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)

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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 due diligence period for the project will last through 2026, Westland said. —Deborah Laverty, Chicago Tribune, 10 Mar. 2026

In a statement late Monday, City Manager Kimberly Bizor Tolbert did not directly address the selective tours described in the emails but said the work was part of due diligence authorized by the council. —Devyani Chhetri, Dallas Morning News, 9 Mar. 2026

Rather than expanding rapidly at the expense of quality, Nishioka has implemented a rigorous due diligence process, one that seeks to make sure that new stores align with the brand's standards in food quality, dining experience, and overall performance. —William Jones, USA Today, 9 Mar. 2026

Zeplain’s due diligence process isn’t for everyone, says CrowdStrike cofounder Dmitri Alperovitch. —Allie Garfinkle, Fortune, 6 Mar. 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