Last week, President Trump issued a ban on transactions with TikTok parent ByteDance and Chinese tech juggernaut Tencent (TCEHY 1.92%), citing national security concerns regarding the collection of user data. There are many lingering questions about exactly how the ban will be implemented or what types of transactions are actually included, particularly as Tencent holds investments in a broad range of U.S. companies including Tesla, Activision Blizzard, and Snap, among others.

The ban could also potentially have devastating effects on Apple (AAPL 1.30%).

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iPhone shipments could decline by 25% to 30%

Tencent's WeChat messaging platform is ubiquitous in China, providing everything from communications to digital payments to local e-commerce to news aggregation. Users can even use the service to pay their monthly utility bills for water or electricity or use customer relationship management (CRM) features for their business. The extensive list has made WeChat indispensable to many Chinese consumers and businesses.

Banning transactions with WeChat could potentially neuter the iPhone in the largest smartphone market in the world, according to a recent note from widely followed TF International Securities analyst Ming-Chi Kuo (via MacRumors). That could result in iPhone unit volumes getting decimated.

"Since WeChat is very critical to Chinese users, integrating communications, payments, e-Commerce, social software, news reading, and productivity functions, we believe that the move will tank ‌iPhone‌ shipments in the Chinese market," Kuo wrote in a research note to investors over the weekend. "We estimate that global ‌iPhone‌ shipments will decline by 25–30%."

Additionally, shipments of other product categories could also take a hit of 15% to 25%, according to Kuo, since Apple gadgets lean heavily on each other to create an ecosystem of products and services. That would include AirPods, iPads, Macs, and Apple Watch.

There are a variety of theoretical outcomes because details of the ban remain unclear. The Secretary of Commerce has until Sept. 20 to define what types of transactions are to be prohibited, according to the executive order, and it's still possible that the order could be rescinded before then. If WeChat is only banned in the U.S. App Store, worldwide iPhone unit volumes might decline by only 3% to 6%, in Kuo's estimation. The impact to other products would be less than 3% in that scenario.

China is one of Apple's most important markets, representing approximately 16% of the Cupertino tech giant's total trailing-12-month (TTM) revenue. Apple is no stranger to being caught in the crossfire of escalating geopolitical tensions with China. Thus far, the Mac maker has done a pretty good job of navigating those challenges, including diversifying its supply chain and scoring tariff exemptions in exchange for agreeing to manufacture the Mac Pro in the U.S.

Can Apple escape relatively unscathed again?