How can I find out who the major short sellers are in a stock?
There is no way to know anything about who has shorted stuff or how concentrated the positions are in a few investors.  Short positions are not even reported in 13(F) institutional filings. I'll take the bonus points, though, and point you to the US Equity Short Interest data source at quandl.
Exact rules may be different depending on the size of the investor, the specific broker, and the country.  For both the US and Canada, short sales occur only through one's margin account.  And shares that are borrowed for shorting only come from a margin account. Shares held in a cash account are not available for shorting.  From Wikipedia Short (finance) - The speculator instructs the broker to sell the shares and the   proceeds are credited to his broker's account at the firm upon which   the firm can earn interest. Generally, the short seller does not earn   interest on the short proceeds and cannot use or encumber the proceeds   for another transaction. As with many questions, I'd suggest you contact your broker for the exact details governing your account. 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. "Market makers, traders, and value investors would be who I'd suspect for buying the stock that is declining. Some companies stocks can come down considerably which could make some speculators buy the stock at the lower price thinking it may bounce back soon. ""Short sellers"" are out to sell borrowed stocks that if the stock is in free fall, unless the person that shorted wants to close the position, they would let it ride. Worthless stocks are a bit of a special case and quite different than the crash of 1929 where various blue chip stocks like those of the Dow Jones Industrials had severe declines. Thus, the companies going down would be like Apple, Coca-Cola and other large companies that people would be shocked to see come down so much yet there are some examples in recent history if one remembers Enron or Worldcom. Stocks getting delisted tend to cause some selling and there are some speculators may buy the stock believing that the shares may be worth something only to lose the money possibly as one could look at the bankrupt cases of airlines and car companies to study some recent cases here. Circuit breakers are worth noting as these are cases when trading may be halted because of a big swing in prices that it is believed stopping the market may cause things to settle down." 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. "Q: A: Everyone that is short is paying interest to the owners of the shares that the short seller borrowed. Although this quells your conundrum, this is also unrelated to the term. Interest in this context is just the number. In the options market, each contract also has an open interest, which tells you how many of that contract is being held. For your sake, think of it as ""how many are interested"", but really its just a completely different context." I agree with Mark.  I was quite confuse about the short position at first but then I did a lot of learning and found out that as long as you have enough cash to cover your margin requirement you do not pay any interest since you do not have a debit on your margin balance.  This is not true for a long position though, supposed you have 5k cash and 5k margin balance, if you buy 10K worth of stocks then you will need to pay interest on the 5k of the margin balance since it is a debit.  Since shorting is done at a credit basis, you actually get interest from the transaction but you still may need to pay the borrowing fees for the stocks so they could simply balance each other out.  I have shorted stocks twice through two different companies and neither time I noticed any interest charges.  But make sure you have enough cash to cover your margin requirement, because once your margin balance is used to covered your position then interest would accrual. Learn. No, there is no such list, as the other answers mention it is practically impossible to compile one.  However you can see the institutional investors of a public company.  MSN Money has this information available in a fair amount of details.  For example see the Institutional Investors of GOOG For a company listed on NASDAQ, the numbers are published on NASDAQ's site. The most recent settlement date was 4/30/2013, and you can see that it lists 27.5 million shares as held short.  NASDAQ gets these numbers from FINRA member firms, which are required to submit them to the exchange twice a month: Each FINRA member firm is required to report its “total” short interest positions in all customer and proprietary accounts in NASDAQ-listed securities twice a month. These reports are used to calculate short interest in NASDAQ stocks. FINRA member firms are required to report their short positions as of settlement on (1) the 15th of each month, or the preceding business day if the 15th is not a business day, and (2) as of settlement on the last business day of the month.* The reports must be filed by the second business day after the reporting settlement date. FINRA compiles the short interest data and provides it for publication on the 8th business day after the reporting settlement date. I don't think that you will be able to find a list of every owner for a given stock. There are probably very few people who would know this. One source would be whoever sends out the shareholder meeting mailers.  I suspect that the company itself would know this, the exchange to a lesser extent, and possibly the brokerage houses to a even lesser extent. Consider these resources: Generally the number of shares of a U.S. exchange-listed stock which have been shorted are tracked by the exchange and reported monthly.  This number is usually known as the open short interest.  You may also see a short interest ratio, which is the short interest divided by the average daily volume for the stock. The short interest is available on some general stock data sites, such as Yahoo Finance (under Key Statistics) and dailyfinance.com (also on a Key Statistics subpage for the stock). This is a gross simplification as there are a few different ways to do this. The principle overall is the same though. To short a stock, you borrow X shares from a third party and sell them at the current price. You now owe the lender X shares but have the proceeds from the sale. If the share price falls you can buy back those shares at the new lower price, return them to the lender and pocket the difference. The risk comes when the share price goes the other way, you now owe the lender the new value of the shares, so have to find some way to cover the difference. This happened a while back when Porsche made a fortune buying shares in Volkswagen from short sellers, and the price unexpectedly rose. "If you can't find anyone to lend you the shares, then you can't short. You can attempt to raise the interest rate at which you will borrow at, in order to entice others to lend you their shares. In practice, broadcasting this information is pretty convoluted. If there aren't any stocks for you to buy back, then you have to buy back at a higher price. As in, place a limit buy order higher and higher until someone decides to sell to you. This affects your profit. Regarding the public ledger: This functions different in different markets. United States stock markets have an evolving body of regulations to alleviate the exact concerns you detailed, but Canada's or Dubai's stock markets would have different provisions. You make the assumption that it is an efficient process, but it is not and it is indeed ripe for abuse. In US stocks, the public ledger has a 3 business day delay between showing change of ownership. Many times brokers and clearing firms and other market participants allow a customer to go short with fake shares, with the idea that they will find real shares within the 3 business day time period to cover the position. During the time period that there is no real shares hitting the market, this is called a ""naked short"". The only legal system that attempts to deter this practice is the ""fail to deliver"" (FTD) list. If someone fails to deliver, that means there is a short position active with fake shares for which no real shares have been borrowed against. Too many FTD's allow for a short selling restriction to be placed, meaning nobody else can be short, and existing short sellers may be forced to cover." Adding to the answers above, there is another source of risk: if one of the companies you are short receives a bid to be purchased by another company, the price will most probably rocket... In general you cannot. Once the security is no longer listed on the exchange - it doesn't have to provide information to the exchange and regulators (unless it wants to be re-listed). That's one of the reasons companies go private - to keep their (financial and other) information private. If it was listed in 1999, and is no longer listed now - you can dig through SEC archives for the information. You can try and reach out to the company's investors' relations contact and see if they can help you with the specific information you're looking for. Well, if the short seller has to pay the dividend out of their pocket, what happens to the dividend the company paid out ??  Sounds like there are 2 divdends floating around, the short's, and the company's, but only 1 share of stock.