Due Diligence Checklist for Buying a Business in New Zealand

A deal isn't real until it survives diligence.

Up to that point, everything is a story the seller is telling you, and the price is a number they'd like to hear. Due diligence is where you find out whether the story holds. It is the difference between buying a business and buying someone else's problem with your name on the loan.

This is the practical companion to knowing the warning signs. If the red flags are what to watch for, this due diligence checklist for buying a business is how you go looking for them on purpose, item by item, before you sign. It's the full list of what to check before buying a business, not just what to fear. Here are the red flags that go with it.

I've been through this on real deals, including the ones I closed on and those I didn't. It's been built over time with some suggestions as to how you can get the information you seek. Treat this as a working tool, not theory. Verify everything and assume nothing.

What Due Diligence Actually Is

Due diligence is verification. You take every claim the seller has made, about revenue, profit, customers, staff, the lot, and you check it against evidence across four angles: financial, legal, operational, and commercial.

The financial and legal elements are best guided with industry professionals (accountants and lawyers).

There are two phases, and people muddle them.

The first is light-touch, before you make an offer. Enough to decide if the deal is worth pursuing and roughly what it's worth. The second is the deep dive, after your offer is accepted and you're under contract, usually with a due diligence clause that lets you walk if it doesn't check out. That second phase is where you open the books properly. The business due diligence checklist below is what you work through in that deep dive.

The Due Diligence Checklist for Buying a Business

Here's the core. Work through each category. For each item, the job is the same: get the evidence, tie it to a source, and write down anything that doesn't add up.

Financial Due Diligence

This is where the truth lives, because numbers are harder to dress up than a sales pitch. If you are not confident in doing this yourself, you will never regret having a trained accountant work alongside this with you.

• Three to five years of financial statements and tax returnsNot one good year. The trend. Reconcile them against the actual bank statements so you know the reported numbers are real money that moved.
• Verify revenue and earnings to sourceTie the headline figures back to invoices, contracts, and bank deposits. Then test every add-back the seller has used to inflate earnings. A weak add-back is just the price being talked up.
• Revenue by customerWork out what share each customer represents. If one or two make up most of the income, you're exposed the day they leave.
• Aged receivables and payablesWho owes the business money, how overdue is it, and who does the business owe? Old receivables may never be collected. Stretched payables can mean a cash flow problem dressed up as profit.
• Recurring versus one-off revenueRepeatable income is worth far more than a few big jobs that may not come again. Split the two and value them differently.
• Working capital needsHow much cash does the business need just to keep running between paying for things and getting paid? Underestimate this and you can buy a profitable business and still run out of money in month two.

Legal Due Diligence (New Zealand)

This section is best covered with a lawyer, and I'm not going to suggest you progress through it without one. But it helps to know the ground they'll be covering, so you understand what you're paying for and can keep across it.

In New Zealand, that usually means confirming the company's structure and ownership through the Companies Register, and running a search on the Personal Property Securities Register (PPSR) to check whether the assets you think you're buying already have loans or charges secured against them.

They'll read the contracts that hold the value. Customer agreements, supplier terms, the lease, employment agreements. They'll confirm which ones actually survive a change of ownership, and check the licences and permits the business needs to operate, and whether those transfer to you.

They'll confirm the business is current with Inland Revenue on GST and PAYE, because unpaid tax can follow the business. And they'll make sure the brand, domains and any trademarks (registered through IPONZ) are owned by the company, not sitting in the seller's personal name.

How far this stretches depends on the deal. A complicated business with property, multiple entities or messy contracts will pull your lawyer deep into the weeds. A simple one might need far less. Either way, you want to understand why each check matters, so that when something turns up, you know whether it's a problem to fix, a price to renegotiate, or a reason to walk.

Operational Due Diligence

• Owner dependenceThe big one. Map out exactly what the owner does day to day, then ask what breaks when they leave. If the answer is "most of it," the earnings may walk out with them. This is the item that decides whether you bought an asset or a job.
• Key staff and employment termsWho actually holds the business together, what are they paid, what's in their agreements, and what keeps them there after settlement? Find out who you can't afford to lose.
• Systems, processes, and documentationIs the business written down and repeatable, or does it live in the owner's head? Undocumented businesses cost you a year of rebuilding what should have been on paper or stored somewhere accessible.
• Condition of equipment and assetsInspect the gear. Get the age, condition, and a realistic replacement schedule. A big capital bill arriving soon after you buy is a real cost the asking price usually ignores.
• Supplier dependenceDoes the business rely on a single supplier for something critical? If that supplier raises prices, stops supplying, or fails, how exposed are you?

Commercial and Market Due Diligence

• Industry health and outlookIs the wider market growing, flat, or shrinking? A well-run business in a declining industry is still in a declining industry.
• Competitive positionWhy do customers choose this business over the alternatives, and is that reason durable? Understand what protects the margins.
• Reputation and reviewsRead the reviews, search the name, and ask around. You inherit the reputation along with the business, good or bad.
• The real reason for sellingListen to the stated reason, then test it against everything else you've found. When the reason for selling doesn't match the numbers, dig until it does.

The Handover

Buying the business is one thing. Getting it to keep running after the owner walks is another, and a structured handover might be something you'll rely on.

Verify the transition before you sign, not after. Will the owner stay on to hand over properly, and for how long? Is the knowledge transfer a real, structured plan, or a handshake and a phone number? Are you able to start any of this before settlement? Are the key customer relationships actually being introduced to you?

This is where deal structure earns its keep. A seller carrying vendor finance has a direct reason to make the handover work, because part of their money depends on the business still performing after they've gone. Alignment beats good intentions every time. Here's how vendor finance creates that alignment.

Don't Outsource Your Judgement

Here's the part that matters most, and the part most first-timers get wrong.

You must hire the professionals. A good accountant to dig into the financials and an experienced lawyer to handle the legals are not optional, and trying to save money by skipping them is the most expensive saving you'll ever make.

But hiring them is not the same as handing over the decision. Your accountant checks the numbers. Your lawyer checks the contracts. Each one looks down their own lane. Only you are looking at the whole picture, and only you make the call on whether to buy.

Diligence isn't a box you tick so an advisor can bless the deal. It's how you decide, for yourself, whether a flaw you've found is fixable leverage you can negotiate on, or a reason to walk away. That judgement also feeds straight into your financing: a business that holds up under diligence is one a lender will back, because it can reliably carry the debt used to buy it. It's the same thing your financing depends on.

Advisors inform the decision. They don't make it. Remember, you're in the driver's seat, so you want to stay informed and across everything.