PPH, you said "they could fix most of the problems here by allowing visibility of broker codes - then anyone could see who was an institutional buyer and who was an e-trader pretending to be" but I don't get - just because someone is on eTrade are they less likely (or not allowed) to make multiple trades or large trades? Or are the trading patterns between small and large so obviously different? Also, eTrade has many, many users. All their orders will be identified as being from eTrade. What will this tell you?
Also, I was an eTrade user until recently. I'm now on CommSec. There is a big, big difference between the two. With eTrade you need to have the cleared funds in the eTrade account to place a buy order. When you place the order, these funds are then locked. With CommSec the money only needs to be there when you settle on T+3. Therefore with CommSec I could literally have multiple orders out there worth millions and (I assume) they would not care. What I am getting at is that it is theoretically easier with CommSec to place dummy orders than it is with eTrade.
This reminds me of the recent regulation of the real estate auction process here in Melbourne about a year or two ago. Dummy bidding was finally outlawed at that point. Until then vendor bids were rife but never had to be disclosed. Now they must be disclosed.
Just adding more food for thought to an interesting discussion.
