Shareholders’ Agreement vs Company Constitution in Singapore: Do You Need Both, and What Goes Where?

Two Singapore founders shake hands, file a company constitution with ACRA, and assume the paperwork is done. Eighteen months later, one wants to sell to a competitor, the other wants a right of first refusal, and neither document says a word about what happens next. This is one of the most common gaps in Singapore private company governance: founders treat the constitution as the whole rulebook when it is only half of it.

Raffles Corporate Services works with a panel of experienced Singapore law firms who offer cost-effective and efficient legal service and advice. This article is general information only and is not legal advice.

The confusion is understandable. Every Singapore private company must have a constitution; it is a statutory requirement and a public document. A shareholders’ agreement, by contrast, is optional, private, and often skipped entirely by founders who assume “we trust each other” is a substitute for a contract. It is not. The two documents serve different legal purposes, are enforced differently, and cover different ground. Getting the split wrong, or leaving out a shareholders’ agreement altogether, is how founder disputes escalate into court proceedings.

This article sets out exactly what belongs in each document under Singapore law, where drag-along and tag-along rights should sit, what happens when the two conflict, and how to keep them aligned so your governance structure does not quietly work against itself.

What the Constitution Is, Legally

The company constitution is governed by the Companies Act 1967. It is filed with the Accounting and Corporate Regulatory Authority (ACRA) at incorporation and is a public document that anyone can retrieve. Under section 39 of the Companies Act, the constitution operates as a statutory contract: it binds the company and each member as if every member had signed and sealed it, and as if it contained mutual covenants between the company and each member, and between the members themselves, to observe its provisions.

That statutory status matters. It means the constitution is not just an internal reference document; it is enforceable as a contract between the company and its shareholders, and among the shareholders themselves, without anyone needing to sign a separate agreement. It also means third parties dealing with the company, such as banks, landlords, and counterparties reviewing a director’s authority, can rely on what the constitution says because it is publicly filed and its content is presumed accurate.

We have covered the mechanics of choosing between a model and bespoke constitution in detail in our guide to model versus bespoke constitutions for Singapore companies, which is worth reading alongside this article if you have not yet settled your constitution’s structure.

What a Shareholders’ Agreement Is, Legally

A shareholders’ agreement, sometimes called an SHA, is an entirely different creature. It is a private contract entered into between some or all of the shareholders of a company (and sometimes the company itself as a party). It is governed by ordinary contract law, not the Companies Act, and it is never filed with ACRA. Nobody outside the signing parties has a right to see it.

Because it is a private contract rather than a statutory instrument, a shareholders’ agreement only binds the people who sign it. If a company has five shareholders and only three sign the SHA, the other two are not bound by its terms, even though all five are equally bound by the constitution. This is a critical practical difference: as new investors or co-founders join a company, they need to be brought onto the shareholders’ agreement individually (usually through a deed of adherence), whereas the constitution automatically binds every person who becomes a member.

Constitution vs Shareholders’ Agreement: What Goes Where

In practice, Singapore corporate lawyers and company secretaries follow a fairly consistent division of labour between the two documents. The table below sets out the typical split.

Why Drag-Along and Tag-Along Sit in the Shareholders’ Agreement

Drag-along and tag-along rights are among the most commercially sensitive provisions a founder will negotiate, which is exactly why they belong in the shareholders’ agreement rather than the constitution.

A drag-along right allows a majority shareholder (or a defined threshold, such as shareholders holding 75% of shares) who agrees to sell their shares to a third party to compel the remaining minority shareholders to sell on the same terms. This protects a majority seller from a hold-out minority shareholder blocking an otherwise attractive exit.

A tag-along right (also called a co-sale right) runs the other way: if a majority shareholder is selling, minority shareholders can insist on joining the sale on the same terms, rather than being left behind as minority shareholders in a company now controlled by an unfamiliar buyer.

Both mechanisms depend on commercially negotiated thresholds, valuation formulas, and notice procedures that founders generally do not want sitting in a document available for public inspection at ACRA. Keeping them in the shareholders’ agreement preserves confidentiality and allows the terms to be tailored deal by deal, including differentiating between different classes of investors (for example, giving tag-along rights to a seed investor but not to an employee shareholder holding a small equity grant). If your company is preparing for external investment, our article on convertible notes and SAFEs in Singapore startup fundraising covers related mechanics that often interact with drag-along and tag-along terms once equity actually converts.

What Happens When the Two Documents Conflict

Conflicts arise more often than founders expect, typically because the shareholders’ agreement is drafted later, by a different lawyer, without a careful line-by-line comparison against the existing constitution. Common conflict points include differing quorum requirements for general meetings, inconsistent transfer restriction mechanics, or a shareholders’ agreement that purports to entrench a shareholder’s board seat in a way the constitution’s director removal provisions do not support.

The general position under Singapore law is as follows. The constitution is the public, statutory document that governs the company itself and is what third parties dealing with the company, and the company’s own directors and officers acting in that capacity, are entitled to rely on. Where a matter affects the company’s own internal governance, such as how a director is validly appointed or removed, or whether a board resolution was properly passed, the constitution generally prevails, because the company cannot be bound by a private contract it may not even be a party to in a way that overrides its own constitutional rules.

A shareholders’ agreement, by contrast, operates purely as between the shareholders who signed it. It can regulate how those shareholders exercise their votes, what they promise to do or not do, and what happens between them commercially, but it cannot compel the company to act in a manner that is unlawful or ultra vires its constitution. If an SHA says a shareholder is entitled to appoint a director but the constitution has no mechanism allowing that appointment to take legal effect, the appointment cannot simply happen; the constitution typically needs to be amended, or the parties need to procure the necessary shareholder resolution to give effect to the SHA’s intent through the constitutionally valid route.

This is also why disputes over board conduct or deadlocked director decisions often end up being argued by reference to both documents at once. Our coverage of director meeting disputes and when Singapore courts intervene and our explanation of the section 216 oppression remedy both discuss situations where the interplay, or the absence, of a shareholders’ agreement was central to the dispute.

Practical Consequences of Getting the Split Wrong

Founders who rely solely on the constitution, without a shareholders’ agreement, are exposed in several predictable ways:

• Minority shareholders have no contractual pre-emption, tag-along, or exit mechanism beyond whatever basic transfer restriction the constitution happens to contain.
• There is no agreed process for resolving a genuine 50/50 deadlock between two founders.
• Reserved matters, such as taking on debt, issuing new shares, or entering related-party transactions, can be pushed through by a bare majority unless the constitution itself has been drafted with unusually detailed voting thresholds.
• Departing founders or employees with equity have no enforceable non-compete or non-solicit obligation tied to their shareholding.

Conversely, founders who draft an elaborate shareholders’ agreement but never check it against their constitution risk drafting provisions that are simply unenforceable against the company, because the constitution has not been amended to permit them.

Best Practice: Keeping the Two Documents Aligned

The most reliable way to avoid conflict is to treat the constitution and the shareholders’ agreement as a single governance package that is drafted, or at minimum reviewed, together, rather than as two unrelated documents produced at different points in a company’s life.

1. Mirror Key Mechanical Provisions

Where the shareholders’ agreement depends on a mechanism that only the constitution can give legal effect to, such as a shareholder’s right to nominate a director, the constitution should be amended to expressly permit it. Do not leave a mechanism sitting only in the SHA if the constitution’s default provisions would otherwise block it.

2. Use an Explicit Precedence Clause

A well-drafted shareholders’ agreement should state, as between the contracting parties, which document prevails if there is any inconsistency, and should commit the parties to vote their shares and exercise their powers as directors and shareholders to amend the constitution where needed to remove the inconsistency. This does not override section 39 as against third parties, but it does give the shareholders a contractual obligation to fix the conflict rather than leaving it unresolved.

3. Review Both Whenever Share Capital Changes

Every time shares are allotted or transferred, whether to a new investor, a departing founder’s replacement, or an employee share scheme participant, both documents should be checked. New shareholders need to be joined to the shareholders’ agreement by deed of adherence; the constitution’s share class provisions need to reflect any new class of shares created. Our practical guide on how to allot and transfer shares in a Singapore company sets out the ACRA filing steps that should be run in parallel with this review.

4. Revisit on Any Major Event

A funding round, a founder exit, a change in the board composition, or a proposed reorganisation are all natural trigger points to pull out both documents and confirm they still say consistent things. Leaving this until a dispute is already brewing is the single most common reason these conflicts end up before the courts rather than being resolved by a straightforward amendment.

Do You Need Both?

Every Singapore private company must have a constitution; there is no way around that requirement. Whether you need a shareholders’ agreement depends on your shareholder structure. A single-shareholder company plainly does not need one. A company with two or more unrelated shareholders, particularly where there are external investors, family members, or employees holding meaningful equity, almost always benefits from one, because the constitution alone cannot deliver the confidential, commercially tailored protections that a shareholders’ agreement provides, including drag-along, tag-along, deadlock resolution, and reserved matter protections.

The right approach for most Singapore private companies with more than one shareholder is therefore both documents, drafted or reviewed together, with a clear understanding of which document is doing which job, and a process for keeping them aligned as the company’s ownership evolves.

If you are setting up a new company, bringing in an investor, or simply unsure whether your existing constitution and shareholders’ agreement (or the absence of one) are pulling in the same direction, it is worth having both reviewed together rather than in isolation.

The Editorial Team, Raffles Corporate Services