How to execute a large stock purchase, relative to the order book?
What is the average daily volume traded? It looks like this stock may have a liquidity problem. If that is the case I would not buy this stock at all as you may have the same problem when you try to sell it. Generally try to stay away from illiquid stocks, if your order size is more than 10% of the average daily volume traded, then don't buy it.  I usually stay away from stocks with an average daily volume of less than 100,000. I am able to place an 'all or none' order with my broker. But doing so reduces the number of potential sources to fulfill the order. As others have mentioned, try a limit order to get a specific price. I normally just do a buy limit at the price I want to buy it at. Then it executes when it's that price or lower, but there's still a chance you might purchase some shares at a larger price. But since we're small fry and using brokerages, there's not much we can do about it.
Most stocks are not actively trades by lots of people.   When you buy or sell a stock the price is set by the “order book” – that is the other people looking to trade in the given stock at the same time. Without a large number of active traders, it is very likely the pricing system will break down and result in widely changing prices second by second.   Therefore for the market to work well, it need most people to be trading at the same time. "This is a technical term referring to the ""double entry""-styled book keeping of trades by brokers. Suppose a client executes a buy order with their broker.  The broker's accounting for this ""trade"" will be recorded as two different ""deals"" : One ""deal"" showing the client as buyer and the broker as seller, and a second ""deal"" showing the broker as buyer and the clearing house as seller.  The net result of these two deals is that the broker has no net position while the client has a net buy and the clearing house has a net sell with respect to this broker's account as accounted for internally by the broker. (And the same methods apply for a client sell order.) The client/broker ""deal"" record - i.e., the client side of the trade - is called the ""client side booking"", while the broker/clearing house ""deal"" record is called the ""street side booking""." In general, how does a large open market stock sale affect prices? A very general answer, all other things being equal, the price will move down. However there is nothing general. It depends on total number of shares in market and total turn over for that specific shares. The order book for the day etc. What is the maximum percentage of a company you could sell per day before the trading freezes, and what factors matter? Every stock exchange has rules that would determine when a particular stock would be suspended from trading, generally a 10-20% swing [either ways]. Generally highly liquid stock or stock during initial listing are exempt from such limits as they are left to arrive the market price ...  A large sell order may or may not swing the price for it to get suspended. At times even a small order may do ... again it is specific to a particular stock. You need to use one of each, so a single order wouldn't cover this:  The stop-loss order could be placed to handle triggering a sell market order if the stock trades at $95 or lower.  If you want, you could use a stop-limit order if you have an exit price in mind should the stock price drop to $95 though that requires setting a price for the stop to execute and then another price for the sell order to execute. The limit sell order could be placed to handle triggering a sell if the stock rises above $105. On the bright side, once either is done the other could be canceled as it isn't applicable anymore. "You might consider learning how the ""matching"" or ""pairing"" system in the market operates.  The actual exchange only happens when both a buyer and a seller overlap their respect quotes.   Sometimes orders ""go to market"" for a particular volume.  Eg get me 10,000 Microsoft shares now.  which means that the price starts at the current lowest seller, and works up the price list until the volume is met.  Like all market it trades, it has it's advantages, and it's dangers.  If you are confident Microsoft is going to bull, you want those shares now, confident you'll recoup the cost.  Where if you put in a priced order, you might get only none or some shares. Same as when you sell.  If you see the price (which is the price of the last completed ""successful"" trade.  and think ""I'm going to sell 1000 shares"". then you give the order to the market (or broker), and then the same as what happened as before.  the highest bidder gets as much as they asked for, if there's still shares left over, they go to the next bidder, and so on down the price... and the last completed ""successful"" trade is when your last sale is made at the lowest price of your batch. If you're selling, and selling 100,000 shares. And the highest bidder wants 1,000,000 shares you'll only see the price drop to that guys bid.  Why will it drop (off the quoted price?).  Because the quoted price is the LAST sale, clearly if there's someone still with an open bid on the market...then either he wants more shares than were available (the price stays same), or his bid wasn't as high as the last bid (so when you sale goes through, it will be at the price he's offering).   Which is why being able to see the price queues is important on large traders. It is also why it can be important put stops and limits on your trades, een through you can still get gapped if you're unlucky.  However putting prices (""Open Orders"" vs ""(at)Market Orders"") can mean that you're sitting there waiting for a bounce/spike while the action is all going on without you). safer but not as much gain (maybe ;) ) that's the excitement of the market, for every option there's advantages...and risks... (eg missing out) There are also issues with stock movement, shadowing, and stop hunting, which can influence the price. But the stuff in the long paragraphs is the technical reasons." "You need to negotiate with your broker to allow you to do more exotic order types.  One in particular I recommend is a ""hidden"" aka iceberg order.  You enter two numbers.  The first is the number of shares for your entire order, the second is the amount that will be displayed in the book (this is the tip of the iceberg, the remaining shares are hidden below the surface). The maker/taker rule applies as follows: The amount displayed will receive the rebate for providing liquidity.  The amount hidden will be charged the fee for taking liquidity. Example: You want to sell 10,000 shares total.  You enter a hidden order for 10,000 shares with 1,000 displayed.  On the level 2 screen traders will see 1,000 shares, and those shares will stay displayed there until the entire order is filled.  You receive a rebate for 1,000 shares, you pay the brokerage fee for 9,000 shares. Also, like one of the previous posters mentioned, only trade high liquidity stocks.  Large market cap companies with high volume.  This is why day traders love Tesla, Amazon, Netflix, etc. Large market cap, high volume, and high volatility.  Easy to catch $10+ moves in price. Hope this helps Happy trading" Have you looked into GnuCash? It lets you track your stock purchases, and grabs price updates. It's designed for double-entry accounting, but I think it could fit your use case. I have an ESPP with E*Trade; you can transfer stock like that via a physical (paper) asset-transfer form. Look for one of those, and if you can't find it, call your brokerage (or email / whatever). You own the shares, so you can generally do what you want with them. Just be very careful about recording all the purchase and transfer information so that you can deal properly with the taxes.