Who are UMC’s biggest customers?
Largest customer: 11.8% of FY2025 revenue *
The filing does not name this customer. Hollsteen never guesses names.
“Our largest customer from our wafer fabrication segment accounted for 13.1%, 10.4% and 11.8% of our operating revenues in 2023, 2024 and 2025, respectively.” *
Numbers, method and sources
Quote
Customers named in the filing
“Our customers include industry leaders such as MediaTek, Realtek, Novatek and Texas…” · 20-F · filed Apr 30, 2026
Share of revenue per customer, as the filing states it. US GAAP requires disclosure only for customers with at least 10% of revenue; a year without a customer means below 10% or not disclosed. Labels like “Customer A” are the filer’s own; the same label is not guaranteed to be the same customer every year.
Source: the filing’s tagged data (XBRL ConcentrationRiskPercentage, benchmark revenue), or the filing text where a share is not tagged.
FY2025
- Largest customer (unnamed) 11.8%
Quoted above.
FY2024
- Largest customer (unnamed) 10.4%
Quoted above.
FY2023
- Largest customer (unnamed) 13.1%
Quoted above.
FY2021
- Largest customer (unnamed) 10.3%
As stated in the FY2022 annual report.
“Our largest customer from our wafer fabrication segment accounted for 11.5%, 10.3% and 8.6% of our operating revenues in 2020, 2021 and 2022, respectively.”
FY2020
- Largest customer (unnamed) 11.5%
Quoted above, from the FY2022 annual report.
Top ten customers (group)
“Our top ten customers accounted for 62.0%, 55.6% and 57.0% of our operating revenues in 2023, 2024 and 2025, respectively.”
“(3) Major customers Individual customers accounting for at least 10% of operating revenues for the years ended December 31, 2023, 2024 and 2025 were as follows: For the years ended December 31, 2023 2024 2025 NT$ NT$ NT$ (In Thousands) (In Thousands) (In Thousands) Customer A N/A (Note) $ 24,180,535 $ 28,005,843 Customer B $ 29,242,973 N/A (Note) N/A (Note) Note: The sales amount is less than 10% of the Company’s operating revenues. 13.”
SEC filings only. No market data.
Is UMC getting more dependent on one customer?
Largest disclosed customer, by fiscal year
Which customers does the filing name?
“Our customers include industry leaders such as MediaTek, Realtek, Novatek and Texas Instruments.” *