UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO ARIZONA PUBLIC SERVICE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER , PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. ARIZONA PUBLIC SERVICE COMPANY Floating Rate Note Due 2001 No. 1 $250,000,000 CUSIP No. 040555BZ6 Arizona Public Service Company, a corporation duly organized and existing under the laws of Arizona (herein called the "Company", which term includes any successor Person under the Indenture hereinafter referred to), for value received, hereby promises to pay to Cede & Co., or registered assigns, the principal sum of Two Hundred Fifty Million Dollars on November 15, 2001, and to pay interest thereon from November 8, 1999 or from the most recent Interest Payment Date to which interest has been paid or duly provided for, quarterly in arrears on February 15, May 15, August 15 and November 15 in each year, commencing February 15, 2000, at the rate of LIBOR plus 0.72%, until the principal hereof is paid or made available for payment. The calculation agent, initially The Chase Manhattan Bank, will calculate the interest rate on this Security. The interest rate will be equal to LIBOR plus 0.72%. The interest rate in effect for the period from November 8, 1999 to February 15, 2000, the initial Interest Reset Date, will be LIBOR, as determined on November 4, 1999, plus 0.72% (the "Initial Interest Rate"). The calculation agent will reset the interest rate on each Interest Payment Date (each such day an "Interest Reset Date"). The second London Business Day preceding an Interest Reset Date will be the "Interest Determination Date" for that Interest Reset Date. The interest rate in effect on each day that is not an Interest Reset Date will be the interest rate determined as of the Interest Determination Date pertaining to the immediately preceding Interest Reset Date. The interest rate in effect on any day that is an Interest Reset Date will be the interest rate determined as of the Interest Determination Date pertaining to that Interest Reset Date, except that the interest rate in effect for the period from and including November 8, 1999 to the first Interest Reset Date will be the Initial Interest Rate. The amount of interest payable for any period will be computed on the basis of a 360-day year for the actual number of days elapsed. If any Interest Payment Date (other than the Stated Maturity hereof or a Redemption Date herefor) would otherwise be a day that is not a Business Day, the Interest Payment Date will be postponed to the next succeeding Business Day, except that if such Business Day falls in the next succeeding calendar month, such Interest Payment Date shall be the immediately preceding Business Day. If the Stated Maturity hereof or any Redemption Date herefor is not a Business Day, then payment of principal and interest payable on such date will be made on the next succeeding day which is a Business Day (and without any interest or other payment in respect of any such delay), in each case with the same force and effect as if made on such date. A "Business Day" shall mean any day, except a Saturday, a Sunday or a legal holiday in The City of New York on which banking institutions are authorized or required by law, regulation or executive order to close; provided that the day is also a London Business Day. "London Business Day" means any day on which dealings in United States dollars are transacted in the London interbank market. The calculation agent will determine "LIBOR" in accordance with the following provisions: (i) With respect to any Interest Determination Date, LIBOR will be the rate for deposits in United States dollars having a maturity of three months commencing on the first day of the applicable Interest Period that appears on Telerate Page 3750 as of 11:00 A.M., London time, on that Interest Determination Date. If no rate appears, LIBOR, in respect to that Interest Determination Date, will be determined in accordance with the provisions described in (ii) below. (ii) With respect to an Interest Determination Date on which no rate appears on Telerate Page 3750, as specified in (i) above, the calculation agent will request the principal London offices of each of four major reference banks in the London interbank market, as selected by the calculation agent, to provide the calculation agent with its offered quotation for deposits in United States dollars for the period of three months, commencing on the first day of the applicable Interest Period, to prime banks in the London interbank market at approximately 11:00 A.M., London time, on that Interest Determination Date and in a principal amount that is representative for a single transaction in United States dollars in that market at that time. If at least two quotations 2 are provided, then LIBOR on that Interest Determination Date will be the arithmetic mean of those quotations. If fewer than two quotations are provided, then LIBOR on the Interest Determination Date will be the arithmetic mean of the rates quoted at approximately 11:00 A.M., in The City of New York, on the Interest Determination Date by three major banks in The City of New York selected by the calculation agent for loans in United States dollars to leading European banks, having a three-month maturity and in a principal amount that is representative for a single transaction in United States dollars in that market at that time; provided, however, that if the banks selected by the calculation agent are not providing quotations in the manner described by this sentence, LIBOR determined as of that Interest Determination Date will be LIBOR in effect on that Interest Determination Date. "Telerate Page 3750" means the display designated as "Page 3750" on Bridge Telerate, Inc., or any successor service, for the purpose of displaying the London interbank rates of major banks for United States dollars. "Interest Period" means the period from and including November 8, 1999, to, and excluding, the first Interest Payment Date thereafter and then from, and including, the immediately preceding Interest Payment Date to which interest has been paid or duly provided for to, but excluding, the next Interest Payment Date or the Maturity hereof, as the case may be. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be the fifteenth calendar day immediately preceding the Interest Payment Date (whether or not a Business Day). Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of Securities of this series not less than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Indenture. Payment of the principal of (and premium, if any) and any interest on this Security will be made at the office or agency of the Company maintained for that purpose in The City of New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts; provided, however, that at the option of the Company payment of interest may be made by check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register. Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place. 3 Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed under its corporate seal. ARIZONA PUBLIC SERVICE COMPANY By Michael V. Palmeri ------------------------------------- Vice President, Finance Attest: Betsy A. Pregulman - -------------------------------- Associate Secretary 4 This Security is one of a duly authorized issue of securities of the Company (herein called the "Securities"), issued and to be issued in one or more series under an Indenture, dated as of January 15, 1998 (herein called the "Indenture", which term shall have the meaning assigned to it in such instrument), between the Company and The Chase Manhattan Bank, as Trustee (herein called the "Trustee", which term includes any successor trustee under the Indenture), and reference is hereby made to the Indenture for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Company, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered. This Security is one of the series designated on the face hereof, limited in aggregate principal amount to $250,000,000. The Securities of this series are subject to redemption upon not less than 30 days' notice by mail at the option of the Company, in whole or in part, from time to time on any Interest Payment Date on or after November 15, 2000 at a Redemption Price equal to the principal amount of the Securities of this series to be redeemed plus interest accrued to the Redemption Date (the "Redemption Price") . If notice has been given as provided in the Indenture and funds for the redemption of any Securities (or any portion thereof) called for redemption shall have been made available on the Redemption Date referred to in such notice, such Securities (or any portion thereof) will cease to bear interest on the date fixed for such redemption specified in such notice and the only right of the Holders of such Securities will be to receive payment of the Redemption Price. Notice of any optional redemption of Securities of this series (or any portion thereof) will be given to Holders at their addresses, as shown in the Security Register for such Securities, not more than 60 nor less than 30 days prior to the date fixed for redemption. The notice of redemption will specify, among other items, the Redemption Price and the principal amount of the Securities of this series held by such Holder to be redeemed. If less than all of the Securities of this series are to be redeemed at the option of the Company, the Trustee shall select, in such manner as it shall deem fair and appropriate, the portion of such Securities to be redeemed in whole or in part. The Securities of this series will not be subject to any sinking fund. In the event of redemption of this Security in part only, a new Security or Securities of this series and of like tenor for the unredeemed portion hereof will be issued in the name of the Holder hereof upon the cancellation hereof. If an Event of Default with respect to Securities of this series shall occur and be continuing, the principal of the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture. The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Company and the rights of the 5 Holders of the Securities of each series to be affected under the Indenture at any time by the Company and the Trustee without the consent of such Holders in certain limited circumstances or with the consent of the Holders of 66-2/3% in principal amount of the Securities at the time Outstanding of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities of each series at the time Outstanding, on behalf of the Holders of all Securities of such series, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security. As provided in and subject to the provisions of the Indenture, the Holder of this Security shall not have the right to institute any proceeding with respect to the Indenture or for the appointment of a receiver or trustee or for any other remedy thereunder, unless such Holder shall have previously given the Trustee written notice of a continuing Event of Default with respect to the Securities of this series, the Holders of not less than 25% in principal amount of the Securities of this series at the time Outstanding shall have made written request to the Trustee to institute proceedings in respect of such Event of Default as Trustee and offered the Trustee reasonable indemnity, and the Trustee shall not have received from the Holders of a majority in principal amount of Securities of this series at the time Outstanding a direction inconsistent with such request, and shall have failed to institute any such proceeding, for 60 days after receipt of such notice, request and offer of indemnity. The foregoing shall not apply to any suit instituted by the Holder of this Security for the enforcement of any payment of principal hereof or any premium or interest hereon on or after the respective due dates expressed herein. No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of and any premium and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed. As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the Company in any place where the principal of and any premium and interest on this Security are payable, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees. The Securities of this series are issuable only in registered form without coupons in denominations of $1,000 and any integral multiple thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same. 6 No service charge shall be made for any such registration of transfer or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. Prior to due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary. All terms used in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture. 7 CERTIFICATE OF AUTHENTICATION This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture. THE CHASE MANHATTAN BANK AS TRUSTEE By T. J. Foley ------------------------------------- AUTHORIZED OFFICER 8