Methinks perhaps you need to do some homework on how the ASX...

Methinks perhaps you need to do some homework on how the ASX operates these days. It's called TradeMatch - personally I hate it almost as much as shorting, as it is designed to make things easier for the bot traders (algorithmic trading computers):

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January 2011
ASX TradeMatch® Advanced Order Types

Centre Point Order®

A Centre Point Order® enables execution at the prevailing midpoint of the best bid and offer of the ASX Central Limit Order Book (CLOB). These anonymous orders transact independently of the CLOB and will only transact with another Centre Point Order®. Once a Centre Point order trades, the trade will be displayed in the trade history window with condition code CX.

View ASX Centre Point Market Impact Research Paper (PDF 585KB)

Centre Point Crossing

The Centre Point Crossing enables an ASX Participant to cross at the midpoint of the prevailing best bid and offer in the ASX CLOB. Centre Point Crossings provide greater flexibility to the liquidity search process by removing the so-called ACE requirement to Appear, Create before Executing.

The functionality will provide for a 30 second opportunity between initiating a crossing and executing it at the price that existed at initiation (i.e. the crossing execution price remains available to the Participant irrespective of any movement in the ASX CLOB for that Cash Equity during the 30 second period). Once a Centre Point Crossing order trades, the trade will be displayed in the trade history window with condition code CXXT.

Undisclosed Orders

Undisclosed Orders will be undisclosed to the general market as to volume, but disclosed as to price - provided the order size is above a specified threshold of AU$500,000. Undisclosed Orders execute in the same way as regular limit orders as to price, time priority. The hidden volume of Undisclosed Orders becomes displayed once the remaining volume of the order falls below the specified threshold. In the order book window Undisclosed Orders will be displayed in the quantity field as /u and will be displayed in the order history window in accordance with current practices for standard orders.

Iceberg Orders

Iceberg Orders will provide for large limit orders where only a portion (the displayed volume) of the total order volume will be shown and immediately executable. The displayed volume acts as a limit order in terms of price-time priority execution.

Once the displayed volume has been executed, the Iceberg Order will drop to the bottom of the time queue at its specified price, and the displayed volume will be replenished from the hidden portion of the order. The order cycles through until the total volume is executed. Iceberg Orders are essentially very simple algorithms with latency as close to zero as is possible given the functionality resides in the ASX trading engine.

View Iceberg Orders factsheet (PDF 334KB)

View New Order Types ebooklet

View the Iceberg Webinar

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http://www.asx.com.au/trading_services/new_market_services.htm