why would someone buy or sell just a few shares in stocks
Simple, there is no magic price adjustment after sales - why do you expect the stock price to change? The listed price of a stock is what someone was willing to pay for it in the last deal that was concluded. If any amount of stock changes ownership, this might have the effect that other people are willing to buy it for a higher price - or not. It is solely in the next buyer's decision what he is willing to pay. Example: if you think Apple stocks are worth 500$ a piece, and I buy a million of them, you might still think they are worth 500$. Or you might see this as a reason that they are worth 505$ now. I buy or sell a few shares whenever I have a small amount of money to transfer into out of my mutual funds. Since I'm not paying transaction fees, there is no reason not to, when that is what makes sense. If you are paying a fee for each transaction, of course it makes sense to try to wait until you have a larger amount to move so the overhead per share is lower.
"Consider the futures market. Traders buy and sell gold futures, but very few contracts, relatively speaking, result in delivery. The contracts are sold, and ""Open interest"" dwindles to near zero most months as the final date approaches. The seller buys back his short position, the buyer sells off his longs.  When I own a call, and am 'winning,' say the option that cost me $1 is now worth $2, I'd rather sell that option for even $1.95 than to buy 100 shares of a $148 stock. The punchline is that very few option buyers actually hope to own the stock in the end. Just like the futures, open interest falls as expiration approaches." "A simple way to ask the question might be to say ""why can't I just use the same trick with my own shares to make money on the way down? Why is borrowing someone else's shares necessary to make the concept a viable one? Why isn't it just the inverse of 'going long'?"" A simple way to think about it is this: to make money by trading something, you must buy it for less than you sell it for.  This applies to stocks like anything else.  If you believe the price will go up, then you can buy them first and sell them later for a higher price.  But if you believe the price will go down, the only way to buy low and sell high is to sell first and buy later.  If you buy the stock and it goes down, any sale you make will lose you money. I'm still not sure I fully understand the point of your example, but one thing to note is that in both cases (i.e., whether you buy the share back at the end or not), you lost money.  You say that you ""made $5 on the share price dropping"", but that isn't true at all: you can see in your example that your final account balance is negative in both cases.  You paid $20 for the shares but only got $15 back; you lost $5 (or, in the other version of your example, paid $20 and got back $5 plus the depreciated shares). If you had bought the shares for $20 and sold them for, say, $25, then your account would end up with a positive $5 balance; that is what a gain would look like.  But you can't achieve that if you buy the shares for $20 and later sell them for less. At a guess, you seem to be confusing the concept of making a profit with the concept of cutting your losses.  It is true that if you buy the shares for $20 and sell them for $15, you lose only $5, whereas if you buy them for $20 and sell for $10, you lose the larger amount of $10.  But those are both losses.  Selling ""early"" as the price goes down doesn't make you any money; it just stops you from losing more money than you would if you sold later." The short answer, probably not much.  Unless you have a controlling interest in the company.  If at least 50%+1 of the shareholder votes are in favor of the dilution then it can be done.  There are some SEC rules that should protect against corporate looting and theft like what the Severin side is trying to make it appear as happened. However it would appear that Severin did something stupid.  He signed away all of his voting right to someone who would use them to make his rights basically worthless.  Had he kept his head in the game he could probably have saved himself.  But he didn't. If your average startup started issuing lots of stock and devaluing existing shares significantly then I would expect it would be harder to find investors willing to watch as their investment dwindled.  But if you are issuing a limited amount stock to get leverage to grow bigger then it is worth it.  In the .com bubble there were quite a few companies that just issued stock to buy other companies.  Eventually most of these companies got delisted because they diluted them selves to much when they were overvalued. Any company not just a startup can dilute its shares.  Many if not most major companies issue stock to raise capital.  This capital is then generally used to build the business further and increase the value of all shares.  Most of the time this dilution is very minor (<.1%) and has little if any impact on the stock.  There are rules that have to be followed as listed companies are regulated by the SEC.  There are less regulations with private corporations.  It looks like the dilution was combined with the buyout of the Florida company which probably contributed to the legality of the dilution.     With options they are generally issued at a set price.  This may be higher or lower than the reported sell price of the stock when the option is issued.  The idea is over time the stock will increase in value so that those people who hold on to their options can buy the stock for the price listed on the option.  I worked at an ISP start up in the 90's that made it pretty well.  I left before the options were issued but I had friends still there that were issued an option at $16 a share the value of the stock at the time of the issue of the option was about 12.  Well the company diluted the shares and used them to acquire more ISP's unfortunately this was about the time that DSL And cable internet took off so the dial up market tanked.  The value eventually fell to .10 they did a reverse split and when they did the called in all options.  The options did not have a positive cash value at any time.  Had RMI ever made it big then the options could have been worth millions.  There are some people from MS and Yahoo that were in early that made millions off of their options.  This became a popular way for startups to attract great talent paying peanuts.  They invested their time in the business hoping to strike gold.  A lot of IT people got burned so this is less popular among top talent as the primary compensation anymore. "When you buy a share of stock, you are almost always buying from someone who previously purchased that share and now wants to sell it. The money -- minus broker's fee -- goes to that other investor, which may be a person, a company (rarely the company that issued the stock, but that will occasionally be the case), an investment fund, the ""market maker"" for that stock (websearch for definition of that term), or anyone else. They owned a small percentage of the company; you bought it from them and gave them the money for it, just as you would buy anything else. You don't know or care who you bought from; they don't know or care who they sold to; the market just found a buyer and seller who could agree on the price. There are a very few exceptions to that. The company may repurchase some of its own shares and/or sell them again, depending on its own financial needs and obligations. For example, my own employer has to purchase its own shares periodically so it has enough on hand to sell to employees at a slight discount  through the Employee Stock Ownership Program. But you generally don't know that's who you're selling to; it happens like any other transaction. And during the Initial Public Offering, if you're lucky/privileged enough to get in on the first wave of purchases, you're buying from the investment bank that's managing this process ... though that's an almost vanishingly rare case for ""retail"" investors like us; we're more likely to get the shares after someone has already pushed the price up a bit. But really, when you buy a share the money goes to whoever you bought it from, and that's all you can know or need to know." There are several problems with your reasoning: if I buy one share of GOOGLE now for $830, I could have $860 within the end of tonight -- totally possible and maybe even likely. You can do the same thing with 1,000,000 shares of google, and it's just as likely to go down as go up.   if I were to invest $1,000.00 in gold to have $1,000.00 worth of gold, it's no different than keeping $1,000.00 in cash It's VERY different.  Gold can be just as volatile as stocks, so it certainly is different as just keeping it in cash. Benefits of a larger portfolio: Originally, stocks were ownership in a company just like any other business- you expected to make a profit from your investment, which is what we call dividends to stock holders. Since these dividends had real value, the stock price was based on what this return rate was, factoring in what it might be expected to be in the future, etc.  Nowdays many companies never issue any dividends, so you have to consider the full value of the company and what benefit could be gained by another company if it were to acquire it. the market will likely adjust the share price to factor in what the value of the company might be to an acquirer.  But otherwise, some companies today trading at an astronimical price, and which nevers pays a dividend- chalk it up to market stupidity. In this investor'd mind, there is no logical reason for these prices, except based on the idea that someone else might pay you more for it later... for what reason? I can't figure it out. Take it back to it's roots and imagine pitching a new business idea to you uncle to invest in- it will make almost nothing compared to it's share price, and even what it does make it won't pay anything to him for his investment. Why wouldn't he just laugh at you? "Ditto to MD-Tech, but from a more ""philosophical"" point of view: When you buy stock, you own it, just like you own a cell phone or a toaster or a pair of socks that you bought. The difference is that a share of stock means that you own a piece of a corporation. You can't physically take possession of it and put it in your garage, because if all the stock-holders did that, then all the company's assets would be scattered around all the stock-holder's garages and the company couldn't function. Like if you bought a 1/11 share in a football team, you couldn't take one of the football players home and keep him in your closet, because then the team wouldn't be able to function. (I might want to take one of the cheerleaders home, but that's another subject ...) In pre-electronic times, you could get a piece of paper that said, ""XYZ Corporation - 1 share"". You could take physical possession of this piece of paper and put it in your filing cabinet. I'm not sure if you can even get such certificates any more; I haven't seen one in decades. These days it's just recorded electronically. That doesn't mean that you don't own it. It just means that someone else is keeping the records for you. It's like leaving your car in a parking lot. It's still your car. The people who run the parking lot doesn't own it. They are keeping it for you, but just because they have physical possession doesn't make it theirs." "As the other answer said, the person who owns the lent stock does not benefit directly.  They may benefit indirectly in that brokers can use the short lending profits to reduce their fees or in that they have the option to short other stocks at the same terms.   Follow-up question: what prevents the broker lending the shares for a very short time (less than a day), pocketing the interest and returning the lenders their shares without much change in share price (because borrowing period was very short). What prevents them from doing that many times a day ? Lack of market.   Short selling for short periods of time isn't so common as to allow for ""many"" times a day.  Some day traders may do it occasionally, but I don't know that it would be a reliable business model to supply them.  If there are enough people interested in shorting the stock, they will probably want to hold onto it long enough for the anticipated movement to happen.   There are transaction costs here.  Both fees for trading at all and the extra charges for short sale borrowing and interest.  Most stocks do not move down by large enough amounts ""many"" times a day.  Their fluctuations are smaller.  If the stock doesn't move enough to cover the transaction fees, then that seller lost money overall.  Over time, sellers like that will stop trading, as they will lose all their money.   All that said, there are no legal blocks to loaning the stock out many times, just practical ones.  If a stock was varying wildly for some bizarre reason, it could happen."