'The Final Stretch', page-3

Its called "window dressing". As June 30 is year end and quarter end in Australia it is in some peoples interest to ensure the final traded price is higher. Has been done for decades unofficially as manipulation would be illegal of course!

With a $10 trade you can make your portfolio worth much more and your % returns as a port manager look much better and gives you 3 more months to actually get that magic number in the real world on your full number of shares as an example.

There are a few other reasons that can be particular stock specific especially related to banking covenants and such