Open auction / match pricing - how does this work?

  1. 1,219 Posts.
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    Hi,

    In the broad brushstrokes, I get that open auction matches the buyers and the sellers and trades are made where the price paid may not be the price that buyers/sellers bid and offered at. However, I am struggling to be able to understand the specifics of how this works so that I can estimate what I will pay to buy (or receive if selling).

    Using today's figures for MEP, I haven't been able to crank a spreadsheet to get the numbers shown in IRESSTrader below. Can anybody show me how this works?

    https://hotcopper.com.au/data/attachments/2680/2680189-77aa183537e1ce7cabbab4ef14d8c7d0.jpg
    https://hotcopper.com.au/data/attachments/2680/2680193-138f87865d8d200f4f071df957e55b34.jpg

    I have a follow up question about buy orders where my buy will take out, say, two lines.

    For instance, I want to buy 100,000 XXX and the Asks are 50,000 at 10 cents and 50,000 at 11 cents.
    - If I place an order for 100,000 at 11 cents do I pay 11 cents for all the shares or half at 10 and half at 11 i.e. average of 10.5?
    - If I place an At Market order does my buy take out the 10 cent line and then wait for sellers to drop to 10 cents or take out the 11 cent line as well?

    Thanks in advance for any clarity on this.

    Keith
 
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