system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How does the stock market work?
gpt
Imagine that you own a company that makes shoes. You're selling a lot of shoes, and you're doing pretty well for yourself. But, you just don't have a big enough factory for all the shoes you need to be making to keep up with demand. You need to buy/build a bigger factory! But, that is going to cost a LOT of money. More than you have right now. So, you would like to raise some money, right? Well, this is how you do it. You offer shares/stock of ownership in your company. People give you money in return for a small slice of ownership in your company. That means they get a very small vote in how things are run, and possibly a small amount of the profit that you make every so often. But, it's worth it for you, because you are getting a lot of money from that person right this instant, so it's a fair tradeoff as far as you are concerned. Now, people know that your company is doing very well, so LOTS of people want to buy a stake of ownership in your company. Those new stockholders are giving you TONS of money, in return for a fairly small share of your company. You've raised enough money for that new factory! You're going to produce so many shoes now! Things look super bright for your future! That means that even MORE people want to buy a stake in your company, but here's the problem...You aren't offering any more stakes in your company. You've made your money, and you're not selling shares anymore. So, what happens? Those newcomers ask the people who already have shares of your company if they would like to sell them. So now you have people with shares trying to make a profit by selling their shares to people who don't have shares, but would like to buy some. The better that your company is doing, the more people want to buy shares, which means that the people who already have shares can sell them for a LOT of money, and make a good profit. The prices of the shares are skyrocketing!. But if your company is doing badly, not as many people want those stocks anymore, and the shareholders need to price their shares at a lower price to get anyone to buy them.

That's how the price of stock goes up and down. It depends on how the demand of how many people want to buy stock. If demand is high, price goes up, if demand is low, price goes down.

Basically.