Exhibit 4.8

                           REGISTRATION RIGHTS AGREEMENT

                  REGISTRATION  RIGHTS  AGREEMENT dated as of December 31, 1997,
between Employers Reinsurance  Corporation and ERC Life Reinsurance  Corporation
(collectively, "ERC") and HSB Group, Inc. (the "Company").

                  WHEREAS,  as of the date of this  Agreement,  ERC owns 300,000
capital  securities  (the "Capital  Securities")  of HSB Capital II, a statutory
business  trust created  under the laws of the State of Delaware,  which Capital
Securities are  convertible  into shares of Common Stock of the Company,  no par
value per share (the "Common Stock"),  pursuant to the Trust Agreement among HSB
Group, Inc. as Depositor, The First National Bank of Chicago as Property Trustee
and First Chicago  Delaware Inc. as Delaware  Trustee,  dated  December 31, 1997
(the "Trust Agreement");

                  WHEREAS,  the Board of Directors of the Company has authorized
the  officers of the Company to execute and deliver  this  Agreement in the name
and on behalf of the Company;

                  NOW,  THEREFORE,  in consideration of the mutual covenants and
agreements  herein  contained,  the parties to this  Agreement  hereby  agree as
follows:

                  1.       Definitions.  As used in this Agreement,
the following terms shall have the following meanings:

                  "Holder" means ERC and any other person that owns  Registrable
Securities,  including  their  respective  successors  and  assigns  who acquire
Registrable Securities,  directly or indirectly,  from ERC or such other person.
For purposes of this  Agreement,  the Company may deem and treat the  registered
holder of a Registrable  Security as the Holder and absolute owner thereof,  and
the Company shall not be affected by any notice to the contrary.

                  "Registrable  Securities"  means (a) the Common Stock owned by
ERC upon conversion of the Capital  Securities  pursuant to the Trust Agreement,
(b) any Common  Stock  acquired  by ERC in the open market at a time when ERC is
deemed to be an  Affiliate  (as such term is  defined  under  Rule 144 under the
Securities Act) of the Company,







and (c) any  securities  issued or  issuable  in  respect  of the  Common  Stock
referred  to in clauses  (a) and (b) above,  by way of stock  dividend  or stock
split  or  in  connection  with  a  combination  of  shares,   recapitalization,
reclassification,  merger  or  consolidation,  and any other  securities  issued
pursuant to any other pro rata  distribution  with respect to such Common Stock.
For  purposes  of  this  Agreement,  a  Registrable  Security  ceases  to  be  a
Registrable  Security  when (x) it has been  effectively  registered  under  the
Securities  Act and sold or  distributed  to the  public in  accordance  with an
effective registration statement covering it (and has not been reacquired in the
manner  described in clause (b) above),  or (y) it is sold or distributed to the
public  pursuant to Rule 144 (or any successor or similar  provision)  under the
Securities Act.

                  "SEC" means the Securities and Exchange Commission.

                  "Securities  Act" means the Securities Act of 1933, as amended
from time to time.

                  2. Demand Registration. (a) If at any time Holders that in the
aggregate  beneficially  own a  majority  of  the  Registrable  Securities  then
outstanding  (the  "Majority")  shall request the Company in writing to register
under the Securities  Act all or a part of the  Registrable  Securities  held by
such Holders (a "Demand  Registration"),  the Company  shall use all  reasonable
efforts to cause to be filed (but in no event later than the 45th day after such
Holders'  request  is  made)  and  declared  effective  as  soon  as  reasonably
practicable  thereafter,  a registration  statement, on such appropriate form as
the Company in its  discretion  shall  determine,  providing for the sale of all
such Registrable  Securities held by the Majority. The Company agrees to use its
best efforts to keep any such registration  statement continuously effective and
usable for resale of  Registrable  Securities for a period of 180 days following
the  effective  date  of such  registration  statement.  The  Company  shall  be
obligated  to file two  registration  statements  pursuant to this  Section 2(a)
covering such Registrable Securities. Each registration statement filed pursuant
to this  Section  2(a) is  hereinafter  referred  to as a  "Demand  Registration
Statement."



                                                  2





                  (b) The Company agrees (i) not to effect any public or private
sale, distribution or purchase of any of its securities which are the same as or
similar to the Registrable Securities, including a sale pursuant to Regulation D
under the  Securities  Act but  excluding  a private  sale in the  context of an
acquisition  and any purchases of Common Stock related to the issuance of Common
Stock or rights  under any of the  Company's  benefit  plans for its  directors,
officers or employees or the Company's  dividend  reinvestment  plan, during the
15-day period prior to, and during the 45-day  period  beginning on, the closing
date of each underwritten offering under any Demand Registration Statement,  and
(ii) to use  reasonable  best  efforts  to cause each  holder of its  securities
purchased  from the Company,  at any time on or after the date of this Agreement
(other than in a registered  public  offering) to agree not to effect any public
sale or distribution of any such  securities  during such period,  excluding any
sales by directors or officers pursuant to Rule 144 under the Securities Act.

                  (c) The Company may postpone for a reasonable  period of time,
not  to  exceed  60  days,  the  filing  or  the  effectiveness  of  any  Demand
Registration  Statement  if the Board of  Directors of the Company in good faith
determines that (A) such  registration  might have a material  adverse effect on
any plan or proposal by the Company with respect to any financing,  acquisition,
recapitalization,  reorganization  or  other  material  transaction,  or (B) the
Company is in possession of material  non-public  information  that, if publicly
disclosed,   could  result  in  a  material  disruption  of  a  major  corporate
development  or  transaction  then  pending or in progress or in other  material
adverse consequences to the Company.

                  (d) If at any time the  Majority  desires to sell  Registrable
Securities  in an  underwritten  offering,  such Holders shall have the right to
select any nationally  recognized  investment  banking firm(s) to administer the
offering,  subject to the approval of the Company,  which  approval shall not be
unreasonably withheld, and the Company shall enter into underwriting  agreements
with the  underwriter(s)  of such offering,  which agreements shall contain such
representations and warranties by the Company, and such other terms,  conditions
and  indemnities  as are at  the  time  customarily  contained  in  underwriting
agreements for similar offerings.


                                                  3






                  3.  Incidental  Registration.  Subject to the other  terms and
conditions  set forth in this Section 3, if the Company  proposes at any time to
register any shares of Common Stock (the "Initially  Proposed Shares") under the
Securities  Act for sale,  whether or not for its own  account,  pursuant  to an
underwritten  offering,  the Company will  promptly  give written  notice to the
Holders of its  intention to effect such  registration  (such notice to specify,
among  other  things,  the  proposed  offering  price,  the kind and  number  of
securities  proposed  to  be  registered  and  the  distribution   arrangements,
including  identification  of the  underwriter(s)),  and the  Holders  shall  be
entitled  to  include  in  such  registration  statements,  as a  part  of  such
underwritten  offering,  such number of shares (the "Holder Shares") to be
sold for the  account of the Holders  (on the same terms and  conditions  as the
Initially  Proposed  Shares)  as shall be  specified  in a  request  in  writing
delivered  to the  Company  within 15 days after the date upon which the Company
gave the aforementioned notice.

                  The Company's  obligations to include Holder Shares in a
registration  statement  pursuant  to this  Section 3 is  subject to each of the
following limitations, conditions and qualifications:

                           (i) If, at any time after  giving  written  notice of
         its intention to effect a  registration  of any of its shares of Common
         Stock and prior to the  effective  date of any  registration  statement
         filed in connection with such registration, the Company shall determine
         for any reason not to register all of such shares,  the Company may, at
         its election,  give written notice of such determination to the Holders
         and thereupon it shall be relieved of its obligation to use any efforts
         to  register  any  Holder  Shares  in  connection   with  such  aborted
         registration.

                           (ii)   If,   in   the   opinion   of   the   managing
         underwriter(s) of such offering, the distribution of all or a specified
         portion  of the  Holder  Shares  would  materially  interfere  with the
         registration  and sale, in accordance with the intended method thereof,
         of the Initially  Proposed Shares,  then the number of Holder Shares to
         be included  in such  registration  statement  shall be reduced to such
         number, if any, that, in the opinion of such manag-


                                                  4





         ing  underwriter(s),  can be included  without such  interference.  The
         shares of Common Stock to be included  therein shall be  apportioned as
         follows:  (i) first,  the Company and any holders of  securities of the
         Company  (other than the Holders)  exercising  any demand  registration
         right  granted to such holders shall be entitled to register all shares
         of Common Stock that the Company or such other holders  propose to sell
         for their own account, in such proportion as they shall agree upon; and
         (ii) second,  the Holders shall be entitled to register,  on a pro rata
         basis  (based on the number of shares of Common  Stock  proposed  to be
         registered by each),  up to that number of Registrable  Securities that
         is equal to the  remaining  number of shares of Common  Stock  that the
         managing underwriter(s) will permit to be registered in connection with
         such  offering.  If,  as a  result  of the  cutback  provisions  of the
         preceding sentences, the Holders are not entitled to include all of the
         Holder Shares in such registration,  such Holders may elect to withdraw
         their  request  to  include  Holder  Shares  in  such  registration  (a
         "Withdrawal Election").

                  If the Company shall so request in writing, each Holder agrees
not to effect any  public or private  sale or  distribution  of any  Registrable
Securities  (other than the Holder Shares) during the 15-day period prior to and
during the 45-day  period  beginning  on, the closing  date of any  underwritten
public  offering  of shares of Common  Stock  made for the  Company's own
account.

                  4.  Registration  Procedures.  (a)  Whenever  the  Company  is
required  to use all  reasonable  efforts  to  effect  the  registration  of any
Registrable  Securities  under  the  Securities  Act  pursuant  to the terms and
conditions of Section 2(a) or 3 (such  Registrable  Securities being hereinafter
referred to as "Subject Shares"), the Company will use all reasonable efforts to
effect the  registration  and sale of the Subject Shares in accordance  with the
intended method of disposition  thereof.  Without limiting the generality of the
foregoing, the Company will as soon as practicable:

                           (i) prepare and file with the Securities and Exchange
         Commission  (the "SEC") a  registration  statement  with respect to the
         Subject Shares in form


                                                  5





         and substance  satisfactory to the Holders of the Subject  Shares,  and
         use all  reasonable  efforts to cause such  registration  statement  to
         become effective as soon as possible;

                           (ii)  prepare  and file with the SEC such  amendments
         and supplements to such registration  statement and the prospectus used
         in connection  therewith as may be necessary to keep such  registration
         statement  effective for the  applicable  period and to comply with the
         provisions of the Securities Act with respect to the disposition of all
         Subject  Shares  and  other  securities  covered  by such  registration
         statement;

                           (iii)   furnish   the   Holders   covered   by   such
         registration statement, without charge, such number of conformed copies
         of  such  registration   statement  and  of  each  such  amendment  and
         supplement  thereto (in each case including all exhibits),  such number
         of copies of the  prospectus  included in such  registration  statement
         (including each preliminary prospectus), such documents incorporated by
         reference in such registration statement or prospectus,  and such other
         documents, as such Holders may reasonably request;

                           (iv)  use  all  reasonable  efforts  to  register  or
         qualify the Subject Shares covered by such registration statement under
         the securities or blue sky laws of such  jurisdictions  as the managing
         underwriter(s) shall reasonably recommend, which jurisdictions shall be
         limited to jurisdictions  within the United States,  and do any and all
         other acts and things which may be reasonably necessary or advisable to
         enable the Holders to consummate the disposition in such  jurisdictions
         of the Subject Shares covered by such  registration  statement,  except
         that the  Company  shall not for any such  purpose be  required  to (A)
         qualify  generally  to do  business  as a  foreign  corporation  in any
         jurisdiction  wherein it is not so  qualified,  (B)  subject  itself to
         taxation  in any  jurisdiction  wherein  it is not so  subject,  or (C)
         consent to general  service  of  process  in any such  jurisdiction  or
         otherwise take any action that would subject it to the general


                                                  6





         jurisdiction of the courts of any jurisdiction in
         which it is not so subject;

                           (v) otherwise use its best efforts to comply with all
         applicable rules and regulations of the SEC;

                           (vi)  furnish,   at  the  Company's  expense,
         unlegended certificates  representing ownership of the securities being
         sold in such  denominations  as shall be  requested  and  instruct  the
         transfer agent to release any stop transfer  orders with respect to the
         Subject Shares being sold;

                           (vii)   notify   each  Holder  at  any  time  when  a
         prospectus  relating to the Subject  Shares is required to be delivered
         under the  Securities  Act of the happening of any event as a result of
         which the prospectus  included in such Registration  Statement contains
         any untrue  statement  of a material  fact or omits to state a material
         fact  necessary  to make  the  statements  therein  (in the case of the
         prospectus or any preliminary prospectus, in light of the circumstances
         under which they were made) not  misleading,  and the Company  will, as
         promptly as practicable  thereafter,  prepare and file with the SEC and
         furnish a  supplement  or  amendment  to such  prospectus  so that,  as
         thereafter   delivered  to  the   purchasers  of  Subject  Shares  such
         prospectus will not contain any untrue  statement of a material fact or
         omit to  state  a  material  fact  required  to be  stated  therein  or
         necessary to make the statements therein not misleading;

                           (viii) enter into customary agreements  (including an
         underwriting agreement in customary form in the case of an underwritten
         offering) and make such  representations  and warranties to the sellers
         and  underwriter(s)  as in form and substance and scope are customarily
         made by issuers to underwriters in underwritten offerings and take such
         other actions as the Holders or the managing  underwriter(s)  or agent,
         if any,  reasonably  require in order to  expedite  or  facilitate  the
         disposition of such Subject Shares;



                                                  7





                           (ix) make  available  for  inspection by the Holders,
         any underwriter or agent  participating in any disposition  pursuant to
         such  Registration  Statement,  and any  attorney,  accountant or other
         similar   professional   advisor   retained  by  any  such  holders  or
         underwriter   (collectively  the  "Inspectors"),  all  pertinent
         financial  and  other  records,   pertinent   corporate  documents  and
         properties of the Company (collectively, the "Records"), as shall
         be reasonably  necessary to enable them to exercise their due diligence
         responsibility,  and cause the Company's officers,  directors and
         employees to supply all  information  reasonably  requested by any such
         Inspector in connection with such Registration  Statement.  The Holders
         agree that Records and other information which the Company  determines,
         in good  faith,  to be  confidential  and of  which  determination  the
         Inspectors  are so notified  shall not be disclosed  by the  Inspectors
         unless (i) the  disclosure  of such  Records is  necessary  to avoid or
         correct a misstatement or omission in the Registration Statement,  (ii)
         the release of such  Records is ordered  pursuant to a subpoena,  court
         order or regulatory or agency request or (iii) the  information in such
         Records has been  generally  disseminated  to the  public.  Each Holder
         agrees that it will,  upon learning  that  disclosure of such Record is
         sought  in a  court  of  competent  jurisdiction  or by a  governmental
         agency,  give  notice to the  Company  and allow  the  Company,  at the
         Company's expense,  to undertake  appropriate  action to prevent
         disclosure of the Records deemed confidential;

                           (x) in the case of an underwritten  offering,  obtain
         for delivery to the Company,  the  underwriter(s)  or their agent, with
         copies  to  the  Holders,  a  "cold  comfort"  letter  from  the
         Company's  independent  public  accountants in customary form and
         covering  such  matters  of  the  type  customarily  covered  by  "cold
         comfort" letters as the Holders or the  managing  underwriter(s)
         reasonably request;

                           (xi) in the case of an underwritten offering,  obtain
         for  delivery to the Holders and the  underwriter(s)  or their agent an
         opinion or opinions from counsel for the Company in customary form and


                                                  8





         reasonably satisfactory to the Holder, underwriters
         or agents and their counsel;

                           (xii) make available to its security holders earnings
         statements,  which need not be audited,  satisfying  the  provisions of
         Section 11(a) of the Securities Act no later than 90 days after the end
         of the 12-month period beginning with the first month of the Company's
         first  quarter   commencing  after  the  effective  date  of  the
         Registration  Statement,  which  earnings  statements  shall cover said
         12-month period;

                           (xiii)  make every  reasonable  effort to prevent the
         issuance  of  any  stop  order  suspending  the  effectiveness  of  the
         registration  statement or of any order  preventing or  suspending  the
         effectiveness   of  such   registration   statement   at  the  earliest
         practicable moment;

                           (xiv) cause the Subject Shares to be registered  with
         or approved by such other  governmental  agencies or authorities within
         the United States as may be necessary to enable the sellers  thereof or
         the  underwriters(s),  if any, to consummate  the  disposition  of such
         Subject Shares;

                           (xv)  cooperate  with the  Holders  and the  managing
         underwriter(s),  if any, or any other  interested  party (including any
         interested  broker-dealer) in making any filings or submission required
         to be  made,  and the  furnishing  of all  appropriate  information  in
         connection  therewith,  with the  National  Association  of  Securities
         Dealers, Inc. ("NASD");

                           (xvi)  cause  its  significant  subsidiaries  to take
         action  necessary  to effect the  registration  of the  Subject  Shares
         contemplated   hereby,   including   filing  any   required   financial
         information;

                           (xvii)  effect the listing of the  Subject  Shares on
         the New York Stock Exchange or such other national  securities exchange
         or  over-the-counter  market on which  shares of the Common Stock shall
         then be listed; and



                                                  9





                           (xviii) take all other steps  necessary to effect the
         registration of the Subject Shares contemplated hereby.

                           (b)  The Holders shall provide (in writing
and signed by the Holders and stated to be  specifically  for use in the related
registration  statement,  preliminary  prospectus,  prospectus or other document
incident thereto) all such information and materials and take all such action as
may be required  in order to permit the  Company to comply  with all  applicable
requirements of the SEC and any applicable  state  securities laws and to obtain
any desired  acceleration  of the effective date of any  registration  statement
prepared and filed by the Company pursuant to this Agreement.

                           (c)      The Holders shall, if requested by
the Company or the  managing  underwriter(s)  in  connection  with any  proposed
registration and distribution pursuant to this Agreement,  (i) agree to sell the
Subject Shares on the basis provided in any  underwriting  arrangements  entered
into in connection  therewith and (ii) complete and execute all  questionnaires,
powers of attorney,  indemnities,  underwriting  agreements and other  documents
customary in similar offerings.

                           (d)      Upon receipt of any notice from the
Company that the Company has become  aware that the  prospectus  (including  any
preliminary prospectus) included in any registration statement filed pursuant to
Section  2(a) or 3, as  then in  effect,  contains  any  untrue  statement  of a
material fact or omits to state any material fact required to be stated  therein
or necessary to make the statements  therein not  misleading,  the Holders shall
forthwith discontinue disposition of Subject Shares pursuant to the registration
statement  covering  the same until the  Holders'  receipt of copies of a
supplemented or amended  prospectus and, if so directed by the Company,  deliver
to the Company (at the Company's expense) all copies other than permanent
file copies then in the Holder's  possession,  of the prospectus  covering
the Subject Shares that was in effect prior to such amendment or supplement.

                           (e)  The Holders shall pay all out-of-pocket 
expenses incurred in connection with any Demand Registration Statements filed
pursuant to Section


                                                 10





2(a) of this  Agreement,  including,  without  limitation,  all SEC and blue sky
registration and filing fees (including NASD fees), printing expenses,  transfer
agents and  registrars' fees,  underwriting  discounts,  commissions  and
expenses attributable to securities sold for the account of the Holders pursuant
to such  registration  statement,  fees and disbursements of the Company's
counsel  and  accountants  and fees and  disbursements  of  experts  used by the
Company in connection with such  registration  statement.  The Company shall pay
any such  out-of-pocket  expenses  incurred in connection with any  registration
statement filed pursuant to Section 3 of this Agreement, except that the Holders
shall pay all underwriting  discounts,  commissions and expenses attributable to
the Holder  Shares sold  pursuant  to any such  registration  statement  and the
incremental  portion of the SEC  registration  and filing  fees  relating to the
Holder Shares.

                           (f)  In connection with any sale of Sub-
ject Shares that are registered pursuant to this Agreement,  the Company and the
Holders  shall enter into an  agreement  providing  for  indemnification  of the
Holders by the Company,  and  indemnification of the Company by the Holders,  on
terms customary for such  agreements at that time (it being  understood that any
disputes  arising as to what is  customary  shall be  resolved by counsel to the
underwriter(s)).

                  5.  Notices.  Any notice or other  communication  required  or
permitted to be given  hereunder  shall be in writing and shall be effective (a)
upon hand  delivery or delivery by telex  (with  correct  answerback  received),
telecopy or facsimile at the address or number designated below (if delivered on
a  business  day  during  normal  business  hours  where  such  notice  is to be
received), or the first business day following such delivery (if delivered other
than on a business day during normal  business  hours where such notice is to be
received)  or (b) on the third  business  day  following  the date of mailing by
express  courier  service,  fully  prepaid,  addressed to such address,  or upon
actual service, fully prepaid, addressed to such address, or upon actual receipt
of  such  mailing,   whichever  shall  first  occur.   The  addresses  for  such
communications shall be:


                  If to the Company, to:


                                                 11






                  P.O. Box 5024
                  One State Street
                  Hartford, CT
                  06102-5024
                  Attn:  Roberta O'Brien
                  Telecopy:  (860) 722-5710

                  If to ERC, to:

                  5200 Metcalf
                  P.O. Box 2991
                  Overland Park, KS
                  66201-1391
                  Attn: John Connelley
                  Telecopy: (913) 676-5483

                  If to any other  Holder,  to such name at such address as such
                  Holder shall have indicated in a written  notice  delivered to
                  the other parties to this Agreement.

Any party hereto may from time to time change its address for notices under this
Section 5 by giving at least 10 days' notice of such  changes to the other
parties hereto.

                  6. Waivers. No waiver by any party of any default with respect
to any  provision,  condition  or  requirement  hereof  shall be  deemed to be a
continuing  waiver in the  future  thereof  or a waiver of any other  provision,
condition or requirement hereof; nor shall any delay or omission of any party to
exercise any right hereunder in any manner impair the exercise of any such right
accruing to it thereafter.

                  7.       Headings.  The headings herein are for convenience
only,  do not  constitute  a part of this Agree- ment and shall not be deemed to
limit or affect any of the provisions hereof.

                  8.       Successors and Assigns; Amendments.  This
Agreement  shall be binding  upon and inure to the  benefit of the  parties  and
their  successors  and assigns,  includ- ing without  limitation and without the
need for an ex- press assignment to each subsequent  Holder of any Regis- trable
Securities.  Except as provided in this  Section 8,  neither the Company nor any
Holder shall assign this Agreement or any rights hereunder without the prior


                                                 12





written consent of the other parties  hereto.  The assignment by a party of this
Agreement or any rights hereunder shall not affect the obligations of such party
hereunder.  This  Agreement  may not be amended  except by a written  instrument
executed by the parties hereto.

                  9. No Third Party  Beneficiaries.  This  Agreement is intended
for the benefit of the parties hereto and their respective  permitted successors
and  assigns  and is not for the  benefit  of, nor may any  provision  hereof be
enforced by, any other person.

                  10.  Governing  Law. This  Agreement  shall be governed by and
construed and enforced in accordance  with the internal laws of the State of New
York; without regard to the principles of conflicts of laws.

                  12.  Entire  Agreement.  This  Agreement  contains  the entire
agreement  of the  parties  hereto in respect of the subject  matter  hereof and
supersedes  all prior  agreements  and  understandings  between the parties with
respect to the subject matter hereof.

                  13.  Execution.  This Agreement may be executed in two or more
counterparts,  all of which shall be considered  one and the same  agreement and
shall  become  effective  when  counterparts  have been signed by each party and
delivered to the other  party,  it being  understood  that both parties need not
sign the same counterpart.



                                                 13




                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Agreement to be duly executed by their respective  authorized officers as of the
date hereof.


                                    HSB GROUP, INC.



                                       By: /s/ Saul L. Basch
                                      Name: Saul L. Basch
                                     Title: Senior Vice President, Treasurer
                                            and Chief Financial Officer



                                    EMPLOYERS REINSURANCE CORPORATION



                                       By: /s/ John M. Connelly
                                      Name: John M. Connelly
                                     Title: Senior Vice President, General
                                            Counsel & Secretary


                                    ERC LIFE REINSURANCE CORPORATION


                                       By: /s/ John M. Connelly
                                      Name: John M. Connelly
                                     Title: General Counsel


0154453.03-01S7a
                                                    14