ABA Files: How Every Owner Gets Paid in One Pass
Published 9 August 2026 · 4 minute read
6–10
Disconnected platforms agencies commonly run
Indium market research
1 in 3
Australian households rent — that's a lot of monthly disbursements
ABS
Ask most principals how their owners actually get paid and you'll get a gesture towards "the software does it". The real answer is a file format older than internet banking: the ABA file. It's worth understanding, because it's the last step in a chain where every earlier step has to be right.
What is an ABA file?
An ABA file is a plain-text file in the Australian Banking Association's format that instructs a bank to make a batch of payments in one go. Every Australian bank's business banking accepts them. One file can carry hundreds of payment instructions — payee, BSB, account number, amount, reference — processed as a single batch.
It is gloriously boring technology, and that's its virtue. No integrations to break, no payment gateway in the middle clipping the ticket, no per-transaction approval marathon. You upload the file to your own bank, authorise the batch, and every owner gets paid.
How does an ABA file pay a whole rent roll at once?
At disbursement time, the software walks the ledger: for each owner, rent collected minus fees, maintenance invoices and any other deductions equals the amount payable. Each owner becomes one line in the file, with their bank details and a statement reference. Trades and other payees can ride in the same batch.
The file is generated, someone with bank authority uploads it and approves the batch, and the bank executes every payment. A disbursement run that would be an afternoon of individual transfers becomes one upload. With roughly a third of Australian households renting, the volume of monthly owner payments across the industry is enormous — the ABA batch is how it stays manageable.
The file is easy. The maths behind it is the whole game.
Generating an ABA file is trivial; every accounting package can do it. The hard part is the ledger arithmetic that decides each line: has this month's rent actually cleared, which invoices are deducted from which owner, were fees calculated on the right basis, does the sum of the batch reconcile to the account.
An error in the file isn't a formatting problem, it's someone paid wrongly — and unwinding a wrong payment to an owner is an awkward phone call at best. The quality of a disbursement run is decided in the ledger, days before the file exists. The file just faithfully exports whatever the ledger believes.
Why the agency keeping control of the bank matters
In Indium's model, rent is paid into the agency's own bank account, Indium computes every owner's entitlement from the ledger, and generates the ABA file for the agency to upload and authorise at its own bank. The money never passes through Indium, and no payment moves without a human at the agency approving the batch.
That design is deliberate. The software's job is to make the arithmetic perfect and the file effortless; the bank authority stays where the accountability already sits — with the agency. You get one-pass payouts without handing custody of client money to your software vendor.
What should you check before authorising a batch?
Three things, every run. First, the batch total reconciles against the ledger's expected disbursement total — one number matching one number. Second, spot-check any owner whose payment differs markedly from last month; the explanation should be visible in their statement. Third, confirm new or changed bank details were verified out-of-band, because payment redirection fraud targets exactly this step.
With a clean ledger, this is a five-minute discipline. Which is rather the point: when agencies run 6–10 disconnected platforms, the check takes an afternoon and gets skipped. Consolidate the ledger and the safest step in the process also becomes the fastest.
Quick answers
What is an ABA file in property management?
A standard Australian bank file containing a batch of payment instructions. Property software uses it to pay every owner and trade in one upload to the agency's bank, rather than individual transfers.
Does Indium hold or move the money?
No. Rent lands in the agency's own bank account. Indium computes each owner's entitlement and generates the ABA file; the agency uploads and authorises the batch at its own bank.
What should I check before authorising an ABA batch?
That the batch total reconciles to the ledger, that unusual payment amounts are explained by the owner's statement, and that any new or changed bank details were verified independently.
Keep going
General information for Australian agencies, current at the date above — not legal or financial advice. Verify obligations against AUSTRAC guidance and your own advisers.