Founder Secondary Sales in the UK: Legal Issues for Startups and Shareholders

A founder secondary sale can look simple on paper. One founder wants some liquidity, an investor or buyer wants shares, and everyone assumes the paperwork will follow. In practice, this is where startups often get caught. Common mistakes include agreeing a price before checking the articles, ignoring pre-emption rights, and treating the sale like a standard share transfer when the cap table, investor consents and leaver rules say otherwise.

That matters because a founder secondary sale changes more than ownership percentages. It can affect control, investor confidence, employee option pools, future fundraising and the story your company tells to the next lead investor. A deal that feels commercially sensible can create friction if the company documents are out of date or if one shareholder is being given a better deal than others without proper approvals.

This guide explains what a founder secondary sale usually involves in the UK, when businesses use confidentiality agreements around these deals, the legal issues to check before you sign, and the common drafting and process mistakes that can turn a clean transaction into a messy one.

Overview

A founder secondary sale is the sale of existing shares by a founder to another person, rather than the company issuing new shares. The core legal question is rarely just price. The real issue is whether the sale fits the company’s constitution, shareholder arrangements and wider funding strategy.

• Check the articles of association for transfer restrictions, pre-emption rights, drag along and tag along provisions.
• Review any shareholders’ agreement for consent rights, founder lock-ins, leaver rules and restrictions on who can buy.
• Confirm whether board approval, shareholder approval or investor consent is required before signing.
• Make sure the share class, number of shares and any rights attaching to them are accurately identified.
• Decide whether an NDA is needed before sharing the cap table, financials, customer data or fundraising information.
• Agree whether warranties, indemnities, price adjustments or deferred consideration are appropriate.
• Prepare the transfer paperwork properly, including the stock transfer form, board minutes and register updates.
• Think about the commercial message, especially if the company is fundraising or telling investors the founders are fully committed for the long term.

When UK Businesses Use NDAs

UK businesses often use an NDA at the early stage of a founder secondary sale, especially where sensitive information will be shared with a potential buyer before terms are finalised. It is not mandatory in every deal, but it is often sensible where the buyer is outside the existing shareholder group or where the company’s commercial information is part of the discussions.

A buyer considering a founder secondary sale may ask for access to information that goes well beyond the public Companies House record. That can include:

• the cap table and details of other shareholders;
• share class rights and investor documents;
• recent management accounts and financial forecasts;
• customer concentration and major contracts;
• information about disputes, IP ownership or regulatory issues;
• details of an upcoming fundraising or exit process.

An NDA helps set boundaries around what can be used, who can see it and how long confidentiality obligations last. It also gives the company and the selling founder a clearer basis for pushing back if information is later misused.

Why an NDA matters in a founder secondary sale

The buyer is often not just assessing the founder’s shares. They are assessing the company itself. That means the transaction can expose a startup’s most commercially sensitive material before there is any binding commitment to proceed.

If the buyer is a competitor, a former employee, a strategic investor or someone already active in the same market, the main risk is obvious. Information shared for the proposed share purchase may become useful for pricing, recruitment, sales strategy or a future investment approach.

A well-drafted NDA for this context should usually deal with:

• what information is confidential, including oral disclosures and data room materials;
• the permitted purpose, namely evaluating the proposed secondary purchase;
• who the recipient can share information with, such as lawyers, accountants or funding partners;
• whether copying is restricted and whether materials must be returned or destroyed if the deal stops;
• how announcements and deal discussions must be kept confidential;
• whether the existence of the discussions themselves is confidential.

When an NDA may be less important

If the buyer is an existing investor or existing shareholder who already has access rights under the shareholders’ agreement, a separate NDA may be less central. Even then, it is worth checking whether those existing rights actually cover all the information that will be disclosed and whether they limit use to shareholder purposes.

Some founder secondary sale discussions also stay narrow. If the buyer already knows the business well and the deal is limited to a small internal transfer, the risk profile may be lower. The right answer depends on who the buyer is, what they will see and how sensitive the company’s position is at that moment.

Legal Issues To Check Before You Sign

Before you sign a contract, the key legal task is to map the proposed sale against every document that governs the shares. Founders often focus on the commercial headline, but the documents usually decide whether the sale can happen at all, on what terms, and with whose consent.

1. Articles of association and transfer restrictions

The articles are usually the first place to look. Many UK startups adopt bespoke articles after an investment round, and these commonly restrict share transfers.

You may find provisions dealing with:

• pre-emption rights, where shares must first be offered to existing shareholders;
• board discretion to refuse to register transfers;
• permitted transfers, such as transfers to family trusts or holding companies;
• tag along rights, allowing other shareholders to join a sale;
• drag along rights, usually relevant on a wider sale of the company;
• compulsory transfer provisions linked to leaver status.

If a founder signs a share purchase agreement without following the transfer process in the articles, the buyer may pay for shares that cannot be properly registered. That is exactly the kind of preventable issue that creates disputes later.

2. Shareholders’ agreement terms

The shareholders’ agreement often goes further than the articles. It may include founder-specific promises that matter directly to a founder secondary sale.

Typical examples include:

• lock-in periods restricting founder sales for a set time;
• good leaver and bad leaver rules;
• investor consent rights over transfers;
• restrictions on selling below market value or to certain categories of buyer;
• requirements for other shareholders to be offered the same price and terms.

This is where founders often get caught after a funding round. They remember the investment completing, but not the founder transfer restrictions that came with it.

3. Board and shareholder approvals

Many founder secondary sales need formal approvals before completion. The company may need to approve the transfer, the board may need to resolve to register it, and certain investor majorities may need to consent under reserved matters provisions.

Do not assume that informal founder agreement is enough. If the constitution or shareholders’ agreement requires formal approval, a side conversation or email chain will not reliably replace that process.

The approval documents may include:

• board minutes approving the transfer and registration of the buyer;
• shareholder resolutions where required;
• written investor consents;
• waivers of pre-emption rights or notices showing the rights were properly followed.

4. Share class and rights analysis

Not all founder shares are equal. You need to confirm exactly what is being sold and what rights attach to those shares.

Questions to answer include:

• Are the shares ordinary shares, growth shares or another class?
• Do they carry voting rights, dividend rights or liquidation preferences?
• Are there vesting arrangements or reverse vesting terms?
• Have any shares been converted, partly paid or reclassified?
• Is the cap table fully up to date?

If the transfer documents describe the shares loosely or incorrectly, the buyer and seller may think they have agreed the same thing when they have not.

5. Warranties and liability

A founder secondary sale agreement often includes warranties from the seller, but the scope should match the deal. A founder selling some personal shares is not always in the same position as a company selling a business.

Buyers may ask for warranties about:

• the seller’s ownership of the shares;
• the shares being free from encumbrances;
• the company’s accounts and solvency;
• IP ownership;
• disputes or claims;
• compliance issues in the business.

The main risk is that the founder gives wide business warranties personally, even though they are only receiving part of the sale proceeds and may not be able to control every company issue. Caps, time limits, knowledge qualifiers and disclosure letters can all matter here, especially when negotiating liability clauses.

6. Deal structure and payment terms

Not every founder secondary sale is a simple cash payment on completion. Some deals involve staged payments, earn-out style elements, or a linked investment in the company.

Before you sign, be clear on:

• the purchase price and how it was calculated;
• whether any amount is deferred;
• whether payment depends on future milestones;
• whether completion is conditional on approvals or due diligence;
• whether there are restrictions on the founder’s future sales.

If the deal is tied to a wider investment round, the sequencing matters. A secondary sale completed on different terms from the incoming investment can raise fairness questions and create confusion in the documents.

7. Company records and completion mechanics

A founder secondary sale is not finished when the contract is signed. The company’s records need to be updated correctly.

That may include:

• a signed stock transfer form;
• board approval to register the transfer if required;
• updating the register of members;
• issuing a new share certificate if appropriate;
• cancelling the old certificate where relevant;
• making any related Companies House filings if other changes happen alongside the transfer.

Messy post-signing administration can cause real problems in future due diligence, especially when the company later raises money or prepares for an exit.

8. Data and information sharing

If personal data about employees, customers or counterparties is being shared during buyer diligence, privacy issues need to be handled carefully. UK GDPR does not stop all sharing, but it does mean the company should think about necessity, minimisation and confidentiality before handing over detailed data sets, in line with its privacy notice and data protection obligations.

Founders sometimes share far more than the buyer needs. In many cases, anonymised or limited information is enough until the deal is further advanced.

9. Future fundraising and investor optics

A founder secondary sale may be legally possible but commercially awkward. Early stage investors often care about founder alignment, and a meaningful founder cash-out at the wrong time can affect sentiment in the next round.

That does not mean founder liquidity is improper. It means the company should think carefully about messaging, board process and whether the proposed sale amount looks proportionate to the stage of the business.

Common NDA Mistakes

The most common NDA mistake in a founder secondary sale is assuming any standard confidentiality form will do. The document needs to fit the deal, the buyer and the type of information being shared.

Using an NDA that is too generic

A short template may miss points that matter in a share sale context, especially restrictions on using the information for anything other than evaluating the proposed acquisition of shares. If the buyer is also commercially active in the same sector, that permitted purpose wording matters a lot.

Forgetting to cover the existence of the discussions

For some startups, the fact that a founder is exploring a secondary sale is itself sensitive. It may trigger internal questions, investor concern or speculation about the founder’s commitment.

If that matters, the NDA should say the discussions and their terms are confidential, not just the documents shared.

Allowing broad onward disclosure

Buyers often want freedom to share information with advisers, funders and affiliates. Some disclosure is reasonable, but it should be controlled.

The NDA should normally state:

• who can receive the information;
• that they must be told it is confidential;
• that the recipient remains responsible for breaches by those people.

Sharing too much too soon

Even with an NDA, startups should limit early disclosures. Founders sometimes send full data room access after a few calls, before price, approvals or seriousness have been tested.

A staged approach is often better. Basic cap table and constitutional information may come first, with more sensitive customer or product material shared later if the deal progresses.

Confusing the NDA with the sale contract

An NDA does not replace the sale agreement or contract review. It may protect confidential information, but it does not usually deal with title to shares, completion mechanics, warranties, pre-emption compliance or liability allocation.

That distinction matters because founders sometimes feel legally covered once an NDA is signed, then move too quickly on the substantive share transfer.

Not matching the NDA to the company documents

If the company is sharing information, the company should often be a party to the NDA or at least clearly protected by it. A founder signing alone may not give the company enough control over its own confidential material.

This is especially relevant where the seller is an individual founder but the information belongs to the company.

FAQs

Can a founder sell shares without telling the other shareholders?

Usually not safely. Even if the law does not always require notice in every case, the articles or shareholders’ agreement often do. Existing shareholders may have pre-emption rights or consent rights that need to be dealt with first.

Does a founder secondary sale mean the company receives the money?

No. In a secondary sale, the payment usually goes to the selling founder because they are selling existing shares. That is different from a primary investment, where the company issues new shares and receives the investment funds.

Do you always need an NDA for a founder secondary sale?

No, not always. But an NDA is often sensible where the buyer will see sensitive company information, especially if they are not already bound by confidentiality obligations under existing investment documents.

Can investors block a founder secondary sale?

Sometimes, yes. Investor consent rights, transfer restrictions, lock-ins and reserved matters can all limit a founder’s ability to sell. The answer depends on the articles, shareholders’ agreement and any founder-specific commitments.

What documents are usually needed to complete the transfer?

The key documents often include the share sale agreement, any NDA used during discussions, pre-emption notices or waivers, board approvals, a stock transfer form, and updates to the register of members and share certificates.

Key Takeaways

• A founder secondary sale is a transfer of existing shares, not a new share issue by the company.
• The main legal checks are in the articles of association, shareholders’ agreement, investor rights and founder-specific restrictions.
• Pre-emption rights, board approval and investor consent can all affect whether the sale can proceed.
• An NDA is often useful where the buyer needs access to sensitive company information before terms are final.
• The sale agreement should clearly cover the shares being sold, price, payment mechanics, warranties and liability limits.
• Completion is not just signing, the company records and register of members must also be updated correctly.
• The commercial context matters, because founder liquidity can affect fundraising optics and shareholder relationships.

If you want help with transfer restrictions, shareholder approvals, confidentiality arrangements, and share sale documents, you can reach us on 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.