Exhibit 99.1

                            UNITED STATES OF AMERICA

                      FEDERAL ENERGY REGULATORY COMMISSION

FACT-FINDING INVESTIGATION OF POTENTIAL                    DOCKET NO. PA02-2-000
MANIPULATION OF ELECTRIC AND
NATURAL GAS PRICES

TO: DONALD J. GELINAS, ASSOCIATE DIRECTOR OF OFFICE OF MARKETS, TARIFFS, AND
    RATES

                     RESPONSE OF THE PINNACLE WEST COMPANIES
                    TO COMMISSION'S MAY 22, 2002 DATA REQUEST

     The following  constitutes  the response of Arizona Public Service  Company
("APS") and its affiliates, Pinnacle West Capital Corporation ("PWCC"), Pinnacle
West Energy Corporation ("PWE"), and APS Energy Services Company, Inc. ("APSES")
(collectively  the "Pinnacle West Companies") to the  Commission's  Data Request
dated May 22,  2002,  addressed  to those  sellers of natural  gas in the United
States portion of the Western Systems Coordinating Council ("WSCC") and/or Texas
during the period 2000-2001 (the "Data Requests").

     In  responding  to the  current  Data  Requests,  and as  described  in the
accompanying  affidavit of David A.  Hansen,  Vice  President  of Pinnacle  West
Marketing and Trading for Pinnacle West Capital  Corporation,  the Pinnacle West
Companies  conducted a thorough  investigation  into the trading  activities  of
their employees and agents in the United States portion of the WSCC and/or Texas
during  the years  2000 and 2001.  This  investigation  included  interviews  of
trading personnel and a review of available  electronic and paper documentation.
To the extent that  additional  documentation  or information is discovered that
warrants  supplementation of this response,  the Pinnacle West Companies will do
so promptly.

     The Request for Admission  and Request for  Production of Documents are set
forth below followed by the Pinnacle West Companies' responses.

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I.   REQUEST FOR ADMISSION

     A. ADMIT OR DENY: THE COMPANY ENGAGED IN ACTIVITIES  REFERRED TO AS "WASH,"
"ROUND  TRIP" OR  "SELL/BUYBACK"  TRADING.  THIS  TRADING  INVOLVES  THE SALE OF
NATURAL GAS  TOGETHER  WITH A  SIMULTANEOUS  PURCHASE OF THE SAME PRODUCT AT THE
SAME PRICE.

The Pinnacle West Companies deny that they engaged in the activity  described in
A above.

     B. IF YOU SO ADMIT, PROVIDE TRANSACTION BY TRANSACTION DETAILS FOR ALL SUCH
TRANSACTIONS  YOUR  COMPANY  ENGAGED  IN,  INCLUDING,  BUT NOT  LIMITED  TO, THE
FOLLOWING:

          1. INDICATE THE METHODS AND  RATIONALE  USED TO ARRIVE AT THE VALUE OR
     COMPENSATION OF SUCH TRANSACTIONS.

          2.  FOR  EACH  TRANSACTION,  INDICATE  WHETHER  THAT  TRANSACTION  WAS
     REPORTED  TO  PLATT'S,   BLOOMBERG,  OR  ANY  ORGANIZATION  THAT  MONITORS,
     PUBLISHES OR REPORTS TRADING DATA (INCLUDING BID-AND-ASK DATA) OR PUBLISHES
     OR REPORTS PRICES OR FORWARD INDICES.

          3. IDENTIFY EACH TRADER THAT  PARTICIPATED  IN SUCH  TRANSACTIONS,  BY
     NAME AND POSITION WITHIN YOUR COMPANY,  IF EMPLOYED BY YOU. IF NOT EMPLOYED
     BY YOU,  IDENTIFY  EACH  TRADER'S  NAME AND  AFFILIATION.  FOR EACH  FORMER
     TRADER, STATE THEIR LAST KNOWN HOME ADDRESS AND TELEPHONE NUMBER.

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          4.  IDENTIFY HOW SUCH  TRANSACTIONS  WERE EXECUTED  (E.G.,  WHETHER AN
     ELECTRONIC  PLATFORM WAS USED TO INITIATE  THE SALE OR  PURCHASE,  WITH THE
     PURCHASE OR SALE TRANSACTION  SUBSEQUENTLY  ARRANGED THROUGH A BROKER OR BY
     TELEPHONE).

          5. DESCRIBE ALL POLICIES AND PROCEDURES THAT HAVE BEEN  IMPLEMENTED TO
     PREVENT FUTURE TRANSACTIONS OF THIS TYPE.

     Not applicable.

II.  REQUEST FOR PRODUCTION OF DOCUMENTS

TO THE EXTENT YOUR COMPANY  ENGAGED IN "WASH,"  "ROUND TRIP," OR  "SELL/BUYBACK"
TYPE TRANSACTIONS, PROVIDE THE FOLLOWING DOCUMENTS:

A.   PROVIDE COPIES OF ALL  COMMUNICATIONS OR  CORRESPONDENCE,  INCLUDING E-MAIL
     MESSAGES, INSTANT MESSAGES, OR TELEPHONE LOGS, BETWEEN YOUR COMPANY AND ANY
     OTHER COMPANY  (INCLUDING  YOUR AFFILIATES OR  SUBSIDIARIES)  THAT REFER OR
     RELATE TO THIS ACTIVITY. PROVIDE THE COPIES IN ELECTRONIC FORMAT.

     Not applicable.

B.   PROVIDE  COPIES OF ALL  MATERIAL,  INCLUDING,  BUT NOT LIMITED TO,  OPINION
     LETTERS, MEMORANDA,  COMMUNICATIONS (INCLUDING E-MAILS AND TELEPHONE LOGS),
     OR REPORTS,  THAT ADDRESS OR DISCUSS YOUR COMPANY'S KNOWLEDGE OF, AWARENESS
     OF,  UNDERSTANDING OF, OR EMPLOYMENT OR USE OF ANY SUCH TRANSACTIONS IN THE
     U.S. PORTION OF THE WSCC AND/OR TEXAS DURING THE PERIOD 2000-2001.

     Not Applicable

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