The guarantee is the surety contract in exchange law"). Emerged in London for the commercial uses of the bill of exchange, it is a unilateral payment commitment, generally joint and several, in favor of a third party (beneficiary), who will receive the benefit in case the guarantor (debtor of the beneficiary) does not comply. The guarantor bound by the guarantee is called guarantor.

The legal rules of the bond are additionally applied to the guarantee. However, this supplementary application does not apply when the guarantor is obliged to pay without reservation of any opposition, in cases in which it is said that he provides the guarantee upon first demand, or upon first request.

The bank guarantee is a particular case of guarantee, for subjective reasons, since here the guarantor is a bank, savings bank, credit union, or another form of credit entity.

The guarantor is a guarantor of other people's obligations, given that it is an instrument by which a third party undertakes to cover the payment of the credit, and its interests, if they have been agreed, in the event that the original debtor (guarantor) does not comply with what corresponds to his creditor (beneficiary of the guarantee).

In law, the figure of a guarantee is only understood to be linked to credit titles, even though in colloquial terms it is understood that there is a guarantee when any third party physically or morally supports the actions of a person.

In practice, normally, whoever wants to receive a bank loan needs someone to guarantee them if they sign a credit instrument. That is, you need to demonstrate to the bank or the entity that lends you the money that, in the event that you cannot return the mutual (loan) in the agreed payments, said entity may require payment and even auction off the assets of both the guarantor and the guarantor to cover the rest of the loan that has not been returned.

In mutual contracts with mortgage guarantee, even when the guarantee is the property, the payment is usually documented with credit instruments and it is common for banks to ask guarantors to be responsible for the payment of the installments in the event that the debtor does not do so. There are "pledged" or non-pledged guarantors and they differ in the need to make a prior financial deposit.

The figure of the guarantee is different from the surety and the joint debt. The guarantor only undertakes credit titles and is always joint and several. The guarantor commits to a surety contract and enjoys the benefits of order and excursion. The joint debtor undertakes a contractual or exchange commitment. A guarantee is essential to grant a loan.