Sandbagging, in the field of mergers and acquisitions law, refers to the act of claiming a breach of a contractual representation or warranty despite having known at the time of the contract that it was untrue.
[1] Delaware and New York law both generally permit sandbagging when a contract is silent on the point, whereas California law does not allow it unless the contract explicitly permits it.
[2] New York case law indicates that sandbagging is not allowed in cases where the information about the falsehood of the representation or warranty came directly from the seller.
The civil code of Quebec imposes a requirement of good faith in the exercise of contractual rights which would likely preclude sandbagging.
[4] The Japanese Civil Code does not allow sandbagging unless the contract explicitly permits it.