What does it mean when the broker does not have enough shares to short?
For Canada No distinction is made in the regulation between “naked” or “covered” short sales. However, the practice of “naked” short selling, while not specifically enumerated or proscribed as such, may violate other provisions of securities legislation or self-regulatory organization rules where the transaction fails to settle. Specifically, section 126.1 of the Securities Act prohibits activities that result or contribute “to a misleading appearance of trading activity in, or an artificial price for, a security or derivative of a security” or that perpetrate a fraud on any person or company. Part 3 of National Instrument 23-101 Trading Rules contains similar prohibitions against manipulation and fraud, although a person or company that complies with similar requirements established by a recognized exchange, quotation and trade reporting system or regulation services provider is exempt from their application. Under section 127(1) of the Securities Act, the OSC also has a “public interest jurisdiction” to make a wide range of orders that, in its opinion, are in the public interest in light of the purposes of the Securities Act (notwithstanding that the subject activity is not specifically proscribed by legislation). The TSX Rule Book also imposes certain obligations on its “participating organizations” in connection with trades that fail to settle (see, for example, Rule 5-301 Buy-Ins).  In other words, shares must be located by the broker before they can be sold short. A share may not be locatable because there are none available in the broker's inventory, that it cannot lend more than what it has on the books for trade.  A share may not be available because the interest rate that brokers are charging to borrow the share is considered too high by that broker, usually if it doesn't pass on borrowing costs to the customer.  There could be other reasons as well. If one broker doesn't have inventory, another might.  I recommend checking in on IB's list.  If they can't get it, my guess would be that no one can since IB passes on the cost to finance short sales.
You have to look at stocks just like you would look at smaller and more illiquid markets. Stock trade in auction markets. These are analogous to ebay or craigslist, just with more transparency and liquidity. There is no guarantee that a market will form for a particular stock, or that it will sustain.  When a stock sells off, and there are no bids left, that means all of the existing bidder's limit orders got filled because someone sold at those prices. There is nothing fishy about that. It is likely that someone else wants to sell even more, but couldn't find any more bidders. If you put a bid you would likely get filled by the shareholder with a massive position looking for liquidity. You could also buy at the ask. "Being ""Long"" something means you own it.  Being ""Short"" something means you have created an obligation that you have sold to someone else.  If I am long 100 shares of MSFT, that means that I possess 100 shares of MSFT.  If I am short 100 shares of MSFT, that means that my broker let me borrow 100 shares of MSFT, and I chose to sell them.  While I am short 100 shares of MSFT, I owe 100 shares of MSFT to my broker whenever he demands them back.  Until he demands them back, I owe interest on the value of those 100 shares.  You short a stock when you feel it is about to drop in price.  The idea there is that if MSFT is at $50 and I short it, I borrow 100 shares from my broker and sell for $5000.  If MSFT falls to $48 the next day, I buy back the 100 shares and give them back to my broker.  I pocket the difference ($50 - $48 = $2/share x 100 shares = $200), minus interest owed.  Call and Put options.  People manage the risk of owning a stock or speculate on the future move of a stock by buying and selling calls and puts.  Call and Put options have 3 important components.  The stock symbol they are actionable against (MSFT in this case), the ""strike price"" - $52 in this case, and an expiration, June.  If you buy a MSFT June $52 Call, you are buying the right to purchase MSFT stock before June options expiration (3rd Saturday of the month).  They are priced per share (let's say this one cost $0.10/share), and sold in 100 share blocks called a ""contract"".  If you buy 1 MSFT June $52 call in this scenario, it would cost you 100 shares x $0.10/share = $10.  If you own this call and the stock spikes to $56 before June, you may exercise your right to purchase this stock (for $52), then immediately sell the stock (at the current price of $56) for a profit of $4 / share ($400 in this case), minus commissions.  This is an overly simplified view of this transaction, as this rarely happens, but I have explained it so you understand the value of the option.  Typically the exercise of the option is not used, but the option is sold to another party for an equivalent value.  You can also sell a Call.  Let's say you own 100 shares of MSFT and you would like to make an extra $0.10 a share because you DON'T think the stock price will be up to $52/share by the end of June.  So you go to your online brokerage and sell one contract, and receive the $0.10 premium per share, being $10.  If the end of June comes and nobody exercises the option you sold, you get to keep the $10 as pure profit (minus commission)!  If they do exercise their option, your broker makes you sell your 100 shares of MSFT to that party for the $52 price.  If the stock shot up to $56, you don't get to gain from that price move, as you have already committed to selling it to somebody at the $52 price.  Again, this exercise scenario is overly simplified, but you should understand the process.  A Put is the opposite of a Call.  If you own 100 shares of MSFT, and you fear a fall in price, you may buy a PUT with a strike price at your threshold of pain.  You might buy a $48 June MSFT Put because you fear the stock falling before June.  If the stock does fall below the $48, you are guaranteed that somebody will buy yours at $48, limiting your loss.  You will have paid a premium for this right (maybe $0.52/share for example).  If the stock never gets down to $48 at the end of June, your option to sell is then worthless, as who would sell their stock at $48 when the market will pay you more?  Owning a Put can be treated like owning insurance on the stock from a loss in stock price.  Alternatively, if you think there is no way possible it will get down to $48 before the end of June, you may SELL a $48 MSFT June Put.  HOWEVER, if the stock does dip down below $48, somebody will exercise their option and force you to buy their stock for $48.  Imagine a scenario that MSFT drops to $30 on some drastically terrible news.  While everybody else may buy the stock at $30, you are obligated to buy shares for $48.  Not good!  When you sold the option, somebody paid you a premium for buying that right from you.  Often times you will always keep this premium.  Sometimes though, you will have to buy a stock at a steep price compared to market.  Now options strategies are combinations of buying and selling calls and puts on the same stock.  Example -- I could buy a $52 MSFT June Call, and sell a $55 MSFT June Call.  I would pay money for the $52 Call that I am long, and receive money for the $55 Call that I am short.  The money I receive from the short $55 Call helps offset the cost of buying the $52 Call.  If the stock were to go up, I would enjoy the profit within in $52-$55 range, essentially, maxing out my profit at $3/share - what the long/short call spread cost me.  There are dozens of strategies of mixing and matching long and short calls and puts depending on what you expect the stock to do, and what you want to profit or protect yourself from.  A derivative is any financial device that is derived from some other factor.  Options are one of the most simple types of derivatives.  The value of the option is derived from the real stock price.  Bingo?  That's a derivative.  Lotto?  That is also a derivative.  Power companies buy weather derivatives to hedge their energy requirements.  There are people selling derivatives based on the number of sunny days in Omaha.  Remember those calls and puts on stock prices?  There are people that sell calls and puts based on the number of sunny days in Omaha.  Sounds kind of ridiculous -- but now imagine that you are a solar power company that gets ""free"" electricity from the sun and they sell that to their customers.  On cloudy days, the solar power company is still on the hook to provide energy to their customers, but they must buy it from a more expensive source.  If they own the ""Sunny Days in Omaha"" derivative, they can make money for every cloudy day over the annual average, thus, hedging their obligation for providing more expensive electricity on cloudy days.  For that derivative to work, somebody in the derivative market puts a price on what he believes the odds are of too many cloudy days happening, and somebody who wants to protect his interests from an over abundance of cloudy days purchases this derivative.  The energy company buying this derivative has a known cost for the cost of the derivative and works this into their business model.  Knowing that they will be compensated for any excessive cloudy days allows them to stabilize their pricing and reduce their risk.  The person selling the derivative profits if the number of sunny days is higher than average.  The people selling these types of derivatives study the weather in order to make their offers appropriately.  This particular example is a fictitious one (I don't believe there is a derivative called ""Sunny days in Omaha""), but the concept is real, and the derivatives are based on anything from sunny days, to BLS unemployment statistics, to the apartment vacancy rate of NYC, to the cost of a gallon of milk in Maine.  For every situation, somebody is looking to protect themselves from something, and somebody else believes they can profit from it.  Now these examples are highly simplified, many derivatives are highly technical, comprised of multiple indicators as a part of its risk profile, and extremely difficult to explain.  These things might sound ridiculous, but if you ran a lemonade stand in Omaha, that sunny days derivative just might be your best friend..." When you want to short a stock, you are trying to sell shares (that you are borrowing from your broker), therefore you need buyers for the shares you are selling.  The ask prices represent people who are trying to sell shares, and the bid prices represent people who are trying to buy shares. Using your example, you could put in a limit order to short (sell) 1000 shares at $3.01, meaning that your order would become the ask price at $3.01.  There is an ask price ahead of you for 500 shares at $3.00.  So people would have to buy those 500 shares at $3.00 before anyone could buy your 1000 shares at $3.01. But it's possible that your order to sell 1000 shares at $3.01 never gets filled, if the buyers don't buy all the shares ahead of you.  The price could drop to $1.00 without hitting $3.01 and you will have missed out on the trade. If you really wanted to short 1000 shares, you could use a market order.  Let's say there's a bid for 750 shares at $2.50, and another bid for 250 shares at $2.49.  If you entered a market order to sell 1000 shares, your order would get filled at the best bid prices, so first you would sell 750 shares at $2.50 and then you would sell 250 shares at $2.49. I was just using your example to explain things.  In reality there won't be such a wide spread between the bid and ask prices.  A stock might have a bid price of $10.50 and an ask price of $10.51, so there would only be a 1 cent difference between putting in a limit order to sell 1000 shares at $10.51 and just using a market order to sell 1000 shares and getting them filled at $10.50. Also, your example probably wouldn't work in real life, because brokers typically don't allow people to short stocks that are trading under $5 per share. As for your question about how often you are unable to make a short sale, it can sometimes happen with stocks that are heavily shorted and your broker may not be able to find any more shares to borrow. Also remember that you can only short stocks with a margin account, you cannot short stocks with a cash account. When you set up a short sale for equities you are borrowing stock from someone else; typically another client at the broker.  The broker usually buries an agreement to let your shares be borrowed for short sales in your account details.  So if Client A wants to short a stock, he borrows stock from Client B to do the short sale (it's usually not this direct as they can borrow from many clients).  If Client B then wants to sell his shares; if the broker can't shift around assets to find another client's shares to let Client A borrow; then he has to close the short position out because he doesn't have the shares in the brokerage to let Client A borrow to short anymore. In order to short a stock, you have to borrow the number of shares that you're shorting from someone else who holds the shares, so that you can deliver the shares you're shorting if it becomes necessary to do so (usually; there's also naked short selling, where you don't have to do this, but it's banned in a number of jurisdictions including the US). If a stock has poor liquidity, or is in high demand for shorting, then it may well be impossible to find anyone from whom it can be borrowed, which is what has happened in this instance. "And what exactly do I profit from the short? I understand it is the difference in the value of the stock. So if my initial investment was $4000 (200 * $20) and I bought it at $3800 (200 * $19) I profit from the difference, which is $200. Do I also receive back the extra $2000 I gave the bank to perform the trade? Either this is extremely poorly worded or you misunderstand the mechanics of a short position.  When you open a short position, your are expecting that the stock will decline from here.  In a short position you are borrowing shares you don't own and selling them.  If the price goes down you get to buy the same shares back for less money and return them to the person you borrowed from.  Your profit is the delta between the original sell price and the new lower buy price (less commissions and fees/interest).  Opening and closing a short position is two trades, a sell then a buy.  Just like a long trade there is no maximum holding period. If you place your order to sell (short) 200 shares at $19, your initial investment is $3,800.   In order to open your $3,800 short position your broker may require your account to have at least $5,700 (according to the 1.5 ratio in your question).  It's not advisable to open a short position this close to the ratio requirement.  Most brokers require a buffer in your account in case the stock goes up, because in a short trade if the stock goes up you're losing money.  If the stock goes up such that you've exhausted your buffer you'll receive what's known as a ""margin call"" where your broker either requires you to wire in more money or sell part or all of your position at a loss to avoid further losses.  And remember, you may be charged interest on the value of the shares you're borrowing. When you hold a position long your maximum loss is the money you put in; a position can only fall to zero (though you may owe interest or other fees if you're trading on margin).  When you hold a position short your maximum loss is unlimited; there's no limit to how high the value of something can go.  There are less risky ways to make short trades by using put options, but you should ensure that you have a firm grasp on what's happening before you use real money. The timing of the trades and execution of the trades is no different than when you take a plain vanilla long position.  You place your order, either market or limit or whatever, and it executes when your trade criteria occurs." Overvalued does not mean an opportunity to short.  As long as a company's earnings are decent and there are limited other opportunities in the market, a stock would stay overvalued. its just that future returns on the stock might be limited. For shorting you need an expected trigger. Say you expect an overvalued company's earnings to decline or significantly miss expectations. This would be a candidate for shorting.. "&gt; It just has to finish below the strike price of the short (which can be higher than the stock's current price).  You're talking about a put option.   That's one ""short"" strategy, but it's not shorting a stock, so the terminology is a little jumbled.   There are reasons to not do straight options, because they can be quite risky, and you have to get the time frame correct." When you short a stock, you can lose an unlimited amount of money if the trade goes against you. If the shorted stock gaps up overnight you can lose more money than you have in your account. The best case is you make 100% if the stock goes to zero. And then you have margin fees on top of that. With long positions, it's the other way around. Your max loss is 100% and your gains are potentially unlimited. why can't I just use the same trick with my own shares to make money on the way    down? Because if you sell shares out of your own portfolio, by definition, you are not selling short at all. If you sell something you own (and deliver it) - then there is no short involved. A short is defined as a net negative position - i.e. you sell shares you do not have. Selling shares you own is selling shares you own - no short involved. You must borrow the shares for a short because in the stock market, you must DELIVER. You can not deliver shares you do not own. The stock market does not work on promises - the person who bought the shares expects ownership of them with all rights that gives them. So you borrow them to deliver them, then return them when you buy them back. Brokerage firms are required to report the number of shares being shorted.  This information is reported to the exchange (NYSE of NASDAQ) and is made public.  Most financial sites indicate the number of shares being shorted for a particular stock.  The image below from Yahoo finance shows 3.29 million shares of CMG were being shorted at the close of 9-28-2012.  This is over 12% of the total outstanding shares of CMG.  For naked short selling additional information is tracked.  If the brokerage is unable to borrow shares to deliver before the settlement date of a short sale then the transaction is recorded as fails-to-deliver.  No money or shares are exchanged since the brokerage is unable to deliver the shares that were agreed upon.  A large amount of fails-to-deliver transactions for a stock usually indicates an excessive amount of naked shorting.  When investors and brokerage firms start to aggressively short a stock they will do so without having borrowed the shares to sell.  This will result in a large amount of naked short selling.  When there are a large number of naked short sellers not all the sellers will be able to borrow the necessary shares before the settlement date and many fails-to-deliver transactions will be recorded. The SEC records the number of fails-to-deliver transactions. The table below summarizes the fails-to-deliver transactions from 1-1-2012 through 9-14-2012 (data obtained from here). The “Ext Amount” column shows the total dollar value of the transactions that failed ( i.e. Fail Qty * Share price ).  The “Volume” column is the total number of shares traded in the same time period.  The “% Volume” shows the percentage of shares that failed to deliver as a percentage of the total market volume. The table orders the data in descending order by the quantity of shares that were not delivered.  Most of the companies at the top of the list no longer exist.  For many of these companies, the quantity of shares that failed to deliver where many multiples of the number of shares traded during the same time period.  This indicates massive naked short selling as many brokerages where unable to find shares to borrow before the settlement date. More information here. Michael gave a good answer describing the transaction but I wanted to follow up on your questions about the lender. First, the lender does charge interest on the borrowed securities. The amount of interest can vary based on a number of factors, such as who is borrowing, how much are they borrowing, and what stock are they trying to borrow.  Occasionally when you are trying to short a stock you will get an error that it is hard to borrow. This could be for a few reasons, such as there are already a large amount of people who have shorted your broker's shares, or your broker never acquired the shares to begin with (which usually only happens on very small stocks). In both cases the broker/lender doesnt have enough shares and may be unwilling to get more. In that way they are discriminating on what they lend. If a company is about to go bankrupt and a lender doesnt have any more shares to lend out, it is unlikely they will purchase more as they stand to lose a lot and gain very little.  It might seem like lending is a risky business but think of it as occurring over decades and not months. General Motors had been around for 100 years before it went bankrupt, so any lender who had owned and been lending out GM shares for a fraction of that time likely still profited.  Also this is all very simplified. JoeTaxpayer alluded to this in the comments but in actuality who is lending stock or even who owns stock is much more complicated and probably doesnt need to be explained here. I just wanted to show in this over-simplified explanation that lending is not as risky as it may first seem. "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"")" For every seller, there's a buyer. Buyers may have any reason for wanting to buy (bargain shopping, foolish belief in a crazy business, etc).  The party (brokerage, market maker, individual) owning the stock at the time the company goes out of business is the loser . But in a general panic, not every company is going to go out of business. So the party owning those stocks can expect to recover some, or all, of the value at some point in the future. Brokerages all reserve the right to limit margin trading (required for short selling), and during a panic would likely not allow you to short a stock they feel is a high risk for them. You just disclosed that you are new investor to the stock market. I'd advise that you first understand investing a bit better, as most will advise that investors need to be above a certain level before picking individual stocks.  That said, most stocks trade in high enough volume and have low enough short interest that they don't fall under the category you seek. You want to first ask your broker if they have such a process, not all do. If so, they would need to provide you with the stocks that fall into this odd situation, specifically, the shares that have traders seeking to short the stock, but the stock is unavailable. Even then, the broker may have requirements that you don't fall into, minimum history with broker, minimum size account, etc. Worse, they are not likely to offer this for 100 shares, but may have a 1000 or higher share requirement. Are you willing to buy some obscure $50/sh priced stock to lend out at 1%/mo? The guy trying to short it is far smarter than both you and I, at least regarding this particular stock. This strategy is more appropriate for the 7 figure net worth investor.  If any reader has actual experience with this, I'm happy to hear it. This response is from my recollection of two articles I read about 3 years ago, coincidence they both were published within weeks of each other.