Proffer agreement

In U.S. criminal law, a proffer agreement, proffer letter, proffer, or "Queen for a Day" letter is a written agreement between a prosecutor and a defendant or prospective witness that allows the defendant or witness to give the prosecutor information about an alleged crime, while limiting the prosecutor's ability to use that information against him or her.^[1]

As part of the agreement, the subject may agree to create a statement, known as a proffer statement, setting out their testimony. A meeting in which proffer agreements and statements are negotiated or set out is called a proffer session.^[2] The proffer testimony may be recorded as video evidence, in which case it is known as a proffer video.^[3]

A proffer does not ensure immunity; however, it often involves a deal for leniency. For instance, a defendant might secure a recommendation for a lighter sentence or other significant advantages in return for providing valuable and truthful information.^[4]