Investment Agreement or Shareholders’ Deed? Spot the Differences

If you’re launching or growing a startup in the UK, you’re bound to encounter two key legal documents: the investment agreement and the shareholders’ agreement. Both are crucial for anyone raising capital or bringing new people into their business – but what’s the real difference between them? And how do you know which one your venture really needs?

Understanding these agreements is essential to getting your legal foundations right from day one. The good news? Once you know what each agreement covers and how they work together, you’ll be in a stronger position to manage relationships, protect your business, and attract investors with confidence.

Let’s explore what makes these two documents different, why you might need both, and how to make sure they work for your specific business and funding round.

What Is an Investment Agreement?

When someone decides to invest capital in your company – whether it’s an angel investor, venture capital fund or even friends and family – you’ll typically formalise the deal with an investment agreement. This document sets out the precise terms and conditions under which an investor injects money or assets into your company.

Think of the investment agreement as the contract for the investment “event” itself. It’s where you spell out all the logistics, promises, and requirements that need to be ticked off before money changes hands or shares are issued.

Key Provisions Found in Investment Agreements

• Investment Amount & Valuation: Details exactly how much will be invested and the agreed value of the company.
• Form of Capital: Sets out what is being subscribed for, such as ordinary shares, preference shares, or convertible notes.
• Pre-Completion Conditions: Conditions that must be satisfied before the investment completes – such as due diligence, sign-off by the board, or regulatory approvals.
• Warranties & Representations: Promises made by the company and sometimes the founders about the business (e.g. financial position, ownership of assets, no undisclosed liabilities).
• Completion Mechanics: Process for transferring funds and issuing shares.

Once these terms are agreed and the conditions are met, everyone is legally bound to complete the investment. For many startups, agreeing the investment terms can be time-consuming, but it’s essential to get them right to protect both sides and avoid disputes down the track.

For more detail, see our in-depth guide on how equity financing works.

What Is a Shareholders’ Agreement?

While the investment agreement deals with the specifics of bringing new money (and usually a new shareholder) on board, the shareholders’ agreement kicks in once they’re in the business. It’s an agreement between all (or most) of the company’s shareholders that sets out the rules for running the company and how everyone will work together going forward.

Think of the shareholders’ agreement as the “rulebook” for your company. It covers everything from the day-to-day management of your business, to what happens if a shareholder wants out, to how major decisions are made.

Key Issues Covered in Shareholders’ Agreements

• Board and Management Rights: Who appoints directors, how the board is structured, and what powers the directors and shareholders have.
• Decision Making/Voting: What decisions require a shareholder vote, and what percentage is needed for approval (e.g. 75% to sell the company; majority to appoint a new director).
• Share Transfer & Exit: Restrictions or procedures for shareholders wanting to sell, including rights of first refusal, “drag-along” and “tag-along” rights.
• Profit Distribution: When and how dividends are paid out to shareholders.
• Dispute Resolution: Steps to follow if shareholders disagree about a key issue, often including mediation or buyout provisions.
• Confidentiality, Non-Compete & Other Protections: Clauses to prevent shareholders from competing with the business or leaking sensitive information.

Having a properly drafted shareholders’ agreement is one of the single best ways to protect your business from conflicts and misalignments as you grow. You can learn more about what to include and why in our guide to shareholders’ agreements.

How Do Investment Agreements and Shareholders’ Agreements Work Together?

It’s common, especially in early-stage UK startups, to have both documents. One isn’t a substitute for the other – in fact, they work in tandem.

Here’s how the process usually goes:

1. Investor commits to invest capital: The parties negotiate and sign an investment agreement which states how, when, and how much will be invested.
2. Shareholders’ agreement comes into play: The new investor becomes a shareholder. All (or a majority) of the shareholders sign a shareholders’ agreement, agreeing how the company will be operated and managed going forwards.
3. Together, they provide clarity and protection: The investment agreement protects both the investor and the company during the deal process; the shareholders’ agreement protects everyone involved once they’re actually in business together.

Sometimes the documents are combined, though usually only in very simple cases – or there may be a “subscription and shareholders’ agreement” for smaller rounds or tight-knit businesses. However, using templates or combining agreements can be risky if you don’t know exactly what to include. For comprehensive protection, it’s best to tailor both documents to your company’s circumstances and investor needs. You can see an overview of each type of investment document here.

What Are the Main Differences? Here’s a Side-by-Side Comparison

Let’s break it down even more simply, so you can quickly spot the role of each agreement:

Investment Agreement	Shareholders’ Agreement
Governs the terms of the investment itself (who, what, how much, and when)	Governs the ongoing relationship between shareholders (rights, responsibilities, and company management)
Used at the time of capital injection	Applies for as long as the business operates
Includes price, type of shares, payment schedule, conditions precedent, warranties, disclosures	Includes shareholder voting rights, board structure, transfer restrictions, company policies, exit mechanisms
Binds parties to complete the deal once conditions are met	Binds parties to ongoing conduct, dispute resolution, and cooperation
Protects company and investors during the transaction	Protects shareholders (including new investors) and the company’s long-term stability

Still working out which you need? The simple answer is: if you’re raising outside capital, you almost always need both to ensure you’re protected at each stage – first for the deal, then for managing long-term relationships.

Do I Need a Share Agreement Template UK When Raising Investment?

You might be tempted to use a simple 'share agreement template UK' you find online, but proceed with caution. While generic templates are a starting point, they rarely cover the unique issues that arise in a genuine investment scenario, especially for fast-growing startups.

Key risks with relying solely on a share agreement template include:

• Missing crucial investor rights or obligations (like anti-dilution, pre-emption, or drag-along/take-along clauses)
• Failure to address specific founder, employee or investor protections
• Incompatibility with your fundraising round structure (many templates aren’t tailored for EIS, SEIS, or multiple share classes)
• Potential to miss compliance obligations under company law and FCA rules

It’s essential to have documents that are tailored to your company’s situation and that incorporate any prior investment rounds, special rights, and your overall exit strategy. Using an off-the-shelf contract may be appropriate for very simple scenarios, but for proper protection and growth, you should have documents drafted or reviewed by an experienced solicitor. Check out our article on copying terms and conditions templates for more insight on why generic contracts can cause more harm than good.

Why Is Professional Legal Advice Crucial For These Agreements?

Investment and shareholders’ agreements aren’t just formalities – they’re the glue holding your business and its investors together, often for years to come. And because every company and fundraising journey is different, the right provisions can make all the difference.

Here’s why you should get legal help (rather than going the DIY route):

• Fair Terms: Lawyers help you negotiate terms that protect your company’s vision and make your offer attractive to investors.
• Clarity & Risk Reduction: They make sure responsibilities are crystal clear and address “what ifs” before they trip you up.
• Bespoke Drafting: Your agreements are tailored to your business, not just a template everyone else is using.
• Compliance Confidence: Your documents do what they’re supposed to – and meet UK legal and regulatory standards (like Companies Act 2006 and FCA requirements).
• Dispute Prevention: Many legal headaches can be avoided with good drafting and built-in resolution steps for shareholder disagreements.

At Sprintlaw, we help startups and scale-ups across the UK put the right documents in place to stay protected as you grow. Our team can advise whether an investment agreement, shareholders’ agreement, or a full fundraising package is right for your venture.

Common Mistakes To Avoid When Setting Up Investment or Shareholders’ Agreements

• Not having both agreements in place when raising outside investment.
• Failing to update your constitutional documents (such as articles of association) to match your agreements.
• Using an out-of-date or overseas template not aligned with current UK law.
• Not including dispute resolution, transfer restrictions, or exit mechanics in your shareholders’ agreement.
• Skipping legal advice or trying to patch different templates together yourself.

Want more on key legal documents? Read our guide to essential legal documents for your business.

Key Takeaways

• The investment agreement covers the terms, obligations, and mechanics for injecting capital into your company, protecting both the investor and the business during the transaction.
• The shareholders’ agreement regulates how shareholders will interact, make decisions, and manage the company after the investment, safeguarding everyone’s long-term interests.
• Both documents are key to a legally robust and investor-friendly UK startup or small business – and are often used together.
• Templates can miss important commercial or legal protections; professional legal advice ensures agreements fit your business model, investment round, and future plans.
• Getting your documents right from day one prevents disputes, smooths the capital raising process, and boosts investor confidence.

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If you’d like guidance on drafting, reviewing, or negotiating an investment or shareholders’ agreement for your business, Sprintlaw is here to help. Reach out today for a free, no-obligations chat at 08081347754 or team@sprintlaw.co.uk and make sure your legal foundations are built for growth!