iPhone sales in China are lagging, causing concern, and Apple (AAPL.US) stock experienced its largest one-day decline since early August.

Apple's (AAPL.US) stock price plunged more than 4% on Thursday, marking its biggest single-day drop since August 5 last year, amid reports of weak iPhone sales in China. This performance was closely linked to several reports on the sluggish iPhone sales in China. As of now, Apple's stock has plummeted nearly 12% from its recent high in December last year, becoming one of the worst performers among the top seven tech stocks in 2025. Market research firm Canalys reported in a report released on Thursday that Apple's smartphone sales in China have slipped to third place, behind local vendors Vivo and Huawei. According to the report, Apple sold 15% of the smartphones in China last year, totaling 284 million units, down 17% year-on-year. In contrast, Vivo and Huawei saw strong growth in their sales. Taiwan Semiconductor Manufacturing Company (TSMC.US), a major supplier for Apple, released its forecast for smartphone sales in the first quarter of 2025 on Thursday, expecting a nearly 6% decline from the previous quarter. TSMC, which produces core chips for Apple devices, attributed the decline to seasonal factors. In addition, TSMC said that more than half of its fourth-quarter revenue came from AI chips, not the smartphone business that used to account for the largest share. Renowned Apple supply chain analyst Ming-Chi Kuo said on Monday that he expects a 6% year-on-year decline in iPhone shipments in the first half of 2025, with the biggest drop in the second quarter. He noted that Apple's AI system "Apple Intelligence" has not yet been launched in China, failing to stimulate demand for iPhones. Kuo wrote in his report: "There is no evidence that 'Apple Intelligence' can promote the hardware replacement cycle or service business growth." Apple plans to release its fourth-quarter (ended in December) 2024 earnings report on January 30. As concerns about iPhone sales and supply chain performance intensify, investors will closely monitor the report to assess Apple's future performance trends.