system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we have so many different stock markets? Why not just have one?
gpt
I can answer this.

In simple terms, stock markets today are businesses. They provide the meeting place, they provide the market information and they provide the rules and enforcement.  So for every trade that goes through they charge a tiny portion that covers that infrastructure and then some.  They charge the stock brokers you buy your shares through, they charge the traders etc.

Now, each of these meeting places, the information services and the rules are all slightly different for each market.  It starts to get a bit more technical, but NYSE operates differently to NASDAQ in matching buyers and sellers.  The NYSE is what we call an auction market, while NASDAQ is a dealer's market.  When you buy stocks on NYSE you are trading directly with another seller, but when you buy or sell through NASDAQ you are actually buying from NASDAQ who acts as a middleman, who keeps a stockpile of company shares ready to be bought and sold.  

There are different characteristics why some traders prefer one over the other, but consider this: When you buy a birthday gift, sometimes you can plan ahead and shop around to get the best price, but sometimes you need it immediately.  Same things with shares. Some traders just need the stock immediately, whereas some think they know what is a fair price and will wait until someone can deliver it at that price.  This is what we refer to as 'best execution'.

The next question is where do you want to raise money? Companies list their shares to raise funds, and if you are a German company it probably makes more sense to list in Frankfurt than in New York, as that's where people likely to know and be interested in your company are from.  You want a market where people are going to actively trade your stock because this would ensure it is liquid, and someone can't just squeeze the price of your shares.

Also, what if you're a company and don't want to comply with strict disclosure rules, maybe you can list on a different exchange with more relaxed rules.

**TL;DR** We have different stockmarkets because they provide different services, and companies generally list where they can raise the most money.