SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


                         March 30, 1999 (March 30, 1999)
                Date of report (Date of earliest event reported)


                             MARKETSPAN CORPORATION
             (Exact name of registrant as specified in its charter)



         New York                   1-14161                  11-3431358
(State or other jurisdiction      (Commission            (I.R.S. Employer
      of incorporation)            File Number)          Identification No.)


    175 East Old Country Road
         Hicksville, New York                                11801

      One MetroTech Center
        Brooklyn, New York                                   11201
(Address of principal executive offices)                  (Zip code)


Registrant's telephone number, including area code:  (516) 755-6650 (Hicksville)
                                                     (718) 403-1000 (Brooklyn)




Item 5.  Other Events

              Rights  Agreement.  On March 30,  1999,  the Board of Directors of
MarketSpan  Corporation,  doing  business  as KeySpan  Energy  (the  "Company"),
declared  a dividend  distribution  of one Right for each  outstanding  share of
common stock,  par value $.01 per share,  of the Company (the "Common Stock") to
shareholders  of record at the close of business on April 14, 1999 (the  "Record
Date").  Each Right entitles the registered  holder to purchase from the Company
one  one-hundredth  of a share of a series of cumulative  preferred stock of the
Company designated Series D Preferred Stock (the "Preferred  Stock"), at a price
of $95.00 (the "Purchase  Price"),  subject to adjustment.  The  description and
terms of the Rights are set forth in a Rights Agreement (the "Rights Agreement")
by and  between  the  Company  and The Bank of New York,  as Rights  Agent  (the
"Rights Agent"),  which is filed as Exhibit 4 hereto and is incorporated  herein
by reference.

              Until the Distribution  Date (or earlier  redemption or expiration
of the  Rights),  which is defined  below,  the Rights will be  evidenced,  with
respect  to  any of the  Common  Stock  certificates  outstanding  prior  to the
Distribution  Date, by such Common Stock  certificates.  Until the  Distribution
Date, (or earlier  redemption or expiration of the Rights),  (i) the Rights will
be  transferred  with and only with the  Common  Stock,  (ii) new  Common  Stock
certificates  issued  after the Record Date upon  transfer,  replacement  or new
issuance  of Common  Stock  will be deemed to be  issued  with  Rights  and will
contain a notation incorporating the Rights Agreement by reference and (iii) the
surrender for transfer of any  certificate for Common Stock will also constitute
the transfer of the Rights  associated with the Common Stock represented by such
certificate.

              As soon as practicable  following the Distribution Date,  separate
certificates  evidencing the Rights  ("Rights  Certificates")  will be mailed to
holders  of  record  of the  Common  Stock as of the  close of  business  on the
Distribution  Date. From and after the  Distribution  Date, such separate Rights
Certificates alone will evidence the Rights.  Except as otherwise  determined by
the Board of Directors,  and except in connection  with the exercise of employee
stock  options,  any other  issuance  of Common  Stock  with  respect  to awards
outstanding  under employee benefit plans  outstanding on the Distribution  Date
and in connection  with the  conversion of convertible  securities  issued after
March 30, 1999, only Common Stock issued prior to the Distribution  Date will be
issued with Rights.

              "Distribution  Date"  shall  mean the  earlier  to occur of (i) 10
business  days  following  the  date of a  public  announcement  that a  person,
together with persons affiliated or associated with it, has acquired  beneficial
ownership  of 20% or more of the  outstanding  Common  Stock or (ii) 10 business
days  following  the  earlier  of  the  commencement  of,  or the  first  public
announcement  of the intent to commence,  a tender offer or exchange  offer by a
person other than the Company if, upon  consummation of the offer,  such person,
together with persons  affiliated or associated with it, would be the beneficial
owner  of 20% or  more of the  outstanding  Common  Stock.  The  Rights  are not
exercisable until the Distribution  Date. The Rights will expire at the close of
business  on March 30,  2009  (the  "Final  Expiration  Date"),  unless  earlier
redeemed or exchanged by the Company as described below.

                                      



              The Purchase Price payable and the number of and kind of shares of
Preferred  Stock or other  securities or property  issuable upon exercise of the
Rights are subject to  adjustment  from time to time to prevent  dilution (i) in
the  event  of  a  stock   dividend  on,  or  a   subdivision,   combination  or
reclassification  of, the Preferred Stock, (ii) upon the grant to holders of the
Preferred  Stock of  certain  rights,  options  or  warrants  to  subscribe  for
Preferred Stock (or shares having the same rights, privileges and preferences as
the shares of  Preferred  Stock) at less than the  current  market  price of the
Preferred Stock or (iii) upon the distribution to holders of the Preferred Stock
of evidences of  indebtedness,  securities,  cash or assets  (excluding  regular
periodic  dividends  out of earnings or retained  earnings)  or of  subscription
rights  or  warrants  (other  than  those  referred  to  above).   With  certain
exceptions,  no  adjustment  in  the  Purchase  Price  will  be  required  until
cumulative  adjustments  require an  adjustment  of at least 1% in the  Purchase
Price. No fractional  shares of Preferred Stock will be issued upon the exercise
of any Right or Rights (other than fractions which are integral multiples of one
one-hundredth of a share of Preferred Stock),  and in lieu thereof an adjustment
in cash will be made based on the current market price of the Preferred Stock on
the last trading day prior to the date of exercise.

               Any of the events  described in the succeeding  second and fourth
paragraphs are defined as a "Triggering Event."

              "Acquiring  Person"  shall  mean any  person  who  constitutes  an
"Interested  Shareholder"  as defined in  Section  912 of the New York  Business
Corporation Law, in effect from time to time,  (generally defined to include any
person who or which, together with all persons affiliated or associated with it,
shall be the beneficial  owner of 20% or more of the shares of Common Stock then
outstanding),  but shall not include the Company, any subsidiary of the Company,
any employee benefit plan of the Company or of any subsidiary of the Company, or
any person or entity  organized,  appointed  or  established  by the  Company or
pursuant to the terms of any such plan.

              In the event that a person,  together  with persons  affiliated or
associated  with  it,  becomes  an  Acquiring  Person  (except  as a  result  of
repurchases  of  stock  by  the  Company  or  certain   inadvertent  actions  by
institutional or certain other shareholders),  proper provision shall be made so
that each holder of a Right, except as provided below, shall thereafter have the
right  to  receive,  upon  exercise  thereof,   Common  Stock  (or,  in  certain
circumstances  as determined by the Company,  other  securities,  cash, or other
property) having a value of two times the Purchase Price. Notwithstanding any of
the  foregoing,  following  the  occurrence  of the  event  set  forth  in  this
paragraph, all Rights that are, or (under certain circumstances set forth in the
Rights  Agreement)  were,  beneficially  owned by any  Acquiring  Person  (or by
certain related parties and transferees)  will be null and void.  Rights are not
exercisable  following  the  occurrence  of the event set forth above until such
time as the Rights are no longer redeemable by the Company, as set forth below.

              For example,  at an exercise price of $95.00 per Right, each Right
not owned by an Acquiring Person (or by certain related parties and transferees)
following an event set forth in the preceding paragraph would entitle its holder
to purchase  $190.00  worth of Common  Stock (or other  consideration,  as noted
above)  for  $95.00.  Assuming  that the Common  Stock had a per share  value of
$47.50 at such  time,  the  holder of each  valid  Right  would be  entitled  to
purchase 4 shares of Common Stock for $95.00.

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              In the event that,  at any time  following  the Stock  Acquisition
Date,  which is defined below,  (i) the Company is acquired in a merger or other
business  combination  transaction  in which the  Company  is not the  surviving
corporation  (other than a merger which follows an offer described in the second
preceding  paragraph),  or (ii)  fifty  percent  (50%) or more of the  Company's
assets,  cash flow or earning  power is sold or  transferred,  proper  provision
shall be made so that each holder of a Right (other than Rights that theretofore
become  null and void as  described  in the second  preceding  paragraph)  shall
thereafter have the right to receive, upon exercise thereof, common stock of the
acquiring  company  having a value equal to two times the exercise  price of the
Right.

              At any time until the close of business on the tenth  business day
following  the  date of a  public  announcement  that a  person  has  become  an
Acquiring Person (the "Stock Acquisition Date"), the Company may redeem all, but
not less than all, the then outstanding Rights at a redemption price of $.01 per
Right  (the  "Redemption  Price").  Immediately  upon the action of the Board of
Directors  of the Company  ordering  redemption  of the Rights,  the Rights will
terminate  and the only  right of the holder of Rights  will be to  receive  the
Redemption Price.

              At any  time  after  the  acquisition  by a  person  or  group  of
affiliated or associated  persons of beneficial  ownership of 20% or more of the
outstanding  shares of Common Stock and prior to the  acquisition by such person
or group of 50% or more of the outstanding  shares of Common Stock, the Board of
Directors  may  exchange  the Rights  (other than Rights owned by such person or
group which have become void),  in whole or in part, at an exchange ratio of one
share of Common Stock, or one one-hundredth of a share of Preferred Stock (or of
a share of a class or series of the Company's  preferred stock having equivalent
rights, preferences and privileges), per Right (subject to adjustment).

              Any of the  provisions  of the Rights  Agreement may be amended by
the  Board  of  Directors  of  the  Company  prior  to  the  Distribution  Date.
Thereafter,  the provisions of the Rights  Agreement may be amended by the Board
of Directors of the Company in order to (i) cure any ambiguity,  (ii) shorten or
lengthen any time period under the Rights Agreement,  or (iii) make changes that
will not adversely affect the interests of the holders of Rights;  provided such
lengthening is for the purpose of protecting, enhancing or clarifying the rights
of, and/or the benefits to, the holders of Rights, and further;  provided,  that
no amendment may be made at such time as the Rights are not redeemable.

              Until a Right is exercised, the holder thereof, as such, will have
no rights as a shareholder of the Company,  including,  without limitation,  the
right to vote or to receive dividends. While the distribution of the Rights will
not be taxable to shareholders or to the Company, shareholders may, depending on
the circumstances,  recognize taxable income in the event that the Rights become
exercisable  for Common  Stock (or other  consideration)  of the  Company or for
common stock of the acquiring company as set forth above.

              The Rights have  certain  anti-takeover  effects.  The Rights will
cause  substantial  dilution  to a person or group that  attempts to acquire the
Company  without  conditioning  the offer on  redemption  of the  Rights or on a
substantial  number of Rights being  acquired.  The Rights  should not interfere
with any merger or other business combination approved by the Board of Directors
of the  Company  prior  to the time  that the  Rights  may not be  redeemed  (as
described  above) since the Board of Directors  may, at its option,  at any time

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until such date redeem all but not less than all of the then outstanding Rights.
The Rights  are  designed  to  provide  additional  protection  against  abusive
takeover tactics such as offers for all shares at less than full value,  partial
tender offers and selective  open-market  purchases.  The Rights are intended to
assure  that the  Company's  Board  of  Directors  has the  ability  to  protect
stockholders  and the Company if efforts are made to gain control of the Company
in a  manner  that  is  not  in the  best  interests  of  the  Company  and  its
stockholders.

              The  foregoing  description  of the Rights  does not purport to be
complete and is qualified in its entirety by reference to the Rights Agreement.

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Item 7. Financial Statements, Pro Forma Financial Information and Exhibits

(c)   Exhibits

              (i)          Rights  Agreement,  dated  March  30,  1999,  by  and
                           between  MarketSpan  Corporation,  doing  business as
                           KeySpan  Energy,  and The Bank of New York, as Rights
                           Agent.  The Rights  Agreement  includes  as Exhibit A
                           thereto  the   Certificate   of   Amendment   to  the
                           Certificate  of   Incorporation   for  the  Series  D
                           Preferred  Stock,  as  Exhibit B thereto  the Form of
                           Rights  Certificate  and as  Exhibit  C  thereto  the
                           Summary  of Rights  to  Purchase  Series D  Preferred
                           Stock.

              (ii)         Press Release, dated March 30, 1999.


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                                   SIGNATURE

               Pursuant to the  requirements  of the Securities  Exchange Act of
1934,  the  registrant has duly caused this report to be signed on its behalf by
the undersigned, thereunto duly authorized.

                                   MARKETSPAN CORPORATION



Dated:  March 30, 1999             By: /s/ Craig G. Matthews
                                       ---------------------
                                       Craig G. Matthews
                                       President and Chief Operating Officer


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                               INDEX TO EXHIBITS


   Exhibit
     No.                                    Description
- -------------        -----------------------------------------------------------

      4              Rights  Agreement,  dated  March 30,  1999,  by and between
                     MarketSpan  Corporation,  doing business as KeySpan Energy,
                     and The Bank of New  York,  as  Rights  Agent.  The  Rights
                     Agreement  includes as Exhibit A thereto the Certificate of
                     Amendment  to the  Certificate  of  Incorporation  for  the
                     Series D Preferred  Stock, as Exhibit B thereto the Form of
                     Rights  Certificate and as Exhibit C thereto the Summary of
                     Rights to Purchase Series D Preferred Stock.


      99             Press Release, dated March 30, 1999.





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