View:

                            SCHEDULE 14A INFORMATION
 
                  Proxy Statement Pursuant to Section 14(a) of
            the Securities Exchange Act of 1934 (Amendment No.    )
 
    Filed by the Registrant /X/
    Filed by a Party other than the Registrant / /
 
    Check the appropriate box:
    / /  Preliminary Proxy Statement
    / /  Confidential, for Use of the Commission Only (as permitted by Rule
         14a-6(e)(2))
    / /  Definitive Proxy Statement
    /X/  Definitive Additional Materials
    / /  Soliciting  Material  Pursuant  to  Section  240.14a-11(c)  or  Section
         240.14a-12
                     KANSAS CITY POWER AND LIGHT COMPANY
- --------------------------------------------------------------------------------
                (Name of Registrant as Specified In Its Charter)
 
- --------------------------------------------------------------------------------
    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)
 
Payment of Filing Fee (Check the appropriate box):
 
/ /  $125 per  Exchange Act  Rules 0-11(c)(1)(ii),  14a-6(i)(1), 14a-6(i)(2)  or
     Item 22(a)(2) of Schedule 14A.
/ /  $500  per  each party  to  the controversy  pursuant  to Exchange  Act Rule
     14a-6(i)(3).
/ /  Fee  computed  on   table  below   per  Exchange   Act  Rules   14a-6(i)(4)
     and 0-11.
     1) Title of each class of securities to which transaction applies:
        ------------------------------------------------------------------------
     2) Aggregate number of securities to which transaction applies:
        ------------------------------------------------------------------------
     3) Per unit price or other underlying value of transaction computed
        pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the
        filing fee is calculated and state how it was determined):
        ------------------------------------------------------------------------
     4) Proposed maximum aggregate value of transaction:
        ------------------------------------------------------------------------
     5) Total fee paid:
        ------------------------------------------------------------------------
/X/  Fee paid previously with preliminary materials.
/ /  Check box if any part of the fee is offset as provided by Exchange Act Rule
     0-11(a)(2)  and identify the  filing for which the  offsetting fee was paid
     previously. Identify the previous filing by registration statement  number,
     or the Form or Schedule and the date of its filing.
     1) Amount Previously Paid:
        ------------------------------------------------------------------------
     2) Form, Schedule or Registration Statement No.:
        ------------------------------------------------------------------------
     3) Filing Party:
        ------------------------------------------------------------------------
     4) Date Filed:
        ------------------------------------------------------------------------

xyz
 
                                                                  April 29, 1996
 
Dear Shareholder:
 
    In  its continuing attempt to block the formation of a strong and formidable
competitor, Western Resources is now  attempting to solicit proxies against  the
merger of Kansas City Power & Light Company with UtiliCorp United Inc. Western's
disruptive proxy contest, coupled with its highly conditional exchange offer, is
driven solely by its own agenda, at your expense.
 
    IN  CONTRAST,  THE PROPOSED  MERGER  OF KCPL  AND  UTILICORP IS  A STRATEGIC
COMBINATION DESIGNED TO BUILD SUSTAINABLE VALUE  FOR YOU BY ENHANCING GROWTH  IN
REVENUE  AND  INCOME  IN A  RAPIDLY  CHANGING COMPETITIVE  MARKETPLACE.  YOU ARE
STRONGLY URGED TO  VOTE FOR  OUR MERGER WITH  UTILICORP BY  SIGNING, DATING  AND
MAILING THE ENCLOSED WHITE PROXY TODAY.
 
    In   seeking  to   distract  your  attention   from  the   benefits  of  the
KCPL/UtiliCorp merger, Western wants you to believe that it is making a superior
financial offer.
 
                                DON'T BE FOOLED
               WESTERN IS NOT GUARANTEEING YOU $28 PER KCPL SHARE
 
    Western proposes to exchange each of your KCPL shares for a fractional share
of its own common stock. They're telling  you that the value of the  transaction
is  $28 a share -- but  that figure is speculative, based  on a number of flawed
assumptions and "strings" that Western has tied to its proposal.
 
Consider the following:
 
    - WESTERN'S PROPOSAL CONTAINS A "COLLAR," WALL STREET JARGON FOR A MECHANISM
      WHICH PLACES THE RISK OF ANY DECLINE IN WESTERN'S STOCK PRICE SQUARELY  ON
      YOUR SHOULDERS. The collar also makes it impossible to figure out what the
      Western deal will be worth when -- and if -- it is ever completed.
 
    - WESTERN  ADMITS ITS  EXCHANGE OFFER  MAY BE  FULLY TAXABLE  TO YOU  AT THE
      FEDERAL LEVEL. In that case, its $28 a share promise would be history.
 
    - KANSAS REGULATORS ARE ABOUT TO HIT WESTERN WITH RATE REDUCTIONS THAT  WILL
      HAVE  A NEGATIVE EFFECT ON WESTERN'S REVENUES AND EARNINGS AND WILL NOT BE
      GOOD NEWS  FOR ITS  SHARE VALUE.  While Western  is trying  to limit  this
      reduction  to  $8.7 million,  intervenors  such as  the  Citizens' Utility
      Ratepayer Board  have  already said  they  will seek  substantially  more.
      Western  is trying  to delay any  further action on  rate reductions until
      AFTER you vote on the KCPL/UtiliCorp merger.
 
    - WESTERN'S PROPOSAL ASSUMES $500 MILLION OF "PHANTOM" COST SAVINGS. Western
      claims it can achieve $1 billion of cost savings from its merger with your
      company. However, less  than a  year ago, Western's  same synergy  experts
      arrived  at savings of only $500 million. Is Western inflating its savings
      estimate in an attempt to support its stock price?

    - WESTERN'S ASSUMPTION  THAT IT  WILL BE  ABLE TO  KEEP 70  PERCENT OF  COST
      SAVINGS  IS  FICTION. In  other utility  mergers, regulators  have allowed
      companies to keep only 50 percent of cost savings. In fact, Western itself
      is under an order from Kansas  regulatory officials to share savings on  a
      "50/50" basis with ratepayers.
 
    IN  STARK CONTRAST TO THE WESTERN  PROPOSAL, THE SHARE-FOR-SHARE EXCHANGE IN
THE MERGER OF KCPL AND UTILICORP IS FIXED, REGARDLESS OF FLUCTUATIONS IN  KCPL'S
OR  UTILICORP'S STOCK PRICE. You will get full benefit of any price appreciation
that occurs between now and consummation of the KCPL and UtiliCorp merger. Plus,
our proposed combination doesn't  depend on inflated  cost savings estimates  or
overly optimistic assumptions about sharing of these cost savings.
 
           WESTERN'S DIVIDEND MAY BE SUBSTANTIALLY LESS THAN PROMISED
 
    Western's   promise  of  a   so-called  23%  dividend   increase  is  highly
questionable. Take a closer look:
 
    - WESTERN'S ABILITY TO MAINTAIN ITS  CURRENT DIVIDEND WILL BE THREATENED  IF
      WESTERN  CAN'T ACHIEVE ITS FORECAST MERGER  SAVINGS AND KEEP MOST OF THEM.
      Remember, Western's proposal is based on  cost savings of more than  twice
      Western's  own  estimates  less than  a  year  ago. It  also  assumes that
      regulators will allow it to keep a far greater percentage of these savings
      than is realistic.
 
    - WESTERN'S DIVIDEND  WILL  BE  FURTHER  THREATENED  BY  ADVERSE  REGULATORY
      TREATMENT. Remember, Western is using its proposal as a delaying tactic to
      avoid  what may be inevitable -- cuts  in electric rates that will further
      reduce revenues and earnings.
 
    WESTERN CANNOT  SUPPORT THE  ALLEGED VALUE  OF ITS  MERGER PROPOSAL  WITHOUT
GROSSLY  INFLATED  ESTIMATES  AND  UNREALISTIC  MERGER  ASSUMPTIONS.  Western is
betting that it can fool you with a highly conditional promise of Western common
stock with dubious value and a dividend that may not be sustainable. Western  is
hoping  that its flawed assumptions  and empty promises will  get you to give up
the tangible benefits and dividend safety of a KCPL/UtiliCorp merger.
 
             IT IS UNLIKELY WESTERN'S OFFER WILL EVER BE COMPLETED
 
    The fact is, there  are a number of  very significant hurdles Western  would
have to overcome before it could exchange a single share of KCPL stock. Here are
just three of many:
 
1.    AT LEAST  90  PERCENT OF  KCPL'S OUTSTANDING  SHARES  MUST BE  TENDERED TO
    WESTERN. Given the legitimate  questions about the  real value of  Western's
    offer, is this realistic?
 
2.    WESTERN  MUST  RECEIVE  APPROVAL  FROM  ITS  OWN  SHAREHOLDERS.  Once they
    understand that this deal could erode their investment in Western stock,  is
    this realistic?
 
3.     WESTERN'S PROPOSAL  MUST SATISFY  THE MISSOURI  BUSINESS COMBINATION LAW,
    WHICH REQUIRES  YOUR  BOARD'S APPROVAL.  Given  the KCPL  board's  unanimous
    rejection of the Western proposal, is this realistic?

    REMEMBER,  WESTERN HAS NO FIDUCIARY OBLIGATIONS  TO YOU. In fact, Western is
free to pursue its own personal and selfish agenda by any means available to it.
Your board of directors and management believe you deserve better, which is what
you will get through a strategic merger of equals with UtiliCorp.
 
    THE ELECTRIC UTILITY INDUSTRY IS FACING INTENSE COMPETITION IN A DEREGULATED
MARKET.  Prudently  managed,  forward-looking  utilities  must  adapt  to   this
fundamental  change by developing effective  long-term revenue and income growth
strategies. The combined KCPL  and UtiliCorp will be  a growth company that  can
compete  effectively in national and  global markets with a  new array of energy
products and services. The new company  will be uniquely positioned to meet  the
challenges of a deregulated marketplace for power.
 
    To us, and to your board, the choice is clear: KCPL/UtiliCorp.
 
                             YOUR VOTE IS IMPORTANT
 
    SINCE  THE KCPL/UTILICORP MERGER REQUIRES THE AFFIRMATIVE VOTE OF TWO-THIRDS
OF KCPL'S  OUTSTANDING  SHARES,  THE  VOTE OF  EVERY  SHAREHOLDER  IS  EXTREMELY
SIGNIFICANT.  A FAILURE TO VOTE IS THE SAME AS A VOTE AGAINST THE KCPL/UTILICORP
MERGER. IN  YOUR OWN  BEST INTEREST,  YOU ARE  EARNESTLY REQUESTED  TO VOTE  FOR
ADOPTION  OF THIS  MERGER BY  SIGNING, DATING  AND RETURNING  THE ENCLOSED WHITE
PROXY CARD TODAY.
 
          THANK YOU.
                                           Sincerely,
 
                                           Drue Jennings
                                           Chairman of the Board, President and
                                           Chief Executive Officer
 
  FAILURE TO APPROVE THE KCPL/UTILICORP MERGER WILL LEAVE YOU WITH NOTHING BUT
                                EMPTY PROMISES.
 
                                   IMPORTANT
 
Please make sure your latest  dated proxy is a WHITE  card voting FOR the  KCPL/
UtiliCorp  merger (proposal #1).  FAILURE TO RETURN  A PROXY WILL  HAVE THE SAME
AFFECT AS  A  VOTE  AGAINST THE  MERGER.  If  you have  any  questions  or  need
assistance  in voting your  KCPL shares, please call  D. F. King  & Co., Inc. at
(800) 714-3312 (toll-free).

                       KANSAS CITY POWER & LIGHT COMPANY
                                  1201 WALNUT
                          KANSAS CITY, MISSOURI 64106
                                 (516) 556-2200
                               ------------------
 
                           PR0XY STATEMENT SUPPLEMENT
 
                             ---------------------
 
    This  Proxy Statement Supplement  is furnished by the  Board of Directors of
Kansas City Power  & Light  Company ("KCPL")  in connection  with KCPL's  Annual
Meeting  of  Shareholders  scheduled to  be  held on  May  22, 1996  and  at any
adjournment or postponement thereof.  It amends and  supplements, and should  be
read  in  conjunction with,  the Joint  Proxy  Statement/Prospectus of  KCPL and
UtiliCorp  United  Inc.  ("UCU"),  dated   April  4,  1996  (the  "Joint   Proxy
Statement/Prospectus").  Capitalized terms used herein and not otherwise defined
herein shall have the  respective meanings assigned to  such terms in the  Joint
Proxy Statement/Prospectus.
 
       THE  BOARD OF DIRECTORS OF KCPL URGES YOU TO VOTE FOR THE PROPOSED
       MERGER WITH UTILICORP. YOUR VOTE  IS IMPORTANT. PLEASE SIGN,  DATE
       AND MAIL THE ENCLOSED WHITE PROXY CARD TODAY.
 
                   RECENT DEVELOPMENTS -- WESTERN RESOURCES'
                         HIGHLY CONDITIONAL HOSTILE BID
 
    Set forth below is a description of certain significant developments.
 
    On  April 14, 1996, Mr.  A. Drue Jennings, Chairman  of the Board, President
and Chief Executive Officer of KCPL, received a telephone call from Mr. John  E.
Hayes,  Jr.,  Chairman  of the  Board  and  Chief Executive  Officer  of Western
Resources, Inc. ("Western Resources"), in which Mr. Hayes informed Mr.  Jennings
that he was delivering to Mr. Jennings an unsolicited proposal to the KCPL Board
pursuant  to which Western  Resources would acquire all  of the outstanding KCPL
Common Stock in exchange for shares of common stock, par value $5.00 per  share,
of  Western Resources  ("Western Resources Common  Stock") valued  at $28.00 per
share of KCPL Common Stock, subject to adjustment.
 
    Following such telephone conversation,  on April 14,  1996 Mr. Jennings  and
the  members of  the KCPL  Board received from  Western Resources  a letter (the
"April 14 Letter") setting forth Western Resources' unsolicited merger proposal.
In the letter, Western Resources proposed that KCPL and Western Resources  merge
in  a transaction in which each holder of KCPL Common Stock would receive $28.00
worth of Western  Resources Common  Stock, subject  to a  "collar" limiting  the
amount of Western Resources Common Stock that holders of KCPL Common Stock would
receive  to no  more than 0.985  share and no  less than 0.833  share of Western
Resources Common  Stock for  each  share of  KCPL  Common Stock.  Shortly  after
delivery  of  the  April 14  Letter,  Western Resources  publicly  announced its
unsolicited merger proposal.
 
    On April 15,  1996, Western Resources  filed an application  with the  State
Corporation  Commission  of  the State  of  Kansas seeking  approval  of Western
Resources' proposed business combination with  KCPL and a Petition to  Intervene
in the Merger.
 
    A  meeting of  the KCPL Board  was held  on April 19  and April  21, 1996 to
consider Western Resources' proposal. At  this meeting, the KCPL Board  received
presentations  from KCPL's management  and its financial  and legal advisors. On
April 21,  the  KCPL Board,  based  upon  the presentations  given,  the  advice
received,  and the considerations  discussed at such meeting  of the KCPL Board,

determined that further exploration of the Western Resources proposal was not in
the best interests of KCPL, its  shareholders, its employees and its  customers.
Also  on such date,  the KCPL Board  reaffirmed its approval  of the Merger with
UCU.
 
    On April 22, 1996, Mr. Jennings delivered to Mr. Hayes a letter stating that
the KCPL  Board had  rejected  Western Resources'  proposal. Mr.  Jennings  also
telephoned Mr. Hayes to inform him of the decision of the KCPL Board.
 
    On  April 22, 1996, Western Resources announced that it intended to commence
an unsolicited exchange offer, and that it had filed preliminary proxy materials
for use in soliciting proxies from holders of KCPL Common Stock in opposition to
the  approval  and  adoption  of  the  Merger,  the  Merger  Agreement  and  the
transactions  contemplated thereby. On  the same day,  Western Resources filed a
registration statement on Form S-4 which included a preliminary prospectus  (the
"Western  Resources  Preliminary  Prospectus")  relating  to  Western Resources'
unsolicited offer to exchange each outstanding share of KCPL Common Stock for an
amount of  Western Resources  Common Stock.  Pursuant to  the Western  Resources
Preliminary  Prospectus, Western Resources proposes to offer, upon the terms and
subject to  the  conditions  set  forth in  the  Western  Resources  Preliminary
Prospectus  and  in a  related Letter  of  Transmittal (together,  the "Proposed
Western Resources  Offer"),  to exchange  less  than  a full  share  of  Western
Resources  Common Stock for each outstanding  share of KCPL Common Stock validly
tendered on or prior to the Expiration Date (as defined in the Western Resources
Preliminary Prospectus) of the Proposed Western Resources Offer and not properly
withdrawn. Each such share would be entitled to receive a fraction of a share of
Western Resources  Common Stock  equal to  the Exchange  Ratio, defined  as  the
quotient (rounded to the nearest 1/100,000) determined by dividing $28.00 by the
average  of the high and low sales  prices of the Western Resources Common Stock
(as reported on the NYSE Composite Transactions reporting system as published in
the Wall Street Journal or, if  not published therein, in another  authoritative
source)  on each of the  twenty consecutive trading days  ending with the second
trading day  immediately  preceding  the Expiration  Date;  provided,  that  the
Exchange Ratio shall not be less than 0.833 nor greater than 0.985.
 
    According to the Western Resources Preliminary Prospectus, Western Resources
intends,  as  soon as  practicable after  consummation  of the  Proposed Western
Resources Offer,  to  seek  to merge  KCPL  with  and into  itself  pursuant  to
applicable law (the "Proposed Western Resources Merger").
 
    The  Proposed Western Resources Offer is subject to numerous conditions. The
Proposed Western Resources Offer  is conditioned upon,  among other things,  (i)
there  being validly tendered and  not withdrawn prior to  the Expiration Date a
number of shares  of KCPL  Common Stock which  will constitute  at least  ninety
percent  of the  total number of  outstanding shares  of KCPL Common  Stock on a
fully diluted basis (as though all options or other securities convertible  into
or  exchangeable for shares had been so converted, exercised or exchanged) as of
the date the shares are accepted  for exchange by Western Resources pursuant  to
the Proposed Western Resources Offer, (ii) approval of the issuance of shares of
Western  Resources Common Stock pursuant to the Proposed Western Resources Offer
and the Proposed Western  Resources Merger and approval  of an amendment to  the
Western  Resources articles of incorporation to increase the number of shares of
Western Resources Common Stock authorized for issuance by the holders, voting as
a single class, of a  majority of the shares  of Western Resources Common  Stock
and  Western Resources preferred stock outstanding on the applicable record date
and approval of the Proposed Western Resources Merger by the holders, voting  as
a  single class, of a  majority of the Western  Resources preferred stock, (iii)
Western Resources being satisfied, in  its sole discretion, that the  provisions
of  Section 351.407 of the  MGBCL are inapplicable to  Western Resources and the
transactions contemplated by the Proposed Western Resources Offer or full voting
rights for  all shares  to be  acquired  by Western  Resources pursuant  to  the
Proposed  Western Resources  Offer having been  approved by  the shareholders of
KCPL pursuant to such  statute, (iv) Western Resources  being satisfied, in  its
sole  discretion, that the provisions  of Section 351.459 of  the MGBCL will not
prohibit for  any  period of  time  the  consummation of  the  Proposed  Western
Resources  Merger  or  any  other "Business  Combination"  (as  defined  in such
statute) involving  KCPL and  Western  Resources or  any subsidiary  of  Western
Resources, (v) the shareholders of KCPL not having approved the Merger Agreement
with  UCU, (vi)  all regulatory  approvals required  to consummate  the Proposed
Western Resources Offer and  the Proposed Western  Resources Merger having  been
obtained  and  remaining  in  full  force  and  effect,  all  statutory  waiting

periods in respect thereof  having expired and no  such approval containing  any
conditions  or  restrictions  which  the Western  Resources  board  of directors
reasonably determines in good  faith will have or  reasonably could expected  to
have  a material adverse effect on  Western Resources, KCPL and their respective
subsidiaries taken  as a  whole, (vii)  the receipt  by Western  Resources of  a
letter from its independent public accountants stating that the Proposed Western
Resources  Merger  will  qualify as  a  pooling of  interests  transaction under
generally accepted accounting principles and applicable SEC regulations,  (viii)
Western  Resources being satisfied, in its sole discretion, that it will be able
to consummate the Western Resources Merger as a "short-form" merger pursuant  to
the provisions of Section 351.447 of the MGBCL and Section 17-6703 of the Kansas
General  Corporation Code immediately after consummation of the Proposed Western
Resources Offer and (ix) all outstanding  shares of KCPL Preferred Stock  having
been redeemed.
 
    The Joint Proxy Statement/Prospectus is modified as set forth herein.
 
                  YOUR VOTE IS IMPORTANT -- PLEASE VOTE TODAY
 
    Since  the  Merger between  KCPL and  UCU requires  the affirmative  vote of
two-thirds of  KCPL's  outstanding shares,  the  vote of  every  shareholder  is
extremely important. A failure to vote has the same effect as a vote against the
Merger.  You  are earnestly  requested to  vote  FOR adoption  of the  Merger by
signing, dating and returning the enclosed  WHITE proxy card today. Even if  you
have  sold your  shares since the  April 3, 1996  record date, as  the holder of
record you are still entitled to exercise your right to vote and we urge you  to
do so.
 
                                          By Order of the Board of Directors
 
                                          [SIG]
 
                                          Jeanie Sell Latz
                                          SECRETARY
 
Dated: April 29, 1996