How does the spread on an orderbook affect shorting?
A bid is an offer to buy something on an order book, so for example you may post an offer to buy one share, at $5. An ask is an offer to sell something on an order book, at a set price. For example you may post an offer to sell shares at $6. A trade happens when there are bids/asks that overlap each other, or are at the same price, so there is always a spread of at least one of the smallest currency unit the exchange allows. Betting that the price of an asset will go down, traditionally by borrowing some of that asset and then selling it, hoping to buy it back at a lower price and pocket the difference (minus interest). So, let's say as per your example you borrow 100 shares of company 'X', expecting the price of them to go down. You take your shares to the market and sell them - you make a market sell order (a market 'ask'). This matches against a bid and you receive a price of $5 per share. Now, let's pretend that you change your mind and you think the price is going to go up, you instantly regret your decision. In order to pay back the shares, you now need to buy back your shares as $6 - which is the price off the ask offers on the order book. Because of this spread, you have lost money. You sold at a low price and bought at a high price, meaning it costs you more money to repay your borrowed shares. So, when you are shorting you need the spread to be as tight as possible. It this a real situation or is it a made up example? Because for a stock that has a last traded priced of $5 or $6 and volume traded over $4M (i.e. it seems to be quite liquid), it is hardly likely that the difference from bid to ask would be as large as $1 (maybe for a stock that has volume of 4 to 5 thousand, but not for one having volume of 4 to 5 million). In regards to your question, if you were short selling the order would go in exactly the same as if you were selling a stock you owned. So your order would be on the ask side and would need to be matched up with a price on the bid side for there to be a trade.
To short a stock you actually borrow shares and sell them. The shorter gets the money from selling immediately, and pays interest for the share he borrows until he covers the short. The amount of interest varies depending on the stock. It's typically under 1% a year for large cap stocks, but can be 20% or more for small, illiquid, or heavily shorted stocks. In this scam only a few people own the shares that are lent to shorters, so they essentially have a monopoly and can set really high borrow costs. The shorter probably assumes that a pump-and-dump will crash quickly, so wouldn't mind paying a high borrow cost. This sometimes happens to me. It depends on how liquid the option is. Normally what I see happening is that the order book mutates itself around my order. I interpret this to mean that the order book is primarily market makers. They see a retail investor (me) come in and, since they don't have any interest in this illiquid option, they back off. Some other retail investor (or whatever) steps in with a market order, and we get matched up. I get a fill because I become the market maker for a brief while. On highly liquid options, buy limits at the bid tend to get swallowed because the market makers are working the spread. With very small orders (a contract or two) on very liquid options, I've had luck getting quick fills in the middle of the spread, which I attribute to MM's rebalancing their holdings on the cheap, although sometimes I like to think there's some other anal-retentive like me out there that hates to see such a lopsided book. :) I haven't noticed any particular tendency for this to happen more with puts or calls, or with buy vs sell transactions. For a while I had a suspicion that this was happening with strikes where IV didn't match IV of other strikes, but I never cared enough to chase it down as it was a minor part of my overall P/L. This has never really adequately explained it for me, and I've tried reading up on it all over the place. For a long time I thought that in a trade, the market maker pockets the spread *for that trade*, but that's not the case.  The only sensible explanation I've found (which I'm not going to give in full...) is that the market maker will provide liquidity by buying and selling trades they have no actual view on (short or long), and if the spread is higher, that contributes directly to the amount they make over time when they open and close positions they've made.  It would be great to see a single definitive example somewhere that shows how a market maker makes money. Fair enough. I would imagine the ETF could get a better option pricing if that were the case, plus liquidity and counterpart risk concerns but your point is well taken. Serves me right to shoot my mouth off on something I do not do (short).  Speaking of which, do you do a lot of shorting? Cover positions or speculation? 1) Explicitly, how a company's share price in the secondary market affects the company's operations. (Simply: How does it matter to a company that its share price drops?) I have a vague idea of the answer, but I'd like to see someone cover it in detail.  2) Negative yield curves, or bonds/bills with negative yields  Thanks! I don't think that the trading volume would impact a broker's ability to find shares to short.  You might think that a lot more people are trying to short a stock during regular trading hours than in the pre-market, and that's probably true.  But what's also true is that a lot more people are covering their shorts during regular trading hours than in the pre-market.  For stocks that have difficulty in finding shares to short, any time someone covers a short is an opportunity for you to enter a short. If you want to short a stock and your broker is rejecting your order because they can't find shares to short, then I would recommend that you continue placing that order throughout the day.  You might get lucky and submit one of those orders right after someone else has covered their short and before anyone else can enter a short.  I have had success doing this in the past. A bullish (or 'long') call spread is actually two separate option trades.  The A/B notation is, respectively, the strike price of each trade. The first 'leg' of the strategy, corresponding to B, is the sale of a call option at a strike price of B (in this case $165).  The proceeds from this sale, after transaction costs, are generally used to offset the cost of the second 'leg'. The second 'leg' of the strategy, corresponding to A, is the purchase of a call option at a strike price of A (in this case $145). Now, the important part: the payoff.  You can visualize it as so. This is where it gets a teeny bit math-y.  Below, P is the profit of the strategy, K1 is the strike price of the long call, K2 is the strike price of the short call, T1 is the premium paid for the long call option at the time of purchase, T2 is the premium received for the short call at the time of sale, and S is the current price of the stock.  For simplicity's sake, we will assume that your position quantity is a single option contract and transaction costs are zero (which they are not). P = (T2 - max(0, S - K2)) + (max(0, S - K1) - T1) Concretely, let's plug in the strikes of the strategy Nathan proposes, and current prices (which I pulled from the screen).  You have: P = (1.85 - max(0, 142.50 - 165)) - (max(0, 142.50 - 145)) = -$7.80 If the stock goes to $150, the payoff is -$2.80, which isn't quite break even -- but it may have been at the time he was speaking on TV. If the stock goes to $165, the payoff is $12.20. Please do not neglect the cost of the trades!  Trading options can be pretty expensive depending on the broker.  Had I done this trade (quantity 1) at many popular brokers, I still would've been net negative PnL even if NFLX went to >= $165. "Learn something new every day... I found this interesting and thought I'd throw my 2c in. Good description (I hope) from Short Selling: What is Short Selling First, let's describe what short selling means when you purchase shares of stock. In purchasing stocks, you buy a piece of ownership in the company. You buy/sell stock to gain/sell ownership of a company. When an investor goes long on an investment, it means that he or she has bought a stock believing its price will rise in the future. Conversely, when an investor goes short, he or she is anticipating a decrease in share price. Short selling is the selling of a stock that the seller doesn't own. More specifically, a short sale is the sale of a security that isn't owned by the seller, but that is promised to be delivered.  Still with us? Here's the skinny: when you short sell a stock, your broker will lend it to you. The stock will come from the brokerage's own inventory, from another one of the firm's customers, or from another brokerage firm. The shares are sold and the proceeds are credited to your account. Sooner or later, you must ""close"" the short by buying back the same number of shares (called covering) and returning them to your broker. If the price drops, you can buy back the stock at the lower price and make a profit on the difference. If the price of the stock rises, you have to buy it back at the higher price, and you lose money. So what happened? The Plan The Reality Lesson I never understood what ""Shorting a stock"" meant until today. Seems a bit risky for my blood, but I would assume this is an extreme example of what can go wrong. This guy literally chose the wrong time to short a stock that was, in all visible aspects, on the decline.  How often does a Large Company or Individual buy stock on the decline... and send that stock soaring? How often does a stock go up 100% in 24 hours? 600%?  Another example is recently when Oprah bought 10% of Weight Watchers and caused the stock to soar %105 in 24 hours. You would have rued the day you shorted that stock - on that particular day - if you believed enough to ""gamble"" on it going down in price." "To summarize, there are three basic ways: (3) is the truly dangerous one. If there is a lot of short interest in a stock, but for some reason the stock goes up, suddenly a lot of people will be scrambling to buy that stock to cover their short position -- which will drive the price up even further, making the problem worse.  Pretty soon, a bunch of smart rich guys will be poor guys who are suddenly very aware that they aren't as smart as they thought they were.  Eight years ago, such a ""short squeeze"", as it's called, made the price of VW quadruple in two days.  You could hear the Heinies howl from Hamburg to Haldenwanger. There are ways to protect yourself, of course.  You can go short but also buy a call at a much higher price, thereby limiting your exposure, a strategy called a ""straddle"", but you also reduce your profit if you guessed right. It comes down to, as it always does, do you want to eat well, or to sleep well?" "Below is just a little information on short selling from my small unique book ""The small stock trader"":  Short selling is an advanced stock trading tool with unique risks and rewards. It is primarily a short-term trading strategy of a technical nature, mostly done by small stock traders, market makers, and hedge funds. Most small stock traders mainly use short selling as a short-term speculation tool when they feel the stock price is a bit overvalued. Most long-term short positions are taken by fundamental-oriented long/short equity hedge funds that have identified some major weaknesses in the company. There a few things you should consider before shorting stocks: Despite all the mystique and blame surrounding short selling, especially during bear markets, I personally think regular short selling, not naked short selling, has a more positive impact on the stock market, as: Lastly, small stock traders should not expect to make significant profits by short selling, as even most of the great stock traders (Jesse Livermore, Bernard Baruch, Gerald Loeb, Nicolas Darvas, William O’Neil, and Steven Cohen,) have hardly made significant money from their shorts. it is safe to say that odds are stacked against short sellers. Over the last century or so, Western large caps have returned an annual average of between 8 and 10 percent while the returns of small caps have been slightly higher.  I hope the above little information from my small unique book was a little helpful! Mika (author of ""The small stock trader"")" "Your strategy fails to control risk. Your ""inversed crash"" is called a rally. And These kind of things often turn into bigger rallies because of short squeezes, when all the people that are shorting a stock are forced to close their stock because of margin calls - its not that shorts ""scramble"" to close their position, the broker AUTOMATICALLY closes your short positions with market orders and you are stuck with the loss. So no, your ""trick"" is not enough. There are better ways to profit from a bearish outlook." Not really. The lender is not buying the stock back at a lower price. Remember, he already owns it, so he need not buy it again. The person losing is the one from whom the short seller buys back the stock, provided that person bought the stock at higher price.  So if B borrowed from A(lender) and sold it to C, and later B purchased it back from C at a lower price, then B made profit, C made loss and A made nothing . SeekingAlpha has an article about short squeezes that states: The higher the number of days to cover means the possibility for a short squeeze is greater, and the potential size of the short squeeze is also greater Logically, this makes sense. A short squeeze occurs when a lack of supply meets excess demand for a stock, so the potential for a squeeze increases when supply and demand begin to get out of equilibrium. Think of two things that would cause the days to cover to increase and what effect they would have on supply and demand.  The current short interest (numerator) increases. This implies that if some event triggers short sellers to cover their position, there are a higher number of short sellers who will need to do so. This heightens the chances that demand will exceed supply.  The average daily volume (denominator) decreases. This implies that fewer investors are trading the stock, so if an event triggers short sellers to cover their positions, there might not be enough traders in the market willing to sell their shares. (Obviously, if a short-squeeze occurs, volume may increase because traders who were unwilling to sell their shares become willing). While volume per trade is higher at the open and to a lesser extent at the close, the overall volume is actually lower, on average. Bid ask spreads are widest at the open and to a lesser extent at the close. Generally, bid ask spreads are inversely proportional to overall volumes. Why this is the case hasn't been sufficiently clearly answered by academia yet, but some theories are that They mostly make money off of the spread between your order and the spread of the buy and sell currently in the market. As others have previously explained, their buy/sell spreads are a little lacklustre.