Yes. A business owner in Australia can have multiple ABNs. How many depends on how many separate legal entities they operate through. Each entity gets one ABN and each entity can run unlimited businesses under it.

An ABN follows the legal entity, not the business name or activity. One entity means one ABN. More entities means more ABNs. The number of businesses operating under each ABN is not capped.

TL;DR

• One ABN per legal entity and one entity can run unlimited businesses under that ABN.
• A business owner can hold multiple ABNs only by operating through multiple separate legal entities.
• A sole trader cannot hold two sole trader ABNs simultaneously.
• Separate entities separate their legal liabilities.
• Businesses under the same entity share their exposure.

The Core Rule: One ABN Per Entity, Not Per Business

Three principles govern how ABNs are allocated in Australia:

1. One entity gets one ABN: Each legal entity is issued a single ABN. A sole trader has one ABN. A company has one ABN. A partnership has one ABN. A trust has one ABN. No entity can hold two ABNs simultaneously.
2. One ABN can cover unlimited businesses: There is no limit on how many business activities, brands, or trading names can operate under a single ABN, as long as they all belong to the same entity. A company can run ten different brands under one ABN. A sole trader can run five separate ventures under their one ABN.
3. More entities means more ABNs: A business owner who operates through two separate entities holds two ABNs, one per entity. The entities are legally distinct from each other. Their ABNs, tax obligations, and liabilities are separate.

The Four Entity Types and How ABNs Work for Each

Sole trader

A sole trader is the simplest business structure. You and your business are the same legal person. The ABN is issued to you as an individual carrying on an enterprise.

• One ABN per sole trader registration, covering every business activity and trading name you run as a sole trader.
• No limit on how many businesses can sit under that one ABN.
• Cannot hold two sole trader ABNs simultaneously.

Company (Pty Ltd)

A company is a separate legal entity from the people who own and run it. It must be registered with ASIC first to obtain an Australian Company Number (ACN), after which it applies for its own ABN.

• One ABN per company, regardless of how many businesses or brands that company operates.
• The same company can run unlimited business lines and trading names under its single ABN.
• The company's ABN is completely separate from any ABN held by its directors or shareholders.

Partnership

A partnership is formed when two or more people carry on a business together with the intention of making a profit. The partnership itself is a legal entity separate from the individual partners.

• The partnership registers its own ABN, separate from the personal ABNs of each partner.
• Each partner may also hold their own separate ABN if they carry on individual business activities outside the partnership.
• All partners are jointly liable for the debts and obligations of the partnership.

Trust

A trust holds assets or carries on a business for the benefit of beneficiaries. It is administered by a trustee, who can be an individual or a company. The trust is its own legal entity.

• The trust registers its own ABN, separate from the ABN of the trustee.
• If the trustee is a company, that company also holds its own separate ABN.
• Commonly used for asset protection and tax planning.

Real Scenarios: How Many ABNs in Practice

Scenario 1: One entity, multiple businesses (sole trader)

A sole trader runs a freelance graphic design service and also sells handmade candles online. Both activities sit under their sole trader entity. They register two separate business names via ASIC, both linked to their single ABN. All invoices go out under that one ABN.One entity. One ABN. Two businesses.

Scenario 2: Two entities, separate ABNs (sole trader + company)

A person has been operating as a sole trader consultant with their own ABN. They later incorporate a company to build a software product with a co-founder. The company is registered with ASIC, receives an ACN, then applies for a separate ABN. The person now has two ABNs: their sole trader ABN for consulting work, and the company's ABN for the software product. The company later launches a second digital service under the same company entity. The company's single ABN covers both the original product and the new service.Two entities. A separate ABN for each. Three businesses total.

Scenario 3: Company running multiple businesses under one ABN

A company is incorporated to operate a retail clothing brand and an online course platform. Both operate under the company's single ABN. The company registers two business names, one for each brand. Invoices from both businesses carry the company's ABN. The company is one entity regardless of how many ventures it runs.One entity. One ABN. Two businesses.

Scenario 4: Sole trader plus partnership (two separate ABNs)

A freelance accountant operates as a sole trader with their own ABN. They and a colleague form an accounting partnership, which registers as a separate entity and receives its own ABN. The sole trader continues their individual freelance work under their personal ABN. The partnership takes on shared clients under the partnership's ABN.Two entities. A separate ABN for each. Separate tax records for each.

Scenario 5: Four entities, four ABNs

A business owner builds four separate entities over time: a sole trader entity for consulting work; a company running a tech product and a second digital service under the same company ABN; a partnership with a business partner for a joint venture; and a discretionary trust for investment properties. They hold four separate ABNs across four entities and operate six businesses in total.Four entities. Four separate ABNs. Six businesses total.

When Do You Need a Separate ABN?

A separate ABN is only needed when you create a new legal entity. Common situations:

• Incorporating a company. The new company is a separate entity and must register its own ABN.
• Forming a partnership. The partnership is a separate entity from its partners and registers its own ABN.
• Setting up a trust. The trust registers its own ABN, separate from the trustee's ABN.
• Creating a second company. Each company is a separate entity and holds its own ABN.

When You Do Not Need a New ABN

No new ABN is needed when you are adding activity or a new name to an existing entity:

• Starting a second business as a sole trader. Your existing ABN covers it. Register a new business name via ASIC and link it to your current ABN.
• Adding a trading name to your company. The company's existing ABN covers it. Register the new business name via ASIC.
• Adding new products or services. New offerings under the same entity require no new ABN.
• Changing your business name. Update your ABR details and cancel the old ASIC business name registration. Your ABN remains the same.

For a complete guide to running multiple businesses and trading names under a single ABN, see Multiple Business Names Under One ABN: What You Need to Know.

What Multiple ABNs Mean for Your Obligations

Each ABN is a separate tax identity. Operating through multiple entities means:

• Separate income tax returns for each entity that requires one (companies and trusts file their own; partnerships file a partnership return)
• Separate GST registration and BAS lodgement obligations for each entity if annual turnover exceeds $75,000
• Separate bookkeeping records for each entity

Liability separation is the main reason business owners choose separate entities. Businesses operating under the same entity share their legal exposure. A claim against one activity can reach the assets of the whole entity. Separate entities ring-fence that exposure.

For a comparison of sole trader and company structures and how liability differs between them, see the sole trader vs limited company guide.

Related: Tips for preventing ABN cancellation

Frequently Asked Questions

Can a business owner have multiple ABN numbers (or 2 ABNs) in Australia?

Yes. A business owner can hold multiple ABNs by operating through multiple separate legal entities. Each entity (sole trader, company, partnership, or trust) is issued one ABN. A person operating as a sole trader and through two companies would hold three ABNs, one per entity. There is no upper limit on how many ABNs a person can hold across separate entities.

Can a sole trader have two ABNs (or 2 ABNs)?

No. A sole trader is a single legal entity: you as an individual. You are entitled to one ABN as a sole trader and cannot hold two sole trader ABNs at the same time. All your sole trader business activities and trading names are covered by your single ABN. To hold a separate ABN for a different business, you would need to establish a separate legal entity such as a company or partnership.

Can a company run multiple businesses under one ABN?

Yes. A company is one legal entity and holds one ABN. That company can operate unlimited business lines, brands, and trading names under its single ABN. Each additional trading name is registered through ASIC and linked to the same company ABN. The company invoices all its customers under one ABN regardless of how many brands it operates.

Do I need a new ABN if I start a second business?

Only if the second business operates through a different legal entity. If you are a sole trader adding a new venture or activity, your existing ABN covers it. No separate ABN is needed. If you are incorporating a company for the second business, the company is a new entity and registers its own ABN. The key question is whether the new business involves a new legal structure.

What if I accidentally have two ABNs as a sole trader?

If you have ended up with more than one ABN registered as a sole trader, contact the Australian Business Register to cancel the extra one. A sole trader is only entitled to one ABN at a time. Having two sole trader ABNs creates confusion in the ABR and ATO records and should be resolved as soon as possible. Your registered tax agent can assist with the cancellation process at abr.gov.au.

How many ABNs can one person hold?

There is no legal cap. A person can hold as many ABNs as they have separate legal entities. Someone operating as a sole trader, through two companies, through a partnership, and through a family trust holds five ABNs across five entities. Each ABN belongs to a different entity. The practical limit is the administrative cost and compliance overhead of running multiple entities.

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_{The information in this article is general in nature and provided for informational purposes only. It is based on publicly available information from the Australian Business Register and the Australian Taxation Office and is accurate as at May 2026. Business structure, tax, and ABN registration requirements are subject to change. Always consult a registered tax agent, accountant, or legal adviser for advice specific to your business structure and circumstances.}