SK Hynix American depositary receipts have traded at a steep premium to the company’s South Korea-listed common shares only three sessions after listing, with the gap widening to 51%.
On Tuesday, the ADR rose 27% in a single day, pushing the spread far above the roughly 3% initial premium seen last week when the company raised $26.5 billion through the offering. At the same time, major U.S. options exchanges began listing SK Hynix ADR options, and short-dated call options drew the heaviest trading interest, adding to activity in the name.
While the ADR climbed, the stock in Korea remained under pressure. From July 10 to July 14, ahead of the ADR listing, SK Hynix local shares fell a cumulative 12.25%. Over the past week, the stock posted a return of about -15%, and its maximum drawdown from the period high reached 28.2%. The market had expected the ADR premium to attract buying into the local shares and set up arbitrage, but that mechanism has largely failed to function.
Conversion path remains unavailable before July 29
The immediate reason is straightforward: the channel that links the two markets through share-for-ADR conversion is not yet open.
According to Korea Securities Depository, the newly issued local shares tied to this ADR deal are expected to list domestically on July 29. Applications to convert between local shares and ADRs cannot be submitted until after that listing. The depository said, “The expected date when mutual conversion applications between SK Hynix common shares and ADRs become possible is after July 29, the scheduled domestic listing date of the common shares,” adding that the detailed timetable will be announced separately based on instructions from Citi, the depositary bank for the DR program.
That leaves no practical way, before July 29, to buy local shares in Korea, convert them into ADRs, and sell them in the U.S. market to lock in the spread. Without a working arbitrage route, the price gap cannot be corrected through normal market trading, allowing the premium to keep expanding.
Rules are asymmetric even after the window opens
The constraints do not end with timing. Even after July 29, the structure of the conversion rules is set to limit how efficiently arbitrage can work.
Under Korea Securities Depository rules, ADRs can be canceled into local shares without a quantity limit and moved directly through account transfer. The reverse process is tighter. Local shares can be converted into ADRs only within the issuance cap set by the issuer.
The depository gave an example: if the maximum ADR issuance corresponds to 1 million local shares and already issued ADRs account for 900,000 shares, then no more than 100,000 local shares can still be converted into ADRs.
That design leaves one direction relatively open while restricting the other. So even when the window becomes available, the size of any arbitrage trade is capped, making it difficult to create enough pressure to compress the ADR premium in the U.S. market.
Retail investors are still shut out
There is also a separate access problem. Institutions may be able to attempt the trade after the end of July, but individual investors are still excluded.
Retail holders of local shares cannot currently use mobile trading systems, or MTS, and home trading systems, or HTS, to convert local shares into ADRs. The process involves administrative procedures at Korea Securities Depository as well as foreign-exchange reporting requirements, making it a transaction that, in practice, only institutions are equipped to handle.
A brokerage official said, “There is a price difference between Korean-listed shares and U.S.-listed shares, and there are also limits on the listed quantity. In principle it is not impossible, but many conditions need to be met, so the service is not currently open” for individual investors.
That means the arbitrage setup is not equally accessible across the market, with a clear gap between what institutions can do and what retail investors can do.
TSMC is being used as a reference case
Some market analysts say these structural constraints could allow the SK Hynix ADR premium to persist for a considerable period, and they point to Taiwan Semiconductor Manufacturing Co. as a useful comparison.
An iM Securities analyst said that mutual conversion between local shares and ADRs involves enough friction to keep arbitrage from operating smoothly, adding that, as with TSMC, “there is a possibility that U.S. ADRs maintain a meaningful premium overall.”
Another analysis cited in the source said TSMC ADRs can be canceled and withdrawn into local Taiwan shares relatively freely, but converting local shares into U.S. ADS is constrained by approval volumes and regulatory limits. Because of those arbitrage frictions, TSMC’s premium has averaged 19.1% since 2024 and about 17.5% since 2026.
Based on the information available, the premium in SK Hynix ADRs reflects both demand from U.S. investors for a leading memory-chip stock and the market structure that blocks efficient arbitrage. With conversion applications unavailable before the new local shares list, with one-way conversion rules still restrictive, and with retail investors unable to participate, there is little in the current setup that would naturally close the gap in the near term.