Selling part of a business is a different transaction from selling all of it, and the difference is that afterwards you still have to work with the person who bought. That reframes the whole exercise: price matters, and governance matters more, because the terms you agree now are the ones you will live under for years.
How to sell a percentage of your business: what the percentage carries
How to sell a percentage of your business starts with what the percentage carries. Shares can come with different rights, and the important ones are voting, distributions, information and what happens on a future sale. A minority stake with no protections is worth much less than the same percentage with the right to see the accounts and to be carried along if you sell. Both parties are better served by making those explicit than by assuming that a number of shares settles the question.
How to sell a portion of your business: the terms you will live under
A shareholders' or operating agreement is where a partial sale is really negotiated: who decides what, what needs unanimous consent, how a deadlock is broken, whether either side can force a sale later, and what happens if one of you wants out. How to sell a portion of your business without settling these is common and regretted. This is squarely your solicitor's work rather than a template exercise, and it is the part worth spending on.
How to sell your share of a business to an existing partner
How to sell your share of a business, where the buyer is already inside it, has one recurring difficulty: the buyer knows everything, so there is no information advantage and the negotiation is purely about price and terms. Your existing agreement may already set a valuation method or give the other party pre-emption rights, and reading it first tells you whether you have a market or a single counterparty. If it prescribes a valuation mechanism, that mechanism, not the open market, is what determines the number.
Questions people ask about how to sell part of your business
What should a percentage of a business come with?
Explicit rights: voting, distributions, information, and what happens on a future sale. A minority stake without protections is worth much less than the same percentage with them.
What has to be agreed when selling part of a business?
Governance, in a shareholders' or operating agreement: who decides what, what needs consent, how deadlock breaks, and how either side can exit later.
How do I sell my share to my business partner?
Read the existing agreement first. It may set a valuation mechanism or give pre-emption rights, and if so that mechanism, not the market, determines the number.