(refers to US) To short stocks your broker borrows shares on your behalf and sells them for you. You will pay an amount in lieu of dividends on dividend dates. If you're an institutional investor you will be credited interest, but most brokers pocket it for retail. If its an illiquid stock, your broker may be unable to locate the borrow, or if they do find shares, may have to give them back at little or no notice. (i.e. close out your short by buying shares and giving them back to the lender). It's normally not possible to short shares less than $5. Shorting exposes you to theoretically unlimited risk since a long position can only go to zero, wheras a stock can double or more. The uptick rule applies to common stock, but ETF's like QQQ are exempt I believe. Generally, You should be very comfortable with the ins and outs of investing long before you think of shorting. Price patterns are also very different on the short side - a whole different world for technical analysis. The key in shorting is to have a broker with a good access to shares to borrow - as noted, IB do a good job on this, but any of the larger frims should be fine. But only short liquid stocks.