UMC's September 2026 revenue was 27.2% higher than the same month a year earlier. The move from August was tiny, and peers grew faster. The latest quarter shows fatter margins.
Record month, but the month itself barely moved
UMC is a foundry A company that manufactures chips to other firms' designs. It earns money from making, not from selling the final product.: it makes chips that other companies design. Once a month it reports how much it sold, long before the full accounts arrive. September 2026 revenue The money a company takes in from selling things, before any costs are taken out. It is not profit. set the highest monthly figure on the chart below.
Glossary
- foundry
- A company that manufactures chips to other firms' designs. It earns money from making, not from selling the final product.
- revenue
- The money a company takes in from selling things, before any costs are taken out. It is not profit.
Data table
| period | revenue | yoy |
|---|---|---|
| 2024-10 | NT$21.4bn | 11.4% |
| 2024-11 | NT$20.0bn | 6.7% |
| 2024-12 | NT$19.0bn | 11.7% |
| 2025-01 | NT$19.8bn | 4.2% |
| 2025-02 | NT$18.2bn | 4.3% |
| 2025-03 | NT$19.9bn | 9.3% |
| 2025-04 | NT$20.5bn | 3.6% |
| 2025-05 | NT$19.5bn | -0.2% |
| 2025-06 | NT$18.8bn | 7.3% |
| 2025-07 | NT$20.0bn | -4.1% |
| 2025-08 | NT$19.2bn | -7.2% |
| 2025-09 | NT$19.9bn | 5.2% |
| 2025-10 | NT$21.3bn | -0.4% |
| 2025-11 | NT$21.2bn | 5.9% |
| 2025-12 | NT$19.3bn | 1.7% |
| 2026-01 | NT$20.9bn | 5.3% |
| 2026-02 | NT$19.3bn | 6.3% |
| 2026-03 | NT$20.8bn | 4.9% |
| 2026-04 | NT$22.7bn | 10.8% |
| 2026-05 | NT$22.9bn | 17.8% |
| 2026-06 | NT$23.1bn | 22.9% |
| 2026-07 | NT$23.8bn | 19.0% |
| 2026-08 | NT$25.0bn | 30.7% |
| 2026-09 | NT$25.4bn | 27.2% |
Against August, that is a gain of just 1.2%. Against the same month of 2025, the jump is 27.2%, and that is the number the headlines picked up. One catch sits in the same chart: the yearly growth line is lower in September 2026 than at its peak in August 2026, so the growth rate itself eased even as sales set a high. For the first nine months of 2026, the running total is 16.1% bigger than the same stretch of last year. So the year is clearly bigger, while the month itself hardly moved.
Slower than its neighbours, and the stock drifted in the same window
One month on its own tells you little. The useful trick is to look at the neighbours in the very same month. The middle peer in the group grew 54.6% in the same month. UMC's 27.2% sits well below that. The gap to that middle peer is -27.4 pp. The comparison uses 3 peers, so one unusual month at one company can shift the middle.
How fast did the middle company in UMC's peer group grow its sales that month, versus a year earlier?
Actual54.6%
The middle peer in the group grew 54.6% in the same month. That is the surprise: a growth number that reads as strong on its own can be the slow one in the room.
Show answer
54.6% The middle peer in the group grew 54.6% in the same month. That is the surprise: a growth number that reads as strong on its own can be the slow one in the room.
Data table
| day | series | value | series_role |
|---|---|---|---|
| -5 | UMC | 0.7% | target |
| -4 | UMC | 5.2% | target |
| -3 | UMC | 5.2% | target |
| -2 | UMC | -0.7% | target |
| -1 | UMC | -3.9% | target |
| 0 | UMC | -3.3% | target |
| 1 | UMC | -3.9% | target |
| 2 | UMC | -5.2% | target |
| 3 | UMC | -7.8% | target |
| 4 | UMC | -7.5% | target |
| 5 | UMC | -13.0% | target |
| -5 | Peer basket | 1.9% | peer |
| -4 | Peer basket | 2.6% | peer |
| -3 | Peer basket | 3.9% | peer |
| -2 | Peer basket | 4.0% | peer |
| -1 | Peer basket | 4.8% | peer |
| 0 | Peer basket | 3.8% | peer |
| 1 | Peer basket | 2.5% | peer |
| 2 | Peer basket | 1.0% | peer |
| 3 | Peer basket | -2.6% | peer |
| 4 | Peer basket | -0.7% | peer |
| 5 | Peer basket | -6.4% | peer |
| -5 | Cumulative abnormal return | -1.3% | neutral |
| -4 | Cumulative abnormal return | 2.6% | neutral |
| -3 | Cumulative abnormal return | 1.4% | neutral |
| -2 | Cumulative abnormal return | -4.4% | neutral |
| -1 | Cumulative abnormal return | -8.4% | neutral |
| 0 | Cumulative abnormal return | -6.8% | neutral |
| 1 | Cumulative abnormal return | -6.2% | neutral |
| 2 | Cumulative abnormal return | -6.1% | neutral |
| 3 | Cumulative abnormal return | -5.2% | neutral |
| 4 | Cumulative abnormal return | -6.8% | neutral |
| 5 | Cumulative abnormal return | -7.1% | neutral |
The chart tracks UMC against a basket of 3 peers in the days around the announcement. In the five trading days before the release, UMC trailed that basket by -8.4%. On announcement day itself it sat 1.6% ahead of the basket. Counting from announcement day onward, UMC was 1.3% ahead of the basket, so the picture after the news is not the picture before it. Only 6 trading days from day zero are in the data, and a price path in the same window tells you nothing about cause. My reading is that the order rush in this cycle is landing hardest somewhere other than UMC's mix of older chip lines.
The quarter shows what the month cannot: better margins
Revenue says nothing about profit. The quarterly accounts, which run through 2026Q3, the last period available, fill that gap. Gross margin The share of sales left after the direct cost of making the product. Higher means each sale carries more money. was 34.0% in 2026Q3. Operating margin The share of sales left after making costs and running costs such as research and admin. was 25.1%. Operating margin was 3.4 pp higher than in the quarter before.
Glossary
- Gross margin
- The share of sales left after the direct cost of making the product. Higher means each sale carries more money.
- Operating margin
- The share of sales left after making costs and running costs such as research and admin.
So a quiet month sits on top of a quarter in which more of each dollar of sales stayed inside the company. For a beginner the lesson is plain: a monthly sales figure counts orders, it does not tell you how profitable those orders were. Keep an eye on the gross margin line in the next quarterly report, and on whether the yearly growth number closes the distance to the peer group.
Risks
- Monthly revenue is unaudited and can be restated later.
- One month is noisy: shipment timing and currency moves swing it.
- The peer group is small and not identical, so the comparison carries limited weight.
Sources
- FinMind 月營收 2303（原始來源：公開資訊觀測站 營收公告） — data as of 2026-09-30; fetched 2026-11-05 19:21 UTC; License note: FinMind open data; original source MOPS (公開資訊觀測站)
- 臺灣證券交易所 個股日成交資訊 6770 — data as of 2026-10-21; fetched 2026-11-05 19:22 UTC
- 臺灣證券交易所 個股日成交資訊 2330 — data as of 2026-10-21; fetched 2026-11-05 19:22 UTC
- 臺灣證券交易所 個股日成交資訊 2303 — data as of 2026-10-21; fetched 2026-11-05 19:22 UTC
- 證券櫃檯買賣中心 個股日成交資訊 5347 — data as of 2026-10-21; fetched 2026-11-05 19:22 UTC