HSB GROUP, INC.
                 Global Floating Rate Junior Subordinated
                           Debentures, Series B

No. R-___                                                        $_________

      HSB Group, Inc., a Connecticut corporation (hereinafter called the
"Corporation", which term includes any successor Person under the
Indenture hereinafter referred to), for value received, hereby promises
to pay to The First National Bank of Chicago, as Property Trustee,
pursuant to the Amended and Restated Trust Agreement of HSB Capital I,
dated as of July 15, 1997, or registered assigns, the principal sum of
____________ ($________) Dollars on July 15, 2027; provided that the
Corporation may shorten the Stated Maturity of the principal of this
Security to a date not earlier than April 15, 2012, in the circumstances
described on the reverse hereof. The Corporation further promises to pay
interest on said principal sum from October 15, 1997 or from the most
recent Interest Payment Date to which interest has been paid or duly
provided for quarterly (subject to deferral as set forth herein) in
arrears on January 15, April 15, July 15, and October 15 of each year,
commencing Janu ary 15, 1998, at the variable annual rate of LIBOR plus
 .91% on the principal amount thereof, together with Additional Sums, if
any, as provided in Section 10.6 of the Indenture until the principal
hereof is paid or duly provided for or made available for payment;
provided that any overdue principal, premium or Additional Sums and any
overdue installment of interest shall bear Additional Interest at the
variable annual rate of LIBOR plus .91% (to the extent that the payment
of such interest shall be legally enforceable), compounded quarterly from
the dates such amounts are due until they are paid. The amount of
interest payable for any period will be computed on the basis of the
actual number of Days in the applicable payment period (which actual
number of days shall include the first day but exclude the last day of
such payment period) divided by 360. LIBOR shall mean the rate for
Eurodollar deposits having a three month maturity determined in
accordance with the First Supplemental Indenture hereinafter referred to.
The interest so payable, and punctually paid or duly provided for, on any
Interest Payment Date will, as provided in the Indenture, be paid to the
Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular
Record Date for such interest installment, which shall be the January 1,
April 1, July 1 or October 1 (whether or not a Business Day), as the case
may be, next preceding such Interest Payment Date. Any such interest not
so punctually paid or duly provided for shall forthwith cease to be
payable to the Holder on such Regular Record Date and may either be paid
to the Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on a Special Record
Date for the payment of such Defaulted Interest to be fixed by the
Trustee, notice whereof shall be given to Holders of Securities of this
series not less than 10 days prior to such Special Record Date, or be
paid at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange on which the Securities of this
series may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in said Indenture.

      So long as no Event of Default has occurred and is continuing, the
Corporation shall have the right, at any time during the term of this
Security, from time to time to defer the payment of interest on this
Security for up to 20 consecutive quarterly interest payment periods with
respect to each deferral period (each an "Extension Period") at the end
of which the Corporation shall pay all interest then accrued and unpaid
(including any Additional Interest, as provided below); provided,
however, that no Extension Period shall extend beyond the Stated Maturity
of the principal of this Security, as then in effect, and no such
Extension Period may end on a date other than an Interest Payment Date.
During any such Extension Period, the Corporation shall not and shall not
permit any subsidiary of the Company to, (i) declare or pay any dividends
or distributions on, or redeem, purchase, acquire or make a liquidation
payment with respect to, any of the Corporation's capital stock, or (ii)
make any payment of principal of or interest or premium, if any, on or
repay, repurchase or redeem any debt securities of the Corporation that
rank pari passu in all respects with or junior in interest to this
Security or (iii) make any guarantee payments with respect to any
guarantee by the Corporation of the debt securities of any subsidiary of
the Corporation if such guarantee ranks pari passu with or junior in
interest to this Security (other than (a) dividends or distributions in
common stock of the Corporation, (b) any declaration of a dividend in
connection with the implementation of a stockholders' rights plan, or the
issuance of stock under any such plan in the future, or the redemption or
repurchase of any such rights pursuant thereto, (c) payments under the
Guarantee and (d) purchases of common stock related to the issuance of
common stock or rights under any of the Corpora tion's or its
subsidiaries' benefit plans for their directors, officers or employees).
Prior to the termination of any such Extension Period, the Corporation
may further defer the payment of interest, provided that no Extension
Period shall exceed 20 consecutive quarterly interest payment periods,
extend beyond the Stated Maturity of the principal of this Security or
end on a date other than an Interest Payment Date. Upon the termination
of any such Extension Period and upon the payment of all accrued and
unpaid interest and any Additional Interest then due on any Interest
Payment Date, the Corporation may elect to begin a new Extension Period,
subject to the above conditions. No interest shall be due and payable
during an Extension Period, except at the end thereof, but each
installment of interest that would otherwise have been due and payable
during such Extension shall bear Additional Interest (to the extent that
the payment of such interest shall be legally enforceable) at the rate of
LIBOR plus .91% per annum, compounded quarterly and calculated as set
forth in the first paragraph of this Security, from the dates on which
amounts would otherwise have been due and payable until paid or made
available for payment. The Corporation shall give the Holder of this
Security and the Trustee notice of its election to begin any Extension
Period at least one Business Day prior to the next succeeding Interest
Payment Date on which interest on this Secu rity would be payable but for
such deferral or so long as such Securities are held by HSB Capital I
(the "Issuer Trust") or a trustee thereof, at least one Business Day
prior to the earlier of (i) the next succeeding date on which
Distributions on the Capital Securities of such Issuer Trust would be
payable but for such deferral, and (ii) the date on which the Property
Trustee of such Issuer Trust is required to give notice to holders of
such Capital Securities of the record date or the date such Distributions
are payable.

      Payment of the principal of (and premium, if any) and interest on
this Security will be made at the office or agency of the Corporation
maintained for that purpose in New York, New York or Chicago, Illinois,
in such coin or currency of the United States of America as at the time
of payment is legal tender for payment of public and private debts;
provided, however, that at the option of the Corporation payment of
interest may be made (i) by check mailed to the address of the Person
entitled thereto as such address shall appear in the Securities Register,
or (ii) by wire transfer in immediately available funds at such place and
to such account as may be designated by the Person entitled thereto as
specified in the Securities Register.

      The indebtedness evidenced by this Security is, to the extent
provided in the Indenture, subordinate and junior in right of payment to
the prior payment in full of all Senior Indebtedness, and this Security
is issued subject to the provisions of the Indenture with respect
thereto. Each Holder of this Security, by accepting the same, (a) agrees
to and shall be bound by such provisions, (b) authorizes and directs the
Trustee on such Holder's behalf to take such actions as may be
necessary or appropriate to effectuate the subordination so provided,
and (c) appoints the Trustee his or her attorney-in-fact for any and all
such purposes. Each Holder hereof, by such Holder's acceptance hereof,
waives all notice of the acceptance of the subordination provisions
contained herein and in the Indenture by each holder of Senior
Indebtedness, whether now outstanding or hereafter incurred, and waives
reliance by each such holder upon said provisions.

      Reference is hereby made to the further provisions of this Security
set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

      Unless the certificate of authentication hereon has been executed
by the Trustee referred to on the reverse hereof by manual signature,
this Security shall not be entitled to any benefit under the Indenture or
be valid or obligatory for any purpose.

      IN WITNESS WHEREOF, the Corporation has caused this instrument to
be duly executed under its corporate seal.

                                          HSB GROUP, INC.

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

Attest:







      SECTION 2.3.   Form of Reverse of Security.

      This Security is one of a duly authorized issue of securities of
the Corporation (herein called the "Securities"), issued and to be issued
in one or more series under the Junior Subordinated Indenture, dated as
of July 15, 1997 (herein called the "Indenture"), between the Corporation
and The First National Bank of Chicago, as Trustee (herein called the
"Trustee", which term includes any successor trustee under the
Indenture), the First Supplemental Indenture (the "First Supplemental
Indenture") dated as of July 15, 1997, between the Corporation and the
Trustee to which Indenture, First Supplemental Indenture and all
indentures supplemental thereto reference is hereby made for a statement
of the respective rights, limitations of rights, duties and immunities
thereunder of the Corporation, the Trustee, the holders of Senior
Indebtedness and the Holders of the Securities, and of the terms upon
which the Securities are, and are to be, authenticated and delivered.
This Security is one of the series designated on the face hereof ,
limited in aggregate principal amount to $_______).

      All terms used in this Security that are defined in the Indenture
or in the Amended and Restated Trust Agreement, dated as of July 15, 1997
(as modified, amended or supplemented from time to time, the "Trust
Agreement"), relating to Issuer Trust among the Corporation, as
Depositor, the Trustees named therein and the Holders from time to time
of the Trust Securities issued pursuant thereto, shall have the meanings
assigned to them in the Indenture or the Trust Agreement, as the case may
be.

      The Corporation may at any time, at its option, on or after July
15, 2007 and subject to the terms and conditions of Article XI of the
Indenture, redeem this Security in whole at any time or in part from time
to time, at a Redemption Price equal to 100% of the principal amount
hereof, together, in the case of any such redemption, with accrued
interest (including any Additional Interest) to but excluding the date
fixed for redemption.

      In addition, upon the occurrence and during the continuation of a
Tax Event in respect of the Issuer Trust, the Corporation may, at its
option, at any time within 90 days of the occurrence and during the
continuation of such Tax Event redeem this Security, in whole but not
in part, subject to the terms and conditions of Article XI of the
Indenture, at a Redemption Price equal to 100% of the principal amount of
the Junior Subordinated Debentures so redeemed plus accrued and unpaid
interest thereon to the date of redemption.

      In the event of redemption of this Security in part only, a new
Security or Securities of this series for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation
hereof.

      Upon the occurrence and during the continuation of a Tax Event, the
Corporation may, at its option, shorten the Stated Maturity of this
Security to the minimum extent, but in no event to a date not earlier
than April 15, 2012, such that, in the opinion of counsel to the
Corporation experienced in such matters that, after advancing the Stated
Maturity, interest paid on this Security will be deductible for U.S.
federal income tax purposes. Upon the exercise of the right to shorten
the Stated Maturity of this Security, the Corporation will not have the
right to redeem this Security prior to the new Stated Maturity upon the
occurrence of a Tax Event or to further shorten the maturity of this
Security.

      The Indenture contains provisions for satisfaction and discharge of
the entire indebtedness of this Security upon compliance by the
Corporation with certain conditions set forth in the Indenture.

      Upon the occurrence and during the continuation of a Tax Event, the
Corporation may, at its option, shorten the Stated Maturity of this
Security to the minimum extent, but in no event to a date not earlier
than April 15, 2012, such that, in the opinion of counsel to the
Corporation experienced in such matters that, after advancing the Stated
Maturity, interest paid on this Security will be deductible for U.S.
federal income tax purposes. Upon the exercise of the right to shorten
the Stated Maturity of the Corporation will not have the right to redeem
the Security prior to the new Stated Maturity upon the occurrence of a
Tax Event or to further shorten the maturity of this Security.

      The Indenture permits, with certain exceptions as therein provided,
the Corporation and the Trustee at any time to enter into a supplemental
indenture or indentures for the purpose of modifying in any manner the
rights and obligations of the Corporation and of the Holders of the
Securities, with the consent of the Holders of not less than a majority
in principal amount of the Outstanding Securities of each series to be
affected by such supplemental indenture. The Indenture also contains
provisions permitting Holders of specified percentages in principal
amount of the Securities of each series at the time Outstanding, on
behalf of the Holders of all Securities of such series, to waive
compliance by the Corporation with certain provisions of the Indenture
and certain past defaults under the Indenture and their consequences. Any
such consent or waiver by the Holder of this Security shall be conclusive
and binding upon such Holder and upon all future Holders of this Security
and of any Security issued upon the registration of transfer hereof or in
exchange herefor or in lieu hereof, whether or not notation of such
consent or waiver is made upon this Security.

      As provided in and subject to the provisions of the Indenture, if
an Event of Default with respect to the Securities of this series at the
time Outstanding occurs and is continuing, then and in every such case
the Trustee or the Holders of not less than 25% in aggregate principal
amount of the Outstanding Securities of this series may declare the
principal amount of all the Outstanding Securities of this series to be
due and payable immediately, by a notice in writing to the Corporation
(and to the Trustee if given by Holders), provided that, if upon an Event
of Default, the Trustee or such Holders fail to declare the principal of
all the Outstanding Securities of this series to be immediately due and
payable, the holders of at least 25% in aggregate Liquidation Amount of
the Capital Securities then Outstanding shall have the right to make such
declaration by a notice in writing to the Corporation and the Trustee;
and upon any such declaration the principal of and the accrued interest
(including any Additional Interest) on all the Securities of this series
shall become immediately due and payable, provided that the payment of
such principal and interest (including any Additional Interest) on such
Securities shall remain subordinated to the extent provided in Article
XIII of the Indenture.

      No reference herein to the Indenture and no provision of this
Security or of the Indenture shall alter or impair the obligation of the
Corporation, which is absolute and unconditional, to pay the principal
of (and premium, if any) and interest (including any Additional Interest)
on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

      As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Security is registrable in the
Securities Register, upon surrender of this Security for registration
of transfer at the office or agency of the Corporation maintained under
Section 10.2 of the Indenture for such purpose, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to
the Corporation and the Securities Registrar duly executed by, the Holder
hereof or such Holder's attorney duly authorized in writing, and
thereupon one or more new Securities of this series, of like tenor, of
authorized denominations and for the same aggregate principal amount,
will be issued to the designated transferee or trans ferees.

      The Securities of this series are issuable only in registered form
without coupons in denominations of $1,000 and any integral multiple of
$1,000 in excess thereof except that certain Holders may be required to
hold a minimum of $100,000 as provided for in the Indenture. As provided
in the Indenture and subject to certain limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal
amount of Securities of this series and of like tenor of a different
authorized denomination, as requested by the Holder surrendering the
same.

      No service charge shall be made for any such registration of
transfer or exchange, but the Corporation may require payment of a sum
sufficient to cover any tax or other governmental charge payable in
connection therewith.

      Prior to due presentment of this Security for registration of
transfer, the Corporation, the Trustee and any agent of the Corporation
or the Trustee may treat the Person in whose name this Security is
registered as the owner hereof for all purposes, whether or not this
Security be overdue, and neither the Corporation, the Trustee nor any
such agent shall be affected by notice to the contrary.

      The Corporation and, by its acceptance of this Security or a
beneficial interest therein, the Holder of, and any Person that acquires
a beneficial interest in, this Security agree that for United States
Federal, state and local tax purposes it is intended that this Security
constitute indebtedness.

      THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

      The Trustee's certificates of authentication shall be in
substantially the following form:

      This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

Dated:  _______, 1997

                                    THE FIRST NATIONAL BANK OF CHICAGO
                                    as Trustee


                                    By: ______________________________
                                          Authorized Officer