This article is for informational purposes only and is not financial advice. TheGatBull may earn a commission from some links at no cost to you — see our disclosure and full disclaimer.
On July 10, 2026, SK Hynix listed American Depositary Shares on Nasdaq. The ticker is SKHY, the offer price was US$149.00 per ADS, and one ADS represents one-tenth of a common share. The company sold 177,900,000 ADSs for net proceeds of roughly US$26.2 billion. All of that is in the prospectus it filed with the SEC.
That prospectus also records where the stock was trading in Seoul the day before. On July 9, 2026 the KRX close was ₩2,186,000 — which the company itself converts to US$1,421.28 per common share.
The offer price of $149 works out to $1,490 per common-share equivalent. So the ADR launched at a premium of about 4.84%. Narrow, as it should be. ADR premiums are supposed to be narrow, because arbitrage erases them.
Five weeks later that number is 43%.
What this means if you hold SKHY. What you bought is not the stock. It is the American price of the stock. As of August 14 that price sits 43% above the Seoul price. At listing it was 5%. What happened in between is below — and “arbitrage erases it” does not account for this number.
Update — August 18, 2026. Seoul reopened after the two closed sessions. 000660 closed at ₩1,662,000, up 1.03% from the August 14 close used throughout this article. On the other side, SKHY closed at US$166.33 on August 14 and at US$171.38 on August 17, a US session that ran while Seoul was shut — up 3.04%.
Both legs rose. The Nasdaq leg rose faster, so the gap did not narrow. We are not restating the premium as a single figure yet: the matching Nasdaq close for August 18 had not printed when this was written, and pairing a Nasdaq August 17 close with a Seoul August 18 close would mix conventions — the exact problem flagged in section 1. The restatement follows once both closes for the same date, and the 15:30 Seoul rate for it, are in hand.
1. The numbers first
Basis dates, stated plainly. Seoul is the August 14 (Friday) KRX regular-session close at 15:30. Nasdaq is the regular-session close on the same date. The two markets sit 13 hours 30 minutes apart, and the premium below is measured across that gap. The exchange rate is also the 15:30 Seoul close.
| July 9, 2026 (day before listing) FX per the prospectus |
August 14, 2026 | Change | |
|---|---|---|---|
| Seoul, 000660 | ₩2,186,000 | ₩1,645,000 | −24.75% |
| Nasdaq, SKHY | US$149.00 (offer) | US$166.33 | +11.63% |
| Premium, per common share | +4.84% | +43.41% | — |
The arithmetic. 166.33 × 10 = US$1,663.30. The same day’s Seoul close of ₩1,645,000, divided by the 15:30 rate of 1,418.3, is US$1,159.84. The ratio is 1.4341.
Most of that gap is Seoul falling, not Nasdaq rising. And the fall started before the Solidigm reports: back out the August 6 drop of 10.37% and the Seoul price had already given up roughly 24% between July 9 and August 5. We do not have a single primary document that explains that earlier decline, and we are not going to invent one.
Same company. Same claim on the same share. The price differs by 43%. That a gap exists at all was taken apart here; what is new is the size of it and the path it took.
One more thing belongs here, in fairness. Over this stretch the won strengthened against the dollar. Note the two rates are not the same convention: the July 9 figure uses 1,538.05, the Federal Reserve New York noon rate of July 2 that the prospectus itself applied, while the August 14 figure uses the 15:30 Seoul close of 1,418.3. The 4.84% and the 43.41% are therefore not a strictly like-for-like series. There is a second reason they are not: US$149.00 was an offer price, not a traded one — set in negotiation before the first tick. The 4.84% is where the deal was priced, not where the market first put it. The direction still runs one way: a stronger won pushes the measured premium down, not up. It widened anyway.
Under the Gat. “Arbitrage erases it” is correct in the textbook. When 43% stands for five weeks, the textbook is not wrong — the eraser has friction. Buying 000660 in Seoul means foreign investor registration, an account, currency conversion, a settlement cycle. Buying SKHY is one click in a US brokerage account. And the arbitrage that matters here is not retail. It is an institution cancelling ADSs at the depositary, taking delivery of the ordinary shares, and selling them in Seoul. Whether that route is open, and at what cost, is the whole question — and we have not confirmed it. We have not measured the size of that friction either. What 43% tells you is that it is not zero. View, not advice.
2. What ADR buyers were also buying — and what had already moved out of it
The premium was not the only thing that moved. The company’s NAND business moved into a different legal entity.
Start with the name, because it is misleading. Solidigm was not a company name. The prospectus puts it plainly: “We created a subsidiary in the United States to operate the acquired business under the brand name ‘Solidigm’“. The legal entity was SK hynix NAND Product Solutions Corp.
That business exists because in October 2020 SK Hynix agreed to buy Intel’s NAND flash and SSD operations — the Dalian fab in China, the intellectual property, the R&D staff. The consideration was paid in two instalments: US$6.6 billion in December 2021 and US$2.2 billion in March 2025, US$8.8 billion in total.
And then, in a note to the financial statements, this sentence:
“[D]uring the three-month period ended March 31, 2026, the business and assets/liabilities of SK hynix NAND Product Solutions Corp. were transferred to Solidigm Inc.“
Solidigm Inc. is a real, separate legal entity, and the NAND business has already moved into it. That happened in the first quarter of this year.
One more thing about that entity is worth stating precisely. It is not wholly owned. The subsidiary table in the same prospectus puts SK Hynix’s stake at 97.48% as of March 31, 2026, down from 98.49% three months before.
Who holds the remaining 2.52%? The prospectus does not say. It does record restricted stock units granted to employees of that subsidiary, of which 46,994,195 have been exercised. That points one way. We are not going to state it as fact.
3. And the company had already written it down
From early August, Korean outlets reported that Solidigm was preparing a pre-IPO round ahead of a Nasdaq listing. On August 5, SK Hynix filed a clarification saying it was reviewing options but that nothing had been decided. The next day, August 6, the shares closed in Seoul at ₩1,495,000, down 10.37%.
This article does not predict whether that listing happens. The company says it has not decided, and we have no primary document that says otherwise.
What we can point at is something else. The company had already described this scenario in its July prospectus — in the risk factors, in English, for the Americans buying the ADR:
“We may pursue spin-offs or initial public offerings of, or selling portions of our interests in, our subsidiaries, which could dilute our ownership interest and reduce the benefits we receive from those subsidiaries.”
That is not a contradiction. It is a sequence. A risk factor says “this could happen.” A clarification filing says “we have not decided.” Both can be true at once.
There is also a date attached. Korean clarification filings carry a follow-up obligation, and reporting indicates SK Hynix must file an update on its progress by September 4. That is the most checkable item in this article.
One last thing, for American readers specifically. Almost all of the English-language reporting on this has come from the English editions of Korean outlets — the Korea Times, the Korea Herald, the Korea JoongAng Daily, KED Global. This is a Nasdaq-listed issuer. If you bought SKHY from a US brokerage account, this news probably did not arrive where you normally read.
For an American who bought SKHY, the combination is worth reading twice. The 43% premium you paid is on the whole company — and the NAND business inside it has already moved into a separate entity, with the company having said in advance that it could dilute its stake in subsidiaries.
Under the Gat. None of this is bad news. Carving out a subsidiary is ordinary capital raising, and disclosing the possibility in advance is the honest version. The point is narrower: that sentence sits inside a long English document that almost nobody opens. I hadn’t either, until this week. View, not advice.
4. Reading Korea through this — why one share carries two prices
For an American investor an ADR is usually a question of convenience. Buying the ordinary shares abroad is a nuisance, so you buy the receipt instead. The prices track each other closely.
In Korea it becomes a question of access. A foreigner buying 000660 in Seoul needs an investor registration, a local account, currency conversion and a settlement cycle that runs on Seoul’s calendar. SKHY is one click. When two routes to the same asset carry different friction, the asset carries two prices.
So this 43% is a story about SK Hynix and, at the same time, a story about how open the Korean market actually is. If the gap narrows, access friction fell. If it widens, it did not.
Under the Gat. Most of the time “the stock” and “the American price of the stock” are the same sentence. Right now they are 43% apart, and the difference is not about the company at all — it is about how hard it is to get to the company. View, not advice.
5. What to watch next
- ★ September 4 — SK Hynix’s follow-up disclosure deadline. It follows from the August 5 clarification filing. This is the single document that could rewrite section 3, and the easiest date in this article to check (as reported).
- The first Seoul close after the break — now in. The market was shut for Liberation Day on August 15 and its substitute Monday on August 17, while Nasdaq kept trading. That close printed on August 18 and it did not narrow the gap; see the update at the top. The table above remains the August 14 close, the last date with a matching close on both sides.
- August 27 — Bank of Korea rate decision, policy rate currently 2.75%. A weaker won mechanically widens the premium in this article’s arithmetic without either price moving.
- August 31 — the MSCI August review takes effect on that day’s close. Index flows hit the Seoul line of the table, not the Nasdaq one.
- December 2026 — the conditional approval China’s regulator attached to the Intel NAND purchase ran five years from December 2021. It expires this year. What happens on expiry is not spelled out in the prospectus, and we are not going to guess.
Also on this structure: SK Square and the holding-company discount, and the standing page for this stock, the SK Hynix investor hub.
The conclusion
SKHY listed at 4.84% above SK Hynix’s Seoul shares. As of August 14 it trades 43.41% above them. Seoul fell 24.75% over that stretch while the Nasdaq ADR rose 11.63%, and a stronger won — which pushes the measured premium down — did not close the gap.
During the same five weeks the company moved its NAND business into a separate entity, Solidigm Inc. The US entity that held it is 97.48% owned, not 100%. And the prospectus already says subsidiary listings could dilute that ownership.
What you bought is not the stock. It is the American price of the stock.
Not financial advice — a view from Seoul, not a recommendation to buy or sell. All Korean prices are the KRX regular-session close (15:30 Seoul); the premium figures span a 13.5-hour gap between the two closes and use the 15:30 Seoul exchange rate.
Sources
- SEC — SK hynix Inc., Form 424B4 (primary) — offer terms and ADS ratio; the July 9, 2026 Seoul close of ₩2,186,000 and its US$1,421.28 conversion; the Intel NAND consideration of US$6.6bn and US$2.2bn; the “brand name Solidigm” description; the 97.48% subsidiary stake; the transfer of the business to Solidigm Inc.; the restricted stock unit figures; the spin-off and subsidiary-IPO risk factor; the Chinese regulator’s five-year conditions
- Korea Exchange (KRX) — Seoul closing prices, regular session 15:30, and the 15:30 exchange rate
- Nasdaq regular-session closing prices for SKHY
- Financial Supervisory Service DART — SK Hynix clarification filing of August 5, 2026 (reported; the filing text was not read directly)
- The September 4 follow-up deadline is as reported by the English editions of Korean outlets including the Korea Times, the Korea Herald, the Korea JoongAng Daily and KED Global
- Where the English-language coverage originated is our own observation, from an English-language search run on August 17, 2026. It is an observation about what we found, not a proof that other outlets did not cover it
- Our own calculation — the 4.84% and 43.41% premiums and the −24.75% / +11.63% returns are computed by TheGatBull from the prices and exchange rates above; the formulas are stated in section 1
Frequently Asked Questions
Is SKHY the same company as SK Hynix?
Yes. SKHY is an American Depositary Share representing SK Hynix common stock, and one ADS equals one-tenth of a common share. The common shares trade on the KRX KOSPI Market under code 000660.
How was the 43% premium calculated?
SKHY closed at US$166.33 on August 14, 2026. Multiplied by ten, that is US$1,663.30 per common-share equivalent. The Seoul close the same date was ₩1,645,000, which converts to US$1,159.84 at the 15:30 Seoul rate of 1,418.3. The ratio is 1.4341. Note the Seoul close and the Nasdaq close are 13.5 hours apart.
What was the premium at the IPO?
About 4.84%. The offer price of US$149.00 per ADS is US$1,490 per common-share equivalent, against the July 9, 2026 Seoul close the prospectus states as US$1,421.28 per common share. That was an offer price, not a traded one.
What is Solidigm?
It was the brand name of the US business SK Hynix built after agreeing in October 2020 to buy Intel’s NAND and SSD operations. The legal entity was SK hynix NAND Product Solutions Corp. During the three months ended March 31, 2026 that entity’s business and assets were transferred to Solidigm Inc. SK Hynix paid US$6.6 billion in December 2021 and US$2.2 billion in March 2025 — US$8.8 billion in total.
Is Solidigm going public on Nasdaq?
Not decided. SK Hynix said on August 5, 2026 that nothing had been determined. Reporting indicates the company must file an update on its progress by September 4. Separately, the July prospectus already lists spin-offs, subsidiary IPOs and partial stake sales among its risk factors, noting these could dilute its ownership.
Does SK Hynix own that US entity outright?
No. The prospectus subsidiary table shows 97.48% as of March 31, 2026, down from 98.49% three months earlier. The document does not say who holds the rest, though it does record 46,994,195 employee restricted stock units as exercised.
Why did I not see this in the US media?
Most of the English-language reporting we found came from the English editions of Korean outlets — the Korea Times, the Korea Herald, the Korea JoongAng Daily, KED Global. That is what our own search on August 17, 2026 turned up; it is not proof that no one else covered it.
Was the Korean market open on Monday, August 17, 2026?
No. Liberation Day fell on Saturday, August 15, so Monday was a substitute holiday. The next Seoul close is Tuesday, August 18 at 15:30 KST.
Written by Mr.Gat — TheGatBull
Korean market coverage from a Seoul-metro-based operator who reads the filings in the original language. Every price on this site is the KRX regular-session close (15:30 Seoul); every figure states whether it came from a primary filing, the press, or our own calculation. Drafts are AI-assisted, then verified against the original Korean documents and edited by a human before publishing.
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This article is for informational purposes only and is not financial advice. TheGatBull may earn a commission from some links at no cost to you — see our disclosure and full disclaimer.