Courts generally prohibit “claim-splitting.” Claim splitting occurs when a single cause of action is “split and filed or tried piecemeal.” G.B. v. Crossroads Acad.-Cent. St., 618 S.W.3d 581, 591 (Mo. Ct. App. 2020). When more than one lawsuit is filed, and the first results in a judgment, claims that could have been raised by the prevailing party in the first action are merged into, and are barred by, the first judgment. A cause of action may not be split when: the (1) separate actions arise out of the same act, contract or transaction; or (2) the parties, subject matter, and evidence necessary to sustain the claim are the same. Id. at 591-92.
There is an exception. A party can consent or acquiesce to claim-splitting. This happens when the opposing party agrees and consents to the claim-splitting. It can also occur when a party “otherwise” consents.