Generally the bulk of retail trade through commsec, etrade, open markets etc and a couple of others. I'm pretty sure Australian Investments Exchange or something to that effect is Netwealth share trading. 239 is interactive brokers. You can prob email OM for a list of the broker names and codes.
Then you have the investment banks, Morgan Stanley, Goldman, Deutsche etc. So generally you'd consider them the pros.
In the middle is the boutique brokers, they are the ones I pay most attention to as I'm sure most do. They are the Soph and HNW type of brokers, they generally are involved in most of the CR on ASX specs. Pattos, Pershing, Hartleys, Shaw, Bell etc.
Broker data isnt the be all and end all imo tho.
1) It only has ASX traded vol so no Chi-X which leaves it open to sort of "manipluation" if one was so inclined. Offloading through chi to "hide" it if you get me.
(So if a stock im watching is getting belted with supply or line wiped to the max, I'll look to see if most of the selling/buying is through the chi or ASX before I draw a conclusion on the broker data)
2) Also the "retail" and "pro" broker lines are blurry. For instance i use FP for my active trading account and they clear through Deustche (their prime broker i assume).
3) i know that some gun traders and big players use commsec, so their moves would come under the "retail" banner.
(Example: If you look at QNL last year you can marry up the change of holder notices for Shaun Factor and the GTT guys with the volume going through commsec)
However, generally retail (non 708 at least) wont be clearing through the mid tier brokers i mentioned above.
So its pretty handy as an extra tool. As an example of how i use it.
If you look at MQR for the last 2-3 months youll see Hartleys have been loading up 32m odd shares at around 40+c. Then MQR do a raise at 35c through Hartelys and the SP never even glimpses at that on market and instead its bought up to 50c that day. To me this is extremely bulish as IMO it seems like some hartleys clients have been trying hard to accumulate a decent position and have either approached MQR for a raise when it got too hard, too tight, or MQR went to Hartleys. Either way, it says to me that they arent just gonna flip it for pips next week.
Im on the phone but i can post the broker data soon as an example if you want.
I haven't been using it long but hope that helps a bit.
(20min delay)