I’d argue that’s reversing cause and effect. A cratering economy on Main Street often gets reflected as a crash on Wall Street.

Sometimes the outcomes diverge. One common analogy in finance circles is that the stock market is like a hyperactive puppy on a long leash being walked by a slow owner whose gradual movements trend in a particular direction while the puppy erratically moves back and forth near that owner. Maybe it’s some kind of hype or panic moving markets in a way that’s uncorrelated with the underlying economic activity. Or it’s a specific play on a specific type of financial instrument that has become untethered from a thing it used to be tightly wound up with. Many financial panics happen when correlations between things break down, and all the financial engineering in a particular type of product relied on a bad assumption so that it spreads to other financial products.

But in many cases, they move together because the people buying and selling stocks feel sentiment driven by actual economic fundamentals.