The Australian Company Number (ACN) was adopted in Australia on 1 July 2000, as one of the complementary measures when the
Goods and Services Tax (GST) was introduced. All companies registered at the time were issued with an ACN by ASIC. On registration of a company under Australia's
Corporations Act 2001, it is issued with an ACN. Companies are required to display their ACN on the common seal (if any) and every other seal of the company (if any); every public document issued, signed or published by, or on behalf of, the company; every eligible negotiable instrument issued, signed or published by, or on behalf of, the company; and all documents required to be lodged with ASIC. An ACN is not required on (at least): packaging and labelling, including envelopes and transport documents; advertisements which do not make a specific offer which is capable of being accepted (such as advertisements which only promote the company and its goods or services in general); credit cards and
credit card vouchers; machine-generated receipts, including cash-register receipts; business cards and 'with compliments' slips; and items which are not documents (e.g., vehicles, television advertisements). A company's ACN does not change even if the company changes its name or is deregistered. == Relationship to ABN ==