I.O.U. The words I owe you sound like the letters I O U. These letters serve as a brief form of that statement. People call a declaration or memorandum of debt an I.O.U. The usual wording is as follows:
Chicago, January 1, 2012 To Julie Brown. I.O.U. $10.00. Thomas Brown
An I.O.U. includes no promise to pay, so it is not considered a promissory note. It serves as strong, but not definite, legal evidence of debt.