UBS is doing the majority of buying. They look to have a number...

UBS is doing the majority of buying. They look to have a number of very large buy orders on their books. Who this is going to, nobody knows.

The algo is also UBS, and is working the sell side. Its hitting the bids with 2, 1, 31, 18 executions (sells) to try an entice some large sell side volume to appear. Its trying to give the stack the impression that there is increasing sell pressure so that they can fill their large buy orders which are sitting off-screen. You'll notice that from time to time a relatively large buy will go through when some sell volume appears. UBS are sending these buys straight to market as this occurs.

UBS is doing about 70% of volume
Bell Potter at 20% (no surprise as they cover the stock)
COMMSEC at ~5%

The remaining is being done by Shaw, Ord Minnet and a little from RBS and Goldmans.

Hope this makes sense and it useful.

UBS are big in europe. Not sure if this 'means' anything, as it would only be pure-speculation.