An Australian Company Number (usually shortened to ACN) is a unique identifier required by every company registered under Australia’s Corporations Act 2001 (Cth). The ACN is a nine-digit number issued by the Australian Securities & Investments Commission (ASIC) to every Australian company. The number is usually printed in three groups of three digits, and preceded by the letters ACN must be quoted on all correspondence and invoices issued by the company.
A company may also be required to have a Tax File Number (TFN) and an Australian Business Number (ABN). If a company has an ABN, it may use the ABN in place of the ACN on documents, preceded by the letters ABN. A similar nine-digit Australian Registered Body Number (ARBN) is used for non-company entities such as registerable Australian bodies, and for foreign companies.[1]