SECURITIES AND EXCHANGE COMMISSION

                              WASHINGTON, DC 20549

                                    FORM 8-A

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934



                                 HSB GROUP, INC.
             (Exact name of registrant as specified in its charter)

          Connecticut                             06-1475343
(State or other jurisdiction                     (IRS Employer
      of incorporation)                        Identification No.)

      One State Street, Hartford, Connecticut        06102-5024
     (Address of principal executive offices)        (Zip Code)

Registrant's telephone number, including area code - (860)722-1866

Securities to be registered pursuant to Section 12(b) of the Act:

                                               Name of each exchange
         Title of each class                   on which each class is
         to be so registered                   to be registered
         -------------------                   ----------------

         Preferred Stock Purchase              New York Stock
         Rights                                Exchange, Inc.


Securities to be registered pursuant to Section 12(g) of the Act:


                                      None
- --------------------------------------------------------------------------------
                                (Title of Class)





Item 1.  Description of Securities To Be Registered
         ------------------------------------------

     On September  21, 1998,  the Board of  Directors  of HSB Group,  Inc.  (the
"Company")  declared a dividend  distribution of one Right for each  outstanding
share of Company Common Stock to stockholders of record at the close of business
on November 28, 1998 (the "Record  Date").  Each Right  entitles the  registered
holder to purchase from the Company a unit consisting of one  two-hundredth of a
share (a "Unit") of Series A Junior  Participating  Preferred Stock, without par
value (the "Preferred  Stock"), at a Purchase Price of $162 per Unit, subject to
adjustment.  The  description  and terms of the Rights are set forth in a Rights
Agreement (the "Rights  Agreement")  between the Company and BankBoston N.A., as
Rights Agent.

     Initially,  the Rights will be attached  to all Common  Stock  certificates
representing  shares then outstanding,  and no separate Rights Certificates will
be distributed. Subject to certain exceptions specified in the Rights Agreement,
the Rights will  separate  from the Common  Stock and a  Distribution  Date will
occur upon the earlier of (i) the close of business  on the tenth  business  day
following  a public  announcement  that a  person  or  group  of  affiliated  or
associated persons (an "Acquiring  Person") has acquired,  or obtained the right
to acquire,  beneficial  ownership of 15% or more of the  outstanding  shares of
Common Stock (the "Stock  Acquisition  Date"),  or (ii) the close of business on
the  tenth  business  day (or such  later  date as the  Board  shall  determine)
following the commencement of a tender offer or exchange offer that would result
in a person or group becoming an Acquiring Person. An Acquiring Person shall not
include  Employers  Reinsurance  Corporation  ("ERC")  in  the  event  of  ERC's
conversion  of its  Convertible  Capital  Securities  into  Common  Stock of the
Company  unless  and  until it  acquires  1% or more  additional  shares  of the
outstanding  Common Stock.  Until the Distribution  Date, (i) the Rights will be
evidenced by the Common Stock certificates and will be transferred with and only
with such Common Stock  certificates,  (ii) new Common Stock certificates issued
after the Record Date will contain a notation incorporating the Rights Agreement
by reference

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and (iii) the  surrender  for  transfer  of any  certificates  for Common  Stock
outstanding will also constitute the transfer of the Rights  associated with the
Common Stock represented by such certificate.

     The Rights are not exercisable  until the Distribution Date and will expire
at 5:00 P.M.  (Boston time) on November 28, 2008 (unless  extended prior thereto
by the Board of  Directors),  or earlier if redeemed or exchanged by the Company
as described below.

     As soon as practicable  after the Distribution  Date,  Rights  Certificates
will be mailed to  holders  of  record  of the  Common  Stock as of the close of
business  on  the  Distribution  Date  and,  thereafter,   the  separate  Rights
Certificates alone will represent the Rights.  Except as otherwise determined by
the  Board of  Directors,  only  shares  of  Common  Stock  issued  prior to the
Distribution Date will be issued with Rights.

     In the event that a Person becomes an Acquiring Person,  except pursuant to
an offer for all outstanding shares of Common Stock which the Board of Directors
determines not to be inadequate and to otherwise be in the best interests of the
Company and its stockholders, after receiving advice from one or more investment
banking firms (a "Qualified Offer"), each holder of a Right will thereafter have
the right to receive, upon exercise, Common Stock (or, in certain circumstances,
cash,  property or other  securities of the Company) having a value equal to two
times the exercise price of the Right.  The Exercise Price is the Purchase Price
times  the  number  of  shares of  Common  Stock  associated  with  each  Right.
Notwithstanding any of the foregoing,  following the occurrence of the event set
forth in this  paragraph,  all Rights that are, or (under certain  circumstances
specified in the Rights  Agreement)  were,  beneficially  owned by any Acquiring
Person will be null and void. However,  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.

                                       3


     For example,  at an exercise price of $162 per Right,  each Right not owned
by an Acquiring  Person (or by certain related  parties)  following an event set
forth in the preceding paragraph would entitle its holder to purchase $324 worth
of Common Stock (or other consideration, as noted above) for $162. Assuming that
the Common  Stock had a per share value of $40 at such time,  the holder of each
valid Right would be entitled to purchase 8.1 shares of Common Stock for $162.

     In the event that, at any time  following the Stock  Acquisition  Date, (i)
the Company  engages in a merger or other  business  combination  transaction in
which the Company is not the  surviving  corporation  (other than with an entity
which  acquired  the shares  pursuant  to a Qualified  Offer),  (ii) the Company
engages  in a merger  or other  business  combination  transaction  in which the
Company is the  surviving  corporation  and the Common  Stock of the  Company is
changed or exchanged, or (iii) 50% or more of the Company's assets, cash flow or
earning  power is sold or  transferred,  each holder of a Right  (except  Rights
which have previously been voided as set forth above) shall  thereafter have the
right to receive, upon exercise,  common stock of the acquiring company having a
value equal to two times the exercise  price of the Right.  The events set forth
in this paragraph and in the second  preceding  paragraph are referred to as the
"Triggering Events."

     At any time  after a person  becomes an  Acquiring  Person and prior to the
acquisition  by such  person  or  group of  fifty  percent  (50%) or more of the
outstanding  Common Stock,  the Board 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  two-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).

     The Purchase Price payable,  and the number of Units of Preferred  Stock or
other securities or property  issuable,  upon exercise of the Rights are subject
to 

                                       4


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) if holders of the  Preferred  Stock are granted  certain  rights or
warrants to subscribe for Preferred Stock or convertible securities 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  or assets
(excluding  regular  quarterly  cash  dividends)  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  amount to at least 1% of the  Purchase
Price. No fractional Units will be issued and, in lieu thereof, an adjustment in
cash will be made based on the market price of the  Preferred  Stock on the last
trading date prior to the date of exercise.

     At any time until the close of business on the tenth business day following
the Stock  Acquisition Date, the Company may redeem the Rights in whole, but not
in part,  at a price of $.01 per Right  (payable in cash,  Common Stock or other
consideration  deemed  appropriate by the Board of Directors).  Immediately upon
the action of the Board of  Directors  ordering  redemption  of the Rights,  the
Rights  will  terminate  and the only right of the  holders of Rights will be to
receive the $.01 redemption  price.  The foregoing  notwithstanding,  the Rights
generally  may not be redeemed  for one hundred  eighty  (180) days  following a
change in a majority of the Board of Directors as a result of a proxy contest.

     Until a Right is  exercised,  the  holder  thereof,  as such,  will have no
rights as a stockholder 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 stockholders or to the Company,  stockholders may,  depending upon
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 

                                       5


acquiring  company or in the event of the  redemption of the Rights as set forth
above.

     Any of the  provisions of the Rights  Agreement may be amended by the Board
of  Directors  of  the  Company  prior  to  the  Distribution  Date.  After  the
Distribution  Date, the provisions of the Rights Agreement may be amended by the
Board in order to cure any  ambiguity,  to make changes  which do not  adversely
affect the  interests  of holders of Rights,  or to shorten or lengthen any time
period under the Rights Agreement;  provided,  however, that no amendment may be
                                    --------   -------
made at such time as the Rights are not redeemable.

     As of November 28, 1998,  there were  28,968,129  shares of Common Stock of
the  Company  outstanding  and  921,428  shares of  Common  Stock  reserved  for
issuance.  Each share of Common Stock of the Company outstanding at the Close of
Business on  November  28, 1998  received  one Right.  So long as the Rights are
attached  to the  Common  Stock,  one  additional  Right (as such  number may be
adjusted  pursuant to the provisions of the Rights Agreement) shall be deemed to
be delivered for each share of Common Stock issued or transferred by the Company
in the future.  In addition,  following the  Distribution  Date and prior to the
expiration  or  redemption  of the Rights,  the Company may issue Rights when it
issues  Common Stock only if the Board deems it to be necessary or  appropriate,
or in  connection  with the issuance of shares of Common  Stock  pursuant to the
exercise  of stock  options  or  under  employee  plans  or upon  the  exercise,
conversion or exchange of certain  securities of the Company.  There are 250,000
shares of Preferred Stock  initially  reserved for issuance upon exercise of the
Rights.

     The Rights may have certain  anti-takeover  effects.  The Rights will cause
substantial  dilution to a person or group that  attempts to acquire the Company
in a manner which causes the Rights to become  discount  Rights unless the offer
is conditional  on a substantial  number of Rights being  acquired.  The Rights,
however, should not affect any prospective offeror willing to make an offer at a
fair  price  and  otherwise  in the  best  interests  of  the  Company  and  its
stockholders as determined by a 

                                       6


majority of the  Directors  who are not  affiliated  with the person  making the
offer,  or willing to negotiate with the Board.  The Rights should not interfere
with any merger or other  business  combination  approved by the Board since the
Board may, at its option,  at any time until ten  business  days  following  the
Stock  Acquisition Date redeem all but not less than all of the then outstanding
Rights at the Redemption Price.

     The Rights  Agreement,  dated as of November 28, 1998,  between the Company
and  BankBoston,  N.A., as Rights Agent,  specifying  the terms of the Rights is
attached  hereto as an exhibit  and is  incorporated  herein by  reference.  The
foregoing description of the Rights is qualified in its entirety by reference to
such exhibit.  A  Certificate  of  Incorporation  setting forth the terms of the
Preferred  Stock  was  filed  with  the  Secretary  of  State  of the  State  of
Connecticut on June 13, 1997.


Item 2.  Exhibits.
         --------

Exhibit     Description                                               Page
- -------     -----------                                               ----
  1         Rights  Agreement,  dated as of November  28, 1998 
            between HSB Group, Inc. and BankBoston,  N.A., as 
            Rights Agent,  including the form of Rights 
            Certificate  as Exhibit A. Pursuant to the Rights 
            Agreement,  printed  Rights  Certificates  will not
            be mailed  until  after  the  Distribution  Date 
            (as such term is defined in the Rights  Agreement).
            (Incorporated by reference to  Exhibit  No.4 to 
            the  Current  Report  on Form  8-K of HSB
            Group, Inc., dated December 2, 1998)




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                                    SIGNATURE


     Pursuant to the  requirements of Section 12 of the Securities  Exchange Act
of 1934, the Registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, hereunto duly authorized.


Dated:  December 8, 1998             HSB GROUP, INC.


                                     By:    /s/ R. Kevin Price 
                                     Name:  R. Kevin Price
                                     Title: Senior Vice President & Corporate 
                                            Secretary
                                 



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