September 2, 2026

Due diligence when buying a business: a step-by-step NZ guide.

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Due diligence helps you understand what you're really buying before you go unconditional on a business. This guide covers the key financial, legal, commercial and tax checks NZ buyers should make, along with the red flags to watch for.

Exercising due diligence when buying a business in NZ means you have four particular areas covered: financial (verifying the numbers), legal (contracts, leases, IP), commercial (customer concentration, market position), and tax (structure, historic exposure). Here’s a step-by-step checklist that can help you navigate these areas.

You’re a fortnight into the due diligence window, and another folder has just landed on your desk. Lease documents, three years of accounts, a stock list, and a supplier contract that left you scratching your head. The clock’s running, and you can’t shake the feeling that the one thing that matters is buried in that pile of documents somewhere.

Quick summary

Due diligence when buying a business is the investigation you do before going unconditional. It covers the financial, legal, commercial, and tax position of what you are purchasing. The due diligence process NZ buyers follow typically runs about 15 working days from the date the agreement is signed.

You’ll request records, verify them independently, and then use what you find to adjust the purchase price (or walk away) before you make a decision. Your due diligence clause is what allows you to do all of these, so be sure to know the details before you sign.

Financial due diligence and knowing if the profit is real

Exercising financial due diligence uncovers whether the reported profit truly shows the real financial health of a business. Xero recommends reviewing at least three to five years of tax returns and financial statements. Look into these alongside profit and loss statements and cash flow records.

The biggest adjustment here is the working owner’s wage. Many vendors present a profit that assumes nobody needs paying to run the place. If the owner works full-time and takes drawings rather than a salary, that cost never shows up in the accounts.

Add back what you’d pay someone to do the same job. A business reporting $180,000 profit with a full-time owner is really making $110,000 once you consider a salary of $70,000 for a manager.

Then check the following if they are not reported alongside profit figures:

Debtor ageing. This shows how long customers actually take to pay. Having a strong profit means almost nothing if half of the business’s invoices remain unpaid past 90 days.
Dead or seasonal stock. Stock that hasn’t sold in a year. You’ll usually buy stock at the vendor’s cost, so ask what’s been sitting there.
Working capital. The cash tied up to running the business week to week. You fund it at settlement, on top of the purchase price. Buyers most often miss the cost of this.

A Te Puke packhouse contractor, for example, can look strong at a March balance date and thin by September. Monthly figures may show that; annual ones don’t. It’s also the financial due diligence NZ lenders look for before funding a purchase.

Legal due diligence on contracts, leases and IP

Legal due diligence confirms the vendor owns what they are selling and can transfer it to you. Check first with the Personal Property Securities Register. Created under the Personal Property Securities Act 1999, the register records security interests over plant, vehicles and equipment.

A Katikati engineering workshop might list a $90,000 CNC machine as an asset, while the finance company still holds a registered interest over it. In this case, you might be buying a payment schedule instead.

Work through the lease next. Check the remaining term, renewal rights, and whether the landlord must consent to an assignment. A business that looks long established can have 11 months of lease left, and that will not be obvious until you read the lease.

Then confirm who owns the trading name, domain, and intellectual property. Get legal advice on the restraint of trade, since these legal issues tend to surface late if not caught early.

Commercial due diligence: how durable is the business

Commercial due diligence tests whether earnings survive the owner’s departure from the business. You need a reason how loyal key staff, suppliers, and customers are to the outgoing owner. That kind of loyalty is what you pay for in goodwill.

Two questions need to be asked here:

How concentrated is the customer base? If one client is 40% of revenue, you’re buying into a contract that can be cancelled. Ask for revenue by customer across three years.
How much of the business operations relies on the personal knowledge of the owner? If they hold the supplier relationships and pricing knowledge, the handover matters more than the price.

Tax due diligence and what can be passed on to you

Tax due diligence covers two things: how the deal is structured, and what tax debts could follow you from the vendor.

Start with GST. Where both sides are GST-registered and the whole working business transfers, the sale is normally treated as a going concern, and GST is charged at 0%.

Done inaccurately, then GST at 15% folds back into the deal. On a $600,000 business, for example, that’s $90,000. Inland Revenue warns this can lead to a large tax bill for either side.

Next, what you may inherit or get passed to you. Most business owners here structure business purchases as asset and goodwill sales instead of share sales. Buying the shares means buying the company itself, along with everything it has ever owed. This may include unpaid PAYE, a former employee’s grievance, or a warranty claim on work done years ago. Buying the assets leaves that history with the vendor.

Our guide on whether to buy the shares or the assets can help you navigate the trade-offs.

If you’re buying shares, ask for IRD statements of account for every tax type. If buying assets, get the purchase price allocation agreed in writing. It drives your depreciation claims in the long term.

How long the due diligence period takes

It usually takes 15 working days for due diligence in NZ. It may also take another 5 days depending on the finance condition.

Our guide to buying a business in NZ provides more details on how long it may take.

Stage	Typical length	What happens
NDA and information memorandum	1 to 2 weeks	High-level figures before you commit
Conditions start	Day 0	The clock starts on every condition
Due diligence	About 15 working days	Records requested and verified
Finance	About 20 working days	Lender assesses security and servicing
Unconditional to settlement	2 to 6 weeks	Deposit paid, handover planned

If material items are still missing at day 10, you may request an extension.

What your due diligence clause needs to say

Having a due diligence clause gives you a fixed number of working days to conduct due diligence. It also offers an option to cancel. When you’re buying a business contract, how it is worded provides you with leverage that may prove valuable later on.

Consider these four things in coming up with a due diligence clause:

Sole discretion, not “reasonable” satisfaction, which invites an argument about whether your reason was good enough.
Working days from the date the agreement is signed, so there’s no dispute about when the clock started and when it ends.
An extension mechanism that you can trigger by notice when the vendor is slow in supplying information from their end.
How notice is given, and what happens to your deposit if you cancel.

One thing to take note of here. Inland Revenue requires both parties to agree the sale is a going concern and to record that agreement in a document. That belongs in the sale and purchase agreement, and not just a mere side conversation.

Questions to ask before you go unconditional

The best questions to ask a vendor are the ones that make them show you something. In one case we handled, a buyer spent roughly $2,000 on a review. They avoided overpaying by about $100,000 when these questions were addressed.

Work through these:

Why are you selling, and what would you fix if you were staying?
Does the reported profit include a market wage for whoever runs it?
Which customers left in the last two years, and why?
What’s the remaining lease term, and will the landlord consent?
Are any assets subject to finance or a registered security interest?
Which staff are essential to day-to-day operations, and are they staying or leaving?
Are there current disputes such as IRD reviews or employment claims?

Keep the answers in writing. That record becomes the due diligence checklist NZ buyers bring to their accountant, and it supports any later move on price.

Your due diligence checklist

Due diligence when buying a business comes down to what you can actually verify and document. Request the following on paper starting day one. Then chase what’s missing while you still have room to move or adjust. Each of these belongs to a separate area, so work them in parallel.

Area	Request from the vendor	What it confirms
Financial	3 to 5 years of financial statements, tax returns, balance sheets, monthly management accounts, debtor ageing, stock list	The profit survives paying someone a market wage to run the place
Legal	Lease and renewal terms, supplier and customer contracts, employment agreements, IP and trade mark records, plus your own PPSR search	The business owns what it’s selling, and can transfer it
Commercial	Revenue by customer for 3 years, staff list with tenure, supplier terms and pricing	Earnings don’t leave with the vendor
Tax	IRD statements of account for every tax type, GST returns, agreed purchase price allocation	Nothing historic follows you into the new entity

Pay more attention to what the vendor can’t produce than what they hand over quickly.

Frequently asked questions

What is due diligence when buying a business?

Business due diligence NZ buyers run covers four separate investigations: financial, legal, commercial and tax. You verify the numbers against source records, confirm the business can transfer what it’s selling, then test how durable earnings are without the owner.

What are the red flags in due diligence?

The clearest red flags are a vendor who delays supplying records. These also include accounts that don’t reconcile to bank statements. Revenue concentrated in one or two customers is another, as is a short lease.

How long does due diligence take in NZ?

Around 15 working days is standard for an SME purchase, though complex deals may take longer. The countdown starts from the date the agreement is signed. If the vendor is slow in providing additional information, request an extension.

What is a due diligence clause?

It’s the clause making your deal conditional on being satisfied with your investigation. It sets the working days you get, how notice is given, and what happens to your deposit. Without it, your investigation is limited.

Can you give an example of due diligence?

A buyer reviews a Mount Maunganui café and requests three years of accounts. The reported profit excludes any wage for the owner, who works full-time in the kitchen. Adjusting for that cuts real profit by $65,000. That’s due diligence in business transactions.

What happens after due diligence?

You can either confirm the condition and renegotiate on what you found, or cancel. Most buyers who find potential issues renegotiate rather than walk away. Once every condition is confirmed, the deal goes unconditional, and you move to settlement.

Before you sign

Due diligence is not about getting through the paperwork faster.

It tells you what to look for when buying a business in NZ, and which parts to investigate first.

That is how the pile on your desk turns into a decision you can defend.

We’re the Bay of Plenty’s leading independent chartered accounting firm, and we’ve worked the buyer’s side of this table from Katikati to Te Puke for over 60 years.

Our free Better Business Buying guide can help you go deeper into this topic as well.

About to sign on a business and want a second pair of eyes? We have sat on the buyer’s side of this table many times, and we are happy to look over what you have. Get in touch with our team and let us know how we can help.