Before buying a house, you inspect it. You check the roof, the wiring, the foundation. You look for problems the seller might not mention. Due diligence in business is the same idea applied to a potential investment or acquisition. It is an investigation or audit of a target company to confirm the facts, uncover risks, and decide whether to proceed.

Due diligence covers financial, legal, operational, and strategic ground. Financial due diligence verifies revenue, costs, and debt. Legal due diligence checks contracts, lawsuits, and intellectual property. Operational due diligence examines supply chains, technology, and staffing. Strategic due diligence asks whether the deal makes sense in the first place. The process can take weeks or months and cost significant money. That cost is worth it when it prevents a bad deal.

The term is also used more broadly. A politician vetting a running mate does due diligence. A company checking a supplier's labor practices does due diligence. The common thread is careful investigation before a commitment. Skipping it is risky. What you do not know can hurt you, especially when the other side has an incentive to present things favorably.