Short Term Trading Week Starting: 4 Sept, page-257

Brokers or instos (who pay no brokerage) will attempt to manipulate the price up or down a tick in the last seconds of the after market auction to manipulate the market or chart ...ie, to make the chart look more or less appealing to mums and dad traders (example of and uneven playing ground) AKA ... manipulation by bot algorithmic trading.

OR

... a school kid has who a few spare coins of left over lunch money has decided to have a ping on the sharemarket...