How does high frequency trading work if money isn't available for 2-3 days after selling?
Margin accounts do not have the problem you are imagining, which is unique to cash accounts High frequency trades are intra day. The would buy a stock for 100 and sell for 100.10 multiple times. So If you start with 100 in your broker account, you buy something [it takes 2-3 days to settle], you sell for 100.10 [it takes 2-3 days to settle]. You again buy something for 100. It is the net value of both buys and sells that you need to look at. Trading on Margin Accounts. Most brokers offer Margin Accounts. The exact leverage ratios varies. What this means is that if you start with 10 [or 15 or 25] in your broker you can buy stock of 100. Of course legally you wont own the stock unless you pay the broker balance, etc. Purchases and sales from the same trade date will both settle on the same settlement date. They don't have to pay for their purchases until later either. Because HFT typically make many offsetting trades -- buying, selling, buying, selling, buying, selling, etc -- when the purchases and sales settle, the amount they pay for their purchases will roughly cancel with the amount they receive for their sales (the difference being their profit or loss). Margin accounts and just having extra cash around can increase their ability to have trades that do not perfectly offset. In practice, the HFT's broker will take a smaller amount of cash (e.g. $1 million) as a deposit of capital, and will then allow the HFT to trade a larger amount of stock value long or short (e.g. $10 million, for 10:1 leverage). That $1 million needs to be enough to cover the net profit/loss when the trades settle, and the broker will monitor this to ensure that deposit will be enough. "As previously answered, the solution is margin. It works like this: You deposit e.g. 1'000 USD at your trading company. They give you a margin of e.g. 1:100, so you are allowed to trade with 100'000 USD.  Let's say you buy 5'000 pieces of a stock at $20 USD (fully using your 100'000 limit), and the price changes to $20.50 . Your profit is 5000* $0.50 = $2'500. Fast money? If you are lucky. Let's say before the price went up to 20.50, it had a slight dip down to $19.80. Your loss was 5000* $0.2 = 1'000$. Wait! You had just 1000 to begin with: You'll find an email saying ""margin call"" or ""termination notice"": Your shares have been sold at $19.80 and you are out of business. The broker willingly gives you this credit, since he can be sure he won't loose a cent. Of course you pay interest for the money you are trading with, but it's only for minutes. So to answer your question: You don't care when you have ""your money"" back, the trading company will always be there to give you more as long as you have deposit left. (I thought no one should get margin explained without the warning why it is a horrible idea to full use the ridiculous high margins some broker offer. 1:10 might or might not be fine, but 1:100 is harakiri.)"
I should also add that the 7/63 won't do much for you. If you're really interested in finance, you have a few options.  1) Sales - in which case the 7/63 is about all you need. The rest is just time and practice.  2) A job as an analyst. Your best bet here is to pursue the CFA charter.   3) A financial planner/advisor. This job is kind of a subcategory of #1. I always like to say that an advisor's primary job is to sell, giving meaningful advice is secondary. Nonetheless, a CFP is helpful here.  4) A trader. CFA charter is helpful here as with #2.  5) High Frequency Trading - Masters/PhD in math or a quant discipline and C++ is a must. The everyday investor buys at the ask and sells at the bid but the market maker does the opposite This is misleading; it has nothing to do with being either an investor or a market maker. It is dependent on the type of order that is submitted. When a market trades at the ask, this means that a buy market order has interacted with a sell limit order at the limit price. When a market trades at the bid, this means that a sell market order has interacted with a buy limit order at the limit price. An ordinary investor can do exactly the same as a market maker and submit limit orders. Furthermore, they can sit on both sides of the bid and ask exactly as a market maker does. In the days before high frequency trading this was quite common (an example being Daytek, whose traders were notorious for stepping in front of the designated market maker's bid/ask on the Island ECN). An order executes ONLY when both bid and ask meet. (bid = ask) This is completely incorrect. A transaction occurs when an active (marketable) order is matched with a passive (limit book) order. If the passive order is a sell limit then the trade has occurred at the ask, and if it is a buy limit the trade has occurred at the bid. The active orders are not bids and asks. The only exception to this would be if the bid and ask have become crossed. When a seller steps in, he does so with an ask that's lower than the stock's current ask Almost correct; he does so with an order that's lower than the stock's current ask. If it's a marketable order it will fill the front queued best bid, and if it's a limit order his becomes the new ask price. A trade does not need to occur at this price for it to become the ask. This is wrong, market makers are the opposite party to you so the prices are the other way around for them. This is wrong. There is no distinction between the market maker and yourself or any other member of the public (beside the fact that designated market makers on some exchanges are obliged to post both a bid and ask at all times). You can open an account with any broker and do exactly the same as a market maker does (although with nothing like the speed that a high frequency market-making firm can, hence likely making you uncompetitive in this arena). The prices a market maker sees and the types of orders that they are able to use to realize them are exactly the same as for any other trader. "Here I thought I would not ever answer a question on this site and boom first ten minutes.  First and foremost I am in the automotive industry, specifically one of our core competencies is finance department management consulting and the sales process both for the sale of the care as well  as  the financial transaction. First and foremost new vehicle gross profits are nowhere near 20% for the dealership.  In an entry level vehicle like say a Toyota Corolla there is only a  few hundreds of dollars in markup from invoice to M.S.R.P.  There is also something called holdback that dealers get for achieving certain goals such as sales volume. These are usually pretty easy to hit. As a matter of fact I have never heard of a dealer not getting the hold back on a deal.  This hold back is there to cover overhead for the car, the cost of getting it ready to sell, having a lot to park it on, making it ready for delivery, offset some of the cost of sales labor  etc.  Most dealerships consider the holdback portion of the invoice to not be part of the deal when it comes to  negotiations.  Certain brands such as KIA and Chrysler have something called ""Dealer Cash"" these payouts are usually stair stepped according to volume and vary by dealer, location, past history, how the guys at the factory feel that day and any number of combinations.  Then there is CSI or Customer Service Index payments, these payments are usually made every 1/4 are on the Parts Statement not the Sales Doc and while they effect the dealers bottom line they almost never affect the sales managers or sales persons payroll so they are not considered a part of the cost of the car.  They are however extremely important to  the dealer and this is  why after you have your new car they want you to bring in your survey for a free oil change or something.  IF you are going to give a bad survey they want to throw it away and not send it in, if you are going to give a good survey they want to  make sure you fill it out correctly.  This is because lets say they ask you on a scale of 1-10 how was your sales person and you put a 9 that is a failing score. Dumb I know but that is how every factory CSI score system I have seen worked.  According to NADA the average New Vehicle gross profit including hold back and dealer cash is around $1000.00.  No where near 20%.  Dealerships would love it if they made 20% on your new F250 Supercrew Diesel at around $50,000.00.  One last thing there is something on the invoice called Wholesale Finance Reserve.  This is the amount of money the factory forwards to the Dealership to offset the cost of financing vehicle on the floor plan so they can have it for you to look at before you buy.  This is usually equal to around 3 months of interest and while you might buy a vehicle that has been on the lot for 2 days they have plenty that have been there much longer so this equals out in a fair to middling run store. General Mangers that know what they are doing can make this really pad their net profit to statement. On to incentives, there are basically 3 kinds.  Cash to customer in the form of rebates, Dealer Cash in the form of incentives to dealerships based on volume or the undesirability of a vehicle, and incentive rates or Subvented leases.  The rates are pretty self explanatory as they advertised as such (example 0% for 60 Months).  Subvented Leased are harder to figure out and usually not disclosed as they are hard to explain and also a source of increased profit.  Subvented leases are usually powered by lower cost of money called a money factor (think of it as an interest rate) that is discounted from the lease company or a subsidized residual.  Subsidized residuals are virtually verboten on domestic vehicles due to their poor resell values.  A subsidized residual works like this, you buy a Toyota Camry and the ALG (automotive lease guide) says it has a residual at 36 months of 48%.  Well Toyota Motor Credit says we will give you a subvented residual of 60% basically subsidizing a 2% increase in residual.  Since they do not expect to be able to sell the car at auction for that amount they have to set aside the 2% as a future expense.  What does this mean to you, it means a lower payment.  Also a good rule of thumb if you are told a money factor by your salesperson to figure out what the interest rate is just multiply it by 2400.  So if a money factor is give of .00345 you know your actual interest rate is a little bit lower than 8.28% (illustration purposes only money factors are much lower than that right now). So how does this save you money well a lease is basically calculated by multiplying the MSRP by the residual and then subtracting that amount from the ""Capitalized Cost"" which is the Price paid for the car - trade in + payoff + TT&L-Rebate-Down Payment.  That is the depreciation.  Then you divide that number by the term of the loan and you have the depreciation amount.  So if you have 20K CC and 10K R your D = 10K / 36 = 277 monthly payment.  For the rest of the monthly payment you add (I think been a long time since I did this with out a computer) the Residual plus the CC for $30,000 * MF of .00345 = 107 for a total payment of 404 ish.  This is not completely accurate but you can use it to  make sure a salesperson/finance person is not trying to do one thing and  say another as so often happens on leases. 0% how the  heck do  they make money at that, well its simple.  First in 2008 the Fed made all the ""Captive"" lenders into actual banks instead of whatever they were before.  So now they have access to the Fed's discounting window which with todays monetary policies make it almost free money.  In the past these lenders had to go through all kinds of hoops to raise funds and  securitize loans even for super prime credit.  Those days are essentially over.  Now they get their short term money just like Bank of America does.  Eventually they still bundle these loans and sell them.  So in the short term YOU pay for the 0% by giving up part or all of your rebate.  This is really important DO NOT GIVE up your rebate for 0% unless it makes sense to do so.  When you can get the money at 2.5% and get a $7000.00 rebate (customer cash) on that F250 or 0% take the cash.  First of all make the finance guy/gal show you the the difference in total cost they can do do this using the federal truth in lending disclosures on a finance contract.  Secondly how long will you keep the vehicle?  If you come out ahead by say $1500 by taking the lower rate but you usually trade out every three years this is not going to work.  Also and this is important if you are involved in a situation with a total loss like a stolen car or even worse a bad wreck before the breakeven point you lose that price break.  Finally on judging what is right for you, just know that future value of the vehicle on for resell or trade-in will take into effect all of these past rebates and value the car accordingly.  So if a vehicle depreciates 20% a year for the first 3 years the starting point will essentially be $7000.00 less than you actually paid,  using rough numbers. How does this help the dealers and car companies?  Well while a dealer struggles to make money on new cars the factory makes all of their money on the  new cars and the new car financing.  While your individual loan might lose money that money is offset by the loss of rebate and I think Ford does actually pay Ford Motor Credit Company the difference in the rate.  The most important thing is what happens later FMCC now has 2500 loans with people with perfect credit.  They can now use those loans to budle with people with not so perfect credit that they financed at 12%-18% and buy that money with interest rates in the 2%-3% range.  Well that is a hell of a lot of profit.  'How does it help the dealership, well the more super prime credit they have in their portfolio the more subprime credit the banks will buy for them.  This means they have more loans originated that are more profitable for them.  Say you come in for the 0% but have 590 credit score, they get FMCC to buy the deal because they have a good portfolio and you win because the dealer gets to buy the money at say 9% and sell it to you at say 12% making the spread.  You win there because you actually qualified for a rate of around 18% with a subprime company like Santander or Capital One (yes that capital one) so  you save a ton on your overall cost of the car. Any dealership that is half way well run makes as much or money in the finance and insurance office than the rest of the dealership.  When you factor in what a good F&I Director can do to get deals done with favorable terms that really goes up.  Think about that the guys sitting a desk drinking coffee making more than the  service department guys all put together. Well that was long winded but there I broke down the car business for whoever read this far." There are 2 main types of brokers, full service and online (or discount). Basically the full service can provide you with advice in the form of recommendations on what to buy and sell and when, you call them up when you want to put an order in and the commissions are usually higher. Whilst an online broker usually doesn't provide advice (unless you ask for it at a specified fee), you place your orders online through the brokers website or trading platform and the commissions are usually much lower. The best thing to do when starting off is to go to your country's stock exchange, for example, The ASX in Sydney Australia, and they should have a list of available brokers. Some of the online brokers may have a practice or simulation account you can practice on, and they usually provide good educational material to help you get started. If you went with an online broker and wanted to buy Facebook on the secondary market (that is on the stock exchange after the IPO closes), you would log onto your brokers website or platform and go to the orders section. You would place a new order to buy say 100 Facebook shares at a certain price. You can use a market order, meaning the order will be immediately executed at the current market price and you will own the shares, or a limit price order where you select a price below the current market price and wait for the price to come down and hit your limit price before your order is executed and you get your shares. There are other types of orders available with different brokers which you will learn about when you log onto their website. You also need to be careful that you have the funds available to pay for the share at settlement, which is 3 business days after your order was executed. Some brokers may require you to have the funds deposited into an account which is linked to your trading account with them. To sell your shares you do the same thing, except this time you choose a sell order instead of a buy order. It becomes quite simple once you have done it a couple of times. The best thing is to do some research and get started. Good Luck. "My take on this is that with any short-selling contract you are engaging in, at a specified time in the future you will need to transfer ownership of the item(s) you sold to the buyer. Whether you own the item(s) or in your case you will buy your friend's used  car in the meantime (or dig enough gold out of the ground - in the case of hedging a commodity exposure) is a matter of ""trust"". Hence there is normally some form of margin or credit-line involved to cover for you failing to deliver on expiry." Because someone smarter than you by 50 IQ points (a quant) will depart their larger position long before you have a chance to see it coming. Your stop losses are useless as the market will open with the issue below your sell price. Your trade even if place at the same mine would settle after theirs. don't piss in the tall grass with the big dogs. If they are wrong or right does not matter you will be haircut or whipsawed. "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." First you will need a plan stating three main points: You will have to decide what criteria you will use to answer these points. You might use Fundamental Analysis to find what to buy and Technical Analysis to decide when to buy and when to sell (your buy and sell triggers). Once you have a Trading Plan in place you would need to find a broker with conditional orders. You can place conditional buy orders to get in a trade (for example if the price moves above or below a target price). You can place conditional stop loss orders if your trade goes against you, and you can also place conditional profit target stops to automatically get out if rises to your desired profit target. You can place one, two or many conditional orders after hours which will enable you to trade without being in front of your screen all day long.