Equity between startup co-founders is split by each person’s real contribution, valued in money: cash at face value, work at the market cost of hiring that specialist, and the idea by how far it has been validated.
Shares are fixed before the work starts, but with vesting and adjustment rules so they follow actual contributions.
In a Spanish SL all this is set out in the shareholders’ agreement (pacto de socios).
How equity is split between partners plays a fundamental role and affects many aspects of the business.
Below: why getting it right matters, how to value different kinds of contribution, how to protect equity when a partner leaves, and how it is done in Spain.
Why the equity split matters
- Motivation and commitment. A fair split keeps every partner as committed as possible. If a share does not match the contribution or role, it leads to dissatisfaction and even departures.
- Risk management. Risks are shared fairly: those who contribute or risk more get a correspondingly larger share.
- Preventing conflict. A well-thought-out, fair split lowers the chance of disputes, because everyone feels their interests are protected.
- Raising investment. Investors look at the ownership structure. A sound split makes the project more attractive; a poor one puts investors off.
- Business development. Shares that reflect each partner’s contribution support balanced use of resources and decision-making.
Overall, a fair equity split is the basis for healthy partner relationships, business growth and fewer conflicts.
Investors look at it too: an established team with clear stakes raises the project’s valuation — more in Can you raise investment before building a team?
How to value each partner’s contribution
And in practice? How do you value contributions that differ in kind — one partner had the idea, another put in money, a third took on sales?
Surprisingly, you value them in money: what it would cost to hire an outsider to do the work that matches the partner’s contribution.
What a business idea is worth
An idea is hard to value: on its own it is rarely worth much without the work of implementing and validating it. Its value depends on:
- Novelty and uniqueness. Innovative solutions and new approaches to existing problems are worth more; with no direct competitors, the idea is worth more still.
- Market and demand. Ideas for large, fast-growing markets are worth more, and potential demand matters too.
- Development stage. An idea validated through an MVP, pilots or data is worth more than a concept on paper. The more work has gone into validation, the higher the value.
- Technical feasibility. Ideas that can be built with available technology and resources are worth more; a prototype or proof of concept raises the value.
- Potential profitability. Ideas with high monetisation potential are valued higher; financial forecasts and a business plan play a key role.
- Competitive advantage. Patents, unique technology and exclusive agreements raise the value.
- Team. A strong, experienced team increases the idea’s value: investors assess not only the idea but the people who will deliver it.
Illustrative benchmarks by level of validation:
- no development — a bare idea without validation is worth very little, a few thousand or less;
- some validation — surveys, market analysis, a simple prototype — from tens to hundreds of thousands;
- a ready MVP and first customers — signs of demand and profitability — from hundreds of thousands to millions.
So if the founder has not personally validated the idea and it is not original — an online search returns plenty of similar ones — it is worth close to zero. If it is validated on all these factors, it is worth a lot.
One more important factor is how much money the idea needs to be implemented. All else being equal, the more expensive the implementation, the cheaper the idea:
- Low investment. An idea that can be tested and brought to market with minimal spending — a mobile app, say — may be worth more if it can grow fast at relatively low risk.
- High investment. An idea that needs heavy investment — a new biotech product, building a factory — is valued with its large costs and risks in mind. It can be worth a lot with a big market and revenue, but may be worth less because of the high upfront cost and long payback.
The sales partner’s contribution
Simple: look at how many products or services they have already sold for the project. A promise to perform a function well does not mean the partner will actually perform it well.
The project leader’s contribution
Look at the monthly market cost of hiring a good project manager or company director.
That is the real value of this partner’s involvement — or rather of the part they are not paid a salary for.
Cash contributions
Cash is counted at face value. If a partner lends money rather than contributing to capital, that is not equity but company debt — the two must not be mixed.
How to structure different kinds of investment: How to structure startup investment in Spain.
A worked example
Four founders agree terms for 24 months (illustrative figures):
| Partner | Contribution | Value | Share |
|---|---|---|---|
| A | Cash into capital | €60,000 | 30.3% |
| B | Project management half-time, unpaid; market rate €4,000 a month full-time | 4,000 × 24 × 0.5 = €48,000 | 24.2% |
| D | Product development half-time; market rate €4,500 a month | 4,500 × 24 × 0.5 = €54,000 | 27.3% |
| C | Sales half-time; market rate €3,000 a month | 3,000 × 24 × 0.5 = €36,000 | 18.2% |
| Total | €198,000 | 100% |
The idea is not valued in the example: nobody has validated it yet, so by the logic above it is worth close to zero.
If its author had an MVP and first customers, their value would be added to that partner’s contribution.
The key rule: equity follows actual contribution
The main thing for partners is to fix shares before contributions are actually made. But shares should change as the startup progresses towards its goals. Two tools help.
Dynamic equity split
The Dynamic Equity Split model lets shares change with each partner’s contribution at different stages, measured in time, money, intellectual property and other resources.
A close relative is Slicing Pie: each contribution is converted into its “market value”, as in the example above, and shares are recalculated until the company starts paying salaries or raises investment.
Vesting and leaver rules
Vesting means earning equity gradually.
Standard startup practice is 4 years with a 1-year cliff: a founder who leaves within the first year gets nothing; after that the equity is earned in equal parts. Leaver rules are added to vesting:
- good leaver — for example, illness: the founder keeps what they have earned or sells at market value;
- bad leaver — for example, breach of obligations or joining a competitor: the shares are bought back at nominal value or at a discount.
Investors almost always ask for founder vesting when they come in: they need the team to stay after the round.
How it is done in Spain
In a Spanish SL the capital is divided into participations (participaciones), which do not “vest” by themselves.
So vesting, leaver rules and adjustments are set out in the shareholders’ agreement (pacto de socios), usually as a right for the company or the other members to buy back a departing founder’s shares at a pre-agreed price.
A pacto de socios binds those who sign it; to make specific rules binding on the company and future members, they are moved into the articles of association as far as the law allows.
Transfers of participations are executed before a notary and are subject to the articles. It is worth agreeing the economics of these terms before seeing the lawyer.
More on the pacto de socios in How to structure startup investment in Spain.
What to do in practice
- Value contributions in money — at face value and at market hiring cost — with a financial expert who can help assess each contribution fairly.
- Have the shareholders’ agreement drafted professionally with all the terms: shares, vesting, leaver rules, adjustments. It prevents conflicts later.
- Check the split against your fundraising plan: every round dilutes the founders, and the team must keep a motivating stake afterwards.
How investors weigh a founder’s contribution: Skin in the game; how to find a partner: How to attract a business partner to your startup online.
Frequently asked questions
How should equity be split between startup co-founders?
By each person’s real contribution valued in money: cash at face value, work at the market cost of hiring, the idea by how far it has been validated. Shares are fixed in advance, but with vesting and adjustment rules.
What is an idea worth when splitting equity?
An unvalidated, unoriginal idea is worth close to zero. Its value grows with validation: research, a prototype, an MVP and first customers. All else being equal, the more expensive the idea is to implement, the less the idea itself is worth.
Should equity be split equally?
Only if contributions really are equal. A default equal split often leads to conflict when contributions diverge over time. It is fairer to value contributions and adjust shares as they are actually made.
What is founder vesting?
Earning equity gradually. Standard practice is 4 years with a 1-year cliff: a founder who leaves within a year gets nothing; after that the equity is earned in equal parts.
How are shares and vesting secured in a Spanish SL?
In the shareholders’ agreement (pacto de socios), usually through a right to buy back a departing founder’s shares at an agreed price. Specific rules are moved into the articles, and share transfers are executed before a notary.
Key points about splitting equity
- Split equity by contributions valued in money, not by gut feeling.
- Value sales by sales already made, management by the market cost of hiring.
- An unvalidated idea is worth close to zero; validation, an MVP and customers give it value.
- Fix shares in advance, but with vesting, leaver rules and adjustments.
- In Spain, set it all out in the pacto de socios and, where needed, the SL’s articles.
The worked example and idea value benchmarks are illustrative.
