Samsung, SK Hynix Whipsaw From 4% Slide to Sharp Rebound on Chip Doubts

South Korea’s two largest memory-chip makers, Samsung Electronics and SK Hynix, swung sharply within a single trading session and reversed the next day: both closed down about 4% on July 20 amid renewed worry that the memory cycle is nearing a peak, then rebounded on July 21 — Samsung by roughly 6% and SK Hynix by about 4% — as investors moved back in at lower prices. The two-day round trip underscores how tightly the Korean market’s direction is now bound to sentiment on the memory-chip cycle.

A one-day drop, then a snap-back

On July 20, both stocks opened lower, briefly turned positive early in the session, and then slid again to finish down around 4% apiece. The selling was driven by concern that demand and pricing for memory chips are approaching a cyclical top — a “peak-out” fear that has repeatedly rattled the sector.

The mood flipped the following day. On July 21 both names opened higher and extended gains intraday, with Samsung climbing about 6% and SK Hynix roughly 4%, helped by bargain buying after the prior day’s decline. The rebound recovered a large share of the ground lost in the previous session, though it did little to resolve the underlying debate over how much longer the current upcycle can run.

Why the two stocks move together

Samsung and SK Hynix sit at the center of the global memory market. SK Hynix, headquartered in Icheon and focused on DRAM and NAND flash, ranks among the “Big Three” memory producers alongside Samsung and Micron, so shifts in the outlook for chip pricing tend to hit both Korean names at once.

The scale involved is substantial. SK Hynix reported sales of about 66.19 trillion won and net income near 19.80 trillion won for fiscal 2024, with a workforce of roughly 46,863 as of that year. Samsung’s electronics arm is far larger still, posting total revenue of about 333.6 trillion won and operating profit of 43.6 trillion won in its 2025 fiscal year. Because these two companies carry heavy weight in Korea’s benchmark index, their paired moves amplify swings in the broader market.

The peak-out question

The core dispute driving the whipsaw is whether the memory upturn has more room to run or is topping out. Bears point to fears of a cyclical peak; the July 21 rebound suggests at least some buyers viewed the sell-off as an overreaction and an entry point rather than the start of a sustained downturn. With no fundamental catalyst resolving the argument in either direction, near-term price action is likely to stay volatile and headline-driven.

For context on the companies behind the tickers: SK Hynix traces its roots to 1983 as Hyundai Electronics and moved under SK Group ownership in 2012, while Samsung — founded in 1938 by Lee Byung-chul and now headquartered in Seoul’s Samsung Town — ranked fifth globally in brand value in 2024.