RE: cross trades Cross trades very simple.
Brokerage House has to Clients they agree on price to buy large block. They do the trade House collects commission.
I always wonder why people believe just because Brokerage House X is buying or selling on any given day that they are doing it from their own accounts. I bet most of the time they are just executing trades orders of their clients.
Remember for every buyer there is a seller and vice versa.