The reason for the weekend crash may be this: yesterday (May 30), Trump posted on Truth Social

Trump: "Some time ago, we imposed tariffs on China, which almost destroyed China. I softened my stance and quickly reconciled with China, but now China is not being honest, and I regret it."

Google Translate is as follows:

Two weeks ago, China was in serious economic danger! The very high tariffs I set made it almost impossible for China to export to the U.S. market, which is the largest market in the world. We actually severed ties with China, which is devastating for them. Many factories have closed, and to say the least, there is 'public discontent boiling over.' I see what is happening, and I don't like it, not for us but for them. I reached a quick agreement with China to save them from what I thought would be a very bad situation, and I didn’t want to see that happen. Thanks to that agreement, everything stabilized quickly, and China returned to normal business. Everyone was happy! This is good news!!! The bad news is that China, perhaps not surprisingly to some, completely violated the agreement we had. Never mind, kind sir!