What should a shareholders' agreement include for a UK startup?
By SuLe · Updated 20 June 2026
A UK startup shareholders' agreement should cover the equity position, founder vesting and leaver provisions, controls on share transfers, drag-along and tag-along rights, reserved matters needing shareholder consent, board arrangements, information rights and a route out of deadlock. It is a private contract that sits alongside your articles of association — and it is where most founder protections actually live.
Key facts
- A shareholders' agreement (SHA) is private — unlike the articles of association, it is not filed at Companies House.
- Without vesting and leaver provisions in the SHA or articles, a departing founder keeps every share.
- Founder vesting is typically 4 years with a 1-year cliff, with unvested shares recoverable at nominal value.
- Good leavers typically keep vested shares or sell at market value; bad leavers can be forced out at the lower of cost and market value.
- New shareholders sign a deed of adherence so the agreement binds them as if they were original parties.
What sections does a startup SHA actually need?
Ten, in practice — and most founder disasters trace back to one of them being missing. Use this as the checklist when reviewing a draft or a template.
| Section | What it does |
|---|---|
| Parties and the cap table | Records who holds what at signing, by share class |
| Vesting and leaver provisions | Typically 4-year vesting with a 1-year cliff; defines good and bad leavers and the price each gets |
| Transfer controls | Pre-emption on transfers and permitted-transfer carve-outs, so shares cannot be sold to strangers freely |
| Drag-along and tag-along | Lets a majority deliver a whole-company sale; lets minorities join a sale on the same terms |
| Reserved matters | A consent list for major decisions — new share issues, borrowing, changing the business, selling |
| Board and decision-making | Who can appoint directors, how the board decides, quorum |
| Information rights | The accounts and updates shareholders are entitled to receive |
| Deadlock resolution | A defined route out when votes stall — critical for 50/50 companies |
| Confidentiality and IP | Keeps company information and IP with the company |
| Deed of adherence mechanics | Forces every future shareholder to sign up to the same rules |
How should it deal with founder shares and leavers?
This is the section that earns the document its fee. UK founder vesting is reverse vesting — each founder owns their shares from day one, and the SHA gives the company or remaining shareholders the right to recover unvested shares at nominal value if that founder leaves.
Pair the schedule with leaver definitions. Good leavers — death, serious illness, dismissal without cause — typically keep vested shares or sell at market value; bad leavers — early resignation, dismissal for cause — can be forced to sell at the lower of cost and market value.
Both the labels and the consequences are entirely negotiable, which is exactly why they must be written down before anyone is actually leaving.
What controls should it put on share transfers?
Enough that no stranger can appear on your cap table uninvited. The standard package is pre-emption on transfers — existing shareholders get first refusal — plus permitted transfers for narrow cases, with everything else needing consent.
Drag-along and tag-along complete the set. Drag lets a defined majority force everyone into a genuine sale of the company; tag lets small holders insist on joining a majority sale on identical terms.
Finally, the deed of adherence: every new shareholder, whether investor, employee or transferee, signs a short deed binding them to the SHA as if an original party. Skip it once and part of your cap table is outside the rules.
How does an SHA work with your articles of association?
The two documents divide the labour. The articles are the company's constitution under the Companies Act 2006 — public, filed at Companies House, binding the company and all members; the SHA is a private contract that can hold terms you would rather not publish, like leaver pricing.
Some machinery works best in the articles — share classes, compulsory-transfer and deferred-share mechanics — while commercial promises sit naturally in the SHA. Most startups amend their articles and sign an SHA as a matched pair.
Where the two conflict, a well-drafted SHA says which prevails between the shareholders. Have both reviewed together, not in isolation.
Worked example
Theo, Zara and Malik incorporate an occupational-health platform with 100,000 ordinary shares: 40,000 each to Theo and Zara, 20,000 to Malik, who keeps a part-time consultancy during year one. Their SHA puts all three on 4-year vesting with a 1-year cliff, defines good and bad leavers, and lists reserved matters — including any borrowing over £25,000 and any new share issue.
Eighteen months in, an angel subscribes £150,000 for new shares. Because transfers, drag and tag and information rights are already in place, the angel's solicitor asks for a deed of adherence and two additions to the reserved-matters list rather than a from-scratch renegotiation.
The round closes in weeks — the SHA's real return on investment.
Where founders go wrong
Assuming the model articles cover any of this.
They contain no vesting, no leaver provisions, no drag or tag and no reserved matters — they were not written with startups in mind.Copying a US template.
Delaware concepts do not map onto Companies Act 2006 mechanics, and the mismatch surfaces at the worst moment: due diligence.Leaving out leaver provisions.
The most expensive omission available: without them, a founder who quits in month nine keeps everything.Forgetting deeds of adherence.
Every new shareholder who has not signed one is a shareholder your agreement does not bind.
Related questions
Do we still need a shareholders' agreement if we have articles of association?
Usually, yes. The articles are your public constitutional document and every company must have them, but the standard model articles say nothing about vesting, leavers, drag and tag or investor consents. Startups typically end up with bespoke articles and a shareholders' agreement working together. [More: Should I use model articles or bespoke articles of association?]
What are reserved matters and why do they matter?
A reserved-matters list names decisions the board cannot take without a defined level of shareholder or investor consent — issuing new shares, borrowing beyond a threshold, changing the business, selling the company. It protects minority founders early on, and investors will bring their own list at your first round. [More: What are reserved matters (investor consent rights)?]
How do new shareholders become bound by the agreement?
Through a deed of adherence — a short document by which each new shareholder agrees to be bound by the existing shareholders' agreement as if they had signed it originally. Make it a condition of every share issue or transfer, or the agreement quietly stops covering your cap table. [More: What is a deed of adherence?]
What are drag-along and tag-along rights for?
Drag-along lets a defined majority force all shareholders to sell in a genuine exit, so one small holdout cannot block the deal. Tag-along is the mirror: if the majority sell, minorities can insist on selling on the same terms. Buyers expect both to be in place. [More: What are drag-along and tag-along rights?]
Do solo founders need a shareholders' agreement?
Not while there is genuinely one shareholder — there is nobody to agree with. The moment a co-founder, investor or employee-shareholder arrives, the calculation flips, and it is far easier to set terms while you still hold all the shares. [More: Do I need a shareholders' agreement as a solo founder?]
A shareholders' agreement is the document that decides what happens when a founder leaves, an investor pushes or a 50/50 vote stalls — long after everyone has stopped reading it. A SuLe solicitor can draft one that fits your cap table and stage, or review the template you are about to sign. Get your founder documents reviewed — book a free consultation and get the protections in before you need them.
Keep reading: Founders' agreement vs shareholders' agreement — what's the difference? · What are good leaver and bad leaver provisions? · What is founder vesting and how does it work in the UK? · What happens to a co-founder's shares if they leave? · How should co-founders split equity in a UK startup? · What are pre-emption rights — and how are they disapplied?
Primary sources: Companies Act 2006 · GOV.UK — Running a limited company
