Due Diligence in Finance: What It Is and How It Works

What Is Due Diligence?

Due diligence is the comprehensive investigation a buyer conducts on a target business before completing an acquisition, investment, or major commercial transaction. It verifies that the information provided by the seller is accurate, identifies risks and liabilities that could affect value, and informs the final pricing and deal terms. The phrase comes from the legal concept that a buyer cannot later claim ignorance of information they could have discovered through reasonable investigation.

Types of Due Diligence

Financial due diligence (FDD) is the core exercise for most M&A transactions — examining historical financial statements, quality of earnings, working capital dynamics, debt, and off-balance-sheet commitments. Legal due diligence covers contracts, litigation, regulatory compliance, and intellectual property. Commercial due diligence assesses the market position, competitive dynamics, customer concentration, and growth prospects. Tax due diligence identifies historic tax exposures and optimises post-completion tax structure. Operational due diligence evaluates IT systems, supply chain, and operational capacity.

What Financial Due Diligence Covers

Finance teams and advisors conducting FDD will typically examine: three to five years of historic financial statements; the quality and sustainability of EBITDA (removing one-off items, owner costs, and non-recurring revenues); normalised working capital — establishing what level of working capital is required to run the business; net debt and debt-like items (contingent liabilities, deferred consideration, pension deficits, finance leases); and capital expenditure requirements (distinguishing maintenance capex from growth capex).

Virtual Data Rooms

Due diligence is conducted through a virtual data room (VDR) — a secure online repository where the seller uploads documents and the buyer's advisors review them. Ansarada, Intralinks, and Datasite are commonly used platforms. Access is controlled and all activity is logged.

Red Flags

Common red flags in financial due diligence: revenue concentrated in very few customers; aggressive revenue recognition policies; EBITDA growing faster than cash conversion; unexplained year-end movements in working capital; contingent liabilities not adequately disclosed; related party transactions on non-commercial terms. Any of these can lead to a price reduction, additional warranties, or deal withdrawal.