What is Commercial Paper?

Legal Definition
Commercial paper, in the global financial market, is an unsecured promissory note with a fixed maturity of no more than 270 days.

Commercial paper is a money-market security issued (sold) by large corporations to obtain funds to meet short-term debt obligations (for example, payroll), and is backed only by an issuing bank or company promise to pay the face amount on the maturity date specified on the note. Since it is not backed by collateral, only firms with excellent credit ratings from a recognized credit rating agency will be able to sell their commercial paper at a reasonable price. Commercial paper is usually sold at a discount from face value, and generally carries lower interest repayment rates than bonds due to the shorter maturities of commercial paper. Typically, the longer the maturity on a note, the higher the interest rate the issuing institution pays. Interest rates fluctuate with market conditions, but are typically lower than banks' rates.

Commercial paper – though a short-term obligation – is issued as part of a continuous rolling program, which is either a number of years long (as in Europe), or open-ended (as in the U.S.).
-- Wikipedia
Legal Definition
Shortterm, unsecured discount DEBT securities issued by highly rated financial companies (as FINANCIAL PAPER) and industrial companies (as INDUSTRIAL PAPER). Although most CP is unsecured, there is also a market for assetbacked CP and LETTER OF CREDITbacked CP. In the US market CP maturities range from overnight to 270 days, while in the EUROMARKETS maximum maturity may extend to 360 days; the most common maturities in both markets are in the 14 to 30 day sector. Most CP is issued via DEALERS in the form of BEARER SECURITIES, although issues of REGISTERED SECURITIES are possible. In the US market it is common for CP programs to be partially backed by SWINGLINES so that issuers can access funds in the event they are unable to roll over their maturing notes. See also EURO COMMERCIAL PAPER.
Legal Definition
The term "commercial paper" means bills of exchange, promissory notes, bank-checks, and other negotiable instruments for the payment of money, which, by their form and on their face, purport to be such instruments as are, by the law-merchant, recognized as falling under the designation of "commercial paper " In re Hercules Mut. Li. Assur. Soc., 6 Ben. 35, 12 Fed. Cas. 12. Commercial paper means negotiable paper given in due course of business, whether the element of negotiability be given, it by the law-merchant or by statute. A note given by & merchant for money loaned is within the meaning. In re Sykes, 5 Biss. 113, Fed. Cas. No. 13,708.
-- Black's Law Dictionary
Legal Definition
Negotiable instruments.
-- Ballentine's Law Dictionary