Actually there are many reasons not to sell. If someone is offering billions and you think it's worth millions, then either you're right and the buyer is wrong,

Actually there are many reasons not to sell. If someone is offering billions and you think it's worth millions, then either you're right and the buyer is wrong, or the buyer is right and you're wrong. Or the buyer wants to make a risky play on the business you don't think is right. Maybe the buyer is offering illiquid stock or something. In any case, if you enjoy the business you have, and feel it is making enough money, then why would you sell it? It's risky to sell, it could be a mistake for various reasons, seen and unforseen. You're putting your baby in someone else's hands and you will have to find a new job. So that's a big change already. There are many reasons you would want to sell too, of course. Just saying it's not clear cut just because of valuations.