Conflicting growth figures leave open whether TSMC's record quarter sped up

The two reported growth rates for TSMC's record quarter imply two different year-ago quarters ^[17][18]. NT$1.49 trillion ^[1] divided by 1.39 puts the third quarter of 2025 near NT$1.07 trillion ^[19]. Divided by 1.51, it comes out near NT$987 billion ^[20]. They cannot both be right. TSMC's own comparison with the year-ago quarter, due with full results on the 15th, will show which one is ^[4].

The difference matters because of the nine-month figure. Revenue for January through September rose 41.1% ^[7], and that rate is a weighted blend of first-half growth and third-quarter growth. A third quarter growing 39% sits below the blend, so the first half grew faster and the third quarter slowed ^[21]. A third quarter growing 51% sits above it, so the first half grew more slowly and the quarter sped up ^[21].

September can be read two ways. Its 54.6% rise implies September 2025 revenue of about NT$331 billion ^[12]. The quarterly figure is the sum of three monthly figures ^[5], so what is left of each year-ago quarter belongs to July and August. On the 39% figure, those two months grew about 32% combined, and September then jumped far ahead of them ^[22]. On the 51% figure, July and August grew about 49% and September ran a little faster ^[23]. The second path is the smoother one, and it is the figure Seoul Economic Daily attributed to Bloomberg and CNBC, while Quartz's 39% was its own calculation from the filing ^[18][17]. I think 51% is the more likely figure, and on that figure demand sped up through the quarter. A year-ago base near NT$1.07 trillion in TSMC's results would prove that wrong ^[19].

Against that, the September dip is small. August revenue works out to about NT$515 billion ^[13], so the 0.6% decline is roughly NT$3 billion ^[14]. Take August and September out of the quarterly total and July comes to about NT$463 billion ^[15]. Because the quarterly total is rounded, that estimate could be off by a few billion. Revenue rose about 11% from July to August and stayed close to that level in September ^[16].

TSMC shares fell 1.35% on Thursday before the figures were published ^[8], so that close reflected none of them. According to Seoul Economic Daily, investors want to hear about next year's equipment spending and pricing for advanced chips on the 15th ^[6]. Much of the spending is going to the US. TSMC has committed $265 billion to its Arizona manufacturing hub and is weighing further expansion in Texas ^[9].