An “all-or-none” (AON) order is a type of buy or sell trade that instructs the broker to execute the entire order at once, or not at all. The directive to the broker keeps the order active until it is ultimately executed per its instructions or canceled.
If you enter an AON order to buy 5,000 shares, you are requesting that none of the order be executed unless it is for the entire 5,000 shares. If the broker was able to buy 4,500 shares at one price and 500 shares at another, the order won’t be executed.
A limit all-or-none order is a regular AON order with a specific price target. Defined by the investor for the broker, the limit is a restriction on the maximum price to be paid or the minimum price to be received for the stock.
For example, if you wanted to purchase 5,000 shares of Company Alpha at $15.00 per share all or none, the broker would have to find all 5,000 shares at $15.00 to complete the transaction. If the broker could transact 4,500 shares at $15.00 and 500 at $15.15, then the order wouldn’t go through.
Should I do all or none in stock trading?
For retail investors, an AON order prevents you from having orders partially filled. This order is most useful for stocks with liquid market demand, such as Apple Inc. 
(AAPL). If you place an AON stock order, understand that the order may not be speedily executed by your broker, especially if the stock is thinly traded.
Keep in mind that brokers also give priority to orders without trade conditions. Because an AON order is set with conditions, it may take longer to execute than other order types.
The size and price limit of the AON order matter to how executable the trade is. Large AON orders on illiquid stocks are harder to execute because they represent a greater portion of the shares trading that day. The broker will have less opportunity throughout the trading day to execute your orders.
Closing
Setting an all-or-none condition to your trade orders will ensure that a broker will only execute your entire order if it can do so all at once in a single transaction. AON orders can be made even more specific with the addition of a price limit on the trade. These order limits work best for stocks with decent daily trading activity, or for buying stocks based on specific factors, such as valuation.
However, for the average individual investor, the drawbacks of an AON order may outweigh the benefits. AON designation may make an order impossible to execute due to its limitations on the broker.
