What is an Australian Company Number (ACN)?
When you build your company on Legal Consolidated’s website, ASIC assigns your new company a unique, nine-digit number. This is its Australian Company Number, or ACN. Think of it as your company’s unique identifier; it stays with the company for life.
Under section 219 of the Corporations Act 2001 (Cth), this ACN and your company’s full legal name must appear on a range of business documents.
The ACN is the cornerstone of Australia’s national business system. It allows your Pty Ltd company, incorporated in Victoria, to trade in New South Wales without needing to register separately in that state. It simplifies national business.
Why must my company display its name and ACN?
A tiny detail, a huge impact. Missing your ACN on documents can expose you to personal liability. Don’t let a small oversight become a big problem!
The Corporations Act is strict for one simple reason: transparency. People dealing with your company have a right to know they are dealing with a corporate entity that has limited liability. They also have a right to know the exact identity of that company.
In the English case of Jenice Ltd v Dan [1993] BCLC 1349, the policy is:
“to ensure that people dealing with companies know both that they are dealing with a limited company and know the identity of the particular limited company with which they are dealing”.
At Legal Consolidated, we believe this is a fundamental protection for both the public and for you as a director. If people do not know they are dealing with a ‘Pty Ltd’ company, they may later try to sue you personally for the company’s debts. This is not just a theoretical risk.
On which documents must the company name and ACN appear?
The requirements apply to all of your company’s ‘public documents’ and ‘eligible negotiable instruments’. This is a very broad category defined in section 88A(1) of the Corporations Act 2001 (Cth).
In practice, this includes almost every official document your company produces:
- Business letters, invoices, receipts, and orders
- Statements of account and official notices
- Contracts, agreements, and deeds
- Your company website’s homepage
- Email signatures for company correspondence
Essentially, if a document is issued or signed by or on behalf of your company in the course of business, it must include the full company name and ACN.
Electronics materials must also show the Company’s ACN
Public documents are not just paper. They include:
- Websites
- Mobile checkout pages
- Business apps
- Social media business profiles
- Email signatures
If the platform is used to do business, then your company’s name and ACN must appear. A missing footer in your app or website can be as dangerous as a missing ACN on a paper contract.
Traps for directors using the ACN: Checklist
Check these traps:
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All invoices, contracts, emails, receipts and notices must carry the full company name followed by the ACN.
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After a name change or rebrand, update your stationery, letterhead, websites, email signatures and business apps.
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The ACN remains the same—only the company name changes.
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Check that your brand logo or business name also carries the full legal name and ACN somewhere clear on the document.
What are the penalties for getting it wrong?
The consequences of non-compliance are severe.
- Criminal Offence: Firstly, it is a strict liability criminal offence under the Corporations Act 2001 (Cth). Your company can be fined, and as a director, you can be held responsible for the breach.
- Personal Liability: More alarmingly, it opens the door for you, the director, to be held personally liable for the company’s debts. We saw a client whose company entered a large contract. The director signed the agreement but failed to include the company’s ACN. When the company was unable to pay, the creditor sued the client personally. The document was not correctly identified as a company document, and the director had signed it in their personal capacity. The corporate veil was at risk.
This is the most dangerous trap for new company owners. A simple administrative error on an invoice or contract can destroy the limited liability protection that is the main reason for using a company structure.
How do I correctly display my company’s name and ACN?
The law requires the company’s full name, followed by “Australian Company Number” (or more commonly, the abbreviation ACN) and the nine-digit number. The ACN must appear immediately after the company’s full name is first mentioned.
For example:
- “Blue Wren Holdings Pty Ltd ACN 111 222 333”
- “Blue Wren Holdings Proprietary Limited A.C.N. 111 222 333”
The courts are notoriously unforgiving. Breaches have been found for:
- Omitting “Pty Ltd” (Penrose v Martyr (1858) 120 ER 595).
- Using the wrong word order (Atkin & Co v Wardle (1889) 58 LJQB 377).
- Leaving out an ampersand (“&”) (Hendon v Alderman (1973) 117 Sol Jo 631).
A common letterhead example would be having your brand “BLANCO” at the top of the page, as long as the full legal name “Blanco Whitegoods Pty Ltd ACN 123 456 789” appears clearly, say in the footer.
Full Name then ACN – Order Matters
The law is strict. The ACN or ABN must follow the company’s name the first time it appears on a document.
- Correct: “Blue Wren Holdings Proprietary Limited ACN 123 456 789”
- Incorrect: “ACN 123 456 789 – Blue Wren Holdings Proprietary Limited”
Put it in the wrong order and you are in breach.
Can I use abbreviations for my company’s name?
Yes, but only the specific abbreviations permitted under the Corporations Act 2001 (Cth). Do not invent your own.
Permitted abbreviations include:
- Pty for Proprietary
- Ltd for Limited
- & for and
- ACN or A.C.N. for Australian Company Number
- Co or Coy for Company
Using unapproved shorthand like “P/L” is non-compliant and can expose you to the same penalties as leaving the words out entirely.
How should I format the ACN?
ASIC issues all ACNs as a nine-digit number, often with leading zeroes (e.g., “012 345 678”). ASIC recommends displaying the number in three groups of three, separated by spaces.
While removing a leading zero (e.g., “12 345 678”) is technically compliant because the numerical value is the same, it can cause confusion.
At Legal Consolidated, we recommend you always use the full nine digits, including any leading zeroes, exactly as issued by ASIC. It removes all doubt and demonstrates professional compliance.
Correct compliance is not optional. It is a core part of your director’s duties and protects your personal assets. Build your Pty Ltd company with our law firm. Our legally compliant documents ensure you start on the right footing from day one.
What if my company uses a business name?
Even if you are trading under a registered business name, you must still show your company’s legal name and ACN on all public documents. The business name does not replace this legal requirement.
If your company, “Blue Wren Holdings Pty Ltd ACN 111 222 333”, owns the business name “Melbourne’s Best Builders”, your invoices and website must contain “Blue Wren Holdings Pty Ltd ACN 111 222 333”. Just showing the business name is a breach of the law.
ACN versus ABN – Know the Difference or Pay
Your company has two numbers. The Australian Company Number (ACN) and the Australian Business Number (ABN).
They are not the same.
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The ACN is a nine-digit number issued by ASIC when you register your company.
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The ABN is an eleven-digit number issued by the Australian Taxation Office. It is mainly about tax and the Goods and Services Tax.
If your company has an ABN, it may use that instead of the ACN on public documents. But do not think that the ABN replaces the ACN. The ACN is the true legal identifier.
A Family Trust, Unit Trust, and Bare Trust, with no corporate trustee, and a partnership do not have an ACN. This is because there is no company involved in how those structures were set up. They only have an ABN. This is also the case when humans are trustees of their own Self-Managed Superannuation Fund.
What if I misspell the company name by mistake?
Some joy can be found under ASIC Practice Note 47 (PN 47)
‘The [company] name need not be absolutely correct, however. Obvious spelling mistakes and other minor departures with no tendency to confuse or mislead may be held not to offend (Jenice Ltd v Dan [1993] BCLC 1349).’
However, at Legal Consolidated, we have found that relying on this is not best practice. It shows that you are uncaring. Are you fit to run a company if you cannot even spell your company name? When dealing with regulators, keep your head down and act demure; worthy but difficult traits for many alpha males running a business.
Build these company documents online |
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| Superannuation Trustee Company (Special Purpose) – Includes ASIC fees | |
| New company – Includes ASIC fees, minutes & Constitution | |
| Shareholders Agreement | |
| Deed of Debt Forgiveness | |
| Deed of Gift | |
| Power of Attorney for a Company – Corporate POA | |
| Division 7A Loan Deed – Lending money to a company (revolving; never needs updating) | |
| Loan to a Company – to prove a loan (escape Debt/Equity rules) | |
Upgrade company rules |
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| Upgrade Company Constitution – also allows for single director company | |
| Replace Old Memo and Articles of Association – upgrade from Replaceable Rules | |
| Replace Lost Company Constitution | |
| Convert Old Company Into a Special Purpose Company – to be trustee of SMSF | |
| Replace Replaceable Rules |