this is getting complex and i am not familiar with all the excruciating details of how ex-clearing transactions are tracked.
if customer A and customer B are from the same broker then the trades get settled relatively fast i.e assuming A & B have settled trades i.e their shares positions have been cleared i.e no FTDs.
on the other hand if customer A from broker XYZ makes a purchase from customer B of broker ABC and ABC/B enter into a contract with broker XYZ to deliver the shares later at a specified price, then this would one example of ex-clearing. But there several other examples....I am not sure what exactly triggers ex-clearing..probably something a broker would want to hide their counterparty risks as well as their own. it is a very manual process...it is a similar process to the trades hitting the tape but done manually and with lot of deviations! I am sure you are throughly confused by now!
Just google ex-clearing and you'll find lot of help!
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