This is from the Aust S/H Assoc Jul22 EQUITY newsletter by John...

This is from the Aust S/H Assoc Jul22 EQUITY newsletter by John Campbell 'HFT & Algorithmic Trading'
My emphasis added -
HFT systems are defined by reference to their ability to transact at high speed – issuing and cancelling orders within miliiseconds of a market event – a change in price of a stock. They achieve this by colocation and connectivity with exchange computing systems such that they are able to react to a change practically instantaneously. Much of their order activity takes place competitively with other HFT traders. ASIC’s report 597 analysed trading in the year to March 2018 and found that about 20 HFT traders accounted for25% of all market turnover in that year but were responsible for47% of all orders submitted to the market on a success ratio of about 8 to one generally – i.e., only one order executed for everyeight placed into the market. ASIC found that close to 80% of HFTtrades were bought and sold within the day’s trading – i.e., ending the day with no stocks carried over to the following day’s trading. Weighted average holding periods for stocks were 53 minutes inMarch 2018 but 47% of all trades were unwound within 17 minutesand 13% within 2 minutes. HFT traders hedged the risk of an adverse price movement in a traded stock by holding an opposite position in another stock with similar characteristics – 74% of all trading was hedged in this manner within 17 minutes of the position being taken. We understand that there has been no major change since then as regards HFT’s share of market activity.