Hey @BernardLunn I think some of the reasons behind this is investment guidelines which Institutional investors think/believe are smart to follow. Some of these are actual legal guidelines, like mutual funds are not allowed to invest in a company until it has reached a certain size.
I forget the exact detail, but when I traded for Fidelity, there was some rule and the number 5 is stuck in my head. So It may have been $50 million revenue, or market cap, or something else. This prevents funds from investing in penny stocks.
There are other guidelines like “we dont invest in seed stage” which I have heard way more than is pleasing. This also makes little sense, because these investors are seeking high returns, but dont want to take risk. Which is like looking for gravity that makes you float. It does not exist.
I can easily see an unofficial guideline with thinking like, “If it is over 2 billion in market cap, and we need to dump, there should be enough order flow for us to unload a rather large position”. or some other idea about Risk decreasing after hitting that threshold. Keen observation any which way.