Your stockbroker or brokerage service will always try to buy or sell the specified number of shares in your limit order, but this is not always possible, especially if your limit order is for a large number of shares. Investors can prevent their limit order from being split by designating it as a "fill or kill" order. This requires all the shares in your limit order to be bought or sold, or the limit order is canceled. You would then have to place your limit order again if you want the same terms. Investors also can designate limit orders as "all or none." This prevents the limit order from being split but keeps the limit order active in case the stock price reaches your limit order price again. Keeping your entire order intact saves on fees. A split order can be treated as two different transactions. [links]