Ordinary investors in shares are usually subject to a minimum initial purchase amount of $ 500 as well as a broker commission ranging typically from $ 9.50 per purchase (or sale) to $ 19.95.

Some traders are exempt with no dollar limit and no commission

Many high speed trading algorithms use this exemption to create false impressions of price movements to "encourage" buyers to buy or others to sell.

This is widely viewed as manipulation for ulterior motives.

If nothing is done genuine market investors are misled and may suffer losses.

In summary this favoured access to misleading small trades, often hundreds or even thousands in a day seriously disadvantage ordinary investors and favours the wealthy with access to complex computer algorithms, designed to create false impressions of market movements.

It is known in some quarters as scalping, and should be made illegal.

The Federal Government should investigate this as a matter of urgency and take action to prevent manipulation by those with favoured access for unfair and improper purposes.  This favoured access when used for disreputable purposes should be made criminal, with heavy penalties.