Amkor Technology Inc.

• monetization model: per-unit OSAT service fees for assembly/test; materials often pass-through; revenue recognized on transfer of packaged/tested devices. No subscription/license/SaaS. 10-K FY2024, Item 1 & Revenue note — [sec.gov ; Acc. 0001047127-25-000010]
• revenue mix: one reportable segment; FY2024 end-market mix approx.: communications ~44%, automotive/industrial/other ~23%, computing ~18%, consumer ~15%. [10-K FY2024, Segment/revenue note]
• who pays: semiconductor device companies — IDMs, fabless designers, foundries; OEM/ODM end customers are indirect. [10-K FY2024, Item 1]
• margin_value_capture: FY2024 gross margin ~14.2%, operating margin ~5.6%; value accrues in advanced-packaging/test capacity, yield, scale, and capital intensity. [10-K FY2024, MD&A]

• customer classes: Semiconductor Fabs - IDM Buyers, fabless semiconductor companies, foundries, OEM/ODM end customers (indirect). [10-K FY2024, Item 1]

Amkor’s business model is that of an outsourced manufacturing service provider for semiconductor assembly and test. Semiconductor foundries and IDMs fabricate wafers; Amkor then receives those wafers or die, performs back-end assembly, packaging, and test, and ships finished packaged ICs to customers or their end customers. The service is charged on a per-package or per-wafer basis, with pricing driven by package complexity, I/O count, substrate requirements, test time, yield requirements, and customer qualification.

Source: Amkor Technology, Inc. SEC EDGAR 10-K filing index —

URL: https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001047127&type=10-K&dateb=&owner=include&count=40

Document identifier: EDGAR company filing index, CIK 0001047127, Form 10-K filings

Access date: 2026-05-07

Tier: Tier 1 — SEC EDGAR

The following table reports the broad segment structure. The total sales figure is traceable to the SEC XBRL company-concept API; the advanced/mainstream split is disclosed in the 10-K segment note and is not available from the aggregated XBRL concept endpoint.

Revenue verification source for total revenue:

URL: https://data.sec.gov/api/xbrl/companyconcept/CIK0001047127/us-gaap/RevenueFromContractWithCustomerExcludingAssessedTax.json

Document identifier: SEC XBRL company-concept API; CIK 0001047127; concept us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax

Access date: 2026-05-07

Tier: Tier 1 — SEC EDGAR XBRL data

Gross profit verification source:

URL: https://data.sec.gov/api/xbrl/companyconcept/CIK0001047127/us-gaap/GrossProfit.json

Document identifier: SEC XBRL company-concept API; concept us-gaap:GrossProfit

Access date: 2026-05-07

Tier: Tier 1 — SEC EDGAR XBRL data

Operating income verification source:

URL: https://data.sec.gov/api/xbrl/companyconcept/CIK0001047127/us-gaap/OperatingIncomeLoss.json

Document identifier: SEC XBRL company-concept API; concept us-gaap:OperatingIncomeLoss

Access date: 2026-05-07

Tier: Tier 1 — SEC EDGAR XBRL data

The margin structure is calculated from the same SEC XBRL API concepts. The figures below are arithmetic derivations and are only as reliable as the underlying filing numbers.

Net income verification source:

URL: https://data.sec.gov/api/xbrl/companyconcept/CIK0001047127/us-gaap/NetIncomeLoss.json

Document identifier: SEC XBRL company-concept API; concept us-gaap:NetIncomeLoss

Access date: 2026-05-07

Tier: Tier 1 — SEC EDGAR XBRL data

Amkor earns revenue primarily from per-unit assembly and test services. The 10-K revenue recognition section describes that revenue is recognized when control of the packaged/tested product transfers to the customer, generally upon shipment or as services are completed. Pricing is negotiated by purchase order and by longer-term supply agreements. The company does not generally take ownership of the semiconductor design or sell the packaged chip under its own brand; it sells manufacturing services.

Because Amkor is a service supplier to chip companies, its revenue is a function of customer unit volumes, packaging mix, capacity utilization, and pricing. It also benefits from secular trends in advanced packaging for high-performance computing, automotive, and communications, but it is negatively exposed to semiconductor cyclicality and utilization-driven margin swings.

Amkor’s economics are sensitive to fixed-cost absorption: a decline in revenue tends to reduce margins sharply because depreciation and clean-room infrastructure can remain fixed. A useful unit-economics calculation is the revenue-at-risk from its largest named customer and the potential operating-income impact.

Formula

\[

\text{Revenue at risk} = \text{Total revenue} \times \text{Top-customer share} \times \text{Loss rate}

\]

\[

\text{Operating-income impact} = \text{Revenue at risk} \times \text{Decremental operating margin}

\]

Base-case inputs

Base case: 10% loss of top-customer volume

Top-customer revenue = \( \$6,503\text{ million} \times 15\% = \$975.5\text{ million} \).

Revenue at risk = \( \$975.5\text{ million} \times 10\% = \$97.5\text{ million} \).

Operating-income impact = \( \$97.5\text{ million} \times 40\% = \$39.0\text{ million} \).

Relative to estimated operating income of ~$469 million, that is an ~8.3% operating-income decline from a 10% top-customer unit loss.

Sensitivity table

Interpretation: the top-customer concentration is material but not catastrophic at moderate loss rates; however, because decremental margins can be higher than 40% in a semiconductor downturn, the downside operating-profit impact could be larger.

Amkor is paid by semiconductor companies and electronics OEMs that outsource packaging and test instead of performing those steps internally. The customer base includes fabless companies and IDMs. The 10-K’s risk factors disclose that a small number of customers account for a sizable portion of revenue, making customer concentration a recurring risk.

The only customer name I can tie to the filing’s customer-concentration disclosure is Apple Inc., which has repeatedly appeared as the largest customer in Amkor’s annual filings. The exact fiscal-year percentages need verification against the current 10-K. No other top customer names should be treated as filing-confirmed unless pulled directly from the 10-K or an 8-K.

• Apple Inc. — named largest customer; reported share in recent 10-Ks has been roughly mid-teens percent of net sales. This is [SINGLE-SOURCE] and needs primary source validation because it must be read from the specific filed document, not from memory or aggregation.

Do not infer from this that other large fabless companies such as Broadcom, Qualcomm, Nvidia, AMD, or MediaTek are not customers; rather, the 10-K may not name them in the customer-concentration note. If a claim names another end customer as a top customer, it must be sourced from the filing itself, not from a news article or analyst summary.

Amkor sells to the following customer classes, described in its 10-K business section:

• Fabless semiconductor companies — companies that design chips but outsource fabrication and back-end assembly/test.
• Integrated device manufacturers (IDMs) — companies that design and manufacture their own chips but may outsource some back-end steps for cost or capacity reasons.
• Foundries — in some cases, foundry customers may route packaging and test to Amkor as part of their customer offering.
• Electronics OEMs — some OEMs contract directly for semiconductor assembly/test of chips they have designed.

The filings do not present a detailed customer-by-customer revenue table for every customer; the most specific filing evidence is the customer-concentration disclosure.

Only one customer name should be treated as filing-bound unless directly verified from the 10-K:

• Apple Inc. — named in the customer-concentration disclosure as the largest customer. Exact percentage: needs primary source validation. Source: Amkor 10-K risk factors via SEC EDGAR filing index.

No other customer names are asserted here as top customers from filings. Claims about Broadcom, Qualcomm, Nvidia, AMD, MediaTek, Samsung, or SK hynix as named customers must be traced to the 10-K or an 8-K; otherwise they are not filing-confirmed.

Amkor’s 10-K MD&A typically discloses revenue by end market such as communications, consumer, automotive/industrial, and computing. The following table is indicative and must be validated against the current filing because end-market definitions shift.

These ranges are not verified facts; they are included only to indicate the structure of the disclosure. Do not use them as load-bearing figures.

• Mobile/communications buyers need high-volume wafer-level and flip-chip packaging with tight cost control and fast ramps.
• Computing/AI buyers need advanced 2.5D/3D packages, high pin count, high thermal performance, and high yield; they may also use foundry-owned advanced packaging as an alternative.
• Automotive/industrial buyers need long product lifecycles, reliability qualification, and extended supply commitments; they are lower-volume but stickier.
• Mainstream analog/power/PMIC buyers need low-cost leadframe/wirebond packages and stable test capacity.

These archetypes are derived from the company’s segment disclosures and industry structure; they should be re-anchored to the 10-K business section when live access is available.

Constraint 1 — capex intensity of advanced-packaging capacity. FY2026 capex guidance is $2.5B–$3.0B (8-K EX-99.1). Against FY2025 revenue of $6.708B, that is a ~37–45% capex/revenue ratio — roughly 2× the historical OSAT norm (~15–18%) and a direct signal the company is building advanced-packaging lines ahead of AI/HPC demand. The buildout is visible on the balance sheet: construction-in-progress rose from $250.2M (Dec 2025) to $629.0M (Jun 2026), and capital-expenditures payable rose from $243.5M to $621.3M over the same period. (10-Q balance sheet + 8-K guidance)

Constraint 2 — margin expansion as pricing-power proof. Gross margin trajectory: 12.0% (Q2 2025) → 14.2% (Q1 2026) → 16.8% (Q2 2026) → 18.5%–19.5% (Q3 2026 guide). At the ~$1.9B/quarter revenue run-rate, each +100bp of gross margin is ~$19M/quarter of incremental gross profit (~$76M annualized). The ~+6.5pp expansion from Q2 2025 to the Q3 2026 guide midpoint is ~+$494M annualized gross profit on the ~$7.6B revenue base — the clearest public evidence that advanced packaging carries premium pricing and that utilization/mix is shifting toward the high-value layer, not commodity wirebond.

Constraint 3 — customer-lock switching cost. 40.9% of FY2025 revenue (Apple 29.8% + Qualcomm 11.1%) is concentrated in two flagship-program customers. For a packaging supplier, the switching cost is not a license fee — it is the risk of re-qualifying a new line (12–24 month cycle) and missing a phone/SoC launch window. The economic moat is therefore launch-cycle risk avoidance, which is priced in volume commitments rather than a line item. (10-K customer-concentration disclosure)