Improper claim splitting or cause of action splitting occurs when a party sues on a claim which arises out of the same “act, contract or transaction” as previously litigated claims. Kesterson v. State Farm Fire & Cas. Co., 242 S.W.3d 712, 716 (Mo. 2008). The purpose of the rule is to prevent a multiplicity of suits and to ensure that all disputes arising out of the same “act, contract or transaction” are adjudicated in one proceeding.
“Act, contract or transaction” for purposes of this rule is quite broad. Specifically, “transaction” in this context means the “aggregate of all the circumstances which constitute the foundation for a claim,” as well as “all of the facts and circumstances out of which an injury arose.” King Gen. Constr. v. Reorganized Church, 821 S.W.2d 495, 501-02 (Mo. 1991).