Adding a business partner to your UK company after formation — director, shareholder, or both?

When Arab directors decide to bring in a business partner, the first question is almost always 'how do I add them?' — as if there's one process. There are two, and they're legally distinct. Appointing someone as a director gives them authority to manage the company and act on its behalf. Making them a shareholder gives them an economic stake — a claim on dividends and assets. Your partner can be one, the other, or both. Each requires different paperwork.

Adding a director: file form AP01 with Companies House online. The new director's name, date of birth, nationality, and service address become publicly visible on the Companies House register immediately. From that moment, the new director has legal authority to sign contracts, open bank accounts, and file documents on behalf of the company. Appointing someone director without a clear written agreement about their authority is a common mistake — removing a director who won't cooperate requires either their written consent or a shareholder resolution.

Adding a shareholder: two options. Issue new shares (SH01 form to Companies House, increases the total share pool, dilutes your percentage) or transfer existing shares (J30 stock transfer form, stamp duty at 0.5% if consideration exceeds £1,000). Dilution matters: if you own 100 shares and issue 50 new ones to a partner, you now hold 66.7%, not 100%. If you transfer 50 of your existing 100 shares, you hold exactly 50%. The PSC register must be updated within 14 days if the new partner will hold more than 25% of shares or voting rights.

The document most Arab directors skip: a shareholders' agreement. This is a private contract between shareholders that governs what happens if one party wants to exit, if there's a deadlock on a major decision, or if the company is sold. It isn't filed at Companies House and isn't publicly visible. Without one, the Companies Act defaults apply — and those defaults were designed for a generic company, not your specific partnership. Getting a shareholders' agreement drafted by a UK solicitor before adding any partner is consistently the best investment at this stage.