The Paperwork Before the Party: Founder Agreements UK Startups Wish They'd Signed

Most founder disputes do not start with a betrayal. They start with a sentence everyone half-remembers from a kitchen table: 'We'll split it evenly and sort the details later.' Later arrives when a term sheet lands, when the first hire asks about options or when one founder wants to leave. By then, the friendly ambiguity has become an expensive problem.

At Start Network, we hear versions of this story every month. The details change; the shape does not. A UK limited company is a useful container, but it does not decide who owns what, who decides what or what happens when someone walks away. Those are founder agreements, and they are easier to write before money and ego arrive.

Here is the conversation UK founders wish they had before the first investor meeting.

The equity split that felt fair at the time

Equal splits are common and not automatically wrong. But they are often a proxy for discomfort rather than a considered decision. One Bristol founder told us he gave his co-founder 50% because 'it felt rude to ask for more' after three months of building together. Two years later, the co-founder moved abroad, went part-time and still held half the cap table. The company survived, but every funding conversation became harder.

A better approach is to link equity to contribution over time. That does not mean being ruthless. It means writing down what each person is bringing: cash, code, customers, domain expertise, full-time commitment. Then ask whether the split would still feel fair if one person's contribution doubled and the other's halved. If not, you need a vesting schedule, not a better mood.

Vesting: the clause nobody wants to draft

Founder vesting is standard in the US and increasingly common in the UK. The usual shape is four years with a one-year cliff: you earn your shares over time, and if you leave before the first year, you keep none. In the UK, this is often done through reverse vesting, where shares are issued up front but subject to repurchase rights if a founder leaves.

The detail that matters is the definition of 'good leaver' and 'bad leaver'. A good leaver might be someone who leaves due to illness or mutual agreement and keeps vested shares. A bad leaver might be someone who resigns early or breaches their obligations and loses unvested shares. Get this wrong and you can end up in a dispute that costs more than the shares are worth.

Decision rights: who actually decides?

Investors ask who has control. Founders often discover they have never agreed. If you are two equal founders, who breaks a tie? If you are three, does the CEO decide hiring, or does the board? A shareholder agreement and articles of association can set reserved matters: raising money, issuing shares, changing the business, taking on debt, selling the company.

One Leeds founder described a near-deadlock over whether to accept a small acquisition offer. The founders had equal shares and no chair with a casting vote. The deal fell apart while they argued. A simple decision protocol would have saved the company months. Decide early which decisions need unanimity, which need a board majority and which sit with the CEO.

IP: the asset investors actually buy

Investors are not buying your enthusiasm. They are buying the company's intellectual property. If a founder developed the core product before incorporation, the company may not own it. If a contractor wrote code without an IP assignment, the company may only have a licence. If a university or former employer has a claim, the diligence process will find it.

Every founder, employee and contractor should sign an IP assignment. The company should own the domain names, code repositories, designs and brand. Founders should check their employment contracts, especially in universities and large corporates, for inventions clauses. This is not a legal nicety. It is the difference between a clean data room and a delayed round.

Time commitment and the side project problem

A founder who is 'helping out' is not the same as a founder who is full-time. Write down expected hours, exclusivity and whether side projects are allowed. If one founder is keeping a consulting gig, say so and explain how it affects their equity and decision rights. Investors will ask.

One Cardiff founder learned this the hard way when a co-founder's consultancy became a competing business. There was no non-compete and no exclusivity clause. The fix was expensive and slow. A short conversation at the start would have been cheaper.

What happens if one founder leaves?

This is the conversation most founders avoid. What happens to unvested shares? Does the company have the right to buy back vested shares? At what price? Who pays? What happens to the departing founder's director role and access to company accounts?

A founder leaving is not a failure of the friendship. It is a business event. The agreement should say how it is handled: notification, handover, share repurchase, confidentiality and non-disparagement. It should also cover death or long-term illness, which is uncomfortable but necessary.

The pre-investor checklist

Before you take a term sheet, check that you have:

• A founder agreement or shareholders' agreement signed by everyone.
• Vesting terms with clear good leaver and bad leaver definitions.
• A decision matrix for reserved matters and day-to-day choices.
• IP assignments from founders, employees and contractors.
• Employment or consultancy contracts for anyone working in the business.
• A cap table that matches the share register and Companies House filings.
• Written expectations on time commitment and side projects.
• A process for what happens if a founder leaves or steps down.
• A named person responsible for keeping the paperwork updated.

Have the awkward conversation now

You do not need to lawyer every chat. You do need to write down what you agreed. Use plain English, then ask a solicitor to turn it into articles and a shareholder agreement. Revisit it when you raise money, hire a senior team or bring in a new founder. The goal is not to distrust your co-founder. It is to make the relationship strong enough to survive success.

Start Network is not a law firm, and this is not legal advice. But the founders who get this right tend to have one thing in common: they had the awkward conversation before they had to.