Let's take Disney stock for example:
Go to https://www.google.com/finance and search for Disney.
If I change the date range to 5 year, on October 20, 2023, the volume was 55 million. But if I change the date range to 6 months, on October 20, 2023, the volume was 10 million.
And this occurs to every different stock I've looked at. Why the discrepancy?