A guide to shareholders agreements for founders and family businesses in 2026
Last reviewed: July 2026
Area: Commercial and corporate
Who this is for: founding shareholders, startups and family businesses
Many Spanish companies, especially limited companies with two or three shareholders and startups in their early funding rounds, are incorporated without a shareholders agreement. The assumption is that “we understand each other” and that the bylaws already cover the essentials. That is not the case: bylaws are a public document, aimed at third parties, with a minimum and fairly rigid content that does not get into the nuances of the relationship between shareholders.
The risk of not having a shareholders agreement, or of having a poorly drafted one, tends to surface at the worst possible moment: when the company starts generating real value, when an investor comes in, or when a shareholder decides to leave. At that point, with no rules agreed in advance, the dispute moves to the courts, with costs in time and money that almost always exceed what it would have cost to draft a proper agreement from the outset.
This guide explains what a shareholders agreement is, how it differs from the bylaws, which clauses tend to make the difference between an agreement that genuinely protects shareholders and one that ends up in a drawer, and when it is worth reviewing or updating it. It applies both to traditional limited companies and to startups going through funding rounds, and to family businesses working through succession.
We also go through the most common drafting mistakes, because they tend to be the same ones: using a generic template, leaving a 50/50 deadlock unresolved, or failing to update the agreement when the company’s circumstances change.
What a shareholders agreement is and what it’s for
A shareholders agreement is a private contract between a company’s shareholders that governs how they will relate to one another beyond what the bylaws say: how important decisions are made, what happens if one shareholder wants to sell their stake, what happens if two 50/50 shareholders cannot agree, or what conditions apply to a founder’s shares if they leave the project early.
In essence, it exists to set out in writing, ahead of time, the scenarios that most often generate conflict between shareholders: the entry of new investors, a founder’s departure, the balance of decision-making power, or the sale of the company. It typically includes, among other elements:
- Majority rules for strategic decisions.
- Transfer rules for shares, both between shareholders and towards third parties.
- Orderly exit mechanisms for founders and investors.
- Protective clauses such as non-compete or confidentiality provisions.
A good shareholders agreement does not repeat what the bylaws already say: it complements them, covering everything the bylaws cannot or should not include. The freedom to enter into these agreements stems from the principle of freedom of contract set out in article 1255 of the Spanish Civil Code, which allows parties to agree whatever they consider appropriate, provided it is not contrary to law, morality or public policy.
Shareholders agreement vs. articles of association: which prevails and why
The first common mistake is confusing the two documents. Company bylaws (the articles of association) are public, are registered with the Commercial Registry, and are enforceable against third parties. A shareholders agreement, by contrast, is a private contract that only binds those who sign it: it is not registered, is not public, and can cover matters shareholders would rather not disclose (for example, the economic terms of an exit or financing arrangements).
This private nature has an important legal consequence: if the agreement and the bylaws contradict each other, the bylaws prevail against a third party acting in good faith. Between the shareholders themselves, however, the agreement is fully enforceable and a breach can be claimed in court, including damages or agreed penalties.
That is why it matters for both documents to be well coordinated: what is essential for third parties should be in the bylaws, and what governs the internal relationship between shareholders belongs in the agreement. Without an agreement, many important decisions can be approved with the ordinary majority set out in the Spanish Companies Act, which gives enormous power to any shareholder or block that controls just over 50% of the company.
Clauses that shouldn’t be missing
Not every company needs the same clauses, but in our experience there is a core set that makes the difference between a shareholders agreement that genuinely protects the company and one that ends up in a drawer, never actually doing its job.
Enhanced majorities for key decisions
A well-designed shareholders agreement raises the approval threshold for especially sensitive decisions: borrowing above a set amount, disposing of essential assets, admitting new shareholders, amending the bylaws, or distributing dividends. The practical recommendation is to list, in a closed way, which matters require an enhanced majority (for example, 75% or 80%) and which follow the ordinary regime. An open or vague list generates disputes about its own interpretation — exactly what the agreement should be preventing.
Right of first refusal on share transfers
A right of first refusal gives existing shareholders preference to buy shares that another shareholder wants to sell, before they can pass to an outside third party. It is worth setting a precise deadline to exercise it, a reference price (an agreed valuation, an independent valuer, or the same price offered by the third party), and what happens if several shareholders want to exercise it at the same time. Without this clause, any shareholder can sell their stake to a stranger with no chance for the rest to react.
Drag-along and tag-along
A drag-along clause allows the majority shareholders (or an agreed percentage) to force minority shareholders to sell their shares on the same terms if they decide to sell the company to a third party. This is especially relevant for startups, where an investor buying 100% of the capital is usually unwilling to be left with a minority shareholder who refuses to exit. The important legal nuance here is that drag-along must come with fair-price guarantees: it is normally required that the terms offered to minority shareholders be at least equivalent to those offered to the shareholder driving the sale.
The counterpart is tag-along, or the right to join a sale: if the majority shareholder sells their stake, minority shareholders have the right to sell theirs on the same terms, rather than being left as shareholders of a new controlling party they did not choose. It is worth checking that the agreement clearly defines what “the same terms” means (price, form of payment, timelines), so the right is effective rather than merely theoretical.
| Clause | Mainly protects | Risk if not agreed |
|---|---|---|
| Right of first refusal | Existing shareholders against outside third parties. | An unwanted shareholder joins the company with no way to react. |
| Drag-along | The buyer and the majority shareholders. | A minority shareholder blocks the sale of the whole company. |
| Tag-along | Minority shareholders. | Being stuck with a new controlling shareholder you did not choose. |
| Deadlock mechanism | The continuity of a 50/50 company. | Total paralysis on any strategic decision. |
| Good leaver / bad leaver | The shareholders who remain in the project. | A founder leaves early while keeping capital they did not earn. |
Non-compete and confidentiality
A shareholder who leaves and starts an identical business the next day, using the company’s client base, know-how or contacts, can cause considerable damage. Non-compete clauses limit this for a reasonable period after departure (typically one to two years, with a clearly defined geographic and material scope so the clause is valid and proportionate), while confidentiality clauses protect the company’s sensitive information, both during the relationship and after it ends. It is advisable to pair these clauses with a specific financial penalty for breach, because without one, a court claim tends to be slow and uncertain in outcome.
Resolving deadlocks
In companies with two 50/50 shareholders, or two balanced blocks, the risk of a deadlock is very high: it only takes one strategic disagreement to bring the company to a standstill. A good agreement anticipates this scenario with concrete mechanisms: mandatory prior mediation, a cross buy-sell option (one shareholder offers to buy or sell at a price they set), arbitration, or even agreed dissolution if the deadlock continues beyond a set period. Leaving this issue unaddressed is one of the most frequent causes of shareholder litigation once a company grows and decisions stop being trivial.
Shareholder exits: good leaver / bad leaver, vesting and liquidation preference
Good leaver / bad leaver clauses determine the economic terms a founding shareholder receives when leaving the company, depending on the circumstances of their departure. A “good leaver” (for example, someone who leaves for justified reasons: illness, retirement, mutual agreement) usually keeps the market value of their shares. A “bad leaver” (someone who breaches their obligations, leaves without justification within a short period, or competes unfairly) may see that value reduced, sometimes down to nominal value. This distinction is decisive for startups, where several founders dedicate time and effort from day one: without this clause, someone could leave after a few months while keeping a significant percentage of the capital without having put in the expected work.
Vesting consolidates founders’ ownership of their shares progressively over a period (typically three to four years), rather than handing them over in full from incorporation. It is a standard practice in the startup ecosystem and one of the clauses investors demand most before joining a round. It is usually combined with an initial cliff period (normally one year) during which no shares vest at all if the founder leaves early, after which the rest vests monthly or quarterly.
Liquidation preference is a common clause when an outside investor joins: it guarantees they will recover their investment (or a multiple of it) before other shareholders receive any distribution, in the event of a sale or liquidation of the company. It is reasonable for an investor to require it, but its scope should be negotiated carefully: a simple preference (which also participates in the remaining distribution) is not the same as full-participation preference, which can leave founders with very little in modest exit scenarios. A lawyer specialised in shareholders agreements should review this clause in detail before any funding round is signed, because its wording directly determines how much the founders receive on the day the company is sold.
When it’s worth reviewing: startups, funding rounds and family businesses
A shareholders agreement is not a document you sign once and forget about. There are specific moments in a company’s life when it is worth reviewing, updating or, if it does not yet exist, drafting it before it is too late:
- Incorporation of the company: the ideal moment to build in vesting, majority rules and an exit regime, before any tension between founders exists.
- Closing a funding round: investors will require clauses such as liquidation preference, drag-along or tag-along as a condition for joining; drafting them under pressure, in the middle of a negotiation, tends to produce worse results than doing it calmly.
- A shareholder joining or leaving: this changes the capital structure and, with it, the balance of power the original agreement assumed.
- Family businesses going through succession: the agreement can govern how shares pass to the next generation, what happens if an heir does not want or is not able to run the business, and how shareholders who remain active are protected against those who merely hold shares.
- Significant growth of the company: decisions that used to be trivial (borrowing, hiring senior managers, opening new business lines) start to have a real impact and should be covered by the agreement’s majority rules.
Being a private contract, the shareholders agreement can be amended at any time if all signing shareholders agree, following whatever amendment procedure the agreement itself sets out (usually unanimity or a specific enhanced majority for this purpose).
Common drafting mistakes
Most of the problems we see with shareholders agreements do not come from bad faith between shareholders, but from drafting mistakes that keep repeating:
- Using a generic template without adapting it: generic shareholders agreement templates circulate online, but an agreement drafted without adapting it to the number of shareholders, the sector, the presence of investors, or whether it is a family business rarely covers the real risks of each project. Clauses such as vesting, liquidation preference or majority rules need to be calibrated case by case.
- Leaving the majority rules open or vague: an imprecise list of which decisions require an enhanced majority generates disputes about its own interpretation at the worst possible moment.
- Not providing for a deadlock mechanism: in 50/50 companies or those with balanced blocks, failing to anticipate how to resolve a deadlock is one of the most frequent causes of shareholder litigation.
- Omitting the shareholder exit regime: without good leaver / bad leaver or vesting clauses, a founder can leave after a few months while keeping a percentage of capital that no longer matches their real involvement.
- Failing to coordinate the agreement with the bylaws: if the two documents contradict each other, the bylaws prevail against third parties acting in good faith, so what matters to third parties should be in the bylaws.
- Not updating it when circumstances change: a new shareholder joins, a funding round closes, or the capital structure changes, and the original agreement becomes outdated if no one reviews it.
How GraciaCalbet can help you
At GraciaCalbet we have spent more than 45 years advising companies, founding shareholders and family businesses on the incorporation and organisation of their projects. We do not work from a generic shareholders agreement template: each agreement is drafted around the capital structure, the number of shareholders, the presence or absence of investors, and the specific risks of each business, because a standard document rarely protects what actually matters in each case.
If you are incorporating a company, bringing in a new shareholder, or closing an investment round, we can help you draft or review your shareholders agreement as part of our company incorporation service, integrating bylaws and the agreement as a coherent whole from day one. And if a conflict has already arisen and there is no agreement to govern it, our shareholder disputes team can help you find the least costly way out. If your situation is no longer preventive but responds to an ongoing majority-shareholder abuse, we also recommend reviewing our article on minority shareholder protection, focused precisely on that scenario.
You can reach out through our contact page with no obligation, or explore the rest of our services in commercial and corporate law.
Frequently Asked Questions (FAQs)
What is a shareholders agreement?+
It is a private contract between a company’s shareholders that governs aspects of their relationship the bylaws do not cover, or that are best kept confidential: enhanced majorities, share transfers, the exit regime, non-compete obligations, or deadlock resolution. Unlike the bylaws, it is not registered with the Commercial Registry and only binds those who sign it. It is enforceable between shareholders, although the bylaws prevail against a third party acting in good faith in case of contradiction. It is drafted under the freedom-of-contract principle set out in article 1255 of the Spanish Civil Code.
Is a shareholders agreement mandatory?+
No, the law does not require it. A company can be validly incorporated and operate with only its bylaws. In practice, however, it is highly recommended, especially when there is more than one shareholder with a significant stake, when there is a risk of a 50/50 deadlock, or when outside investors join and will require specific clauses (vesting, liquidation preference) that do not naturally fit into standard bylaws. The absence of an agreement carries no legal penalty, but it does leave the company without tools to resolve future conflicts.
Is there a shareholders agreement template that works for any company?+
Not reliably. Generic shareholders agreement templates circulate online, but an agreement drafted without adapting it to the number of shareholders, the sector, the presence of investors, or whether it is a family business rarely covers the real risks of each project. Clauses such as vesting, liquidation preference or majority rules need to be calibrated case by case. Using a template without review by a lawyer specialised in shareholders agreements usually creates a false sense of protection that is discovered, too late, at the moment of conflict.
What happens if the shareholders agreement contradicts the bylaws?+
Between the shareholders who signed it, the agreement is enforceable and a breach can be claimed in court, including damages or agreed penalties. However, against a third party acting in good faith (a buyer, a bank, a supplier) the bylaws prevail, because they are the public document registered with the Commercial Registry. That is why it is important for both documents to be well coordinated: what matters to third parties should be in the bylaws, and what governs the internal relationship between shareholders, in the agreement.
When should a startup sign a shareholders agreement?+
Ideally from incorporation, before any tension between founders exists, including vesting and exit-regime clauses from the start. In any case, it is essential before closing an investment round, since investors will require clauses such as liquidation preference, drag-along or tag-along as a condition for joining. Drafting the agreement under pressure, in the middle of a funding negotiation, tends to produce worse results than doing it calmly in an early phase of the project.
How much does it cost to draft a shareholders agreement with a lawyer?+
The cost depends on the complexity of the company: number of shareholders, presence of investors, sector of activity, and the specific clauses required. A simple agreement between two or three founding shareholders costs less than one that must integrate liquidation preference, staged vesting and drag-along provisions for an investment round. In any case, the cost of drafting it properly from the start is significantly lower than that of shareholder litigation resulting from not having one, or from having a poorly drafted one.
Can a shareholders agreement be amended once signed?+
Yes. Being a private contract, it can be amended at any time if all signing shareholders agree, following whatever amendment procedure the agreement itself sets out (usually unanimity or a specific enhanced majority for this purpose). It is common, and advisable, to review it whenever relevant circumstances change: a new shareholder joins, an investment round closes, or the capital structure changes significantly.
