Does an individual share of a stock have some kind of unique identifier?
"I agree with the answer by @Michael that this number doesn't exist.  It's hard to see what use it would have and it would be difficult to track. I'm writing a separate answer because I also disagree with the premise of your question:  Individual shares of stock have never to my knowledge had such a number.  Your comment about numbers on stock certificates identifies the certificate document, which will generally represent multiple shares of stock.  That number no more identifies a single share of stock than the serial number on a $10 bill identifies any one of the ten dollars it represents.  Even at the ""collective"" unit of $10, when the bill is eventually replaced with a new one, the new bill has a new number.  No continuity." "There is no unique identifier that exists to identify specific shares of a stock. Just like money in the bank, there is no real reason to identify which exact dollar bills belong to me or you, so long as there is a record that I own X bills and I can access them when I want. (Of course, unlike banks, there is still a 1:1 relationship between the amount I should own and the amount they actually hold). If I may reach a bit, the question that I assume you are asking is how are shared actually tracked, transferred, and recorded so that I know for certain that I traded you 20 Microsoft shares yesterday and they are now officially yours, given that it's all digital. While you can technically try and request a physical share certificate, it's very cumbersome to handle and transfer in that form.  Ownership of shares themselves are tracked for brokerage firms (in the case of retail trading, which I assume is the context of this question as we're discussion personal finance). Your broker has a record of how many shares of X, Y, and Z you own, when you bought each share and for how much, and while you are the beneficial owner of record (you get dividends, voting rights, etc.) your brokerage is the one who is ""holding"" the shares. When you buy or sell a stock and you are matched with a counterparty (the process of which is beyond the scope of this question) then a process of settlement comes into play. In the US, settlement takes 3 working days to process, and technically ownership does not transfer until the 3rd day after the trade is made, though things like margin accounts will allow you to effectively act as if you own the shares immediately after a buy/sell order is filled. Settlement in the US is done by a sole source, the Depository Trust & Clearing Corporation (DTCC). This is where retail and institutional trade all go to be sorted, checked and confirmed, and ultimately returned to the safekeeping of their new owners' representatives (your brokerage). Interestingly, the DTCC is also the central custodian for shares both physical and virtual, and that is where the shares of stock ultimately reside." Nope, think what a nightmare that would be, a bunch of shares would be issued and then sold to tonnes of people, who might sell various partial numbers of them to others, who might buy them and others from 20 others all as part of one order though multiple fills... It would be nuts, and if one were to issue a certificate with the IDs of shares that were carried through such a process the likelihood is the fragmentation would be so great that 100K shares would have consist of almost as many fragments! Imagine a share certificate with 70K IDs/ranges? Yikes!
"A company whose stock is available for sale to the public is called a publicly-held or publicly-traded company.  A public company's stock is sold on a stock exchange, and anyone with money can buy shares through a stock broker. This contrasts with a privately-held company, in which the shares are not traded on a stock exchange. In order to invest in a private company, you would need to talk directly to the current owners of the company. Finding out if a company is public or private is fairly easy.  One way to check this is to look at the Wikipedia page for the company.  For example, if you take a look at the Apple page, on the right sidebar you'll see ""Type: Public"", followed by the stock exchange ticker symbol ""AAPL"".  Compare this to the page for Mars, Inc.; on that page, you'll see ""Type: Private"", and no stock ticker symbol listed. Another way to tell: If you can find a quote for a share price on a financial site (such as Google Finance or Yahoo Finance), you can buy the stock.  You won't find a stock price for Mars, Inc. anywhere, because the stock is not publicly traded." "In an IPO (initial public offering) or APO (additional public offering) situation, a small group of stakeholders (as few as one) basically decide to offer an additional number of ""shares"" of equity in the company. Usually, these ""shares"" are all equal; if you own one share you own a percentage of the company equal to that of anyone else who owns one share. The sum total of all shares, theoretically, equals the entire value of the company, and so with N shares in existence, one share is equivalent to 1/Nth the company, and entitles you to 1/Nth of the profits of the company, and more importantly to some, gives you a vote in company matters which carries a weight of 1/Nth of the entire shareholder body. Now, not all of these shares are public. Most companies have the majority (51%+) of shares owned by a small number of ""controlling interests"". These entities, usually founding owners or their families, may be prohibited by agreement from selling their shares on the open market (other controlling interests have right of first refusal). For ""private"" companies, ALL the shares are divided this way. For ""public"" companies, the remainder is available on the open market, and those shares can be bought and sold without involvement by the company. Buyers can't buy more shares than are available on the entire market. Now, when a company wants to make more money, a high share price at the time of the issue is always good, for two reasons. First, the company only makes money on the initial sale of a share of stock; once it's in a third party's hands, any profit from further sale of the stock goes to the seller, not the company. So, it does little good to the company for its share price to soar a month after its issue; the company's already made its money from selling the stock. If the company knew that its shares would be in higher demand in a month, it should have waited, because it could have raised the same amount of money by selling fewer shares. Second, the price of a stock is based on its demand in the market, and a key component of that is scarcity; the fewer shares of a company that are available, the more they'll cost. When a company issues more stock, there's more shares available, so people can get all they want and the demand drops, taking the share price with it. When there's more shares, each share (being a smaller percentage of the company) earns less in dividends as well, which figures into several key metrics for determining whether to buy or sell stock, like earnings per share and price/earnings ratio. Now, you also asked about ""dilution"". That's pretty straightforward. By adding more shares of stock to the overall pool, you increase that denominator; each share becomes a smaller percentage of the company. The ""privately-held"" stocks are reduced in the same way. The problem with simply adding stocks to the open market, getting their initial purchase price, is that a larger overall percentage of the company is now on the open market, meaning the ""controlling interests"" have less control of their company. If at any time the majority of shares are not owned by the controlling interests, then even if they all agree to vote a certain way (for instance, whether or not to merge assets with another company) another entity could buy all the public shares (or convince all existing public shareholders of their point of view) and overrule them. There are various ways to avoid this. The most common is to issue multiple types of stock. Typically, ""common"" stock carries equal voting rights and equal shares of profits. ""Preferred stock"" typically trades a higher share of earnings for no voting rights. A company may therefore keep all the ""common"" stock in private hands and offer only preferred stock on the market. There are other ways to ""class"" stocks, most of which have a similar tradeoff between earnings percentage and voting percentage (typically by balancing these two you normalize the price of stocks; if one stock had better dividends and more voting weight than another, the other stock would be near-worthless), but companies may create and issue ""superstock"" to controlling interests to guarantee both profits and control. You'll never see a ""superstock"" on the open market; where they exist, they are very closely held. But, if a company issues ""superstock"", the market will see that and the price of their publicly-available ""common stock"" will depreciate sharply. Another common way to increase market cap without diluting shares is simply to create more shares than you issue publicly; the remainder goes to the current controlling interests. When Facebook solicited outside investment (before it went public), that's basically what happened; the original founders were issued additional shares to maintain controlling interests (though not as significant), balancing the issue of new shares to the investors. The ""ideal"" form of this is a ""stock split""; the company simply multiplies the number of shares it has outstanding by X, and issues X-1 additional shares to each current holder of one share. This effectively divides the price of one share by X, lowering the barrier to purchase a share and thus hopefully driving up demand for the shares overall by making it easier for the average Joe Investor to get their foot in the door. However, issuing shares to controlling interests increases the total number of shares available, decreasing the market value of public shares that much more and reducing the amount of money the company can make from the stock offering." "Note that these used to be a single ""common"" share that has ""split"" (actually a ""special dividend"" but effectively a split). If you owned one share of Google before the split, you had one share giving you X worth of equity in the company and 1 vote. After the split you have two shares giving you the same X worth of equity and 1 vote. In other words, zero change. Buy or sell either depending on how much you value the vote and how much you think others will pay (or not) for that vote in the future.  As Google issues new shares, it'll likely issue more of the new non-voting shares meaning dilution of equity but not dilution of voting power. For most of us, our few votes count for nothing so evaluate this as you will.  Google's founders believe they can do a better job running the company long-term when there are fewer pressures from outside holders who may have only short-term interests in mind. If you disagree, or if you are only interested in the short-term, you probably shouldn't be an owner of Google. As always, evaluate the facts for yourself, your situation, and your beliefs." Shares are partial ownership of the company. A company can issue (not create) more of the shares it owns at any time, to anyone, at any price -- subject to antitrust and similar regulations. If they wanted to, for example, flat-out give 10% of their retained interest to charity, they could do so. It shouldn't substantially affect the stock's trading for others unless there's a completely irrational demand for shares. Your observation is mostly right, that 1 is a the number around which this varies.  You are actually referencing PEG, P/E to Growth ratio, which is a common benchmark to use to evaluate a stock. The article I link to provides more discussion. "There are several such ""lists."" The one that is maintained by the company is called the shareholder registry. That is a list that the company has given to it by the brokerage firms. It is a start, but not a full list, because many individual shareholders hold their stock with say Merrill Lynch, in ""street name"" or anonymously. A more useful list is the one of institutional ownership maintained by the SEC. Basically, ""large"" holders (of more than 5 percent of the stock) have to register their holdings with the SEC. More to the point, large holders of stocks, the Vanguards, Fidelitys, etc. over a certain size, have to file ALL their holdings of stock with the SEC. These are the people you want to contact if you want to start a proxy fight. The most comprehensive list is held by the Depositary Trust Company. People try to get that list only in rare instances." The value of a share depends on the value of the company, which involves a lot more than the value of its assets -- it requires making decisions about what you think will happen to the company in the future. That's inherently not something that can be reduced to a single formula, at least not unless you can figure out how to represent your guesses and your confidence in them in the formula ... and even if you could do all that it would only say what you think the stock is worth; others will be using different numbers and legitimately get different results. Disagreement over value is what the stock market is all about, I'm afraid. There isn't a single universal way to reference a stock, there are 4 major identifiers with many different flavours of exchange ticker (see xkcd:Standards) I believe CUSIPs and ISINs represent a specific security rather than a specific listed instrument. This means you can have two listed instruments with one ISIN but different SEDOLs because they are listed in different places. The difference is subtle but causes problems with settlement Specifically on your question (sorry I got sidetracked) take a look at  CQS Symbol convention to see what everything means Go to http://www.isincodes.net/, and enter your data. For example entering Alphabet gives you the ISIN US02079K1079 (for standard US shares). If you want to understand the number format (and build them yourself), check wikipedia: https://en.wikipedia.org/wiki/International_Securities_Identification_Number The last column in the source data is volume (the number of stocks that was exchanged during the day), and it also has a value of zero for that day, meaning that nobody bought or sold the stocks on that day. And since the prices are prices of transactions (the first and the last one on a particular day, and the ones with the highest/lowest price), the prices cannot be established, and are irrelevant as there was not a single transaction on that day. Only the close price is assumed equal to its previous day counterpart because this is the most important value serving as a basis to determine the daily price change (and we assume no change in this case). Continuous-line charts also use this single value. Bar and candle charts usually display a blank space for a day where no trade occurred. A share of stock is an asset not much different than any other asset.  If the share is being held in a joint account, it's being jointly owned.  If the share is being held by a company with multiple owners then the share is owned by the various owners.  If you're married and in a community property state, then it's technically owned by both parties. "This information is clearly ""material"" (large impact) and ""non-public"" according to the statement of the problem.  Also, decisions like United States v. Carpenter make it clear that you do not need to be a member of the company to do illegal insider trading on its stock. Importantly though, stackexchange is not a place for legal advice and this answer should not be construed as such.  Legal/compliance at Company A would be a good place to start asking questions." I was thinking that the value of the stock is the value of the stock...the actual number of shares really doesn't matter, but I'm not sure. You're correct.  Share price is meaningless.   Google is $700 per share, Apple is $100 per share, that doesn't say anything about either company and/or whether or not one is a better investment over the other. You should not evaluate an investment decision on price of a share.  Look at the books decide if the company is worth owning, then decide if it's worth owning at it's current price. If the first one is literally a company name, then 'company name' is fine. However, companies can issue shares more than once, and those shares might be traded separately, so you could have 'Google ordinary', 'Google preference', 'Google ordinary issue B'. Seeing the name spelled out in full like this isn't as common as just the company name, but I'd normally see it referred to as 'display name'. The second one is 'symbol', 'ticker', 'ID', and others. Globally, there are many incompatible ways of referring to a stock, depending on where it's listed (companies can have dual listings, and different exchanges have different conventions), and who's referring to it (Bloomberg and Reuters have different sets of IDs, with no predictable mapping between them). So there's no one shorthand name, and the word you use depends on the context. However, 'symbol' or 'ticker' is normally fine. Note that your link shows the shares as of March 31, 2016 while http://uniselect.com/content/files/Press-release/Press-Release-Q1-2016-Final.pdf notes a 2-for-1 stock split so thus you have to double the shares to get the proper number is what you are missing. The stock split occurred in May and thus is after the deadline that you quoted.