Key points
- SK Hynix's US lockup ended
- US shares still trade at a 36% premium
- SK square has to keep at least 20%
On Thursday, SK Hynix (SKHY) shares fell again in US trading. The 90-day lockup from its US share sale had just ended. They ended the day down 4.3% at $170.50. Even after the drop, they were still 36.1% above the equivalent value of its Seoul-listed shares, according to our ADR premium tracker.
The company's lockup didn't restrict investors who bought in the offering. In its July 9 prospectus, SK Hynix promised not to sell more shares for 90 days unless the banks running the offering agreed. It said some of its affiliates "may agree" to the same thing, but it didn't say which ones signed. There's no sign SK Hynix plans to sell more new shares now.
One US share, called an American depositary share or ADS, equals one-tenth of a Seoul share. In Seoul, the shares closed 2.4% lower on Thursday at 1,681,000 won ($1,253). The 36.1% compares that close with SKHY's US close, which came hours later.
The premium was 37.9% on Tuesday and 38.5% on Wednesday. SK Hynix has the widest premium of any company on our tracker.
SK square has to keep at least 20%
SK square is SK Hynix's largest shareholder. Under a Korean law called the Monopoly Regulation and Fair Trade Act, it has to keep at least 20% of SK Hynix's shares, the prospectus says. In March, it owned 20.5%.
SK Hynix said it kept that rule in mind when it decided how big the US sale would be. It sold 17.79 million new shares, in the form of 177.9 million ADSs at $149 each. The new shares reduced SK square's percentage ownership. Assuming it bought or sold no shares after March, its stake would be about 20%, by our arithmetic, leaving little room to sell.
The premium is what investors are watching
When SKHY started trading in July, investors could convert their US shares into Seoul shares, but not the other way around. That was set to change on July 29, Herald Economy reported (헤럴드경제) at the time. Brokers thought the premium would come down slowly rather than all at once.
Since SKHY started trading, the premium has been as low as 15.3% and as high as 60.1%, both in late July around SK Hynix's earnings. Gary Tan, a portfolio manager at Allspring Global Investments, told Bloomberg that how it changes after the lockup will show how strong investor demand really is.
Won figures are converted at 1,342 won to the dollar, the Yahoo Finance rate on October 8, 2026.
