Exhibit 4.1

                                  $300,000,000

                                 HSB CAPITAL II

                         Convertible Capital Securities
                (liquidation amount $1,000 per Capital Security)
        fully and unconditionally guaranteed to the extent set forth in
                                the Guarantee by

                                 HSB Group, Inc.


                               Purchase Agreement


                                December 31, 1997

ERC Life Reinsurance Corporation
Employers Reinsurance Corporation
5200 Metcalf
P.O. Box 2991
Overland Park, Kansas 66201-1391

Ladies and Gentlemen:

         HSB Capital II (the "Trust"),  a statutory business trust created under
the Business  Trust Act of the State of Delaware (the  "Delaware  Business Trust
Act"), and HSB Group, Inc., a Connecticut corporation, as depositor of the Trust
and as Guarantor (the "Guarantor"), propose, subject to the terms and conditions
stated herein  (including the attached term sheet (the "Term Sheet")),  that the
Trust  issue  and  sell to the  Purchasers  named  in  Schedule  I  hereto  (the
"Purchasers"),  an aggregate  liquidation  amount of $300,000,000 of Convertible
Capital  Securities  (liquidation  amount  $1,000  per  Capital  Security)  (the
"Securities")  representing  undivided beneficial interests in the assets of the
Trust, guaranteed by the Guarantor as to the payment of distributions, and as to
payments on liquidation  or  redemption,  to the extent set forth in a guarantee
agreement (the "Guarantee") between the Guarantor and The First National Bank of
Chicago, as Trustee (the "Guarantee  Trustee").  The proceeds of the sale of the
Securities  and an  aggregate  liquidation  amount of  $9,300,000  of its Common
Securities   (liquidation  amount  $1,000  per  common  security)  (the  "Common
Securities")  are to be invested by the Trust in 7.0%  Convertible  Subordinated
Deferrable Interest Debentures (the "Subordinated Debentures") of the Guarantor,
to be issued  pursuant to an Indenture (the  "Indenture")  between the Guarantor
and The First National Bank of Chicago,  as Trustee (the  "Debenture  Trustee").
The Common Stock of Guarantor  issuable upon  conversion of the Securities  (the
"Guarantor  Common  Stock") will be subject to a registration  rights  agreement
("Registration Rights Agreement") between the Guarantor and the Purchasers.  The
Guarantor is the holding  company of The Hartford  Steam  Boiler  Insurance  and
Inspection Company (the "Principal Subsidiary") and certain of its subsidiaries.

         1. The  Guarantor  and the Trust  jointly and  severally  represent and
warrant to, and agree with, the Purchasers that:








                (a) The Principal  Subsidiary's Annual Report on Form 10-K/A for
         the fiscal year ended December 31, 1996 and the  Guarantor's  Quarterly
         Report on Form 10-Q for the quarter ended  September 30, 1997 have been
         made available to the Purchasers in connection with the offering of the
         Securities.  All  documents  of  the  Guarantor  or  of  the  Principal
         Subsidiary  subsequently  filed with the United States  Securities  and
         Exchange Commission (the "Commission") pursuant to Section 13(a), 13(c)
         or 15(d) of the  United  States  Securities  Exchange  Act of 1934,  as
         amended (the  "Exchange  Act"),  on or prior to the date hereof and any
         reference to the documents  prepared or distributed in connection  with
         the offering of the Securities shall be deemed to include any documents
         filed with the Commission  pursuant to Section 13(a), 13(c) or 15(d) of
         the  Exchange  Act after the date  hereof  and prior to such  specified
         date;  all  documents  filed under the Exchange Act by the Guarantor or
         the Principal Subsidiary and so deemed to be included, or any amendment
         or  supplement  thereto,  are  hereinafter  called  the  "Exchange  Act
         Reports".  The Exchange  Act Reports,  when they were or are filed with
         the Commission,  conformed or will conform in all material  respects to
         the  applicable  requirements  of the Exchange  Act and the  applicable
         rules and  regulations of the Commission  thereunder.  The Exchange Act
         Reports did not and will not, as of their respective dates,  contain an
         untrue  statement of a material  fact or omit to state a material  fact
         necessary in order to make the statements  therein, in the light of the
         circumstances under which they were made, not misleading;

                (b) There has not been any  material  adverse  change in, or any
         adverse development which materially affects, the business,  properties
         or financial  condition or results of  operations  of the Guarantor and
         its  subsidiaries  taken as a whole since  September 30, 1997 otherwise
         than as set forth or contemplated herein; and, since September 30, 1997
         and  except  as  otherwise  set  forth  herein,  there has not been any
         material change in the capital stock or long-term debt of the Guarantor
         or any of  its  subsidiaries  or any  material  adverse  change  or any
         development  involving a prospective  material  adverse  change,  in or
         affecting  the  general  affairs,   management,   financial   position,
         shareholders'  equity or results of operations of the Guarantor and its
         subsidiaries  taken  as  a  whole,  otherwise  than  as  set  forth  or
         contemplated herein;

                (c) The  Guarantor  has been duly  incorporated  and is  validly
         existing as a corporation  in good standing under the laws of the state
         of Connecticut,  with power and authority  (corporate and other) to own
         its  properties  and conduct its  business as described in the Exchange
         Act Reports,  and has been duly qualified as a foreign  corporation for
         the  transaction  of business and is in good standing under the laws of
         each  other  jurisdiction  in which it owns or  leases  properties,  or
         conducts  any  business,  so as to require  such  qualification,  or is
         subject to no material liability or disability by reason of the failure
         to be so  qualified  in any such  jurisdiction;  and  each  significant
         subsidiary  (as defined in  Regulation  S-X of the  Commission,  each a
         "Significant  Subsidiary") of the Guarantor has been duly  incorporated
         and is validly  existing as a corporation  in good  standing  under the
         laws of its jurisdiction of incorporation;

                (d) The Guarantor has an authorized  capitalization as set forth
         in the Exchange Act  Reports,  and all of the issued  shares of capital
         stock of the Guarantor have been duly and validly authorized and issued
         and are fully paid and non-assessable;  and all of the issued shares of
         capital stock of each Significant Subsidiary of the Guarantor have been
         duly  and  validly   authorized   and   issued,   are  fully  paid  and
         non-assessable and (except for directors'  qualifying shares) are owned
         directly or indirectly by the  Guarantor,  free and clear of all liens,
         encumbrances, equities or claims;



                                                    2





                (e) The Trust has been duly created and is validly existing as a
         statutory  business trust in good standing under the Delaware  Business
         Trust  Act with the  power  and  authority  to own its  properties  and
         conduct its business as described in the Trust Agreement, and the Trust
         has  conducted no business to date other than as  contemplated  by this
         Agreement,  and it will conduct no business in the future that would be
         inconsistent with the Trust Agreement (as defined below);  the Trust is
         not a party to or bound by any agreement or instrument  other than this
         Agreement,  the  Trust  Agreement  (the  "Trust  Agreement")  among the
         Guarantor,  the  Administrative  Trustees named therein,  and The First
         National Bank of Chicago, as Property Trustee (the "Property Trustee"),
         and First Chicago  Delaware  Inc., as Delaware  Trustee (the  "Delaware
         Trustee"  and,  together  with  the  Administrative  Trustees,  and the
         Property  Trustee,  the  "Issuer  Trustees")  and  the  holders  of the
         Securities  issued  thereunder,  and  the  agreements  and  instruments
         contemplated  by the Trust  Agreement;  the Trust has no liabilities or
         obligations   other  than  those   arising  out  of  the   transactions
         contemplated  by this  Agreement  and the  Trust  Agreement;  based  on
         current  law,  the  Trust  is not  and  will  not be  classified  as an
         association  taxable as a corporation  for United States federal income
         tax purposes; and the Trust is not a party to or subject to any action,
         suit or proceeding of any nature;

                (f) The Securities have been duly and validly  authorized by the
         Trust,  and,  when issued and  delivered  against  payment  therefor as
         provided  herein,  will be duly and  validly  issued and fully paid and
         non-assessable  undivided  beneficial  interests  in the  assets of the
         Trust;  the issuance of the  Securities is not subject to preemptive or
         other similar rights;  the Securities will have the rights set forth in
         the  Trust  Agreement,  and the terms of the  Securities  are valid and
         binding   on  the  Trust;   the   holders   of  the   Securities   (the
         "Securityholders")  will be entitled to the same limitation of personal
         liability  extended to stockholders of private  corporations for profit
         organized under the General Corporation Law of the State of Delaware;

                (g) The  Common  Securities  of the  Trust  have  been  duly and
         validly  authorized  by the Trust and upon delivery by the Trust to the
         Guarantor  against  payment  therefor,  will be duly and validly issued
         undivided beneficial interests in the assets of the Trust; the issuance
         of the Common  Securities is not subject to preemptive or other similar
         rights; and at the Time of Delivery (as defined in Section 4(a) below),
         all of the issued and outstanding  Common  Securities of the Trust will
         be  directly  owned by the  Guarantor  free and  clear of any  security
         interest, mortgage, pledge, lien, encumbrance, claim or equity;

                (h)  The  Guarantee,  the  Subordinated  Debentures,  the  Trust
         Agreement,  the Indenture and the  Registration  Rights  Agreement (the
         Guarantee,  the Subordinated  Debentures,  the Trust Agreement, and the
         Indenture being collectively referred to as the "Guarantor Agreements")
         have  been duly and  validly  authorized  by the  Guarantor  and,  when
         validly executed and delivered by the Guarantor and, in the case of the
         Guarantee,  by  the  Guarantee  Trustee,  in  the  case  of  the  Trust
         Agreement,  by the Trustees and, in the case of the  Indenture,  by the
         Debenture   Trustee,   will   constitute   valid  and  legally  binding
         obligations  of the  Guarantor,  enforceable  in accordance  with their
         respective   terms,   subject,   as  to  enforcement,   to  bankruptcy,
         insolvency,  reorganization,  moratorium  and  similar  laws of general
         applicability relating to or affecting creditors' rights and to general
         equity principles;  and the Subordinated Debentures are entitled to the
         benefits of the Indenture;



                                                    3





                (i)  The  execution  and  delivery  of  this  Agreement  and the
         Guarantor   Agreements  and  the   consummation  of  the   transactions
         contemplated  herein  and  therein,  have been duly  authorized  by all
         necessary  corporate  action  on the  part of the  Guarantor,  and when
         executed  by the  Guarantor  and the  other  parties  thereto  will not
         conflict  with or result in any breach or violation of any of the terms
         or  provisions  of, or  constitute  a default  under,  or result in the
         creation  or  imposition  of any  security  interest,  lien,  charge or
         encumbrance  upon  any  property  or  assets  of the  Guarantor  or its
         Significant  Subsidiaries pursuant to any indenture,  mortgage, deed of
         trust,  loan  agreement,  contract or other  agreement or instrument to
         which the Guarantor or any of its  Significant  Subsidiaries is a party
         or by which the Guarantor or any of its Significant Subsidiaries may be
         bound or to which any of the property or assets of the Guarantor or any
         of its Significant Subsidiaries is subject, nor will such action result
         in any violation of the provisions of the Certificate of  Incorporation
         or the By-laws of the Guarantor or the Certificate of  Incorporation or
         By-laws of any of its  Significant  Subsidiaries  or any statute or any
         order,  rule or regulation of any court or governmental  agency or body
         having  jurisdiction  over  the  Guarantor  or any  of its  Significant
         Subsidiaries  or any of their  properties;  and no  consent,  approval,
         authorization, order, registration or qualification of or with any such
         court or governmental agency or body is required for the issue and sale
         of  the  Securities  or  the  consummation  by  the  Guarantor  of  the
         transactions   contemplated   by  this   Agreement  or  the   Guarantor
         Agreements,  except  such as have been,  or will have been  obtained or
         received prior to the Time of Delivery;

                (j) The Trust is not,  and after  giving  effect to the offering
         and sale of the Securities will not be, an "investment  company", or an
         entity  "controlled"  by an  "investment  company",  as such  terms are
         defined in the United States Investment Company Act of 1940, as amended
         (the "Investment Company Act");

                (k)  Neither   the   Guarantor   nor  any  of  its   Significant
         Subsidiaries  is in violation of its  Certificate of  Incorporation  or
         By-laws or in default in the  performance or observance of any material
         obligation,   agreement,   covenant  or  condition   contained  in  any
         indenture,  mortgage,  deed of trust,  loan  agreement,  lease or other
         agreement or instrument to which it is a party or by which it or any of
         its properties may be bound;

                (l) There are no legal or  governmental  proceedings  pending to
         which the Guarantor or any of its  Significant  Subsidiaries is a party
         or of which any  property of the  Guarantor  or any of its  Significant
         Subsidiaries  is the subject  which,  if  determined  adversely  to the
         Guarantor or any of its Significant Subsidiaries, would individually or
         in the  aggregate  have a  material  adverse  effect on the  current or
         future  financial   position,   shareholders'   equity  or  results  of
         operations of the Guarantor and its subsidiaries taken as a whole; and,
         to the  best of the  Guarantor's  knowledge,  no such  proceedings  are
         threatened or contemplated by governmental authorities or threatened by
         others.

         2. Subject to the terms and conditions  herein set forth, the Trust and
the Guarantor agree that the Trust shall issue and sell to the  Purchasers,  and
the Purchasers  agree to purchase from the Trust,  at a purchase price of $1,000
per Security, the Securities.

         3. (a) The Purchasers  hereby  acknowledge and agree with the Guarantor
and the Trust that the Securities have not been and will not be registered under
the Securities Act of 1933 (the "Securities Act") and may not be offered or sold
except  pursuant  to an  exemption  from the  registration  requirements  of the
Securities Act and subject to the restrictions on


                                                    4





transfer and  redemption  rights of the  Guarantor  under the  Indenture and the
Trust  Agreement.  The  Purchasers  further agree that they have not entered and
will not enter into any contractual arrangement with respect to the distribution
or delivery of the  Securities,  except  with the prior  written  consent of the
Company.

                (b) The Purchasers  hereby  acknowledge and agree that they will
not sell,  transfer,  assign or otherwise  dispose of any Guarantor Common Stock
other than in a broad public  distribution  pursuant to the Registration  Rights
Agreement or Rule 144 under the Securities  Act. In any such  distribution,  the
Purchasers will make reasonable efforts to ensure that no one purchaser or group
of related purchasers acquires more than 3.5% of the outstanding Common Stock of
Guarantor in such distribution.

         4. (a) The Securities to be purchased by the Purchasers  hereunder will
be represented by one or more definitive certificated Securities. The Trust will
deliver the  Securities to the  Purchasers,  against  payment by or on behalf of
such Purchasers of the purchase price therefor by wire transfer of Federal (same
day) funds to an  account  designated  by the Trust or against  payment by or on
behalf of the Purchasers of the purchase price therefor by certified or official
bank  check or checks,  payable to the order of the Trust in Federal  (same day)
funds.  The time and date of such delivery and payment shall be 11:30 a.m.,  New
York  City  time,  on  December  31,  1997 or such  other  time  and date as the
Purchasers  and the  Trust  may agree  upon in  writing.  Such time and date are
herein called the "Time of Delivery".

         (b) The  documents  to be  delivered  at the Time of  Delivery by or on
behalf of the  parties  hereto  pursuant  to  Section 7  hereof,  including  any
additional documents requested by the Purchasers pursuant to Section 7(e) hereof
and the  Securities  will be  delivered  at such time and date at the offices of
Skadden, Arps, Slate, Meagher & Flom LLP ("Skadden Arps"), 919 Third Avenue, New
York, New York 10022 (the "Closing Location"),  all at the Time of Delivery. For
the purposes of this Section 4, "New York  Business Day" shall mean each Monday,
Tuesday,  Wednesday,  Thursday  and Friday  which is not a day on which  banking
institutions  in New  York  are  generally  authorized  or  obligated  by law or
executive order to close.

         5. The Guarantor  and the Trust  jointly and  severally  agree with the
Purchasers:

                (a) Not to have the Trust be or become, at any time prior to the
         expiration  of three  years  after the Time of  Delivery,  an  open-end
         investment  company,  unit  investment  trust,   closed-end  investment
         company or face-amount certificate company that is or is required to be
         registered under Section 8 of the Investment Company Act;

                (b) At any time when the  Guarantor is not subject to Section 13
         or 15(d) of the  Exchange  Act and prior to two years  from the Time of
         Delivery,  for  the  benefit  of the  holders  from  time  to  time  of
         Securities,  to furnish at its  expense,  upon  request,  to holders of
         Securities information (the "Additional Issuer Information") satisfying
         the  requirements  of  subsection  (d)(4)(i)  of Rule  144A  under  the
         Securities Act;

                (c) To make  available to the holders of the  Securities as soon
         as  practicable  after the end of each  fiscal  year an  annual  report
         (including  a balance  sheet and  statements  of income,  shareholders'
         equity  and  cash  flows  of  the   Guarantor   and  its   consolidated
         subsidiaries  certified by independent public accountants) and, as soon
         as  practicable  after the end of each of the first  three  quarters of
         each fiscal year  (beginning  with the fiscal  quarter ending after the
         date  hereof),   consolidated  summary  financial  information  of  the
         Guarantor and its subsidiaries for such quarter in reasonable detail;


                                                    5






                (d) During a period of five years from the date hereof,  to make
         available  to  you  copies  of  all  reports  or  other  communications
         (financial or other) furnished to shareholders of the Guarantor, and to
         make  available  to the  Purchasers  (i) as soon as they are  generally
         available,  copies of any reports and financial statements furnished to
         or filed with the  Commission or any  securities  exchange on which the
         Securities or any class of  securities of the Guarantor is listed;  and
         (ii) such additional  information concerning the business and financial
         condition  of the  Guarantor  as the  Purchasers  may from time to time
         reasonably  request (such financial  statements to be on a consolidated
         basis to the extent the accounts of the Guarantor and its  subsidiaries
         are consolidated in reports furnished to its shareholders  generally or
         to the Commission;

                (e) During the period of two years  after the Time of  Delivery,
         the Guarantor will not, and will not permit any of its "affiliates" (as
         defined  in Rule 144 under the  Securities  Act) to,  resell any of the
         Securities or  Subordinated  Debentures  which  constitute  "restricted
         securities"  under Rule 144 that have been  reacquired  by any of them;
         and

                (f) To  issue  the  Guarantee  and the  Subordinated  Debentures
         concurrently  with the issue and sale of the Securities as contemplated
         herein.

         6. The Guarantor and the Trust jointly and severally covenant and agree
with the  Purchasers  that the  Guarantor  and the Trust will pay or cause to be
paid the  following:  (i) the cost of producing  this  Agreement,  any Guarantor
Agreement,  closing documents (including any compilations thereof) and any other
documents in connection  with the offering,  purchase,  sale and delivery of the
Securities;  (ii) the cost of preparing the  certificates for the Securities and
the Subordinated  Debentures;  (iii) the fees and expenses of the Trustees,  the
Guarantee Trustee and the Debenture  Trustee and any agent of the Trustees,  the
Guarantee  Trustee and the Debenture  Trustee and the fees and  disbursements of
counsel  for the  Trustees  in  connection  with  the  Trust  Agreement  and the
Securities,  counsel for the Guarantee  Trustee in connection with the Guarantee
and counsel for the Debenture  Trustee in connection  with the Indenture and the
Subordinated  Debentures;  and (iv) all other costs and expenses incident to the
performance of its obligations  hereunder  which are not otherwise  specifically
provided  for in this  Section.  It is  understood,  however,  that,  except  as
provided  in this  Section,  the  Purchasers  will pay all of its own  costs and
expenses, including the fees of its counsel.

         7. The  obligations of the Purchasers to purchase the Securities  shall
be subject to the accuracy of the  representations and warranties on the part of
the Guarantor and the Trust contained  herein as of the date hereof and the Time
of Delivery,  to the accuracy of the  statements  of the Guarantor and the Trust
made in any certificates  pursuant to the provisions  hereof, to the performance
by each of the Guarantor and the Trust of its obligations  hereunder and (unless
delivery is not required  until a subsequent  date) to the following  additional
conditions:

                (a) Robert C. Walker,  Senior Vice President and General Counsel
         of the Guarantor and the Trust, shall have furnished to you his written
         opinion,  dated on a date not more  than  five New York  Business  Days
         after the Time of Delivery, in form and substance  satisfactory to you,
         to the effect that:

                    (i) Each of the Guarantor and the Principal  Subsidiary  has
                been duly  incorporated and is validly existing as a corporation
                in good  standing  under the laws of the  State of  Connecticut,
                with  corporate  power and authority to own its  properties  and
                conduct its business as described in the Exchange Act Reports;


                                                    6






                   (ii) The Guarantor has an  authorized  capitalization  as set
                forth in the Exchange Act Reports;  and all of the issued shares
                of capital stock of the Principal  Subsidiary have been duly and
                validly   authorized   and   issued   and  are  fully  paid  and
                non-assessable and (except for directors' qualifying shares) are
                owned,  to the best of such  counsel's  knowledge,  directly  or
                indirectly  by the  Guarantor,  free  and  clear  of all  liens,
                encumbrances, equities or claims;

                  (iii) To the best of such  counsel's  knowledge and other than
                as set  forth in  Exchange  Act  Reports,  there are no legal or
                governmental  proceedings  pending to which the Guarantor or any
                of its  Significant  Subsidiaries  is a party  or of  which  any
                property of the Guarantor or any of its Significant Subsidiaries
                is the subject which,  if determined  adversely to the Guarantor
                or any of its Significant Subsidiaries, could individually or in
                the aggregate  have a material  adverse effect on the current or
                future consolidated financial position,  shareholders' equity or
                results of  operations  of the  Guarantor  and its  subsidiaries
                taken as a whole; and, to the best of such counsel's  knowledge,
                no  such   proceedings   are  threatened  or   contemplated   by
                governmental authorities or threatened by others;

                   (iv) This  Agreement has been duly  authorized,  executed and
                delivered by the Guarantor and the Trust;

                    (v) The Guarantee,  the Trust  Agreement,  the Indenture and
                the   Registration   Rights   Agreement   have  each  been  duly
                authorized,  executed and delivered by the Guarantor,  and, when
                validly  authorized,  executed and  delivered  by the  Guarantee
                Trustee in the case of the Guarantee,  when validly  authorized,
                executed,  and delivered by the Debenture Trustee in the case of
                the  Indenture,  and  when  validly  authorized,   executed  and
                delivered  by the  Issuer  Trustees  in the  case  of the  Trust
                Agreement, will constitute valid and legally binding instruments
                and  obligations  of  the  Guarantor   enforceable  against  the
                Guarantor,  in accordance with their respective terms,  subject,
                as to enforcement, to bankruptcy, insolvency, reorganization and
                other laws of general  applicability  relating  to or  affecting
                creditors' rights and to general equity principles;

                   (vi)  The  Subordinated   Debentures,   when  duly  executed,
                  authenticated  and issued in accordance with the Indenture and
                  delivered and paid for in accordance with this Agreement, will
                  be valid and legally  binding  obligations  of the  Guarantor,
                  enforceable  in accordance  with their terms,  subject,  as to
                  enforcement,   to  bankruptcy,   insolvency,   reorganization,
                  moratorium and other laws of general applicability relating to
                  or  affecting   creditors'   rights  and  to  general   equity
                  principles  (regardless  of  whether  such  enforceability  is
                  considered  in a proceeding  in equity or at law) and entitled
                  to the benefits provided by the Indenture;

                  (vii) The issuance by the  Guarantor of the  Guarantee and the
                Subordinated  Debentures,  the  compliance by the Guarantor with
                all of the  provisions  of  this  Agreement  and  the  Guarantor
                Agreements,  the  execution,  delivery  and  performance  by the
                Guarantor of this Agreement and the Guarantor Agreements and the
                consummation of the transactions herein and therein contemplated
                will not conflict with or result in a breach or violation of any
                of the material  terms or provisions of, or constitute a default
                under, any indenture, mortgage, deed of trust, loan agreement or
                other agreement or instrument known to such counsel to which the
                Guarantor or any of its  Significant  Subsidiaries is a party or
                by


                                                    7





                which the Guarantor or any of its  Significant  Subsidiaries  is
                bound or to which any of the property or assets of the Guarantor
                or any of its Significant Subsidiaries is subject, nor will such
                actions  result  in  any  violation  of  the  provisions  of the
                Articles of  Incorporation  or By-Laws of the  Guarantor  or any
                statute or any order,  rule or regulation  known to such counsel
                of any court or governmental  agency or body having jurisdiction
                over the Guarantor or any of its Significant Subsidiaries or any
                of their properties;

                  (viii)   No   consent,   approval,    authorization,    order,
                registration   or   qualification   of  or  with  any  court  or
                governmental agency or body is required of the Guarantor for the
                consummation by the Guarantor of the  transactions  contemplated
                by this Agreement or the Guarantor Agreements;

                   (ix)  Neither  the  Guarantor  nor  any  of  its  Significant
                Subsidiaries is in violation of its Certificate of Incorporation
                or By-laws or in default in the performance or observance of any
                material obligation,  agreement, covenant or condition contained
                in any contract,  indenture,  mortgage,  loan  agreement,  note,
                lease or other  instrument to which it is a party or by which it
                or any of its properties may be bound;

                    (x) The  Exchange  Act  Reports  (other  than the  financial
                statements  and  related  schedules  and  other  financial  data
                therein, as to which such counsel need express no opinion), when
                they were filed with the Commission,  complied as to form in all
                material respects with the requirements of the Exchange Act, and
                the rules and regulations of the Commission thereunder; and such
                counsel  has no reason to  believe  that any of such  documents,
                when they  were so filed,  contained  an untrue  statement  of a
                material fact or omitted to state a material  fact  necessary in
                order  to make  the  statements  therein,  in the  light  of the
                circumstances  under  which  they were made when such  documents
                were so filed, not misleading;

                   (xi) The offer,  sale and delivery of the  Securities and the
                Subordinated  Debentures  in the  manner  contemplated  by  this
                Agreement do not require  registration under the Securities Act;
                and the Trust Agreement,  the Guarantee and the Indenture do not
                require  qualification under the Trust Indenture Act of 1939, as
                amended; and

                  (xii)  The  Trust  is not,  and  after  giving  effect  to the
                offering and sale of the Securities  will not be, an "investment
                company" or an entity  "controlled" by an "investment  company",
                as such terms are defined in the Investment Company Act.

                Such  opinion  of Robert C.  Walker  may be limited to New York,
         Connecticut,  Delaware  and Federal  law.  To the extent such  opinions
         involve matters  governed by New York law, such counsel may assume that
         there are no differences  between New York Law and Connecticut  law. In
         giving such  opinions,  such  counsel may also rely,  as to all matters
         governed  by the laws of  jurisdictions  in which  such  counsel is not
         qualified,  upon  opinions  of other  counsel,  who  shall  be  counsel
         satisfactory to counsel for the  Purchasers,  in which case the opinion
         shall state that he believes  you and they are entitled to rely on such
         opinions.



                                                    8





                (b) You shall receive not later than five New York Business Days
         from the Time of Delivery the opinion of Skadden Arps, special Delaware
         Counsel for the Trust and the Guarantor, to the effect that:

                    (i) The Trust has been duly created and is validly  existing
                as a business trust in good standing under the Delaware Business
                Trust  Act and,  under  the  Trust  Agreement  and the  Delaware
                Business Trust Act, has the trust power and authority to own its
                properties  and conduct its  business,  all as  described in the
                Trust Agreement,  and all filings required under the laws of the
                State  of  Delaware  with  respect  to the  creation  and  valid
                existence of the Trust as a business trust have been made;

                   (ii) The Trust Agreement, when duly authorized,  executed and
                delivered  by the  Guarantor,  the  Property  Trustee,  and  the
                Delaware  Trustee and when duly  executed  and  delivered by the
                Administrative  Trustee,  will  constitute  a valid and  binding
                obligation of the Guarantor and the Administrative Trustees, and
                is  enforceable  against  the  Guarantor  and the  Trustees,  in
                accordance  with its terms,  and the terms of the  Securities as
                set  forth  in the  Trust  Agreement,  to the  extent  they  are
                obligations of the Trust,  are valid and binding  obligations of
                the Trust in accordance  with the terms of the Trust  Agreement,
                all  subject  to the  effect  upon the  Trust  Agreement  of (a)
                bankruptcy,  insolvency,  reorganization,  moratorium  or  other
                similar laws now or hereafter in effect  relating to  creditors'
                rights   generally,   and  (b)  general   principles  of  equity
                (regardless of whether enforcement is considered in a proceeding
                in equity or at law) and except to the extent that the rights to
                indemnity and contribution  contained  therein may be limited by
                state securities laws or the public policy underlying such laws;

                  (iii)  Under the Trust  Agreement  and the  Delaware  Business
                Trust Act,  the Trust has the trust power and  authority  to (a)
                execute  and  deliver   this   Agreement   and  to  perform  its
                obligations under this Agreement,  and (b) issue and perform its
                obligations under the Securities and the Common Securities;

                   (iv)  Under the Trust  Agreement  and the  Delaware  Business
                Trust  Act,  the  execution  and  delivery  by the Trust of this
                Agreement and the  performance  by the Trust of its  obligations
                thereunder  have been duly  authorized  by all  necessary  trust
                action on the part of the Trust;

                    (v) The Securities have been duly and validly  authorized by
                the Trust  Agreement,  and,  when issued and  delivered  against
                payment  therefor as provided  herein,  will be duly and validly
                issued  and,  subject to the  qualifications  set forth  herein,
                fully paid and non-assessable  undivided beneficial interests in
                the  assets of the  Trust;  under the  Trust  Agreement  and the
                Delaware  Business  Trust Act, the issuance of the Securities is
                not  subject  to  preemptive  or  other  similar   rights;   the
                Securities   will  have  the  rights  set  forth  in  the  Trust
                Agreement;  the  Securityholders,  as  beneficial  owners of the
                Trust,  will be  entitled  to the same  limitation  of  personal
                liability  extended to stockholders of private  corporations for
                profit organized under the General  Corporation Law of the State
                of  Delaware;  provided  that  such  counsel  may note  that the
                Securityholders   may  be  obligated,   pursuant  to  the  Trust
                Agreement,   to  (a)  provide   indemnity   and/or  security  in
                connection  with and pay taxes or  governmental  charges arising
                from transfers or exchanges of Capital  Securities  Certificates
                (as  defined  in  the  Trust  Agreement)  and  the  issuance  of
                replacement Capital Securities Certificates and (b) provide


                                                    9





                security  and  indemnity  in  connection  with  requests  of  or
                directions  to the  Property  Trustee  (as  defined in the Trust
                Agreement)  to exercise its rights and remedies  under the Trust
                Agreement;

                   (vi)  The  Common  Securities  have  been  duly  and  validly
                authorized by the Trust Agreement; under the Trust Agreement and
                the  Delaware  Business  Trust Act,  the  issuance of the Common
                Securities is not subject to preemptive or other similar rights;

                  (vii) This  Agreement has been duly  authorized,  executed and
                delivered by the Trust;

                  (viii)  The issue and sale of the  Securities  and the  Common
                Securities  by the Trust,  the  execution  and  delivery of this
                Agreement by the Trust,  the compliance by the Trust with all of
                the  provisions  of the  Securities,  and  this  Agreement,  the
                purchase  by the Trust of the  Subordinated  Debentures  and the
                consummation of the transactions herein and therein contemplated
                do not violate (a) the Trust  Agreement  or the  Certificate  of
                Trust of the Trust, or (b) any Applicable Delaware Law;

                   (ix) Based on such  counsel's  review of Applicable  Delaware
                Laws,  no  Governmental  Delaware  Approval  which  has not been
                obtained  or  taken  and is not in  full  force  and  effect  is
                required to  authorize  or is required  in  connection  with the
                execution or delivery by the Trust of the Purchase  Agreement or
                the  performance by the Trust of the  transactions  contemplated
                thereby except that such counsel need not express any opinion in
                this paragraph,  however, as to any Governmental Approvals which
                may be required under state securities of "blue sky" laws.

                In giving such opinion, Skadden Arps may state that (a) the term
         "Applicable  Delaware  Laws"  means only the  Delaware  Trust Act,  the
         General  Corporation Law of the State of Delaware and those laws, rules
         and regulations of the State of Delaware which, in its experience,  are
         ordinarily  applicable to transactions of the type  contemplated by the
         Purchase  Agreement   (excluding  those  laws,  rules  and  regulations
         relating  specifically to insurance  holding  companies);  (b) the term
         "Delaware  Governmental  Authorities"  means any Delaware  legislative,
         judicial,  administrative or regulatory body under Applicable Laws; (c)
         the term "Delaware Governmental Approval" means any consent,  approval,
         license,  authorization  or validation of, or filing,  qualification or
         registration  with,  any Delaware  Governmental  Authority  pursuant to
         Applicable  Laws. In giving such opinion,  Skadden Arps may rely, as to
         all matters governed by the laws of jurisdictions in which such counsel
         is not qualified,  upon opinions of other counsel, who shall be counsel
         satisfactory to counsel for the  Purchasers,  in which case the opinion
         shall state that they believe you and they are entitled to rely on such
         opinions.

                (c) Skadden Arps,  special tax counsel for the Guarantor and the
         Trust, shall furnish to you their written opinion, dated not later than
         five New York  Business  Days after the Time of  Delivery,  in form and
         substance satisfactory to you, to the effect that:

                    (i) The Trust will be  classified as a grantor trust and not
                as an  association  taxable as a  corporation  for United States
                federal income tax purposes.



                                                    10





                   (ii)  The  Subordinated  Debentures  will be  classified  for
                United States federal income tax purposes as indebtedness of the
                Company.

                (d) Prior to the Time of Delivery,  the  Guarantor and the Trust
         shall have furnished to you such further information,  certificates and
         documents as you may reasonably request.

                (e) (i) There has not been any  material  adverse  change in, or
         any  adverse  development  which  materially  affects,   the  business,
         properties  or  financial  condition  or results of  operations  of the
         Guarantor and its  subsidiaries  taken as a whole since the date hereof
         otherwise than as set forth or contemplated  herein, and (ii) since the
         date hereof  there shall not have been any change in the capital  stock
         or  long-term  debt  of  the  Guarantor  or  any  of  its   Significant
         Subsidiaries or any change, or any development  involving a prospective
         change,  in or affecting  the general  affairs,  management,  financial
         position,   shareholders'  equity  or  results  of  operations  of  the
         Guarantor and its subsidiaries taken as a whole,  otherwise than as set
         forth or  contemplated  herein,  the effect of which,  in any such case
         described in Clause (i) or (ii),  is in the judgment of the  Purchasers
         so material and adverse as to make it  impracticable  or inadvisable to
         proceed  with the  offering or the  delivery of the  Securities  on the
         terms and in the manner contemplated herein;

                (f) On or  after  the  date  hereof  and  prior  to the  Time of
         Delivery,  there shall not have  occurred any of the  following:  (i) a
         suspension or material limitation in trading in securities generally on
         the New York Stock Exchange;  (ii) a suspension or material  limitation
         in  trading  in the  Guarantor's  securities  on  the  New  York  Stock
         Exchange,  (iii) a general  moratorium on commercial banking activities
         declared by either Federal, New York State or Connecticut  authorities;
         or (iv) the outbreak or escalation of hostilities  involving the United
         States or the declaration by the United States of a national  emergency
         or war, if the effect of any such event  specified  in this clause (iv)
         in the judgment of the Purchasers makes it impracticable or inadvisable
         to proceed with the offering or the delivery of the  Securities  on the
         terms and in the manner contemplated herein;

                (g) The  Guarantor  and the Trust  shall have  furnished  to you
         certificates of the Guarantor and the Trust, signed, in the case of the
         Guarantor,  by the Chief Executive  Officer,  the President or a Senior
         Executive  Vice  President  of  the  Guarantor  and  by  the  principal
         accounting or financial  officer of the  Guarantor,  and in the case of
         the Trust, by an Administrative Trustee, dated the Time of Delivery, as
         to the accuracy of the  representations and warranties of the Guarantor
         and the  Trust  herein at and as of such  Time of  Delivery,  as to the
         performance  by the Guarantor and the Trust of all of their  respective
         obligations  hereunder  to be  performed  at or prior  to such  Time of
         Delivery,  and as to such  other  matters  as the  you  may  reasonably
         request.

         8. (a) As of the  Closing,  the  Purchasers  and their  Affiliates  (as
defined in the Exchange  Act) will have no  beneficial  ownership (as defined in
Rule 13d-3  promulgated  under the Exchange Act) of any  securities of Guarantor
other than as a result of the Purchasers' acquisition of the Securities.

                (b) The  Purchasers  hereby agree that, for a period of five (5)
         years from the date hereof,  the Purchasers and their  Affiliates  will
         not:



                                                    11





                    (i) in any manner acquire, agree to acquire, make any public
                or private  offer or proposal to acquire or announce or disclose
                any intention to make an offer or proposal to acquire,  directly
                or indirectly,  by purchase or otherwise  (except  pursuant to a
                stock split,  stock dividend,  or other pro rata distribution by
                Guarantor to holders of any class of its outstanding  securities
                entitled to vote generally in the election of directors ("Voting
                Securities") or upon conversion of the  Securities),  any Voting
                Securities other than the Securities;

                   (ii)  propose to enter into,  or  announce  or  disclose  any
                intention to propose to enter into, directly or indirectly,  any
                merger,  business  combination or similar transaction  involving
                Guarantor  or  its  Affiliates  or  to  purchase,   directly  or
                indirectly, all or a material portion of the assets of Guarantor
                or any of its Affiliates;

                  (iii) make, or in any way participate, directly or indirectly,
                in any "solicitation" of "proxies" (as such terms are defined or
                used in Regulation  14A of the Exchange Act) to vote, or seek to
                advise or  influence  any person with  respect to the voting of,
                any Voting Securities, or become a "participant" in an "election
                contest" (as such terms are defined or used in Regulation 14A of
                the  Exchange  Act)  relating to the  election of  directors  of
                Guarantor,  or  initiate,  propose or solicit  holders of Voting
                Securities for the approval of any  shareholder  proposal (under
                Rule 14a-8 under the Exchange Act or  otherwise),  provided that
                the  Purchasers  shall  not  be  deemed  to  have  engaged  in a
                "solicitation"  or to have become a "participant"  in accordance
                with this Agreement or by reason of participation in Guarantor's
                solicitation of proxies in connection with any annual or special
                meeting of shareholders of Guarantor;

                   (iv)  form,  join  or in any  way  participate  in a  "group"
                (within the meaning of Section  13(d)(3) of the Exchange Act) or
                otherwise act in concert with any Person, (x) for the purpose of
                circumventing  the  provisions of this  Agreement or (y) for the
                purpose of acquiring, holding, voting or disposing of any Voting
                Securities;

                    (v)  (x)  request  Guarantor  (or its  directors,  officers,
                employees or agents), directly or indirectly, to take any action
                which might require Guarantor or any of its Affiliates to make a
                public  announcement   regarding  the  possibility  of  (A)  the
                acquisition  of  Voting  Securities  by  the  Purchasers,  (B) a
                business  combination,  merger or similar transaction  involving
                the  Purchasers,  on the one hand,  and  Guarantor or any of its
                Affiliates, on the other hand, (C) the sale to the Purchasers of
                all or a material  portion of the assets of  Guarantor or any of
                its  Affiliates,  or (D) the  amendment  or waiver of any of the
                provisions  hereof,  or (y) make any public statement  regarding
                any of the foregoing or with respect to the business, management
                or conduct of Guarantor or its Affiliates;

                   (vi)  deposit  any  Voting  Securities  in a voting  trust or
                subject them to a voting agreement or other agreement of similar
                effect;

                  (vii) arrange,  or participate in the arranging of,  financing
                for the  purchase  of any  Voting  Securities  by any  person or
                entity,  provided  that  the  Purchasers  may,  as part of their
                normal  business  practices  (now  or as  hereinafter  adopted),
                provide  bona  fide  financing  to a third  party so long as the
                effect of such financing would not otherwise  violate any of the
                provisions of this Agreement;


                                                    12






                  (viii)  participate  in any action by  written  consent of the
                shareholders of Guarantor  unless so requested by the management
                or board of directors of the Guarantor; or

                   (ix)   otherwise   act,  alone  or  in  concert  with  others
                (including by providing financing for another party), to seek or
                offer to control or influence,  in any manner,  the  management,
                Board of Directors or policies of Guarantor,  including, without
                limitation,  by seeking to add or remove any member of the Board
                of Directors of Guarantor.

                (c)  Notwithstanding  the provisions of clause (ii) of paragraph
         (b), the  Purchasers  shall be  permitted to make a proposal  otherwise
         subject  thereto if  another  person or entity has made such a proposal
         and such  proposal has been  publicly  announced,  provided (i) ten New
         York Business  Days have elapsed since the date of public  announcement
         of such other  party's  proposal  and the  Guarantor  has not  publicly
         rejected  such  proposal  and (ii)  the  Purchasers'  proposal  is made
         privately to the Guarantor and is not  publicized by the  Purchasers in
         any manner.  Notwithstanding  the  provisions  of clause  (v)(x)(D)  of
         paragraph  (b),  the  Purchasers  may request an amendment or waiver of
         paragraph  (b),  provided  that  (i) the  Purchasers'  request  is made
         privately to the Chief  Executive  Officer of the Guarantor and (ii) if
         rejected,  no  further  communication  with  respect  thereto  is  made
         publicly  by  the  Purchasers  to  any  person  in  any  manner.  It is
         anticipated  that the  Purchasers  and the Guarantor will be discussing
         and entering  into  various  business  and  contractual  relationships.
         Notwithstanding  the  provisions  of clause (ix) of paragraph  (b), the
         Purchasers  shall be free to (i) discuss  such  relationships  with the
         Guarantor  and to fully assert and protect  their rights  thereunder or
         (ii) meet privately with the Chief Executive Officer and/or Chairman of
         the Board of  Guarantor  to discuss  matters  generally  of interest to
         shareholders other than matters related to control or change of control
         of Guarantor.

                (d) The  Purchasers  agree that they will,  and will cause their
         Affiliates  to, vote any Voting  Securities  of Guarantor in accordance
         with the  recommendation  of the Board of Directors of Guarantor at any
         annual or special meeting or in any action by consent. If the foregoing
         provision is inconsistent  with any law, rule or regulation  applicable
         to Guarantor, such Voting Securities will be voted in proportion to the
         votes of all other holders of Voting Securities.

               (e) The parties hereto  jointly and severally  agree and covenant
          that any breach of this Section 8 by any of them will cause  immediate
          and  irreparable  harm to the other,  for which  there is no  adequate
          remedy at law, and each hereby  acknowledges and consents to the right
          of the other to seek the entry, by a court of competent  jurisdiction,
          of any  temporary,  preliminary  or  permanent  injunction,  or  other
          remedial  relief  which would  arrest or redress any such  breaches of
          this Section 8.

         9. The  respective  agreements,  representations,  warranties and other
statements of the Guarantor  and the Trust and the  Purchasers,  as set forth in
this Agreement or made by or on behalf of them,  respectively,  pursuant to this
Agreement,   shall  remain  in  full  force  and  effect,   regardless   of  any
investigation  (or any statement as to the results thereof) made by or on behalf
of the Purchasers or any controlling person of any Purchasers,  or the Guarantor
and the Trust, or any officer or director or controlling person of the Guarantor
or the Trust, and shall survive delivery of and payment for the Securities.



                                                    13





         10.  This  Agreement  may be  terminated  by  mutual  agreement  of the
parties, in which event, (i) the Guarantor and the Trust shall not then be under
any  liability or obligation to the  Purchasers  with respect to the  Securities
except as provided in Section 6 hereof and (ii) the Purchasers shall not then be
under  any  liability  or  obligation  to the  Guarantor  with  respect  to this
Agreement except as provided in Section 6 or 8 hereof.

         11. All statements, requests, notices and agreements hereunder shall be
in writing,  and if to the Purchasers  shall be delivered or sent by mail, telex
or facsimile  transmission  to: ERC Life  Reinsurance  Corporation and Employers
Reinsurance  Corporation,  5200 Metcalf,  P.O. Box 2991,  Overland Park,  Kansas
66201-1391,  Attention:  General  Counsel;  and if to the Guarantor or the Trust
shall be delivered or sent by mail or facsimile transmission to HSB Group, Inc.,
One State Street, Hartford,  Connecticut 06102, Attention:  General Counsel. Any
such statements,  requests, notices or agreements shall take effect upon receipt
thereof.

         12.  This  Agreement  shall be binding  upon,  and inure  solely to the
benefit of, the  Purchasers,  the Guarantor  and the Trust and their  respective
successors  and assigns,  and no other  person  shall  acquire or have any right
under or by virtue of this Agreement. No purchaser of any of the Securities from
the  Purchasers  shall be deemed a successor or assign by reason  merely of such
purchase.

         13. Time shall be of the essence of this Agreement.

         14. This  Agreement  shall be governed by and  construed in  accordance
with the laws of the State of New York.

         15.  This  Agreement  may be executed by any one or more of the parties
hereto in any  number of  counterparts,  each of which  shall be deemed to be an
original, but all such respective counterparts shall together constitute one and
the same instrument.


                                                    14





         If the foregoing is in accordance with your understanding,  please sign
and return to us six counterparts hereof, and upon the acceptance hereof by you,
this letter and such  acceptance  hereof shall  constitute  a binding  agreement
between the Purchasers and the Guarantor and the Trust.


Very truly yours,

HSB CAPITAL II

By:   HSB GROUP, INC.,
      as  Depositor


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



HSB GROUP, INC.



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

Accepted as of the date hereof:

EMPLOYERS REINSURANCE CORPORATION


By:/s/ John M. Connelly

ERC LIFE REINSURANCE CORPORATION


By:/s/ John M. Connelly





                                                 SCHEDULE I

                                                                    Liquidation
                                             Number of              Amount of
                                            Securities              Securities
                                             to be                   to be
        Purchasers                          Purchased               Purchased
        ----------                          -----------            ------------
Employers Reinsurance Corporation.........  180,000                $180,000,000
ERC Life Reinsurance Corporation..........  120,000                 120,000,000
                                            ===========            ============
     
           Total..........................  300,000                $300,000,000
                                            ===========            ============





                                                    16


                                                              December 30, 1997

                       TERMS OF $300 MILLION CONVERTIBLE SECURITY

A.  Preliminary financial terms

Issuer :            newly created HSB Delaware business trust

Maturity:           20 years

Ranking:            Pari passu with HSB Group Global Floating Rate Junior
                    Subordinated  Debentures,  Series B  (subordinate  to senior
                    indebtedness)

Rate:               7.0% coupon, payable semi-annually

Extension  periods:  Interest may be deferred for up to 10 consecutive  interest
                    periods,  provided  that  during  such period HSB cannot pay
                    dividends  on its common stock or repay debt that ranks pari
                    passu or junior provided that no extension period may extend
                    beyond the stated maturity date.

Redemption:         Upon maturity
                    At option of ERC  (non-transferable  right), (i) upon change
                    in  control  of HSB Group  occurring  within  five  years of
                    issuance, redemption at par plus redemption premium, if any,
                    calculated  in  accordance  with  Schedule  A; (ii) if ERC's
                    purchase of IRI does not close before March 31, 1998;  (iii)
                    if after  good-faith  negotiations and revisions (if any) to
                    the  documentation  in accordance with this Term Sheet,  ERC
                    determines  that  the  Securities  do  not  conform  to  the
                    fundamental  economic  terms  set forth  herein  or  contain
                    provisions that impose material legal or tax consequences or
                    risks  on  ERC  that   could   not  have   been   reasonably
                    anticipated.

Callable:           Upon  change in  control  of  purchaser,  at par
                    "Tax event" (loss of tax  deductibility)
                    After 7 years at par under any circumstances
                    If ERC's purchase of IRI does not close before March 31,
                    1998
                    In the event that HSB vetos a  purchaser  of the convertible
                    securities

Convertibility:     HSB Group common stock at any time, subject to regulatory
                    approval, at conversion price of  $85

B. Standstill Agreement

Term:               5 year term; subject to earlier termination as mutually
                    agreed by the parties

Voting:             Agreement to vote its shares in accordance with
                    recommendation of Board, or if unenforceable in accordance
                    with NYSE policy, then proportionate to voting of 
                    non-affiliated shareholders

Prohibited
activities:         Acquiring additional shares beyond current ownership (need
                    representation on this) and conversion
                    Participating in proxy solicitation/consent solicitation
                    Making  shareholder  proposal
                    Public or private proposal with respect to a business
                    combination, except for private  proposal to HSB  following
                    a public  proposal for business  combination which has not
                    been rejected within 10 business days thereafter by Board of
                    Directors
                    Seeking to add/remove director from board
                    Forming 13D group with other stockholders
                    Making public statements on business management or conduct
                    of HSB
                    Requesting amendment of standstill agreement, other than a
                    non-public request to CEO which, if rejected, may not be
                    followed by a public request

Dispositions of
Convertible:        Rule 144A placement where purchaser agrees to be bound by
                    agreement, subject to HSB right to call at par and to veto
                    the purchaser(s); limit on number of purchasers
                    No registration rights

Disposition of
Common:             Demand registration rights; limits on frequency and number
                    of shares that can be covered; must be in broad public
                    distribution with limit on blocks that can be purchased by
                    third parties; subject to customary hold-backs and 
                    black-outs



                                   Schedule A
                              (assuming 7% coupon)

     In the event of a change in control of HSB Group  within five years of the
     closing,  if the per share  price paid in the  acquisition  comprising  the
     change in control is below the per share price specified below for the year
     within which the change in control  occurs,  HSB Group must redeem the note
     at the redemption value specified in the following table.

             Minimum                                                    Minimum
             Per share  Premium             Redemption  Redemption      ERC
Redemption   Price      to Par   Par Value  Premium     Value           IRR*
- ----------   -------    -------  ---------  ----------  ----------      -------
Year 1       $92.65     9.00%    $300 M    $ 27,000,000  $327,000,000    16.00%
Year 2        90.95     7.00%     300 M      21,000,000   321,000,000    10.33%
Year 3        89.25     5.00%     300 M      15,000,000   315,000,000     8.53 %
Year 4        87.55     3.00%     300 M       9,000,000   309,000,000     7.67%
Year 5        85.85     1.00%     300 M       3,000,000   303,000,000     7.17%

      *assuming payments at year-end