On the heels of a recent rally, Apple (AAPL +0.64%) stock's market capitalization climbed above the $4 trillion level for the first time in the company's history this week. As of this writing, Apple's market cap is now ahead of Microsoft's, which just dipped back to just below $4 trillion. Meanwhile, Nvidia is sitting at the top of the heap with a market cap of approximately $4.95 trillion, having fallen back a bit after topping $5 trillion earlier in the week.

NASDAQ: AAPL
Key Data Points
In addition to news of strong sales for the company's iPhone 17 lines, there's another huge catalyst that has helped Apple's valuation surge to a new all-time high, with the company joining the illustrious ranks of the $4 trillion club.
Image source: Apple.
Apple is surging on improved China outlook
Over the last week, President Donald Trump and administration officials have made comments suggesting that it's likely that the U.S. will be able to reach a trade agreement with China in the near future. If so, that would be great news for Apple.
Tense relations between the U.S. and China have contributed to relatively sluggish sales performance for Apple's hardware in the Chinese market as shoppers in the territory have increasingly opted for domestic brands. While Apple is making big investment commitments to expand its manufacturing capabilities in the U.S., the tech giant still relies on Chinese factories for a large percentage of its hardware manufacturing. As a result, the company stands to face some significant headwinds if high tariffs remain in place.
With signs that tensions between the U.S. and China could de-escalate in the near term, some of the biggest potential headwinds facing Apple could be alleviated. On the other hand, investors should keep in mind that there is still the potential for unfavorable twists and turns when it comes to U.S.-China relations -- and Apple could face valuation volatility if signs emerge that the dynamic is souring again.