Semiconductors · Information cutoff: October 10, 2026, 12:29 UTC · September release: October 8
TSMC’s September revenue fell 0.6% from August, yet its July–September total reached a record. Both statements can hold because the monthly change measures one step, while the quarter adds three elevated sales levels. The more useful question is whether September meaningfully weakened that larger total.
The October 8 company release puts September consolidated revenue at approximately NT$511.86 billion, up 54.6% from September 2025. Its SEC filing gives the underlying monthly figures. The calculations below use those published New Taiwan dollar amounts; no exchange-rate conversion is needed.
Read the monthly and quarterly views together
Two time windows, two scales
Consolidated revenue, NT$ billions. Each panel starts at zero; the monthly and quarterly panels use different scales.
Monthly scale: 0–550 billion. August to September: −2.949 billion.
Quarterly scale: 0–1,600 billion. Q2 to Q3: +223.862 billion.
The three Q3 months sum to NT$1.494243 trillion, 17.62% above Q2’s NT$1.270381 trillion. TSMC’s second-quarter results report that earlier quarter at a rounded NT$1.27038 trillion. A quarter can therefore grow strongly even when its final month fails to exceed the immediately preceding month.
An average gives another way to understand the comparison. Dividing both quarterly totals by three leaves their percentage difference unchanged. It expresses the same information as a typical monthly sales level, without pretending that any individual month actually produced that amount. This is especially useful when a headline switches between monthly and quarterly figures.
How much can one month change a quarter?
Holding September flat to August would give NT$1.497192 trillion for Q3; actual sales were 0.20% below that hypothetical total. Keeping the other two months unchanged isolates the arithmetic effect of the last monthly step. This is a sensitivity calculation, not a forecast or an estimate of sales that should have occurred.
The comparison helps discipline the headline. A negative monthly percentage can attract attention even when it moves the completed quarter only slightly. Conversely, a record quarterly total cannot establish that momentum accelerated throughout the quarter. Here, the evidence supports a strong aggregate sales level followed by a nearly flat final month; the sales series alone cannot identify the operational reason for that pattern.
For the longer comparison, TSMC’s approved Q3 2025 figures report NT$989.92 billion of revenue. That baseline belongs to the same calendar quarter a year earlier. It answers a different question from September’s 54.6% year-over-year growth, which compares just one month in each year. Keeping the denominator attached to each rate prevents attributing one window’s performance to another.
Open the complete inputs and calculation table
Amounts below are in NT$ millions. Growth equals (new amount ÷ comparison amount − 1) × 100. Rounded monthly inputs can differ slightly from later quarterly statements.
| Item | Amount or formula | Result / status |
|---|---|---|
| April 2026 | 410,726 | Reported |
| May 2026 | 416,975 | Reported |
| June 2026 | 442,680 | Reported |
| July 2026 | 467,580 | Reported |
| August 2026 | 514,806 | Reported |
| September 2026 | 511,857 | Reported |
| Q2 2026 monthly sum | 410,726 + 416,975 + 442,680 | 1,270,381 |
| Q3 2026 monthly sum | 467,580 + 514,806 + 511,857 | 1,494,243 |
| Quarterly increase | 1,494,243 − 1,270,381 | 223,862; +17.62% |
| September monthly change | 511,857 − 514,806 | −2,949; −0.57% (company: −0.6%) |
| Q3 2025 baseline | 989,920 | Converted from rounded NT$989.92bn |
| September-flat scenario | 467,580 + 514,806 + 514,806 | 1,497,192; hypothetical |
| Gap below flat scenario | 2,949 ÷ 1,497,192 × 100 | 0.20% |
Inputs: 2026 monthly table, September SEC filing and Q3 2025 board-approved revenue.
What the record does, and does not, establish
CNA’s October 8 report identifies Q3 as a record quarter and attributes the performance to AI demand and smartphone-related orders, citing analysts. Those explanations provide industry context. The monthly revenue disclosure itself does not separate the contribution of AI, smartphones, pricing, unit shipments or currency translation, so it cannot quantify which driver mattered most.
That distinction matters for anyone following the semiconductor cycle. Strong foundry sales can coexist with very different conditions across customers and end markets. One company’s consolidated revenue is a useful observation, but it cannot establish that every chip segment is expanding at the same rate. A convincing demand argument needs segment evidence as well as the headline total.
The next analytical step is to connect sales with costs and cash generation when the fuller quarterly information is available. Revenue growth does not mechanically translate into equal profit growth: manufacturing costs, depreciation and the mix of products can change the conversion. This article therefore draws no conclusion about Q3 earnings, margins or a fair share price from the monthly series.
Does revenue settle an investment question?
It establishes the scale of reported sales, subject to the unaudited status of the monthly inputs. An investment judgment also needs valuation, profitability, capital spending, cash generation and risks. None can be replaced by choosing whichever growth rate looks strongest. Keep the reporting currency, time window and comparison base visible before comparing companies or drawing conclusions about future returns.
The practical takeaway is to read three layers together: the latest month, the completed quarter and the matching period a year earlier. For TSMC, a small sequential monthly decline sits inside a much stronger quarterly sales picture. That resolves the apparent contradiction while leaving the causes and financial consequences open to the evidence that can actually answer them.
Source dates: September revenue and CNA report, October 8, 2026; Q2 results, July 16, 2026; approved Q3 2025 baseline, November 11, 2025. Calculations use consolidated revenue and retain the original reporting currency. General financial analysis, not personalized investment advice.
