If you get an IOU for your signature, it's probably the guarantor's \x0d\ depending on whether your signature is your own name. If it's his own name, then the loan guarantee \x0d\ if it's his brother's name \x0d\ later, his brother can claim that he doesn't know that there is a guarantee \x0d\ if so \x0d\ it is estimated that it is unlikely to defraud the loan.