Asset managers are a tricky client for any dealer. They execute huge block derivatives trades at billions of dollars of notional at a time, but require a special infrastructure to suit their unique set-up.
This is because they don't take exposure themselves, but on behalf of their sub-funds. So after the block trade is executed, it's broken up into smaller pieces and allocated to the relevant fund.
Executing in large size can make the allocation of the execution costs to the sub-funds fairly