The swing in the stock price every day is fueled by supply and demand. The stock goes up 20c because the only person selling it wants a little more than the last sale price. It goes down 20c when someone wants to sell at the last price but the only people willing to pay that much already bought their shares. And that's not even including what happens to stop and limit orders that trigger automatically when the stock swings just a little bit farther than people anticipated. Just a small shift changes the slope of the price trend, which may cause people to shift demand away from that stock.
These days, when I'm mostly hands-off with my portfolio, more of my orders expire than actually trigger. Sometimes only just missing having done so.
It's part of the magic thinking about the stock market. We don't often discuss it in this sort of thread, but we definitely do when people are talking about HFT and AI for stock purchases and sales. Your orders don't happen in a vacuum, and they can affect future orders.
Bill, as I recall, had a much larger percentage of MSFT when he retired. Microsoft used to dilute their shares via employee stock grants, so I'm not sure how much of that is attrition and how much is divestiture on his part. One source on the internet says he was estimated to owns 4.3% as recently as two years ago. And I see another article from March of last year talking about him leaving the board of directors, and owning 1.36%.
I wonder if anyone has analyzed how much of the MSFT stock stagnation that occurred after his retirement could be attributed to his divestiture plan, rather than Ballmer's fault.