Lenders quote trail as a gross rate, aggregators take their share, and what remains is net trail. It is the number to use for income reporting, cash-flow planning and valuation, and it is the number most brokers do not know precisely because it is spread across hundreds of lines on a monthly statement.
Net trail is also the figure that reveals run-off. Comparing this month's net trail with last month's, loan by loan, shows which clients left, which paid down sharply and which lenders' rates changed. Annualising it gives the base for a valuation; tracking it over twelve months gives the trend a buyer will ask about.
GST complicates the reading. Statements show inc-GST and ex-GST columns, and the inc-GST commission line is the cash received. Income for the business is the ex-GST amount; the GST is collected on the tax office's behalf.