Joint and several liability is where the financial burden of harm among the parties at fault is allocated between two or more defendants. Smith v. Coffey, 37 S.W.3d 797, 799 (Mo. 2001).
With tort-based claims, joint or concurrent tort-feasors are severally and jointly answerable to the injured party for the full amount of the injuries. Gramex Corp. v. Green Supply, Inc., 89 S.W.3d 432, 440 (Mo. 2002).
A similar rule exists for contracts. When two or more people undertake the performance of an obligation, the presumption is that the undertaking was joint. Schubert v. Trailmobile Trailer, L.L.C., 111 S.W.3d 897, 902-903 (Mo. Ct. App. 2003). As such, if two or more promisors are jointly bound to fulfill obligations under a joint contract, either of them may be charged with the entire liability under the contract. Id.