> I'm reading that companies are going to do better in the future and will see a rise in stock price, and it makes sense, so I sometimes buy them. I think that

> I'm reading that companies are going to do better in the future and will see a rise in stock price, and it makes sense, so I sometimes buy them. I think that way about my index funds too. But then it's impossible to know the reason for the price rise. Maybe it's because of millions of other guys like me who read the same articles, came to the same conclusion as me, and put their money in too.