Lex loci solutionis (Latin: "law of the place of performance"), in conflict of laws, is the law applied in the place of an event.
If a case comes before a court and all the main features of the case are local, the court will then apply the lex fori, the prevailing municipal law, to decide the case. If there are foreign elements to the case, the forum court may then be obliged under the conflict of laws system to consider whether the forum court has jurisdiction to hear the case (see forum shopping).
It then characterises the issues and allocate the factual basis of the case to its relevant legal classes. It then applies choice of law rules to decide the law to be applied to each class.
Lex loci solutionis is one of the possible choice of law rules applied to cases that test the validity of a contract or that deal with a tort. For example, if a person domiciled in Bolivia and a person habitually resident in Germany make a contract by e-mail and agree to meet in Arizona to research a book, there would be several possibly-relevant choice of law rules:
- the lex domicilii, lex patriae or the law of habitual residence to determine whether the parties had the capacity to enter into the contract;
- lex loci contractus, which could be difficult to establish since both parties never left their own state (reliance on postal rules for offer and acceptance in the several putative lex causae might produce different results)
- lex loci solutionis might be the most relevant since Arizona is the most closely connected to the substance of the obligations assumed
- the proper law
- lex fori, which might have public policy issues if one of the parties is a minor.