I spent the weekend in Shanghai taking in the excitement of Alibaba’s (BABA) Singles Day, where online sales rocketed to a new record of $30.8 billion—exceeding the $19.6 billion Americans spent between Thanksgiving and Cyber Monday last year plus the $4 billion they spent on Amazon’s (AMZN) June 16 Prime Day combined. Alibaba executives hailed that result as proof that China’s economy is doing just fine, thank you, and that its consumers don’t care about the escalating U.S.-China trade war. And there was some good news for Apple, which emerged as the top-selling smartphone brand on Alibaba’s platform during the festival, eclipsing Chinese rivals including Huawei and Xiaomi.

And yet, by Monday, Apple’s (AAPL) share price was tanking, dragging the Dow down 600 points and triggering a selloff in Asia. The source of the scare was Lumentum, a key Apple supplier of facial recognition technology, which cut its quarterly profit outlook, citing reduced demand from a major customer. That triggered fears that Apple sales are faltering going into the holiday season. Other Apple suppliers, including Foxconn, Japanese parts manufacturers TDK and Taiyo Yuden, tumbled in tandem.

Monday night brought a glimmer of hope, as the Wall Street Journal reported that Treasury Secretary Steven Mnuchin had resumed discussions with China’s top negotiator Liu He about a possible U.S.-China trade deal. The two men spoke by telephone Friday, according to the Journal. In Hong Kong Tuesday, the South China Morning Post reported that Liu He had reinstated a scuttled plan to visit the U.S. for trade talks.

As I write, Wednesday midday in Hong Kong, Chinese markets are drifting lower as investors try to figure out what’s going on. All eyes are on the Group of 20 summit in Buenos Aires at the end of this month, where presidents Trump and Xi are slated to meet for dinner. Trump may be in the stronger bargaining position. But it’s hard to imagine how the Chinese leader could accede to all of the demands set forth by the White House—particularly the U.S. demand that Xi dismantle his signature “Made in China 2025” initiative for upgrading China’s technological capabilities. Adding to the uncertainty: Trump’s own economic advisers remain deeply divided about the value of a trade truce.

China’s leaders had hoped Trump would be keener for a deal in the aftermath of Republican mid-term losses, but it’s far from clear Trump himself sees it that way. To date, he has shown few signs of concern about the economic pain higher tariffs on China will inflict on the U.S. economy. If nothing else, the week’s developments offer fresh evidence of how interdependent the two economies have become; how tightly matters of technology, trade, and global markets remain intertwined; and how high the stakes of a protracted stalemate have grown.