Not technically manipulation by ASX and ASIC tolerance levels,...

Not technically manipulation by ASX and ASIC tolerance levels, just the new natural order of electronic and algorithimic marketing making, alas, all tolerated as a necessary compromise for increased liquiidity provision. ASIC is a bit of a raging tiger with retail and easily provable stuff, but a toothless one when it comes to algorithmic market making and execution by the big boys - all a bit too much for a $80K a year market officer to compete with mutli-million dollar algorithms. You average punter does not appreciate how much volume is electronic.

Around 50% of equities execution in the US market is now electronic. AUS will not be far behind:

"Electronic trading platforms captured 44% of buy-side US equities order flow in 2023, up from 42% in 2022, according to a Coalition Greenwich report, US Equity Markets 2024: Trends and Opportunities.16 Jan 2024Electronic platforms capture growing share of US equity" (this just buy-side)

"Passive investments such as index funds and exchange-traded funds control about 60% of the equity assets, while quantitative funds, those which rely on trend-following models instead of fundamental research from humans, now account for 20% of the market share, according to estimates from J.P. Morgan."

(passive funds will be as much as 80% electronic execution in the US - AUS I can't tell you).