If you’re investing more than a few percent of your portfolio in any one company, you’re probably gambling though.
I read a forum post many years ago about people that put all their retirement money into some company that was going to be the sole supplier for some components for the iPhone. Apple didn’t end up going with them, and the company was relying entirely on that contract. The company went bankrupt, and the people that invested lost all their money.
In the end, why invest in a small number of companies when you can invest in practically all of them? Bogleheads three fund portfolio (total US stock + total world stock + bonds) is very simple yet will beat most actively-managed portfolios over the long run.
The market is wild sometimes. I work for a fairly large company. Sometimes in our earnings reports, we exceed EPS and revenue expectations (which is good of course), but don’t exceed them as much as some analysts think we’ll exceed them, so the stock goes down. The expectation is that we’ll always exceed the expectations lol