Stocks Returned 3.33% Less During Mercury Retrograde. Coincidence or a Real Pattern?

I came across a finance paper that claimed stock returns were around 3.33% lower during Mercury Retrograde, so I pulled up the chart.

The weird part isn't astrology.

It's that every grey zone (Mercury Retrograde period) seems to line up with noticeable slowdowns or dips. Not perfectly. Not every time. But enough to make you stop scrolling and actually look.

Fewer new buyers means fewer people pushing prices up. So prices simply drift till the Mercury Retrograde period ends.

Now here's the real question:

Is this...

a genuine seasonal/statistical anomaly?

pure data mining and coincidence?

or just another reminder that humans are excellent at finding patterns where none exist?

As traders, we're always looking for edges. Sometimes they come from macro data, sometimes from market structure, and sometimes from research that sounds completely ridiculous.

The only thing that matters is:

Does it hold up when you test it? Especially with AI picking up every tiny detail and the way traders approach markets changing so quickly. If everyone has access to the same information, is it even an edge anymore?

What's the strangest market "edge" you've ever tested that actually surprised you?