> ## Content Index > Fetch the complete content index at: https://www.sotkn.com/llms.txt > Use this file to discover other available public pages before exploring further. # What Does SK hynix Do? The HBM Business Model - URL: https://www.sotkn.com/stack/semiconductors/hbm/what-does-sk-hynix-do/ - Published: 2026-09-24T04:45:10.000Z - Updated: 2026-09-24T04:45:10.000Z - Description: SK hynix builds HBM stacks, sells them under long agreements to a short customer list, and gets paid when those stacks ship — allocation is the stuck step. - Author: Sean - Tags: #layer-hbm *SK hynix builds high-bandwidth memory stacks, sells them under long agreements to a short customer list, and gets paid when those stacks ship — allocation, not open wafers, is the stuck step.* `HBM` · `Data as at 24 Sep 2026` · `Next update: after Q3 2026 results` **Affects:** Semiconductors · HBM · Korea It is the largest specialist supplier of [HBM](https://www.sotkn.com/explained/hbm-explained/) — the tall DRAM stacks that sit beside an AI GPU inside one package. That is a different job from [TSMC](https://www.sotkn.com/explained/foundry-advanced-packaging-explained/), which prints the compute die and joins the stacks on [CoWoS](https://www.sotkn.com/explained/cowos-explained/). For the country door, see [Korea HBM](https://www.sotkn.com/markets/korea/korea-hbm-memory-september-2026/). **In short:** SK hynix makes DRAM and NAND, and the AI cash sits in HBM — stacked memory sold under long-term agreements to around 10 key customers. Q2 2026 revenue was KRW 79.32 trillion, up 257% year-on-year, with a 76% operating margin. The model works if qualified stacks keep shipping into booked demand — and if [CoWoS-class packaging](https://www.sotkn.com/explained/cowos-explained/) can attach them. *Education only, not advice to buy or sell any security. Figures are from company filings and company releases dated as shown.* ## Numbers that matter Q2 2026 revenue KRW 79.32tn +51% QoQ · +257% YoY · quarter ended 30 Jun 2026 Record Operating profit / margin KRW 60.54tn · 76% +61% QoQ · +557% YoY Pricing power Long-term agreements \~10 customers Booked list, not an open book · 29 Jul 2026 Stuck Cash vs interest-bearing debt KRW 88tn / 18.6tn Net cash KRW 69.4tn · end-Q2 2026 Fortified HBM4 shipments Mass from Q2 2026 H2 ramp · HBM4E samples in H1 Ramping HBM revenue share (research) SK 50% Samsung 33% · Micron 18% · Counterpoint Q2 2026 Estimate Sources: SK hynix 2Q26 results, 29 Jul 2026; Counterpoint Global DRAM and HBM Market Share, 1 Sep 2026 (research estimate, not a company filing). Status chips are Second Order's read. **Contents:** [What does SK hynix actually do?](#what-it-does) · [How does it make money?](#how-it-earns) · [What limits it?](#what-limits) · [Who else does this?](#who-else) · [What would change this view](#what-would-change) · [Practical takeaways](#practical-takeaways) · [FAQ](#faq) --- ## What does SK hynix actually do? Three steps, in order. 1. **It stacks scarce memory.** SK hynix is a memory maker: DRAM and NAND. The AI product that binds the build chain is [HBM](https://www.sotkn.com/explained/hbm-explained/) — DRAM dies stacked on a logic base die, then placed a few millimetres from the GPU inside an advanced package. Regular server DRAM still matters. It is not the stuck step. 2. **It qualifies and allocates.** Stacks do not sell like commodity DIMMs. A platform has to qualify the generation, the height, and the yield. The company said on 29 July 2026 that it has long-term agreements with around 10 key customers, and that “the ability to deliver requested volumes in a timely manner has emerged as a core business competitiveness.” That sentence is the business. Demand is not the question. Who is on the list is the question. 3. **It ships into someone else’s package.** Finished HBM cubes go to a [CoWoS-class](https://www.sotkn.com/explained/cowos-explained/) attach line — mostly TSMC — where they sit beside the compute die. From HBM4, SK hynix also uses TSMC’s advanced logic for the base die (company keynote at the TSMC Technology Symposium, 23 Apr 2026). The memory maker does not own the last join. | Step | What it means | Where the risk sits | | -------- | ------------------------------------------------- | -------------------------------------------- | | Stack | Build qualified HBM (and the rest of DRAM / NAND) | Yield, generation, tools | | Allocate | Sell under multi-year agreements to a short list | Who is on the list — and who is not | | Attach | Ship cubes into CoWoS-class packages | Packaging can re-bind even when stacks exist | --- ## How does SK hynix make money? It gets paid for bits that ship. The AI cash, though, is not “any DRAM.” It is mix, price, and a booked customer list. Three things decide the print: - **Mix** — HBM and AI-server DRAM earn more than older PC or phone parts on the same wafer capacity - **Contract price** — long agreements lock volume and ASP before open supply exists - **Qualification** — a stack that is not qualified on the leading platform does not invoice at the leading price On 29 July 2026 the company printed KRW 79.3187 trillion of revenue and KRW 60.5426 trillion of operating profit for the quarter ended 30 June 2026\. Operating margin was 76%. Revenue was up 51% on the prior quarter and 257% on a year earlier. First-half revenue crossed KRW 100 trillion for the first time. **Our arithmetic.** Add the two published quarters: Q1 KRW 52.5763 trillion + Q2 KRW 79.3187 trillion = **KRW 131.895 trillion** for the first half. That is the company’s own “over 100 trillion” claim, shown in full. Operating margin on the Q2 print is 60.5426 ÷ 79.3187 = **76.3%**, which the company rounds to 76%. Cash followed the operating print. Cash and cash equivalents reached KRW 88 trillion at the end of the second quarter, up KRW 33.6 trillion from the prior quarter. Interest-bearing debt fell KRW 0.7 trillion to KRW 18.6 trillion. The company put net cash at KRW 69.4 trillion. **Our check:** 88 − 18.6 = **69.4**. The balance sheet is not the CoreWeave story. This is a memory maker collecting cash at a scarce step, not a fleet borrowing against machines. Net profit was KRW 93.9226 trillion — larger than operating profit. We do not treat the 118% net margin as the memory run-rate. Items below the operating line added to that print. The number that teaches the HBM business is the 76% operating margin on KRW 79.32 trillion of sales. The company said both DRAM and NAND prices rose sharply quarter-on-quarter, and that it expanded sales in HBM, AI-server DRAM, and enterprise SSD. It began mass shipments of HBM4 in the second quarter and said it will ramp production in the second half. HBM4E samples shipped in the first half. That is how the money sticks: contracted HBM and AI memory, not leftover commodity bits sold into an open market. --- ## What limits it? Allocation first. Packaging second. Own capacity third. **1\. The customer list is short.** Around 10 long-term agreements is not a spot market. A 76% operating margin and a record export tape can live together only if late buyers cannot walk to a third supplier and clear the same stacks. Micron exists. It does not open SK hynix’s book. See the [Korea chip-export Pulse](https://www.sotkn.com/markets/korea/korea-chip-exports-september-2026/) for what allocated memory looks like after it clears the port: Korea Customs printed US$34.128 billion of semiconductor exports in the first 20 days of September 2026\. That is the invoice, not a free queue. **2\. CoWoS can re-bind.** A stack that cannot be attached does not become a finished accelerator. TSMC’s chairman said on the Q2 2026 call (16 Jul 2026) that packaging capacity was “so tight that now it’s limiting my customers’ growth.” Our [Wire on CoWoS-L through 2028](https://www.sotkn.com/wire/cowos-l-mainstream-through-2028-wire/) keeps that path as the packaging stuck step. HBM and CoWoS are neighbours. Either clock can set the ship date. **3\. Capacity adds on a multi-year clock.** The company is pulling M15X forward and pointed to Yongin Phase 1 cleanroom opening in early 2027, plus later P&T7 packaging, M17 NAND, and a new cluster — “executed in phases based on customer demand and investment efficiency,” with capex discipline. Nameplate slides are not this quarter’s qualified stack. **4\. HBM4 inserts a foundry step SK hynix does not own.** Through HBM3E the stack was mostly a memory process. From HBM4 the company said it is adopting TSMC advanced logic for the base die. That is a second scarce input: logic wafers and the join, not only DRAM yield. The honest uncertainty is generation. HBM3E is still where most near-term GPU volume binds. HBM4 is the ramp. A supplier can be sold out on one generation and still be racing on the next. Those are different clocks. We are not going to pretend a capacity headline settles both. --- ## Who else does this? Roles, not a league table. | Company | What it does | What makes it different | | ------------ | -------------------------------------------------------------------------- | ---------------------------------------------------------------------------- | | **SK hynix** | Largest HBM supplier by dated research share; memory specialist | \~10 LTAs; HBM4 mass shipments from Q2 2026; TSMC logic on the HBM4 base die | | **Samsung** | HBM plus foundry plus its own advanced packaging | Only name that can try memory, logic, and attach under one roof | | **Micron** | Third scaled HBM supplier | Smaller share; same allocation logic, different qualification clock | | **TSMC** | Prints the compute die; joins HBM on CoWoS; makes SK hynix’s HBM4 base die | Not a memory maker. Owns the attach gate | Counterpoint’s public HBM revenue-share table for Q2 2026 (published 1 Sep 2026) put SK hynix at 50%, Samsung at 33%, and Micron at 18%. That is a dated research estimate, not a company filing. It is useful as a role map. It is not a scoreboard to trade. The question that separates them is not who announced the most wafers. It is who is qualified on the leading platform, who is on the long-agreement list, and whether the attach slot is free when the stack is ready. --- ## What would change this view? The read on the model weakens if: - Q3 language says HBM is available off the LTA list for new late buyers - Bit-growth guidance rises while allocation language cools for more than one quarter - Three suppliers qualify volume HBM4 onto the same leading platform at similar timing - Operating margin falls for reasons other than a planned yield ramp on a new stack - Packaging, not memory, becomes the louder gate on GPU ship dates — the stuck step would then sit in [Taiwan](https://www.sotkn.com/markets/taiwan/), not Korea - A hyperscaler or [neocloud](https://www.sotkn.com/stack/neoclouds/what-does-coreweave-do/) cuts or defers memory commitments in a dated print It stays intact while long-term agreements cover most near-term HBM output, HBM4 is still ramping into unmet demand, and the company still talks about delivering requested volumes on time. --- ## Practical takeaways - SK hynix’s AI model is Stack → Allocate → Attach: build qualified HBM, sell it to a short list, ship it into someone else’s package - Q2 2026: KRW 79.32tn revenue (+257% YoY), 76% operating margin, \~10 LTAs — cash is sticking at the memory door - Net profit (KRW 93.92tn) is larger than operating profit; use the 76% operating margin to read the memory business - The stuck step is allocation, not “did Korea ship chips” and not all DRAM - CoWoS can still stop a finished module after the stack leaves Korea - Next hard read: SK hynix Q3 2026 results (late October) — HBM4 ramp versus allocation language --- ## FAQ **What does SK hynix do?** SK hynix makes DRAM and NAND memory. In the AI build chain its scarce product is high-bandwidth memory — stacked DRAM sold under long-term agreements and attached beside a GPU inside an advanced package. **What does SK hynix do in simple terms?** It builds the tall memory stacks that sit next to an AI chip, and it decides which customers get them first. **Is SK hynix profitable?** Yes, on a reported operating basis. It posted KRW 60.54 trillion of operating profit on KRW 79.32 trillion of revenue in the quarter ended 30 June 2026 — a 76% operating margin (29 Jul 2026). Net profit was higher still; we read the operating line as the memory business. **How is SK hynix different from TSMC?** TSMC prints leading-edge logic and joins chips on CoWoS. SK hynix makes the memory stacks that go into that package. From HBM4, SK hynix also buys a TSMC logic base die. They are neighbours on the same module, not substitutes. See [CoWoS, explained](https://www.sotkn.com/explained/cowos-explained/). **What is HBM allocation?** A booked list of customers under multi-year agreements. SK hynix said it has long-term agreements with around 10 key customers. Stacks on that list ship. Late buyers wait. A record export print is what a booked list looks like after it clears the port — not proof the queue opened. See [SK hynix and the HBM allocation cycle](https://www.sotkn.com/markets/korea/sk-hynix-hbm-allocation/). **Should I buy SK hynix shares?** We do not make buy or sell calls, and nothing here is a recommendation. What we can tell you is what the company does, how it gets paid, and which figures would change the picture. The decision is yours. --- ## Keep reading on the map - **The layer:** [HBM](https://www.sotkn.com/stack/semiconductors/hbm/) — how this memory gate sits inside [semiconductors](https://www.sotkn.com/stack/semiconductors/) - **The term:** [HBM, explained](https://www.sotkn.com/explained/hbm-explained/) - **The neighbour gate:** [CoWoS, explained](https://www.sotkn.com/explained/cowos-explained/) · [Wire: CoWoS-L through 2028](https://www.sotkn.com/wire/cowos-l-mainstream-through-2028-wire/) - **Where it happens:** [Korea](https://www.sotkn.com/markets/korea/) — [HBM still allocated](https://www.sotkn.com/markets/korea/korea-hbm-memory-september-2026/) · [September export invoice](https://www.sotkn.com/markets/korea/korea-chip-exports-september-2026/) - **Who else makes it:** [Who makes HBM](https://www.sotkn.com/explained/who-makes-hbm/) ## Members' Analysis: if HBM4 ships while CoWoS stays short, who captures the next dollar? The free part: SK hynix’s 76% operating margin is what a scarce allocated step looks like in cash. The two clocks can bind at different times. The members cut on where the stuck step moves is already live: [Where does the stuck step move?](https://www.sotkn.com/analysis/where-does-the-stuck-step-move/). This page stays the free Stack read of the SK hynix HBM model. ## Get the Wire Free daily brief on what changed in the AI chip map. [Subscribe free →](https://www.sotkn.com/#daily-wire) ## Sean Writes Second Order by TKN — a plain-English map of AI infrastructure and semiconductors for non-specialist investors. Focus: who gets paid, where money sticks, and which step is stuck. Not investment advice. Covers AI infrastructure, semiconductors, and second-order stack reads. [Author page →](https://www.sotkn.com/author/sean/) · [Editorial standards →](https://www.sotkn.com/editorial-standards/) ## How we check this Figures come from company filings and government releases, each dated in the list below. Capacity and timing from press reports are labelled as reported, not guided. Share tables from research houses are labelled as estimates, not filings. Where we work something out ourselves, the arithmetic is shown in full. **Last reviewed:** 24 Sep 2026 · **Next review:** after Q3 2026 results Spot an error? Tell us and we will correct it and note the change here. [Our editorial standards →](https://www.sotkn.com/editorial-standards/) ## Sources 1. SK hynix, [SK hynix Announces 2Q26 Financial Results](https://news.skhynix.com/en/q2-2026-business-results/?ref=sotkn.com) (newsroom), 29 Jul 2026 — revenue, operating profit, operating margin, net profit, cash, debt, net cash, \~10 LTAs, HBM4 mass shipments, HBM4E samples, capacity comments 2. SK hynix, [“Overcoming Technological Limits Requires the Integration of Memory and Logic”](https://news.skhynix.com/en/tsmc-technology-symposium-2026/?ref=sotkn.com) (newsroom), 23 Apr 2026 — TSMC advanced logic for the HBM4 base die 3. Counterpoint Research, [Global DRAM and HBM Market Share: Quarterly](https://counterpointresearch.com/en/insights/global-dram-and-hbm-market-share?ref=sotkn.com), 1 Sep 2026 — HBM revenue share Q2 2026 (research estimate) 4. TSMC Q2 2026 earnings call, 16 Jul 2026 — C.C. Wei on packaging capacity limiting customer growth, via [TSMC quarterly results](https://investor.tsmc.com/english/quarterly-results/2026/q2?ref=sotkn.com) 5. Second Order, [Korea chip exports $34.1bn (Sep 2026)](https://www.sotkn.com/markets/korea/korea-chip-exports-september-2026/) — Customs 1–20 September invoice as the allocation tape All external links `rel="nofollow noopener"`.