Qui tarn claimant

“Qui tarn” is short for the Latin phrase “qui tarn pro domino rege quam pro si ipso in hac parte sequitur” which means “Who sues on behalf of the King as well as for himself”. A person, usually an informer, who brings an action under a statute which establishes a penalty for the omission or commission of a certain act. The person (claimant) who is suing on behalf of him/herself also sues on behalf of the state and consequently splits any recovery with the state. Examples of statutes are the Whistleblower Acts, and the False Claims Act.