What happened?
Asia-based chip maker Taiwan Semiconductor (NYSE:TSM), a key supplier to Apple (NASDAQ:AAPL), announced its results for Q4 and fiscal 2015. For the quarter, the company's consolidated revenue amounted to just over NT$203 billion ($6.0 billion), a 9% drop from the same period of 2014. Net profit was down by roughly the same percentage, landing at NT$73 billion ($2.2 billion). The bottom-line figure beat the average analyst estimate of just over $2 billion, although the top-line figure slightly missed expectations.

For the full year, the company's revenue was NT$844 billion ($25.1 billion), with net profit coming in at $9.2 billion on a U.S. dollar basis. Those numbers were up 11% and 16%, respectively, higher on a year-over-year basis.

Taiwan Semiconductor also provided guidance for its current Q1. The company anticipates it will post revenue between NT$198 billion and NT$201 billion ($5.4 billion to $5.5 billion), with an operating profit margin of 36.5% to 38.5% (the Q4 figure was 38.3%).

The company attributed the declines to consumer reluctance, and implied that weakness in Asia's biggest market had a negative impact. CFO Lora Ho said that "[w]hile the China smartphone market shows signs of recovery, customers remain cautious in general."

Does it matter?
Apple is a large and very important fruit for Taiwan Semiconductor; the American tech giant was responsible for around 15% of the Asian company's revenue in fiscal 2015. The slump in iPhone sales is a key reason Taiwan Semiconductor saw dips in its top and bottom lines.

In light of that, the quarter's results shouldn't be taken as alarming and/or surprising (investors weren't spooked, judging by the fact that the stock dropped more or less in concert with broader indices). Firstly, on an annual basis, the company actually showed quite robust growth, and secondly, it's doubtful those quarterly declines will persist. Apple's iPhone 7 series is coming down the pipe, and like most new generations of the durably popular device, it's sure to sell well. And apparently, Taiwan Semiconductor will be a critical part of it; the latest rumors strongly suggest the company is the supplier of choice for the A10 chips that will power Apple's upcoming phones.