Buying an established business can be one of the fastest paths to ownership in Australia — a working customer base, trained staff, immediate cash flow. It can also be one of the fastest paths to losing several hundred thousand dollars if the numbers behind the sale price do not survive close inspection. Due diligence is the difference between the two outcomes, and it is rarely something the buyer can shortcut.

This guide from Trinity Accounting Practice sets out what proper financial due diligence on a business purchase looks like in Australia, what the typical red flags are, and how a buyer can structure the review so the offer they make actually reflects the business they are buying.

Why due diligence matters more than the asking price

There is no legal requirement in Australia to perform due diligence before buying a business. Plenty of buyers skip it, or rely on a cursory look at the seller’s profit and loss statement. The result is predictable: the business that produced $380,000 in adjusted earnings during the sale pitch produces $210,000 in the buyer’s first year. The “loyal customer base” loses two of its three largest accounts within six months of settlement. The staff who were “very capable” turn out to need the previous owner present to function.

None of these issues are dishonest in most cases. They are simply the gaps between what a vendor naturally emphasises and what an independent reviewer would find. Due diligence is the structured process of closing those gaps before the contract is signed, not afterwards.

What financial due diligence actually covers

Done properly, a financial due diligence review verifies the integrity of the numbers the buyer is relying on, then re-builds the picture of the business from the source documents up. At Trinity we typically work through the following areas on a Sydney SME acquisition:

Revenue verification. Sales figures reconciled to bank deposits, BAS lodgements, and customer-level invoicing. Look for one-off contracts that inflated the most recent year and will not recur.
Expense normalisation. Owner’s salary, related-party rent, personal expenses run through the business — all need to be identified and adjusted so the buyer sees what the business actually earns under arm’s-length operation.
Customer concentration. How much of revenue comes from the top five customers? A business with 65% of revenue tied to two clients is a very different risk to a business with 200 active accounts.
Employment costs and entitlements. Accrued leave, long service liability, superannuation arrears, contractor classifications, and award compliance. Underpayments at settlement become the new owner’s problem.
Gross margin trend. Has margin been declining quietly across three years while revenue held steady? That tells a story the headline EBITDA does not.
Working capital required. Inventory levels, debtor days, creditor days. The business that looks profitable can still need $150,000 of working capital injected on day one.
Forward budget and cash flow. The vendor’s projection tested against the historical actuals. Buyers should never accept a forecast that contradicts the trend without an explanation.

The red flags that should slow a buyer down

Inconsistent records. Profit and loss statements that do not reconcile to the BAS lodged with the ATO. Bank balances that do not match the trial balance.
Cash sales that “just happen”. Unbanked cash in industries where it is plausible — and where the vendor expects it to be priced in. This is both a tax risk and a transferability risk.
Significant related-party transactions. Rent paid to the owner’s family trust, management fees to a holding company, loans between entities. All need to be normalised to an arm’s-length basis.
Recent supplier or landlord changes. Has a key supplier contract just rolled over, or is the lease coming up for renewal in the buyer’s first year? Pricing and terms may not transfer.
Owner-dependency. Where the owner is the rainmaker, the technician, the relationship manager, or all three, the buyer is acquiring an income stream that walks out the door at settlement.
Litigation or ATO disputes. Unpaid PAYG, outstanding super guarantee charges, payroll tax queries, ongoing legal matters — verify the state of all of them.

Due diligence is not an audit, and it is not a valuation

This distinction trips up plenty of first-time buyers. An audit provides assurance over a complete set of financial statements against the accounting standards. A valuation arrives at a specific dollar figure. Due diligence does neither. It is a targeted commercial review that asks a different question: are the numbers the vendor has put forward defensible enough that I am comfortable paying this price?

That distinction matters for cost and scope. A full statutory audit on a Sydney SME could run into tens of thousands of dollars and several months of work. A well-scoped due diligence review on the same business is typically a two-to-four week engagement, focused on the specific risks and value drivers the buyer cares about.

How long it takes and how to scope it

For a small Australian business — turnover under $2 million, single location, straightforward operations — financial due diligence is usually a two to three week process. Larger SMEs with multiple locations, inventory, related-party complexity or specialised regulatory requirements take four to six weeks, sometimes longer.

We typically structure the engagement in three phases:

Initial scoping. Buyer’s concerns and the key value drivers are identified. We agree what is in and what is out of scope.
Document review and analysis. Profit and loss, balance sheet, cash flow, BAS, tax returns, payroll records, customer and supplier contracts, leases, employment agreements.
Findings report and recommendations. A structured document covering the financial picture, the issues identified, the impact on value, and where re-trading or contract conditions are warranted.

What documents the buyer should request

Three years of profit and loss statements, balance sheets and cash flow statements
Three years of tax returns for the business entity
Twelve months of BAS lodgements with reconciliation to the P&L
Aged debtors and aged creditors listings as at the most recent month-end
Bank statements for the trading account, twelve months
Payroll records, employee list, awards or agreements, accrued entitlements
Top 20 customers by revenue, top 20 suppliers by spend
Lease agreements, key supplier contracts, software licences, franchise agreements
Asset register and depreciation schedule
Any current disputes, legal matters or ATO correspondence

Before, during, and after the review

Due diligence is most effective when it is integrated into the broader acquisition process rather than tacked on at the end. Before the review, the buyer should already have decided on the right ownership and tax structure (company, trust, partnership) and how the acquisition will be funded. During the review, the findings should feed back into negotiation and the contract conditions. After the review, the buyer should have an integration plan that addresses the issues the review surfaced.

For a Sydney buyer this often means three professionals working in parallel: the accountant on financial and tax structure, the lawyer on the contract and warranties, and the finance broker (such as Nexus Wealth Partners, our finance arm) on the funding structure. Each can flag issues the other might miss.

Buyer’s due diligence checklist

Three years of financial statements reconciled to bank, BAS and tax returns
Owner’s add-backs and normalisations independently verified
Customer concentration mapped and risk-rated
Employment entitlements quantified at settlement date
Lease, franchise and major supplier contract review
Working capital requirement post-settlement modelled
Forward cash flow tested against historical trend
Acquisition ownership structure confirmed before contract
Finance structure confirmed and conditional clauses drafted
Post-settlement integration plan documented

A Trinity insight from 22 years in practice

The most expensive due diligence reviews are the ones that get skipped because the deal “feels right”. After working with Sydney business buyers since 2003, the pattern we see most often is the buyer who paid the asking price without an independent review, then spent the first twelve months discovering issues that should have been priced into the contract. A targeted due diligence review typically costs a fraction of what the buyer pays on day one of ownership for working capital, accrued entitlements or unrecorded liabilities. The cost is not the risk. The cost is the safeguard against the risk.

What this means for you

If you are seriously considering an acquisition: book a scoping call before signing the heads of agreement, not after.
If the vendor is pushing a fast timeline: that is information. A clean business will support a proper review. A rushed timeline often indicates an issue that will surface anyway.
If the price feels low for the earnings claimed: the earnings claim is the part to test first. The bargain may not be one.
If owner-dependency is high: structure the deal around transition support, earn-outs, or a deferred component tied to retention of key clients.

How Trinity can help

Trinity Accounting Practice has supported Sydney business buyers through due diligence, structure advice, financing coordination and post-settlement integration since 2003. We offer scoped due diligence engagements sized to the transaction, working alongside the buyer’s legal and finance team. Where we identify issues, we model the dollar impact and translate it into either a re-trade, a contract condition, or a price adjustment the buyer can take back to the vendor.

Book a due diligence scoping call with the Trinity team →

General advice only. This article contains general information current as at May 2026 and does not constitute tax, financial or legal advice. It does not take into account your personal circumstances, objectives or needs. Before acting on any information in this article, you should consider its appropriateness to your situation and seek professional advice from Trinity Accounting Practice or another qualified adviser. Liability limited by a scheme approved under Professional Standards Legislation.