<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2009) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2009) (Learn how and when to remove this template message) </Td> </Tr> <P> An IOU (abbreviated from the phrase "I owe you") is usually an informal document acknowledging debt . An IOU differs from a promissory note in that an IOU is not a negotiable instrument and does not specify repayment terms such as the time of repayment . IOUs usually specify the debtor, the amount owed, and sometimes the creditor . IOUs may be signed or carry distinguishing marks or designs to ensure authenticity . In some cases, IOUs may be redeemable for a specific product or service rather than a quantity of currency, constituting a form of scrip . </P> <P> Also referred to as "IOUs" by the U.S. state of California, the term "Registered Warrants", which specify a future payment date, is meant to differentiate these IOUs from regular, or "normal" payroll warrants which permit the holder to exchange their warrant for cash immediately . For both types of warrants, redeeming them may be delayed until funds are available . Because of this uncertainty, warrants are not negotiable instruments . Registered Warrants were issued in July 2009 due to a temporary inability of the state of California to redeem its warrants . Warrants are issued as payment to state employees, private businesses, local governments, taxpayers receiving tax refunds, and owners of unclaimed money . </P>

What is the acronym of iou in finance