> ## 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 ASE Do? The Outsourced Packaging and Test Model - URL: https://www.sotkn.com/stack/semiconductors/what-does-ase-do/ - Published: 2026-11-03T04:48:07.000Z - Updated: 2026-11-03T04:48:07.000Z - Description: ASE gets paid to package and test chips it does not design. The profit sits in that arm. In the quarter to 30 September 2026, cash for floors and testers left faster than operations brought it in. - Author: Sean - Tags: #layer-semiconductors STACK · Semiconductors · Status: Tightening · Last reviewed: 3 Nov 2026 ASE Technology gets paid to package and test chips other companies design, and the profit sticks in that arm while the contract-manufacturing arm mostly passes the parts bill through. **In short.** In the quarter to 30 September 2026, ASE reported group revenue of NT$244.2 billion. Assembly, test and materials did NT$151.5 billion of that at a 30.6% gross margin. Electronic manufacturing did NT$93.5 billion at an 8.3% gross margin, and raw materials were 82% of that revenue. Our read: toolmakers and builders are paid now. ASE is paid when the new floor runs. The company guides the assembly arm up another 11% to 13% this quarter, so the stuck step is the floor, not the order. Why this sits on the map: a finished die is not a sellable chip until it is joined, sealed and tested. TSMC keeps the leading chip-on-wafer-on-substrate step, [CoWoS](https://www.sotkn.com/explained/cowos-explained/), inside the foundry. The outsourced work beside it is a different business. If you want the mechanism first, start with [who makes advanced packaging](https://www.sotkn.com/explained/who-makes-advanced-packaging/) and [foundry and advanced packaging](https://www.sotkn.com/explained/foundry-advanced-packaging-explained/). This page is the company that does the outsourced share. ## Numbers that matter | Number | What it is | Why it matters | | -------------- | ------------------------------------- | ------------------------------------------------------------------------------------------- | | **NT$244.2bn** | Group revenue, quarter to 30 Sep 2026 | Up 44.8% year on year and 27.8% on the quarter. ASE's own dollar figure is US$7,642 million | | **30.6%** | ATM gross margin | Up from 27.3% in the second quarter. Operating margin 20.0% | | **about 91%** | ATM share of operating income | NT$30.2 billion against group operating income of NT$33.1 billion (our arithmetic) | | **US$2.10bn** | Equipment spending in the quarter | Testing US$1,067 million, packaging US$991 million. Testers in service 8,831 | | **NT$125.9bn** | Cash paid for plant and equipment | Operating cash was NT$50.5 billion. Net debt to equity rose from 0.47 to 0.66 | *Dated 29 October 2026, for the quarter ended 30 September 2026\. Dollar revenue is ASE's own figure from its 12 October filing. The 91% share is our arithmetic.* ## What does it actually do? A wafer leaves the foundry as a set of dies. Someone has to put contacts on them, set them on a substrate or in a package, add the chips that sit beside them, seal the package and check that it works. ASE sells that service. It does not, on these accounts, sell the design. The 29 October release describes the group as assembly and test, plus materials, plus electronic manufacturing through USI. Those are two businesses. ATM is assembly, testing and materials. EMS, through USI, builds modules and finished assemblies. In the quarter, packaging was about 50% of group revenue, testing about 11%, EMS about 38% and other items about 1%. On the slides filed the same day, after sales between the arms are removed, ATM was 61.7% of holding-company revenue and EMS was 38.1%. Inside ATM, bumping, flip chip, wafer-level packaging and system-in-package were 51% of revenue. Wirebonding was 24%. Testing was 17%. A year earlier the first two shares were 48% and 26%. By end use, computing was 34% of ATM, up from 25% a year earlier, and communication was 38%, down from 45%. On those rounded shares, computing was about NT$52 billion, against about NT$25 billion (our arithmetic). Test here is a service, not a machine sale. ASE reported 8,831 testers in service at 30 September 2026, against 7,066 a year earlier, about 25% more (our arithmetic). Wirebonders were 24,801, against 25,120\. It is adding the machines that check advanced packages, not the machines that do classic wirebond. Who sells the testers is [Advantest](https://www.sotkn.com/stack/semiconductors/what-does-advantest-do/). The chain around them is [who tests AI chips](https://www.sotkn.com/explained/who-tests-ai-chips/). One ATM customer was above 10% of that revenue. The five largest were about 46% and the ten largest 63%. Integrated device manufacturers were 46%, up from 41% in the second quarter. The release names no customer. On the EMS side the five largest were about 70%, and two were each above 10%. ## How does it make money? Group gross margin was 22.1%, up from 21.0% in the second quarter and 17.1% a year earlier. Group operating margin was 13.6%, up from 11.1% and from 7.8%. Those rates mix a thick business with a thin one. ATM gross margin was 30.6%, up from 22.6% a year earlier, and operating margin was 20.0%. EMS gross margin was 8.3% and operating margin 3.3%. ATM operating income was NT$30,243 million, against group operating income of NT$33,142 million and EMS operating income of NT$3,111 million. The arms add to slightly more than the group, because sales between them are eliminated. ATM was about 91% of group operating income (our arithmetic). The cost lines show why. Raw materials were 27% of ATM revenue and 82% of EMS revenue. Labour was 13% of ATM and 4% of EMS. The company's depreciation, amortisation and rental line was NT$19,131 million inside ATM and NT$1,289 million inside EMS. EMS mostly passes the parts bill through. ATM is the process: people, tools and the package. That is where the money sticks. Net income for shareholders was NT$26,996 million, up from NT$10,870 million a year earlier, and basic earnings per share were NT$6.13, against NT$2.50\. For the nine months, revenue was NT$608,887 million against NT$467,472 million, and net income NT$62,193 million against NT$25,945 million. The fourth-quarter slides, filed the same day, assume NT$31.9 to the US dollar. Group revenue is guided up 6% to 8%, gross margin to 23% to 24%, and operating margin to 14.5% to 15.5%. ATM revenue is guided up 11% to 13%, with gross margin up another 100 to 200 basis points. EMS is guided flat, with an operating margin around 2%. On those ranges, group revenue would be about NT$259 billion to NT$264 billion and ATM revenue about NT$168 billion to NT$171 billion (our arithmetic). The implied ATM gross margin is about 31.6% to 32.6%. The next step up, on the company's own guide, is assembly and test. ## What limits it? Not the order. ASE guides the thick arm up another 11% to 13%, with margin up another point or two. September was already the largest month of the quarter, at NT$88,130 million, up 7.2% from August (12 October filing). The limit is the cash and the time it takes to turn that book into more running floor. Operations generated NT$50,462 million. Cash paid for plant and equipment was NT$125,852 million, a gap of about NT$75.4 billion (our arithmetic), before dividends of NT$28,958 million. Net new borrowing was NT$100,925 million. Long-term borrowings rose from NT$209,603 million to NT$276,633 million, and bonds payable from NT$14,985 million to NT$42,201 million. The current portion of long-term debt fell, from NT$11,787 million to NT$5,141 million. Net interest expense was NT$2,611 million, against NT$1,428 million a year earlier, up about 83% (our arithmetic). The balance-sheet gauge ASE publishes, net debt to equity, rose from 0.47 at 30 June to 0.66 at 30 September. Property, plant and equipment rose from NT$517,715 million to NT$621,962 million, about a fifth in three months (our arithmetic). At the NT$31.96 rate printed in the same release, the NT$125.9 billion plant cheque is about US$3.9 billion (our arithmetic). Equipment was US$2,104 million of that story. The rest of the cash is the buildings, the cleanrooms and the plant around the tools. Credit is not the bind. Unused credit lines were NT$457,283 million and cash was NT$88,421 million. Headcount rose from 114,558 to 119,346\. Receivables rose from NT$143,318 million to NT$174,495 million, and inventories from NT$86,268 million to NT$99,721 million. Growth also ties cash up in the customer book. Who gets paid, from these figures: toolmakers and builders now (testing took US$1,067 million of the equipment bill, packaging US$991 million, EMS US$41 million), then lenders, on a rising interest bill, with the lines still open. ASE's own ATM margin, 20% at the operating line, arrives only once a package or a test is done. EMS is paid too, but 82% of that revenue walks back out as parts. Our read of the stuck step is the open floor. The guide says demand is still ahead. The cheque has already left. The capacity counts when the tools run. ## Who else does this? Amkor is the other large outsourced house with a full public quarter beside this one. Its 26 October 2026 release, for the quarter ended 30 September, reported sales of US$1,991 million, a gross margin of 18.3% and an operating margin of 11.3%. Advanced products, Amkor's term for flip chip, memory, wafer-level work and the related test, were US$1,632 million. Mainstream products were US$359 million. Advanced was about 82% of sales (our arithmetic). Packaging was 88% of sales and test 12%. Computing was 26%. ASE's own dollar figure for ATM is US$4,741 million. That arm alone was about 2.4 times Amkor's whole company (our arithmetic). The margin comparison that belongs here is ATM at 30.6% against Amkor at 18.3%. The mixes differ. Amkor guides fourth-quarter sales of US$1.9 billion to US$2.0 billion and full-year 2026 capital spending of about US$2.5 billion. ASE spent US$2.1 billion on equipment in the third quarter alone. One figure is a quarter of tools. The other is a year of spending. TSMC is not an outsourced house. It keeps the leading CoWoS join inside the foundry. That door is [what TSMC does](https://www.sotkn.com/stack/semiconductors/cowos/what-does-tsmc-do/) and [CoWoS](https://www.sotkn.com/explained/cowos-explained/). The substrate under the package is a further gate, [IC substrates and ABF](https://www.sotkn.com/explained/ic-substrates-abf-explained/). Tester makers are paid when ASE buys the machines. See the Wire note on [NVIDIA reserving US test capacity, and Amkor](https://www.sotkn.com/wire/nvidia-1-1bn-kyec-amkor-3bn-substrate-capacity-wire/). ## What would change this view? ATM misses the 11% to 13% revenue guide, or gross margin does not rise by 1 to 2 points. That would weaken the read that orders are still ahead of the floor. A miss in EMS would matter less. That arm is not where the profit sits. The machine counts reverse. Testers are up about 25% in a year and wirebonders are slightly down. If wirebonders jump and testers stall, the mix read is wrong. If operating cash covers the plant bill and net debt to equity turns down from 0.66 while ATM keeps the guide, the floor is starting to earn. If the ratio keeps rising and the guide is missed, the build has got ahead of the work. Computing falls back toward last year's 25% of ATM. The margin and that share moved together. If the share drops and the margin holds, something else is doing the work. Concentration is the other stick: one unnamed customer is already above 10% of ATM, and the top five are 46%. This page will not guess the name. ## Practical takeaways Split the company before you read the margin. A 22.1% group gross margin is a 30.6% assembly arm averaged with an 8.3% manufacturing arm. About 91% of operating income was in ATM. Read the machines with the equipment bill. Testers 8,831, wirebonders 24,801\. Of US$2.1 billion of equipment, US$1,067 million was testing and US$991 million was packaging. The stuck step is the open floor, not the revenue print. NT$125.9 billion went out for plant against NT$50.5 billion of operating cash, and net debt to equity stepped from 0.47 to 0.66\. Unused credit of NT$457 billion means lenders are not the ones saying no. Size the arm against Amkor: ATM at US$4,741 million was about 2.4 times Amkor's entire sales, and Amkor's full-year spending guide of about US$2.5 billion is close to ASE's equipment bill for one quarter. Different scopes. The gap is still the point. October monthly revenue was not out as of this writing. September's note was 12 October, so that monthly note is the near check. The fourth-quarter results test the 11% to 13% ATM guide. The week-of read is the [Taiwan Pulse on this quarter](https://www.sotkn.com/markets/taiwan/taiwan-ase-q3-capex-new-floors-october-2026/). ## FAQ **What does ASE do?** ASE Technology Holding packages and tests chips for other companies, and through USI it builds electronic modules. It does not, on these accounts, sell the chip design. In the quarter to 30 September 2026, packaging was about half of group revenue, testing about 11%, and electronic manufacturing about 38%. **Where does ASE profit sit?** In assembly, test and materials, which ASE calls ATM. That arm had a 30.6% gross margin and a 20.0% operating margin in the third quarter of 2026\. Operating income there was NT$30.2 billion, about 91% of the group's NT$33.1 billion (our arithmetic). The EMS arm had an 8.3% gross margin, and raw materials were 82% of its revenue. **Who else packages and tests chips?** Amkor is the other large outsourced house. For the quarter to 30 September 2026 it reported sales of US$1,991 million, an 18.3% gross margin and an 11.3% operating margin. TSMC keeps CoWoS inside the foundry. Advantest sells testers. ASE buys tools and runs the service. **What limits ASE right now?** Not the order, on the company's own outlook. It guides assembly-and-test revenue up another 11% to 13% in the fourth quarter, with gross margin up another 1 to 2 points. The limit is the floor and the tools. In the third quarter it generated NT$50.5 billion of operating cash and paid NT$125.9 billion for plant and equipment. Net debt to equity rose from 0.47 to 0.66. **Is this a recommendation to buy ASE shares?** No. This page explains how ASE makes money and where it can get stuck. It gives no buy or sell calls. Not investment advice. Do your own research. ## Keep reading on the map Layer: [Semiconductors](https://www.sotkn.com/stack/semiconductors/). Also on the layer: [TSMC](https://www.sotkn.com/stack/semiconductors/cowos/what-does-tsmc-do/), [Advantest](https://www.sotkn.com/stack/semiconductors/what-does-advantest-do/) and [ASML](https://www.sotkn.com/stack/semiconductors/what-does-asml-do/). Explained: [who makes advanced packaging](https://www.sotkn.com/explained/who-makes-advanced-packaging/), [CoWoS](https://www.sotkn.com/explained/cowos-explained/), [who tests AI chips](https://www.sotkn.com/explained/who-tests-ai-chips/) and [IC substrates](https://www.sotkn.com/explained/ic-substrates-abf-explained/). Markets door: [Taiwan](https://www.sotkn.com/markets/taiwan/), and the quarter's Pulse, [who gets paid while ASE's new floors catch up](https://www.sotkn.com/markets/taiwan/taiwan-ase-q3-capex-new-floors-october-2026/). Wire: [TSMC, CoWoS prices and longer tests](https://www.sotkn.com/wire/tsmc-cowos-price-rise-20-percent-ai-chip-testing-wire/) and [NVIDIA's test reservation and Amkor](https://www.sotkn.com/wire/nvidia-1-1bn-kyec-amkor-3bn-substrate-capacity-wire/). Analysis: [what ASE's price assumes about the packaging stuck step](https://www.sotkn.com/analysis/ase-packaging-stuck-step-what-price-assumes/). [Get the Wire](https://www.sotkn.com/#/portal/signup) — short daily notes when packaging lines, test capacity and the floor count move. Not investment advice. Do your own research. ## How we check this Figures come from ASE's unaudited release of 29 October 2026, the slides filed that day, the 12 October monthly filing for ASE's own dollar totals, and Amkor's 26 October release. Read on 3 November 2026\. Figures that appear only in a secondhand call transcript are not used. Ratios, the fourth-quarter ranges, the plant-bill conversion at NT$31.96 and the tester growth rate are our arithmetic. Who gets paid, and the open floor as the stuck step, are our read. The featured image is a graded cleanroom photograph with one uninstalled tool, not an ASE factory. No buy or sell call. Not investment advice. **Last reviewed:** 3 Nov 2026 · **Next review:** after ASE's October monthly revenue release and its fourth-quarter results Spot an error? [Tell us](mailto:sean@thekopinotes.com). [Our editorial standards →](https://www.sotkn.com/editorial-standards/) ## Sources 1. [ASE Technology Holding — unaudited third-quarter results (29 Oct 2026)](https://www.prnewswire.com/news-releases/ase-technology-holding-co-ltd-reports-its-unaudited-consolidated-financial-results-for-the-third-quarter-of-2026-302923021.html?ref=sotkn.com) — group revenue, margins, ATM and EMS cost lines, equipment spend, tester and wirebonder counts, cash, borrowing and customer concentration. 2. [ASE Technology Holding — Form 6-K earnings slides (29 Oct 2026)](https://www.sec.gov/Archives/edgar/data/1122411/000095010326016323/dp255782%5F6k.htm?ref=sotkn.com) — holding-company mix, end-use shares, and the fourth-quarter outlook. 3. [ASE Technology Holding — Form 6-K monthly revenues (12 Oct 2026)](https://www.sec.gov/Archives/edgar/data/1122411/000095010326015458/dp254866%5F6k.htm?ref=sotkn.com) — September revenue and the company's own dollar totals for the quarter. 4. [Amkor Technology — third-quarter results (26 Oct 2026)](https://ir.amkor.com/news-releases/news-release-details/amkor-technology-reports-financial-results-third-quarter-2026?ref=sotkn.com) — sales, margins, advanced and mainstream split, and the 2026 capital-spending figure. S **[Sean](https://www.sotkn.com/author/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. [Author page →](https://www.sotkn.com/author/sean/) · [Editorial standards →](https://www.sotkn.com/editorial-standards/)