due diligence

noun

1

law : the care that a reasonable person exercises to avoid harm to other persons or their property

failed to exercise due diligence in trying to prevent the accident

2

business : research and analysis of a company or organization done in preparation for a business transaction (such as a corporate merger or purchase of securities)

Did you know?

Doing Your Due Diligence

Due diligence has been used since at least the mid-fifteenth century in the literal sense “requisite effort.” Centuries later, the phrase developed a legal meaning, namely, “the care that a reasonable person takes to avoid harm to other persons or their property”; in this sense, it is synonymous with another legal term, ordinary care. More recently, due diligence has extended its reach into business contexts, signifying the research a company performs before engaging in a financial transaction. This meaning may also apply to individuals: people are often advised to perform their due diligence before buying a house, signing a loan, or making any important purchase.

Examples of due diligence in a Sentence

Recent Examples on the Web

The school is in the due diligence period and aims to close on the property soon ahead of renovation work to turn office space back into classrooms for the 2027-28 school year. — Chris Higgins, Kansas City Star, 1 Aug. 2026

Cultural fluency belongs in due diligence, not just in the brand deck. — Peter Su, Forbes.com, 1 Aug. 2026

As reported, Aeffe, parent of Alberta Ferretti, Moschino and Pollini and listed on the Euronext Milan market of Borsa Italiana, received an offer from Oxy Capital Srl in May, followed by due diligence, that would allow a corporate turnaround. — Luisa Zargani, Footwear News, 31 July 2026

This case has been hanging over Chelsea’s head since the Todd Boehly-Clearlake consortium began its due diligence when buying the club in May 2022. — Simon Johnson, New York Times, 31 July 2026

Word History

First Known Use

1598, in the meaning defined at sense 1

Legal Definition

due diligence

noun

1

: such diligence as a reasonable person under the same circumstances would use : use of reasonable but not necessarily exhaustive efforts

called also reasonable diligence

Note: Due diligence is used most often in connection with the performance of a professional or fiduciary duty, or with regard to proceeding with a court action. Due care is used more often in connection with general tort actions.

2

a

: the care that a prudent person might be expected to exercise in the examination and evaluation of risks affecting a business transaction

b

: the process of investigation carried on usually by a disinterested third party (as an accounting or law firm) on behalf of a party contemplating a business transaction (as a corporate acquisition or merger, loan of finances, or especially purchase of securities) for the purpose of providing information with which to evaluate the advantages and risks involved

the greatest exposure…for failure to conduct adequate due diligence arises in the context of public offerings of securities

—G. M. Lawrence

c

: the defense (as to a lawsuit) that due diligence was conducted