60 a barrel and is ending June about $12 higher, after spiking above $120 in late April when the closure of the Strait of Hormuz fueled supply shortages.
The U.S. S&P 500 index gained 7.4% so far this year, closing at 7,354 points at the end of last week. Mark Haefele, chief investment officer at UBS Global Wealth Management, predicted the index would reach 8,200 points by June 2027, citing continued strength in AI capital expenditure, a resilient U.S. economy, and strong credit creation.