Consistent $14.25 trades, page-5

Generally it's institutional traders, via a robot (bot). Bots get programmed to do all sorts of things. Here is an example of an accumulate/distribute algo. https://www.interactivebrokers.com.au/en/index.php?f=1223

Experienced traders know bots are also used to manipulate price. You just have to accept that cheating is condoned by ASIC and that retail traders have no voice - that's just FACT. Accepting this as fact, try to work out what the bots are doing and work around it, or even use it to your advantage.

Small regular lots going through is not necessarily price manipulation however. Could be quite legit, as per the link provided.