1.Banking: Informal letter from a bank indicating its willingness to support a customer with a short-term loan, if and when required. It is not a letter of commitment.
2.Corporate affairs: Parent-firm's letter, issued to reassure a subsidiary-firm's lender or supplier, that it would support the subsidiary in case of financial difficulties. Specific terminology used in the letter determines whether such assurance constitutes a binding contract or only a moral obligation. A comfort letter, however, does signify that the loan request is authorized, is in order, and that the parent firm will keep a careful eye on the entire transaction. Also called letter of comfort, it may also be issued by a government to back up the obligations of its agencies.