An **[[ABN|Australian Business Number (ABN)]]** is a unique identifier allocated to a registered business entity. They are managed by the [[ABR|Australian Business Register (ABR)]], which is a service of the [[ATO|Australian Taxation Office (ATO)]]. ^about You must have an ABN if you carry out business activities and your annual revenue is at least AUD 75,000. You may optionally register for GST if your annual revenue does not exceed that amount. However, note that having an ABN is a gateway requirement into many other business management activities, including [[PAYG]], [[GST]], grants, claiming expenses, and dealing with larger companies and B2B activities. These may be desirable or even required for your business, irrespective of your expected annual revenue. Conversely, ABNs are reserved expressly for business purposes. They should not be sought if there is a lack of intent to carry out business activities. Refer to [ABR's official site](https://www.abr.gov.au/) or specifically [Applying for an ABN](https://www.abr.gov.au/business-super-funds-charities/applying-abn) for more information.