Can There Be Partial Trade Fill Percentage?
"I place a trade, a limit order on a thinly traded stock. I want to buy 1000 shares at $10. The current price is $10.50. Someone places a market order for 500 shares. Another trader has a limit order for $10.10 for 400 shares. His order fills, and I get 100 at my price. I wait another day to see if I get any more shares. This is just an example of how it can work. I can place my order as ""all or none"" if I wish to avoid this."
But what about the following scenario which is my paraphrasing of a Nanex article (I'm hoping you can help clarify this for me).  1. I observe a 1,000 lot @$10 advertised for Sell on a lit exchange.  2. I try to lift the 1,000 by placing a limit order @10.  3. My order goes through some kind of order routing process. First, 3 orders get executed on a dark pool. Let's say I got a 50 lot filled (so available offer reduces to 950).  4. My order hits a lit exchange. I get a partial fill for 100 (offer shrinks to 850); but the offered size shrinks instead to 500. Or 0.  5. Now, in order to execute my trade, I will have to take a higher price than the original advertised liquidity.  My question (maybe you can answer this) is why did my original order size of 1,000 appear in smaller blocks? Is this because the order routing algorithm breaks up the size?  Or is it that market makers only post offers in small block sizes (e.g. 100) So even if the order book looked like:  100 @ 10  100 @ 10  100 @ 10  100 @ 10  100 @ 10  100 @ 10  All the way to 1,000 total -- as soon as the first 100 shares were lifted, the MM can immediately cancel the remainder of the advertised liquidity -- in practical terms making it impossible to execute large orders at an advertised price. "Yes, there is a lot they are leaving out, and I would be extremely skeptical of them because of the ""reasons"" they give for being able to charge $0 commissions. Their reasons are that they don't have physical locations and high overhead costs, the reality is that they are burning venture capital on exchange fees until they actually start charging everyone they suckered into opening accounts. They also get paid by exchanges when users provide liquidity. These are called trade rebates in the maker-taker model. They will start offering margin accounts and charging interest. They are [likely] selling trade data to high frequency trading firms that then fill your stock trades at worse prices (Robinhood users are notorious for complaining about the fills). They may well be able to keep commissions low, as that has been a race to the bottom for a long time. But if they were doing their users any actual favors, then they would be also paying users the rebates that exchanges pay them for liquidity. Robinhood isn't doing anything unique as all brokers do what I mentioned along with charging commissions, and it is actually amazing their sales pitch ""$0 commissions because we are just a mobile app lol"" was enough for their customers. They are just being disingenuous." Should do it through a limit auction book.   Management and shareholders pre ipo submit sealed limit sell orders. Buyers submit sealed limit buy orders, nobody can see where the price is going.  At 9AM, the price is calculated and whomever fills get filled and ta da everyone is trading at 9:30 when the market is open. Long time /r/economy subscriber and early Ethereum investor here.  I'm 100% biased (full disclosure) but I believe this tech has legs.  There are a lot of companies backing it, governments exploring it and developers building upon it.  It's currently at $365 with a $35bil market cap.  Look for 3 upgrades in the works:  1) Raiden - Should increase transaction capabilities to that of Visa 2) Sharding - Allows for lite clients and partial downloads of the nodes 3) Proof of Stake - No more video card farms wasting electricity.  Put your ethereum as stake to help the network reach consensus and earn a percentage return  I've you've got commodities in your portfolio, I would strongly suggest taking a look at Ethereum "As an exercise, I want to give this a shot.  I'm not involved in a firm that cares about liquidity so all this stuff is outside my purview.  As I understand it, it goes something like this: buy side fund puts an order to the market as a whole (all or most possibly exchanges).  HFTs see that order hit the first exchange but have connectivity to exchanges further down the pipe that is faster than the buy side fund.  They immediately send their own order in, which reaches exchanges and executes before the buy side fund's order can.  They immediately put up an ask, and buy side fund's order hits that ask and is filled (I guess I'm assuming the order was a market order from the beginning).  This is in effect the HFT front running the buy side fund.    Is this accurate?  Even if true, whether I have a genuine issue with this... I'm not sure.  Has anyone on the ""pro-HFT"" side written a solid rebuttal to Lewis and Katsuyama that has solid research behind it?" You can ask for 305rs, but as long as shares are available at lower prices you won't sell. Only when your ask becomes the lowest available price will someone buy from you. See many past questions about how buyers and sellers are matched by the market. Bid and ask prices are the reigning highest buy price and lowest sell price in the market which doesn't mean one must only buy/sell at thise prices. That said one can buy/sell at whatever price they so wish although doing it at any other price than the bid/ask is usually harder as other market participants will gravitate to the reigning bid/ask price. So in theory you can buy at ask and sell at bid, whether or not your order will be filled is another matter altogether. Theoretically IRP works, in practice is a whole new game... I've been longing EURCHF leveraged up at the floor and collecting the rate differential.  When the ECB cuts rates i'll close the trade...  These are called carry trades and more commonly done right now with bonds.