SEOUL — SK Hynix shares dropped as much as 8.2 per cent in early Seoul trade on Monday (July 13) as investors booked profit, after a high-profile US listing saw the world's leading AI memory chipmaker surge 12.8 per cent in its Nasdaq debut on Friday.

The South Korean firm raised over US$26 billion (S$33.7 billion) selling American Depositary Receipts priced US$149 each. 

The ADRs opened 14 per cent above the offer price at US$170 before ending their first trading day with a 12.8 per cent gain.

In Seoul on Monday, the benchmark KOSPI was trading down 2.8 per cent as of 12.57 am GMT (8.57 am SGT).

Ryu Young-ho, a senior analyst at NH Investment & Securities, said investors were profit-taking after the conclusion of the US listing, while sentiment also suffered from caution with regards to SK Hynix's second-quarter earnings.

He said investors had expected shipments of SK Hynix's HBM4 chips to increase from the second quarter, but that the increase does not appear to have materialised at scale.

Ryu also said investors had moderated earnings expectations because SK Hynix, with its greater exposure to the HBM market than cross-town rival Samsung Electronics, was set to benefit less from a recent rise in prices for conventional DRAM chips.

SK Hynix led the market for high bandwidth memory chips with a 58 per cent revenue share in the first quarter, whereas Samsung and US competitor Micron Technology each held 21 per cent, Counterpoint Research data showed.

HBM chips are primarily used in artificial intelligence systems for customers such as Nvidia and Alphabet's Google.