Due diligence is the formal investigation a buyer, investor, or lender conducts before committing to a business transaction. It's how a purchaser verifies that what's being sold matches what's been promised. Skip it, and you might close a deal only to discover hidden debts, unresolved disputes, or financial figures that don't hold up. The process applies equally to business acquisitions, investment rounds, real estate, and mergers.
What due diligence actually covers
Most people think due diligence is just an accountant combing through spreadsheets. It's broader than that. A thorough investigation typically spans four areas.
Financial due diligence is usually the starting point. The buyer examines 3 to 5 years of financial statements, tax returns, accounts receivable, accounts payable, and revenue patterns. The goal is to confirm that reported profits are real and recurring, not inflated by one-off events or creative accounting. If a business claims $2 million in annual revenue, the investigation needs to show where that money came from and whether it will keep coming.
Legal due diligence covers contracts, intellectual property, litigation history, employment agreements, and regulatory compliance. Acquiring a company that's mid-way through an undisclosed court case is a situation many buyers would want to price in, or walk away from entirely.
Operational due diligence looks at how the business actually runs. That includes supplier relationships, customer concentration (a business where 70% of revenue comes from one client carries real risk), systems, staff, and physical assets. For tech companies, this often involves inspecting the codebase and infrastructure.
Commercial due diligence steps back and asks whether the business has a credible future. It interrogates the market size, competitive position, and customer churn. Even a profitable business can be a poor acquisition if its market is shrinking.
Who runs the process and how long it takes
Due diligence is rarely done by one person. Buyers typically assemble a team: an accountant for financials, a lawyer for legal matters, and sometimes an industry specialist for operational review. For small business acquisitions in Australia, the process often takes 4 to 8 weeks. For large mergers or ASX-listed transactions, it can run for months.
The seller provides access to a data room, which is either a physical or secure online repository of documents. Buyers submit questions, the seller's team responds, and the two sides work through the material systematically. Access is carefully controlled. The seller doesn't want sensitive information circulating if the deal falls through.
Due diligence typically begins after a term sheet is signed but before a binding contract is executed. That ordering matters. The term sheet sets the basic agreed parameters; due diligence either confirms them or surfaces reasons to renegotiate.
Red flags that surface during due diligence
Not every investigation leads to a clean result. Common problems include:
- Revenue recognised earlier than it should be, inflating profit figures.
- Undisclosed liabilities such as personal guarantees or contingent tax obligations.
- Key employees who plan to leave once the sale completes.
- Intellectual property owned by an individual founder rather than the company itself.
- Customer contracts that expire or contain change-of-control clauses that could unwind on acquisition.
Finding a red flag doesn't automatically kill a deal. It changes the negotiating position. A buyer who discovers $500,000 in undisclosed legal liabilities will typically seek a price reduction, an escrow arrangement, or specific representations and warranties in the final agreement.
Due diligence in venture capital and startup rounds
Investors conducting due diligence on early-stage startups face a different challenge: there's often limited financial history to examine. The focus shifts toward founder background, product-market fit, intellectual property ownership, and the cap table, which records every equity stake in the company. A messy cap table with unclear founder share splits or unvested equity can complicate a funding round significantly.
Venture firms also scrutinise existing investor agreements. A drag-along clause in an earlier round, for example, shapes how future exit scenarios play out. Investors want to understand what rights sit above them in the ownership structure before committing.
Vendor due diligence: when the seller goes first
In some transactions, sellers commission their own due diligence report before bringing the business to market. This is called vendor due diligence. The idea is to surface problems early, fix what's fixable, and present buyers with a credible, pre-verified picture of the business. It speeds up the process and can attract more confident bids.
Vendor due diligence is common in private equity-led sell-side processes and in competitive auctions where multiple buyers are involved simultaneously. The seller controls the narrative, but buyers typically conduct their own supplementary review regardless.
What happens after due diligence
Once the investigation is complete, the buyer has three realistic options. First, proceed on the agreed terms if the findings confirm what was represented. Second, renegotiate price or structure based on what was uncovered. Third, walk away if the risks are too significant or the information was materially misleading.
The findings feed directly into the final sale agreement. Representations and warranties in the contract are written to cover the specific risks identified during the process. The seller asserts that certain facts are true; if they turn out not to be, the buyer has a legal remedy. That's not a perfect substitute for thorough investigation, but it's the safety net that sits behind it.
Due diligence is ultimately about informed consent. A buyer who signs without it isn't just taking a risk on the numbers. They're agreeing to inherit every problem they didn't look for.