Due diligence is an investigation or audit of a potential investment or product to confirm all facts, such as reviewing all financial records, plus anything else deemed material. It refers to the care a reasonable person should take before entering into an agreement or a financial transaction with another party. Due diligence can also refer to the investigation a seller does of a buyer; items that may be considered are whether the buyer has adequate resources to complete the purchase, as well as other elements that would affect the acquired entity or the seller after the sale has been completed.
Due diligence became common practice (and a common term) in the U.S. with the passage of the Securities Act of 1933. Securities dealers and brokers became responsible for fully disclosing material information related to the instruments they were selling. Failing to disclose this information to potential investors made dealers and brokers liable for criminal prosecution. However, creators of the Act understood that requiring full disclosure left the securities dealers and brokers vulnerable to unfair prosecution if they did not disclose a material fact they did not possess or could not have known at the time of sale. As a means of protecting them, the Act included a legal defense that stated that as long as the dealers and brokers exercised “due diligence” when investigating companies whose equities they were selling, and fully disclosed their results to investors, they would not be held liable for information not discovered during the investigation.