Why is stock dilution legal?
Here's another way that I look at it:  Say you and me were 50-50 partners in a small business. Suppose we wanted to expand our business but that needed money. Someone (let's call him Warren) has the money we need & hence in return for the money we offer Warren an equal stake in the business.  i.e. All three of us own 33% stake now. For both you and me our stake reduced from  50% that it was before Warren's entry to only 33% now.  While that reduction in our share may seem at first sight a bad deal for us, we both agreed to give Warren his share consciously not out of altruism but because it made business sense to helps us expand.  Ergo, what matters is not just your share of the pie but the size of the pie itself! And hence dilution of stake can make sense under certain circumstances.  Two small points: (a) This doesn't  in any way show the dilution must make sense. Only that it can sometimes make sense (b) Of course, in the case of a large corporation they do not need your personal approval for the dilution. But hey, neither do they ask you when they buy a new plant or start a new product. Theoretically, when a company issues more shares, it does not affect the value of your shares.  The reason is that when a company issues and sells more shares, the proceeds from the sale of those shares goes back into the company. Using your example, you have 10 out of 100 shares of the company, for a 10% stake.  Let's say that the shares are valued at $1,000 each, meaning that the market value of the company is $100,000, and your stake is worth $10,000. Now the company issues 100 more shares at $1,000 each.  The company receives $100,000 from new investors, and now the company is worth $200,000.  Your stake is now only 5% of the company, but it is still worth $10,000. The authorized share capital is the amount of shares that a company has already planned on selling.  When you buy stock in a company, you can look up how many shares exist, so you know what your percent stake in the company is.  When a company wants to sell more shares, this is called an increase of authorized share capital.  In order to do this, the company generally needs the approval of a majority of the existing shareholders. Stock dilution is legal because, in theory, the issuance of new shares shouldn't affect actual shareholder value. The other answers have explained fairly well why this is so. In practice, however, the issuance of new shares can destroy shareholder value. This normally happens when the issuing company:  In these cases, the issuance of more shares merely reduces each shareholder's stake in the company without building proportional shareholder value. If that company issues another 100 shares, shouldn't 10 of those new 100 shares be mine? Those 100 shares are an asset of the company, and you own 10% of them. When investors buy those new shares, you again own a share of the proceeds, just as you own a share of all the company's assets. A company only issues new share to raise money - it is a borrowing from investors, and in that way can be seen as an alternative to taking on loans. Both share issuing and a loan bring new capital and debt into a company. The difference is that shares don't need to be repaid. Alot of these answers have focused on the dilution aspect, but from a purely legal aspect, there are usually corporate bylaws that spell out what kind of vote and percentage of votes is needed to take this type of action.  If all other holders of stock voted to do this, so 90% for, and you didn't, so 10% against, it's still legal if that vote meets the threshold for taking the action. As an example of this, I known of a startup where employees got $0/share for their vested shares when the company was sold because the voting stock holders agreed to it.  Effectively the purchase amount was just enough to cover debts and preferred stock. Stock issuing and dilution is legal because there must be some mechanism for small companies to grow into big companies. A company sees a great investment opportunity.  It would be a perfect extension of their activities ... but they cannot afford it. To get the necessary money they can either take out a loan or issue shares. Taking a loan basically means that this is temporary, but the company will go back to being small when the loan is paid back. Issuing new shares basically means that the Board means that this growth is permanent and the company will be big for the foreseeable future. It is utterly necessary that companies have this option for raising cash, and therefore it is legal. As detailed in the other answers, you end up with a smaller percentage of a larger company, usually ending up with more or less the same value. "For new shares to be successfully sold, the price has to be below market price. If you currently own shares of that company, you should always get an option to buy those newly sold shares at that discounted price. The number of options depends on the relative number of shares you hold. Lets say you own 100 out of 1000 shares, currently priced at $10. 100 new shares are to be sold at $9. Since you are holding 10% of all shares, you have the option (i.e. the right) to buy 10 new (cheaper) shares (10% of 100) before anybody else can buy them. Theoretically, the money you save by getting the shares at a discounted price is equal to the money you lose by the share's value being diluted. So, if you're a shareholder and the company is increasing it's capital, you're given the right to ""go with it""."
First off, some companies do something like this.  Microsoft for example was well-known for consistently hitting earnings estimates every quarter - nearly never missed them, and most of the time didn't exceed by much either.  In order to do this and not be prosecuted for accounting fraud, you typically have to be a service or nontangible good company (like Microsoft used to be) where you can manipulate the amount of product on hand and move costs fairly easily from one quarter to the next.  A company like, say, Home Depot or Caterpillar - both of which have tangible goods they're either retailing or producing - has less flexibility there, although they will still try to move profits around to match earnings estimates more closely. However, you have to be consistently doing well to be able to do this.  You can't manufacture additional total revenue; so if you have one 'down' quarter, you have to either have moved some revenue into it from the previous quarter, or you have to be able to move some into it from the next quarter.  That obviously doesn't work consistently unless you're a fast-growing company, or have an extremely stable base.  It's also hard to do this in a legal-seeming fashion - technically this sort of manipulation is illegal, so decisions have to be justifiable.  Companies (like Microsoft) that are expanding can also do things to encourage slightly lower expectations.  A company in need of a stock price bump issues press releases touting its inventions and products as amazing things that will drive profits through the roof and an aggressive profit forecast - just as easy to issue a press release with a conservative forecast, meaning the bar will be lower to hit.   It's also not really necessary to manipulate earnings to have a consistently well-performing stock.  This article for example shows that companies who miss earnings estimates don't really suffer much (when controlling for their actual earnings changes, of course) in the long run.  Your price might drop a bit, but if your company is otherwise sound, it will recover. Finally, companies do sometimes come out with information ahead of earnings that cause expectations to be lowered.  7-Eleven for example just lowered its earnings expectations due to various reasons.  Some companies choose to do this in order to dilute the effect on the market.  I'm not sure if this is ever required, but it seems to me that some companies are much quicker to restate earnings expectations than others. "Some companies issue multiple classes of shares.  Each share may have different ratios applied to ownership rights and voting rights.  Some shares classes are not traded on any exchange at all.  Some share classes have limited or no voting rights.   Voting rights ratios are not used when calculating market cap but the market typically puts a premium on shares with voting rights. Total market cap must include ALL classes of shares, listed or not, weighted according to thee ratios involved in the company's ownership structure.  Some are 1:1, but in the case of Berkshire Hathaway, Class B shares are set at an ownership level of 1/1500 of the Class A shares. In terms of Alphabet Inc, the following classes of shares exist as at 4 Dec 2015: When determining market cap, you should also be mindful of other classes of securities issued by the company, such as convertible debt instruments and stock options.  This is usually referred to as ""Fully Diluted"" assuming all such instruments are converted." This is an old question that has an accepted answer, but it has gotten bumped due to an edit and the answers given are incorrect. I am assuming this means that every other Friday, the company is going into the open public market, buying those shares and then giving it out to the employees. No. Companies will internally hold shares that it intends to offer employees as additional compensation. There are no open market transactions, so the market price of the stock does not change (at least not due to buying pressure).  The only net effect is an equivalent expense for the compensation, but that should already be accounted for in the share price as normal operating expenses. These share may come through an initial buyback from the market, but more common is that when companies issue new shares they keep some internally for exactly this situation.  If they issued new shares every pay period, it would dilute the existing shares several times a quarter which would be difficult to account for. Of course it is a dilution of existing shareholders. When you buy milk in the supermarket - don't you feel your wallet diluted a little? You give some $$$ you get milk in return. You give some shares, you get Watsapp in return. That's why such purchases must go through certain process of approval - board of directors (shareholders' representatives) must approve it, and in some cases (don't know if in this particular) - the whole body of the shareholders vote on the deal. "I can see two possibilities. Either a deal is struck that someone (the company itself, or a large owner) buys out the remaining shares. This is the scenario @mbhunter is talking about, so I won't go too deeply into it, but it simply means that you get money in your bank account for the shares in question the same as if you were to sell them for that price (in turn possibly triggering tax effects, etc.). I imagine that this is by far the most common approach. The other possibility is that the stock is simply de-listed from a public stock exchange, and not re-listed elsewhere. In this case, you will still have the stock, and it will represent the same thing (a portion of the company), but you will lose out on most of the ""market"" part of ""stock market"". That is, the shares will still represent a monetary value, you will have the same right to a portion of the company's profits as you do now, etc., but you will not have the benefit of the market setting a price per share so current valuation will be harder. Should you wish to buy or sell stock, you will have to find someone yourself who is interested in striking a deal with you at a price point that you feel comfortable with." "Some companies issue multiple classes of shares.  Each share may have different ratios applied to ownership rights and voting rights.  Some shares classes are not traded on any exchange at all.  Some share classes have limited or no voting rights.   Voting rights ratios are not used when calculating market cap but the market typically puts a premium on shares with voting rights. Total market cap must include ALL classes of shares, listed or not, weighted according to thee ratios involved in the company's ownership structure.  Some are 1:1, but in the case of Berkshire Hathaway, Class B shares are set at an ownership level of 1/1500 of the Class A shares. In terms of Alphabet Inc, the following classes of shares exist as at 4 Dec 2015: When determining market cap, you should also be mindful of other classes of securities issued by the company, such as convertible debt instruments and stock options.  This is usually referred to as ""Fully Diluted"" assuming all such instruments are converted." There is normally a policy at the organisation that would restrict trades or allow trades under certain conditions. This would be in accordance with the current regulations as well as Institutions own ethical standards.  Typical I have seen is that Technology roles are to extent not considered sensitive, ie the employees in this job function normally do not access sensitive data [unless your role is analyst or production support]. An employee in exempt roles are allowed to trade in securities directly with other broker or invest in broad based Mutual Funds or engage a portfolio management services from a reputed organisation. It is irrelevant that your company only deals with amounts > 1 Million, infact if you were to know what stock the one million is going into, you may buy it slightly earlier and when the company places the large order, the stock  typically moves upwards slightly, enough for you to make some good money. That is Not allowed. But its best you get hold of a document that would layout the do' and don't in your organisation. All such organisation are mandated to have a written policy in this regard. Some investors (pension funds or insurance companies) need to pay out a certain amount of money to their clients. They need cash on a periodical basis, and thus prefer dividend paying stock more.