SK Hynix Sinks 15.4% in Seoul After Nasdaq ADR Blockbuster

SK Hynix's Seoul-listed shares closed 15.4% lower on Monday, the largest single-day fall in the memory-chip maker's history according to LSEG data cited by CNBC. The move landed one trading day after the company's Nasdaq debut, where American Depositary Receipts priced at $149 raised more than $26 billion, opened 14% above the offer at $170, and closed the first session up 12.8%.

The proximate trigger was profit-taking. Korean investors had ridden a rally that more than tripled the stock this year, and the ADR gave them a cleaner exit. In Reuters reporting carried by Yahoo Finance, investors had also expected shipments of SK Hynix's HBM4 chips to increase from the second quarter, and that increase does not appear to have materialised at scale. A KIS note trimming its Q2 earnings forecast added to the selling.

The blast radius went well beyond one ticker. Losses in SK Hynix and Samsung Electronics dragged the benchmark Kospi down about 9% and triggered a 20-minute trading halt, the seventh circuit-breaker trip on the index this year. That is what happens when two names carry this much of an index and both roll over on the same session.

The honest caveat is that this may be a positioning story more than a fundamentals story. ADRs were reportedly trading roughly 30% to 35% above the Seoul line, and some of that gap has to close somewhere; analysts quoted in the reporting still say the pullback is likely temporary, with large-scale HBM4 shipments starting in the third quarter and rising market prices dragging overall ASPs up. What the reporting does not give you is a customer-level read on why Q2 volumes lagged, whether Nvidia in particular pulled in or pushed out, or how much of Monday's selling was Korean funds rotating into the ADR versus straight risk-off.

The 29 July Q2 print is now the pivot. If HBM4 shipment commentary for the second half holds, US-listed SKHY buyers get their thesis confirmed and the Seoul shares have a floor. If it doesn't, the ADR premium unwinds fast, and the assumption that a New York listing permanently re-rates a Korean chip name gets tested a lot earlier than SK Hynix would like.