The escrow is  a legal figure in which the parties agree to hand over the custody of a document or value to an impartial third  party to retain it and deliver it to the other party once the previously agreed conditions are met.

This figure gives contractual security to the parties by identifying them and ensuring compliance with the contractual terms.

The escrow contract is essentially accessory since it is signed for the purpose of executing another main contract, for example, call option, merger or sale, among others.