When South Korea's Kospi index punched through 9,000 for the first time on Wednesday, the catalyst was not a software breakthrough or a consumer gadget. It was a memory chip. SK Hynix had begun shipping samples of its next-generation HBM4E to customers, and investors took it as proof that the most lucrative bottleneck in artificial intelligence runs through a narrow corridor of East Asian factories. The same Korean and Taiwanese suppliers that spent the 2010s building the components inside China's smartphone empire are now the indispensable arms dealers of the AI buildout — and US export controls have quietly turned China from a customer into a bystander.
The reversal, detailed in a New York Times report on June 18, is one of the defining business stories of the AI era. A decade ago, firms such as Samsung, SK Hynix and Taiwan Semiconductor Manufacturing Company sold displays, memory and logic chips into Shenzhen's vast assembly lines, helping Huawei, Xiaomi and Oppo flood the world with phones. That supply chain made China the workshop of consumer electronics. Today the same vendors sell into Nvidia, Google and the US hyperscalers — and Washington's rules bar them from shipping the most advanced AI silicon to Chinese buyers at all.
A memory supercycle with Korean fingerprints
The clearest beneficiary is SK Hynix, which has vaulted from perennial No. 2 to the most profitable chipmaker on earth. The company posted record first-quarter 2026 revenue of 52.58 trillion won — roughly $35.6 billion — up close to 200 percent year over year, on the back of explosive demand for high-bandwidth memory, the stacked DRAM that feeds Nvidia's GPUs. In January, SK Hynix overtook Samsung in annual profit for the first time in its history, a symbolic passing of the crown that captured how thoroughly AI has reshuffled the memory hierarchy.
SK Hynix now controls roughly 58 to 64 percent of the global HBM market by revenue, according to industry trackers, and has said its entire 2026 HBM production capacity is already spoken for. Analysts at several firms expect the shortage to persist into 2028. "SK Hynix will maintain its dominant position in HBM3 and HBM3E until at least 2026, sustaining a total HBM market share of over 50 percent," Goldman Sachs told clients. Samsung, stung by an earlier stumble in qualifying its HBM with Nvidia, is racing to claw back share, while America's Micron remains a distant third.
Taiwan owns the bottleneck nobody can route around
If Korea owns the memory, Taiwan owns the packaging. TSMC's CoWoS — the advanced packaging technology that stitches GPUs and HBM stacks onto a single substrate — has become the single hardest constraint in the entire AI supply chain. The company has earmarked a 2026 capital budget of $52 billion to $56 billion, much of it aimed at roughly doubling CoWoS output from about 35,000 wafers a month in late 2024 to a projected 130,000 and possibly 150,000 by year-end. TSMC's most advanced packaging method is growing at an 80 percent compound annual rate.
Nvidia, preparing the launch of its Rubin generation, has reportedly locked up more than 60 percent of TSMC's 2026 packaging capacity, with bookings extending years out. That leaves rivals — and Chinese buyers — scrapping over what little remains. The leverage flows in one direction: the AI economy's most valuable company is effectively renting Taiwan's factory floor, and Taiwan is happy to collect.
How export controls rewired the map
The China shutout is not incidental; it is policy. On December 31, 2025, the "validated end user" status that had let TSMC, Samsung and SK Hynix freely run their own fabs inside China expired, replaced by an annual licensing regime. Washington has tightened the screws on the most advanced AI accelerators, and Taipei has moved to follow suit: in June, Taiwanese authorities signaled they are weighing far stricter controls on AI chip sales to China, partly to choke off smuggling, after blacklisting Huawei and SMIC.
The result is a supply chain that has been bent toward American demand. Chips that might once have flowed to Chinese data centers are now allocated to US hyperscalers, and the Korean and Taiwanese suppliers who once depended on Chinese assembly customers have found a richer, less politically fraught buyer base. China, for its part, is racing to build domestic HBM and packaging capacity — several Chinese memory and "physical AI" firms are lining up IPOs on Shanghai's STAR Market — but remains generations behind on the highest-end parts.
Analysis: prosperity built on a knife's edge
The windfall has made these two economies dangerously top-heavy. Samsung and SK Hynix together accounted for a record 42.2 percent of the Kospi in May, while Taiwan's Taiex is similarly hostage to TSMC. That concentration cuts both ways. "There certainly is risk with market concentration," Goldman Sachs's Moe warned, pointing to vulnerabilities that span supply disruptions, political backlash against AI infrastructure, capital-market stress and technological disruption from new chip designs.
The deeper fragility is geographic. The world's AI ambitions now rest on a memory cluster in Icheon and Pyeongtaek and a packaging cluster in Hsinchu and Tainan — both within missile range of regional tensions. Export controls solved Washington's China problem by deepening its dependence on two allies whose stability cannot be taken for granted. If a single packaging line in Taiwan or HBM fab in Korea were knocked offline, the entire AI hardware roadmap would stall.
What to watch
Three signals will tell whether this East Asian gold rush holds. First, whether Taiwan formalizes tighter AI-chip export rules in the coming weeks, which would harden the China shutout. Second, whether Samsung can finally qualify its HBM4 with Nvidia and break SK Hynix's near-monopoly, easing — or merely redistributing — the memory shortage. Third, whether the CoWoS bottleneck loosens as TSMC's new capacity comes online, or whether Nvidia's Rubin demand simply absorbs it all. Beneath each lies the same question investors keep deferring: what happens to a Kospi at 9,000 and a Taiex at record highs if data-center spending finally cools.
"There certainly is risk with market concentration."-- Goldman Sachs analyst, On the dominance of a few Korean and Taiwanese chipmakers