ABNs and ACNs

In Australia you will see companies referenced by the letters ACN and businesses by the letters ABN. In this article we look at what they stand for and what they mean.

What is an ACN?

ACN stands for Australian Company Number.

It is a number issued by the Australian Securities and Investments Commission (ASIC).

An ACN is issued automatically by ASIC on the incorporation of a company in Australia.

It is a unique, nine digit, identifying number issued only to companies.

Where an ACN must appear

A company’s ACN must be on all public documents.

Examples of company items on which it should appear include:

  • all documents lodged with ASIC,
  • statements of account, including invoices,
  • orders,
  • business letterheads,
  • official company notices, and
  • written advertisements making a specific offer.

A company’s name and ACN must appear on the first page of any document.

The ACN must always be clear, easily readable, and obvious as to which company it belongs to.

What is an ABN?

ABN stands for Australian Business Number.

It is a number issued by the Australian Tax Office (ATO) to individuals, organisations or companies.

It is a unique, 11 digit identifying number for Australian businesses.

An individual, organisation or company wishing to conduct business in Australia must apply through the Australian Government Business Registration Service for an ABN.


ACNs and ABNs are similar in that they allow a company or business to be clearly identified.

ACNs for all company dealings with ASIC and ABNs for all business dealings with the ATO.

They also allow members of the general public to clearly identify what company and/or what business they are dealing with. Especially in cases where business names might be similar.

And if a company requires an ABN, that ABN will be the company’s nine digit ACN with an additional two digits at the start.

Also, if a company has an ABN, it may use the ABN in place of its ACN on its documents.

Searching for an ACN or ABN

You can search for a company’s ACN online using ASIC Connect.

You can search for an ABN online using ABN Look Up at the Australian Business Register.

Key Takeaway

All companies in Australia will have an ACN.

All businesses in Australia must have an ABN.

ACNs and ABNs are not only used by government departments such as ASIC and the ATO to clearly identify their dealings with companies and businesses, they also help the general public to identify the company or business they are dealing with.



Corporate and Commercial Lawyer for Sydney and Newcastle

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The information in this article is not legal advice and is intended to provide commentary and general information only. It should not be relied upon or used as a definitive or complete statement of the relevant law. You should obtain formal legal advice specific to your particular circumstance. Liability limited by a scheme approved under Professional Standards Legislation.

Senior Associate Solicitor