What is an ABN?
An Australian Business Number (ABN) is a unique 11-digit identifier issued by the Australian Business Register (ABR) to all business entities operating in Australia. The ABN is used for tax purposes, GST registration, and business identification. Unlike the ACN (which is only for registered companies), the ABN is available to all business structures: sole traders, partnerships, trusts, companies, and associations.
The ABN as an AI Identity Signal
The ABN is the most powerful identity signal for Australian businesses in the AI context because it is universal (applies to all business structures), publicly searchable (via ABN Lookup at abn.business.gov.au), and legally required to be displayed on tax invoices. AI systems that encounter an Australian business can use the ABN to verify the business's existence and legal status via the ABN Lookup API.
ABN Lookup: The Public Registry
ABN Lookup (abn.business.gov.au) provides free public access to ABN records, including the business name, entity type, GST registration status, and registered address. AI systems use ABN Lookup as a reference source for Australian business information. AI Verified integrates with ABN Lookup to verify Australian business identity in real time.
ABN and AI Verified
When an Australian business claims an AI Verified passport, the ABN is used as the primary anchor. The passport includes a cryptographic hash of the ABN, creating a tamper-evident record that AI systems can use to verify the business's identity. Silver tier ($19/month) provides ABN-anchored verification.