The reason it looks like that at the end of day is people are...

The reason it looks like that at the end of day is people are jostling to be the FIRST to sell or the FIRST to buy.

Lets pretend there are 50K buyers at end of day auction in terms of total shares.

but only 25K sellers in terms of total shares.

Some of those buyers want to make their "buy price" the highest so they will be at the front of the line so to speak. So suppose somebody puts 10K buy at lets say 8 dollars. That 10K is is first in line so he will get his shares.

That does not mean however that his buy price is 8.00. The ASX algorithm works out between the various "bids" to sell and buy what the final price is. Basically any big outliers you see in terms of weird pricing really low ball sellers or really high ball buyers are simply people trying to be first in line to get shares at the close.

Hope that made sense.