An investment request letter is a document written by an individual or organization to another entity, usually offering a financial stake in the investing project. It outlines the specifics of the proposed venture, such as the purpose, objectives, capital requirements, timeline and more. The letter should be persuasive, succinct and informal yet professional in order to convince the recipient of the project’s viability. At its core, the investment request letter is an attempt to persuade someone else to invest and join forces in a mutually beneficial endeavor.