There are two types of ways to buy shares on the Australian exchange (ASX): Market Orders and Limit Orders.
📊 Market Orders
Market Orders give you the certainty that the amount of shares you’ve selected will be bought and processed by your broker as quickly as possible.
The order screen will show you the estimated total price for your order based on the most recently listed share price - but if the unit price has changed by the time the order is processed, you’ll pay the most up-to-date price (whether higher or lower).
You can only place Market Orders during ASX trading hours (Monday to Friday between 10am and 4pm AEST, excluding public holidays or periods of suspended trade).
These orders are most commonly used by traders who know that they want to buy a certain number of shares and have it fulfilled as quickly as possible - brokers give Market Orders processing priority.
🧾 Limit Orders
Limit Orders are more often used by traders who only want to purchase at a certain price, and are happy to wait without making any purchase if their selected price doesn't become available within the order expiry period (you can set this to 7, 15 or 30 days).
If you placed a Limit Order at $10.00 for 1,000 shares in XYZ stock, your order would only be placed if the price dropped to $10.00.
If the price stayed above your limit (e.g. $10.05 or higher) for the full order period, your order would expire without any shares being purchased.
If you would like to place a Buy Order outside of the market trading hours, you can only do so by placing a Limit Order. These will go into a queue for your broker to process once trading has resumed.
🧮 Partially completed orders
Both Market Orders and Limit Orders may only be partially completed in certain circumstances. This might occur if (although not limited to) you are placing large orders, trading in-demand stocks, or ordering around the open or close of market hours. Limit Orders may also only be partially completed if your nominated unit price becomes available, but for fewer shares than you initially ordered.