The key identifiers in STP¶

Every pay you report to the Australian Taxation Office (the ATO) carries a set of codes that tie the data together. These are the key identifiers. They tell the ATO who the payer is, which software sent the report, which employee the data belongs to, and which file it came in.

Getting these right matters because the ATO uses them to add up each employee's pay for the year. If one of them changes without warning, the ATO can split an employee's totals in two.

In one line

A handful of identifiers — ABN/Branch (or WPN), BMS ID, Payroll ID and Submission ID — tie every STP report together and keep each employee's totals in one place.

Why this matters¶

Single Touch Payroll (STP) sends the ATO a running total for each employee every payday. For those totals to keep building in one place, the ATO needs a stable way to recognise each report. The key identifiers do that job. When they stay steady, the year-to-date figures stay correct.

What you will learn¶

The key identifiers used in an STP report
How the ATO stacks year-to-date totals by those identifiers
What can go wrong when an identifier changes

Understanding the concept¶

There are a few identifiers to know:

ABN/Branch — the business's Australian Business Number and, where used, its branch. This says who the payer is. A business that reports under a Withholder Payer Number (WPN) uses that instead of an ABN.
BMS ID — short for Business Management Software ID. The ATO describes it as a unique identifier within the business that acts like a serial number to identify the instance of the payroll software that created the data in the pay event. It tells the ATO which software sent the report.
Payroll ID — a code that uniquely identifies the employee within the business. The ATO describes it as the code that identifies the individual's set of personal identity and payroll records, and the level where the year-to-date amounts are kept.
Submission ID — a unique reference for each pay event file, per ABN/Branch (or WPN) and BMS ID. It is the reference number for that report.

The ATO displays each employee's income statement, grouped by ABN/Branch (or WPN) / BMS ID / Payroll ID / TFN (Tax File Number). That combination is the key the ATO uses to stack the year-to-date (YTD) totals. If any part of that combination changes, the ATO creates a separate record.

For accountants & bookkeepers

The ATO confirms that if the payer transfers YTD balances between BMS IDs or Payroll IDs, the ATO must be specifically alerted — otherwise it displays both sets of YTD, overstating both the payee's income and the payer's PAYGW. The two documented methods are "zeroing out" the old key identifiers or using the replacing-key-identifiers option (Previous BMS Identifier / Previous Payroll ID). Note that a "Software ID" is a separate, authentication concept — it links your software to the ATO for secure lodgement — rather than one of the key identifiers that group your reported amounts.

Example¶

Meg runs a small business under one ABN with no branch. Her payroll software holds a stable BMS ID for the business, and each employee has their own Payroll ID. When she reports the fortnightly pay, the file gets its own Submission ID. The ATO matches the report to each employee by ABN / BMS ID / Payroll ID / TFN, and adds the pay to the running total already sitting under that combination. Meg's employee sees one clean set of year-to-date figures in myGov.

Common mistakes¶

Assuming the identifiers are just technical detail — they decide where an employee's totals land.
Switching payroll software and letting the BMS ID or Payroll IDs change without carrying the old ones across, which can split an employee's totals in two.
Thinking the Submission ID identifies the employee — it identifies the file, not the person.

How this works in myaccountant¶

In the app — myaccountant creates a stable BMS ID for your business automatically, and reuses it on every pay report. You never enter it. Each employee's Payroll ID is their myaccountant employee ID. myaccountant builds the pay event from your pay run, so these identifiers are set for you rather than typed by hand.

Key points¶

The key identifiers are ABN/Branch (or WPN), BMS ID, Payroll ID and Submission ID.
The ABN/Branch (or WPN) says who the payer is.
The BMS ID says which software sent the report; the Payroll ID identifies the employee within the business.
The Submission ID is a unique reference for each pay event file.
The ATO stacks year-to-date totals by ABN/Branch or WPN / BMS ID / Payroll ID / TFN.
If one of these changes without warning, an employee's totals can split.

Learn next¶

General information only — not tax, super or financial advice.

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