Did a spot of googling for you, @rick64. Hope it helps.
S3XT is what they call a Block Special Crossing , which basically means its a special sized ( usually large ) cross trade.
SP: Block Special Sale (Special crossings where the consideration is greater than $1M)
NXXT is an NBBO Crossing (crossed trade) that has resulted from matching a buyer and a seller of a particular stock, and the buyer and seller are clients of the same broker.
NBBO is an acronym for National Best Bid and Offer. ... For example, if the Bid/Offer on ASX TradeMatch is $1.00/$1.02 and the Bid/Offer on Chi-X Australia is $0.99/$1.01, the Bid/Offer or NBBO will be $1.00/$1.01.
CX is a trade that has occurred in ASX CentrePoint at the current midpoint price.
Oops - somehow the reply bar got lost. Luckily the post is tagged because I can't see how to fix it.
