Cook in November had cited slowing growth in emerging markets such as Brazil, India and Russian Federation when Apple gave first-quarter sales estimates that were lower than expected.
It is rare to hear that iPhone buyers prefer to replace their battery rather than upgrade to a new iPhone, which of course also suggests the converse - that Apple has been benefitting from the throttling of older iPhones and the high cost of replacing their batteries to drive sales.
Apple shares fell 10 percent in New York Thursday, the biggest drop in nearly six years, after the warning.
Trading in the company's shares were temporarily halted as Tim Cook, Apple's chief executive, issued a letter to shareholders explaining the reason for the change. This comes a day after CEO Tim Cook announced a revision to Apple's revenue guidance for the last quarter of 2018. He's also long warned investors against selling Apple's stock. The new iPhone XS, XS Max, and XR began shipping in Q4 2018, leading to fewer sales to be counted in the first quarter of 2019. Well according to Cook, it has something to do with the "economic deceleration" in China amongst other parts of the world. "The iPhone is something that everyone knows and buys, and if people aren't buying it, then it's a pretty good sign they're having a hard time".
Apple isn't the only company facing difficulties in a slowing Chinese economy and escalating trade tensions.
China's Commerce Ministry said talks will be held Monday and Tuesday in Beijing, and market watchers are hoping for signs the world's largest economic powers will make progress toward resolving their dispute.
"It's not going to be just Apple", CEA chairman Kevin Hassett said in an interview on CNN.
Many analysts and investors had anxious about a slowdown in iPhone sales since the company said in November it would stop disclosing unit sales data for its phones and other hardware products.
Hal Eddins, chief economist at Apple shareholder Capital Investment Counsel, said Cook's comments on the impact of the U.S. trade tensions with China "might be a dig at (U.S. President Donald) Trump, but mostly he may be using the trade turmoil as an excuse for some missteps they've made over the past year".
The timing of Apple's announcement blaming its shortcomings partly on President Donald Trump's trade war with China may increase pressure on American officials to ease the tensions quickly.
While iPhone revenue accounted for the forecast cut, Apple's other product categories, including the iPad and services, grew a combined 19 percent year-over-year, he said.
According to that report, most analysts had expected Apple to pull in $91.3 billion in revenue during the Holiday quarter - which is ~$7.3 billion more than Cook's updated estimates.
Apple's decision to cut its sales outlook, "isn't a huge shock at this point", said Shannon Cross of Cross Research.
One thing Cook didn't mention in his letter is Apple's declining market share in China and the rise of domestic rivals like Huawei and Oppo.