Why is a stock trade flat on large volume?
Large volume just means a lot of market participants believe they know where the stock price will be (after some amount of time).  The fact that the price is not moving just means that about 50% of those really confident traders think the stock will be moving up, and about 50% of those really confident traders think the stock will be moving down.
You need a source of delisted historical data.  Such data is typically only available from paid sources. According to my records 20 Feb 2006 was not a trading day - it was Preisdent's Day and the US exchanges were closed. The prior trading date to this was 17 Feb 2006 where the stock had the following data: Open: 14.40 High 14.46 Low 14.16 Close 14.32 Volume 1339800 (consolidated volume) Source: Symbol NVE-201312 within Premium Data US delisted stocks historical data set available from http://www.premiumdata.net/products/premiumdata/ushistorical.php Disclosure: I am a co-owner of Norgate / Premium Data. It is unlikely that buying 100 shares will have any effect on a stock's price, unless the stock's average trading volume is incredibly low.  That being said, no matter how many share you buy, there's no way to know what the impact on the price will be, because that's only one factor in how shares are priced.  If anyone could figure out the answer to your question then they'd be extremely rich, because they'd simply watch for big share trades and then buy those stocks on the way up. The market makers who actually execute the trades are the ones who set the prices, and most stocks have multiple market makers trading the stock, so the bid/ask you see is the highest bid and lowest ask.  The market makers set the price based on what the trend of the stock is.  If, for instance, there's a large number of sell orders against a stock, the market makers will start dropping the bid prices as they fill execution orders, and as they see buy orders increase, they'll raise ask prices as they fill execution orders.  The market makers earn the difference between what they paid to buy someone's stock who was selling and what they get from someone else who buys it. This is a simplified explanation, so pro traders, don't beat me up! (grin) So, basically, it takes quite a bit of share volume in one direction or another to affect a stock's price.  I can guarantee a 100-share trade wouldn't even be noticed by market makers. I hope this helps. Good luck! In general stock markets are very similar to that, however, you can also put in limit orders to say that you will only buy or sell at a given price. These sit in the market for a specified length of time and will be executed when an order arrives that matches the price (or better). Traders who set limit orders are called liquidity (or price) makers as they provide liquidity (i.e. volume to be traded) to be filled later. If there is no counterparty (i.e. buyer to your seller) in the market, a market maker; a large bank or brokerage who is licensed and regulated to do so, will fill your order at some price. That price is based on how much volume (i.e. trading) there is in that stock on average. This is called average daily volume (ADV) and is calculated over varying periods of time; we use ADV30 which is the 30 day average. You can always sell stocks for whatever price you like privately but a market order does not allow you to set your price (you are a price taker) therefore that kind of order will always fill at a market price. As mentioned above limit orders will not fill until the price is hit but will stay on book as long as they aren't filled, expired or cancelled. You can't tell for sure.  If there was such a technique then everyone would use it and the price would instantly change to reflect the future price value. However, trade volume does say something.  If you have a lemonade stand and offer a large glass of ice cold lemonade for 1c on a hot summer day I'm pretty sure you'll have high trading volume.  If you offer it for $5000 the trading volume is going to be around zero. Since the supply of lemonade is presumably limited at some point dropping the price further isn't going to increase the number of transactions.   Trade volumes reflect to some degree the difference of valuations between buyers and sellers and the supply and demand.  It's another piece of information that you can try looking at and interpreting.  If you can be more successful at this than the majority of others on the market (not very likely) you may get a small edge.  I'm willing to bet that high frequency trading algorithms factor volume into their trading decisions among multiple other factors. If one wants to have a bound on the loss percentages that are acceptable, this is would be a way to enforce that. For example, suppose someone wants to have a 5% stop-loss but doesn't want this to be worse than 10% as if the stock goes down more than 10% then the sell shouldn't happen. Thus, if the stock opened in a gap down 15% one day, this triggers the stop-loss and would exit at too low of a price as the gap was quite high as I wonder how familiar are you with how much a stock's price could change that makes the prices not be as continuous as one would think. At least this would be my thinking on a volatile stock where one may want to try to limit losses if the stock does fall within a specific range. If you look at a trade grid you can see how this happens. If there are enough bids to cover all shares currently on the sell side at a certain price, those shares will be bought and increased price quotes will be shown for the bids and ask. If there are enough bids to cover this price, those will get bought and higher prices will be shown and this process will repeat until the sell side has more power than the buy side. It seems like this process is going on all day long with momentum either on the upside or downside. But I think that much of this bidding and selling is automatic and is being done by large trading firms and high tech computers. I also feel that many of these bids and asks are already programmed to appear once there is a price change. So once one price gets bought, computers will put in higher bids to take over asks. It's like a virtual war between trading firms and their computers. When more money is on the buy side the stock will go up, and vice versa. I sort of feel like this high-frequency trading is detrimental to the markets and doesn't really give everyone a fair shot. Retail investors do not have the resources and knowledge in order to do this sort of high frequency trading. It also seems to go against certain free market principles in my opinion. If you're talking about an ETF trading on Arca, it's probably because of the opening auction: The match price is the price that maximizes the volume that can be executed within the Auction Collars. The Core Open Auction will use the match price closest to the closing price of the previous trading day (based on normal market hours) if more than one indicative match price is valid. The core opening auction doesn't really take the opening session activity into account, as you can see - the market runs an auction and whatever price clears the most volume, within certain limits, is the opening print. "What you are saying is a very valid concern.  After the flash crash many institutions in the US replaced ""true market orders"" (where tag 40=1 and has no price) with deep in the money limit orders under the hood, after the CFTC-SEC joint advisory commission raised concerns about the use of market orders in the case of large HFT traders, and concerns on the lack of liquidity that caused market orders that found no limit orders to execute on the other side of the trade, driving the prices of blue chip stocks into the pennies.  We also applaud the CFTC requesting comment regarding whether it is   appropriate to restrict large order execution design that results in   disruptive trading. In particular, we believe there are questions   whether it is ever appropriate to permit large order algorithms that   employ unlimited use of market orders or that permit executions at   prices which are a dramatic percentage below the present market price   without a pause for human review So although you still see a market order on the front end, it is transformed to a very aggressive limit in the back end. However, doing this change manually, by selling at price 0 or buying at 9999 may backfire since it may trigger fat finger checks and prevent your order from reaching the market.  For example BATS Exchange  rejects orders that are priced too aggressively and don't comply with the range of valid prices.  If you want your trade to execute right now and you are willing to take slippage in order to get fast execution, sending a market order is still the best alternative."