Not only does it make sense from a mean scenario, but it makes sense from a human scenario too. When i see a company like Tesla skyrocket to 700, every day that it posts a 10% gain i think it's at the end of it's rally. Eventually, the firm gets way too hot and pressure to buy cools down. Market cap is just how much people are willing to pay for something * outstanding shares. If suddenly everyone thinks the rally has gone on too long, buying pressure ceeds and thus market cap/ stock price.