First you must be able to explain, at least to yourself, why you are certain that the stock price of the company is going to go down, and why it will do that far enough and fast enough to be worth the risk. It happens, don't misunderstand, just not all the time.
If you're over that hurdle, then it matters whether or not your brokerage firm allows margin (I'll explain) and if so, whether or not your account is set up properly to accommodate that.
Margin is the brokerage industry's word when a customer wants to borrow against their own assets without necessarily selling them. This is a website, so I'll avoid the details, but I can explain it all thoroughly to anyone who wants it. Not all brokerage firms even allow it, but when they do, it's a loan, and you'll pay interest on it. Plus, you have to be willing to accept the risk that your loss is potentially infinite.
When you buy "long", that is, you buy a stock with the hope that it goes up in price like most people, the worst thing that could happen is that you lose everything you put into it if the value goes to zero.
When you buy "short", then if the price goes up you're losing money, and theoretically it could go up forever and your losses would become yuuuuuuuge (as they say).
If you're still interested, we should talk a bit (for free). I focus on education and collaboration to help people deal with these things with all the professional expertise except the price tag. And I give customers the same professional tools that are usually limited to the yacht-owner crowd. Let me know!
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