Should I bring in a co-owner or partner, and how do I do it properly?

Cluster: Structure & governance Shape: Decision Slug: adding-a-co-owner-or-partner Status: v1

Short version

"Partner" is one of the most overloaded words in small business. It usually means one of three different things wearing the same label: someone who's putting in capital, someone who's bringing capability the business needs, or someone you're grooming for succession. Each of those points to a different structure, a different deal, and a different set of things to get right. Calling all three "a partner" hides the choices that actually matter.

The structural fork is real. In New Zealand you can add a co-owner three main ways: issue or transfer shares in an existing company, form a partnership under the Partnership Law Act 2019, or convert your existing sole trader operation into one of those structures and bring them in at the same time. Each route has its own tax-side triggers, its own liability exposure, and its own exit mechanics. The route you pick should follow from what you're actually trying to add — capital, capability, or succession — not from what feels normal in your industry.

This entry is a decision wayfinder. It won't tell you which route is right. It tells you which questions to settle before you talk to anyone — including the would-be partner.

Where to find the authoritative answer

⭐ business.govt.nz — Choosing the right business structure (business.govt.nz/getting-started/choosing-the-right-business-structure) — the operational starting point. Covers structures, registration, the trade-offs in plain English.
Companies Office (companiesoffice.govt.nz) — for share issues, share transfers, director and shareholder updates. Filings are the easy part; what you're filing matters more.
Partnership Law Act 2019 (legislation.govt.nz) — the statutory anchor for partnerships. If you don't have a written partnership agreement, this Act's default rules apply, and they often won't match what you actually agreed.
Inland Revenue — Business structures (ird.govt.nz) — for the tax-side consequences of partnership look-through, look-through company elections, and employee share arrangements. Talk to your accountant before signing anything.

What to watch for

1. Name what you're adding before you name them a partner. Capital, capability, succession — these need different deals. If someone's putting in $80,000 of cash, you're talking about a share issue at an agreed valuation, with their stake reflecting that capital and dividend rights attached. If someone's bringing capability — a niche skill, a customer book, a technical capacity — the deal is more about how you value contribution that arrives over time, and what happens if they leave. If someone's a succession candidate, the deal is shaped by a multi-year transfer plan and tax planning for both sides. Trying to draft one agreement that covers all three is how partnerships go wrong before they start. Decide which category you're in. If it's two of them, deal with each one explicitly.

2. Partnerships can form without you meaning to. Section 8 of the Partnership Law Act 2019 defines a partnership as the relationship that exists between persons carrying on a business in common with a view to profit. There's no requirement for a written agreement, no requirement to register, no requirement that the word "partnership" appear anywhere. If you and someone else are sharing work, sharing profit, and presenting yourselves jointly to customers, you may already be in a partnership in the eyes of the law — regardless of what you call the arrangement. That matters because partners are jointly and severally liable (s 25) — meaning each partner is personally liable for the full debts of the firm, and creditors can pursue any one of you for the lot. If you don't intend a partnership, get that into writing before you start trading together. If you do intend one, get an agreement that overrides the Act's defaults, because the defaults rarely match real arrangements.

3. The default rules under the Partnership Law Act will surprise you. Without a partnership agreement, the Act fills in the gaps with rules that are often the opposite of what people assume. Profits and losses are shared equally regardless of capital contribution (s 45). Any partner can dissolve the partnership by giving notice (s 67). New partners need unanimous consent (s 50). One partner can bind the firm to contracts the others didn't see coming (s 17). Most decisions can be made by majority (s 51), but admitting a new partner cannot. These defaults are sensible-ish for a generic two-handed venture. They will not match what you actually agreed if you put in 70% of the capital, do most of the work, or expect to make most of the decisions. The fix is a written partnership agreement that overrides the defaults you don't want.

4. Shares aren't free to issue, even to people who matter. In a company structure, the obvious move when adding a partner is to issue them shares — but if they're getting those shares for less than market value, Inland Revenue treats the discount as taxable. For an employee or contractor receiving shares as part of their role, this falls under the employee share scheme rules in the Income Tax Act 2007, and the difference between market value and what they paid is taxable income to them. It doesn't go away because the arrangement is informal or because the shares are "just a token." Before issuing shares to someone working in the business at a discount, get the tax position confirmed with your accountant. The fix is usually structural — proper valuation, vesting arrangements, sometimes a separate class of shares — but it has to be set up before the shares are issued, not retrofitted afterwards.

5. Look-through company status has hard limits and a one-way feel. A look-through company (LTC) is a New Zealand company that elects to be treated like a partnership for tax — profits and losses flow through to shareholders directly, taxed at their personal rates. It's a useful structure for small businesses with two or three owners who want company-level liability protection and partnership-level tax treatment. The conditions are strict: five or fewer shareholders, all natural persons, trustees, or other LTCs (s HB 1 Income Tax Act 2007). Adding a sixth shareholder breaks the election. Adding a corporate shareholder that isn't an LTC breaks the election. If you're operating as an LTC and bringing in a partner, check whether the addition keeps you eligible before you proceed — coming out of LTC status mid-cycle creates tax complications that take real money to clean up.

6. The exit terms matter more than the entry terms. The conversation when you're bringing someone in is full of momentum and goodwill. The conversation when one of you wants out almost never is. Whatever structure you pick, the exit mechanics are the part you'll actually use — buy-sell triggers, valuation methodology, what happens on death or incapacity, what happens on dispute, what restraints apply if someone leaves. C2 (shareholders agreement essentials) covers the company-structure version of this in detail. For partnerships, the equivalent lives in a partnership agreement. Either way, draft the exit before you sign the entry. If you can't agree on how this ends, that's information. It's better to surface it now than five years in.

A separate point on what people actually mean when they say partner

In practice, owner-operators use the word "partner" to mean four different things, often without distinguishing between them. Naming which one you're actually in is the most useful work this entry can offer.

The capital partner. Someone putting money in. The right structure is almost always shares in a company, with the valuation agreed in writing, the dividend rights spelled out, and a shareholders agreement covering decision rights and exit. The deal is commercial: their money buys a defined slice of the business and the rights that come with it. Their day-to-day role may be minimal. This is the cleanest version because the contribution is measurable.

The working partner. Someone bringing capability the business needs — a co-founder pattern, a senior hire being equity-stretched, a complementary skill that changes what the business can do. This is the hardest version because the contribution arrives over time and is harder to value. Vesting matters here, restraints matter here, and the exit mechanics matter most of all. Get the agreement right, or you end up with someone holding 30% of the company who hasn't been around for two years.

The succession partner. Someone you're grooming to take over, often a key employee or family member. This is a multi-year arrangement, and the structure usually involves a phased transfer of shares over time, often funded by the business itself. The tax planning is significant on both sides. Don't start this without an accountant and a lawyer. The biggest trap here is treating succession like a single transaction instead of a multi-year process with milestones.

The "we're a partnership" partner. Someone you're carrying on a business with informally — a tradie with a mate, two consultants sharing work, a family member helping out who's started to look more like a co-owner. This is the unintentional one, and it's the one the Partnership Law Act catches. If you're sharing profit and presenting jointly to the world, you're probably in a partnership in law even if you haven't said the word out loud. Either get an agreement in place that reflects what you actually intend, or restructure the arrangement so it isn't a partnership. Drifting along undocumented is the worst of both worlds — you have the liability of partnership and none of the clarity of one.

Which one are you in? If you can answer that cleanly, the rest of the work is straightforward.

Where this entry stops

This entry doesn't cover:

The shareholders agreement itself — that's C2, which pairs directly with this entry
The mechanics of share issues, share transfers, or director appointments — Companies Office process
Valuing the business for the purposes of buying someone in — that's accountant territory, and the methodology matters as much as the number
Employee share scheme tax design — Income Tax Act 2007 subpart CE and the surrounding ISR/ESS rules are technical; get specialist tax advice before issuing equity to anyone working in the business
Family or relationship property implications — if your spouse or partner has a relationship property claim that could touch the business, that has to be sorted before you add anyone else
Specific industry restrictions — some sectors (law, accounting, medical practice) have ownership rules that constrain who can hold equity

For all of those, get specialist advice. The cost of an accountant and a lawyer at the front end of this is far cheaper than unwinding a structure that doesn't fit.

Last verified: 11 May 2026.

Related entries:

C2 — Shareholders agreement essentials — pairs directly with this entry; cover both before you proceed
Entry 4 — Sole trader or company — if adding a co-owner means changing structure entirely, start here
Entry 5 — Registering a company — the operational step if you're forming a new company to bring the partner into
D4 — Director duties (sole-director) — if you're adding a co-director, the duties apply to both of you now
C1 — Selling the business — the end-state of one route this decision can take

What lives on the references subpage:

Partnership Law Act 2019 — full statute, particularly s 8 (definition of partnership), s 17 (partner as agent), s 25 (joint and several liability), s 45 (default equal share), s 50 (no new partner without consent), s 67 (notice of dissolution). legislation.govt.nz.
Companies Act 1993 — share issues (s 41–54), share transfers (s 84), constitution (Part 3), shareholder meetings and resolutions (Part 7). legislation.govt.nz.
Income Tax Act 2007 — look-through company rules (subpart HB), employee share scheme rules (subpart CE). legislation.govt.nz.
business.govt.nz — Business structure overview — operational comparison of sole trader, partnership, company, and trust. business.govt.nz/getting-started/choosing-the-right-business-structure.
Companies Office — for the filing mechanics of any structural change. companiesoffice.govt.nz.
Inland Revenue — Business structures and tax — for the tax-side consequences of each structural choice. ird.govt.nz.