What ASIC says about constitutions and the replaceable rules, where a shareholders agreement fits beside them, and the clauses Australian law firms say they usually contain.
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A shareholders agreement is a contract between the people who own a company. It is separate from the company’s constitution. ASIC’s pages describe the constitution and the replaceable rules as the company’s rule set, and mention a shareholders agreement only in passing, as something a company has “if it has one”. We found no ASIC statement that a company must have a shareholders agreement.
This guide sets out what ASIC says about the rules a company already has, where a shareholders agreement fits beside them, and the clauses Australian law firms say these agreements usually contain. Where a point comes from a law firm and not from the Act or ASIC, the guide says so.
This is general information, not advice. CatenaHQ is software. Nothing on this page is legal, financial, tax or investment advice, and it does not take account of your circumstances. Speak to a lawyer, accountant or other qualified adviser about your own position.
ASIC states that a company must be governed by either a constitution or the replaceable rules (Corporations Act s135). The replaceable rules are the default for proprietary companies. A company that uses all of them does not need a constitution. A company that wants to change any of them must have one.
The default rule set for proprietary companies, in the Corporations Act (s135). If a constitution does not cover a topic that a replaceable rule covers, ASIC says the replaceable rule applies.
ASIC describes it as a contract between the company and its members, directors and secretary, and also between the shareholders. A company adopts or changes one by special resolution (s136), which ASIC says needs at least 75% member support.
A separate contract, usually between the shareholders and sometimes the company. LegalVision describes it as optional and confidential. Its terms, including how it can be changed, are whatever the parties wrote into it.
Which one wins in a conflict? One Australian law firm, LegalVision, says a shareholders agreement overrides a constitution to the extent of any inconsistency. That is a law firm’s view, not an ASIC statement, and the answer in your case depends on how the documents are written. Have a lawyer check that the two fit together.
The clauses below come from guides published by Allens and LegalVision, which are secondary sources. They are drafting choices, not requirements of the Act. Which of them a company needs is a question for its lawyer.
Pre-emptive rights can prevent third parties from purchasing shares in the company (Allens).
Lets a majority holder force minority shareholders to sell on the same price and terms (Allens).
Gives the other shareholders a right to join a sale by another holder (Allens).
Shares are allocated incrementally instead of all at once (Allens).
Sets what a departing shareholder receives. Allens says a good leaver will generally be paid the fair market value of their shares.
A method for dealing with deadlocks and disputes (LegalVision).
Allens says a shareholders agreement only imposes obligations on, and grants rights to, shareholders who are party to it. It also says a new shareholder joins by signing a deed of accession with the company and all existing shareholders. Practically, that means each investor who comes in on a later raise needs to be bound to the agreement in the way the agreement itself provides. Your lawyer can confirm the mechanism.
Separately from any agreement, sections 232 and 233 of the Corporations Act deal with conduct that is oppressive to, unfairly prejudicial to, or unfairly discriminatory against a member or members. Under section 233 a court can make any order it considers appropriate, and the orders the section lists include winding up the company, changing or repealing its constitution, regulating its future affairs, and requiring the purchase of a member’s shares.
The share register is the statutory record of who holds which shares. A shareholders agreement is a private contract about how those shares are dealt with. When the two drift apart, the gap tends to surface in due diligence.
CatenaHQ’s cap table module keeps the register at allotment level, and the signed agreement can sit in the data room beside it for investors to review. CatenaHQ is software. It does not draft legal agreements, and nothing here is legal advice.
The ASIC and AustLII pages are primary sources. The Allens and LegalVision pages are secondary sources from law firms. All were read on 22 October 2026.
ASIC's guidance says a company must be governed by either a constitution or the replaceable rules. In the ASIC pages we reviewed, a shareholders agreement is mentioned only as something a company may have. We did not find an ASIC statement that requires one.
ASIC describes a constitution as a contract between the company and its members, directors and secretary, and also between the shareholders. A company adopts or changes it by special resolution, which ASIC says needs at least 75% member support. A shareholders agreement is a separate contract whose terms, including how it can be changed, are whatever the parties wrote.
Australian law-firm guides from Allens and LegalVision name pre-emption, drag-along, tag-along, vesting, good and bad leaver and deadlock provisions. They are drafting choices and not requirements of the Corporations Act.
Allens says a shareholders agreement only binds the shareholders who are party to it, and that a new shareholder joins by signing a deed of accession with the company and all existing shareholders.
Sections 232 and 233 of the Corporations Act allow a court to make orders where conduct is oppressive, unfairly prejudicial or unfairly discriminatory against a member. The orders listed in section 233 include winding up the company, changing its constitution and requiring the purchase of a member's shares.
The agreement and the register need to match. These guides cover the register and the notices that follow a change of shareholders.
What must be in a register of members, where it is kept, and who can ask for a copy.
How a company notifies ASIC when shares are issued or transferred.