AMD's first HBM4 chips are out, and Samsung's $80 billion quarter puts SK hynix's 78.4% margins to the test

Three hours for Samsung, less for SK hynix

Lisa Su gave Samsung's chip chief Jun Young-hyun three hours over dinner at Samsung's Seoul offices on October 7, 2026, seven months after the two signed AMD's HBM4 supply memorandum↗. SK hynix▼−1.92% — SK hynix, down 1.92 percent today chief executive Kwak Noh-jung got his first known meeting with Su on Korean soil earlier that day, and the shorter appointment, on a visit she had already cut from two days to one ¹².

The dinner has a chip attached

Su said that day that AMD's▼−0.94% — AMD, down 0.94 percent today MI455 and Helios systems, both built on HBM4 memory, have begun shipping, on "tremendous support from both Samsung Electronics▼−2.42% — Samsung Electronics, down 2.42 percent today and SK hynix" ³. The March memorandum made Samsung, over SK hynix and Micron▼−1.55% — Micron, down 1.55 percent today, the preferred HBM4 supplier for the Instinct MI455X, the industry's first HBM4 supplier pick for a next-generation AI accelerator ¹².

Samsung has been shipping HBM4 to AMD since, after supplying HBM3E for the MI350 generation ⁴. Su now wants supply contracts of "three to five years or longer", backed by "tens of billions of dollars" of supply-chain investment↗ ³.

The passed-over supplier prints the margins

The seating chart runs against the economics. SK hynix, passed over for the preferred slot, is forecast to earn a 78.4% operating margin this quarter↗ ⁵. Samsung spent the last cycle largely outside Nvidia's▼−0.27% — Nvidia, down 0.27 percent today tent: its HBM3E cleared Nvidia qualification only in the week ended September 14, 2026, its 12-layer HBM4 was still in final qualification in mid-September ⁶, and its 12-layer HBM4E reportedly passed Nvidia and hyperscaler checks in late September↗, which the company declined to confirm ⁷.

SK hynix alone ships the denser 16-layer stacks for Nvidia's Rubin in volume ⁶. Yet on the morning of October 8, 2026, Samsung estimated 107.4 trillion won (about $80 billion) in quarterly operating profit↗, the first Korean company past 100 trillion ⁸.

110 trillion won of memory profit in one quarter

Analysts put Samsung's memory division alone at about 110 trillion won of that, helped by HBM4 sales into Nvidia's Vera Rubin and HBM shipments reportedly up nearly 50% on the quarter↗ ⁸⁹. That is more memory profit in a single quarter than all of SK hynix, which IBK Investment & Securities forecasts at 75.1 trillion won of operating profit this quarter and 96.6 trillion, on 80.3% margins, in the fourth ⁵.

Sold out, and cheap

SK hynix is not losing; it is allocated. It sends a larger share of its HBM output to Nvidia than Samsung does ¹, and IBK calls the shares "significantly undervalued" at 5.0 times this year's earnings and 3.8 times next year's, with at least 90 trillion won of 2026 shareholder returns due and more fourth-quarter buybacks beyond the 40 trillion won already running ⁵. What no forecast in the record shows is the price memory clears once Samsung's HBM4 feeds both big buyers at scale.

Watch October 29

Samsung's division-level breakdown lands on October 29, 2026, the first clean read on HBM4's share of its profit ⁸. Foundry work is the unpriced option: Su says the Samsung partnership runs "not only in memory but also across foundry operations" ³. Margins near 80% assume scarcity, and scarcity now has a second supplier with a record quarter behind it.