Document:

<PAGE>

                                                                   EXHIBIT 10.12

                   Intellectual Property Security Agreement
                   ----------------------------------------

          THIS INTELLECTUAL PROPERTY SECURITY AGREEMENT (this "Agreement"),
dated as of March __, 2001, is made between ARIEL CORPORATION, a Delaware
corporation ("Borrower") and MAYAN NETWORKS CORPORATION, a __________
corporation ("Lender").

          Borrower and Lender hereby agree as follows:

          SECTION 1.   Definitions; Interpretation.
                       ---------------------------
          (a)   All capitalized terms used in this Agreement and not otherwise
defined herein shall have the meanings assigned to them in the Security
Agreement.

          (b)   As used in this Agreement, the following terms shall have the
following meanings:

          "Collateral" has the meaning set forth in Section 2.
           ----------

          "Copyright Office" means the United States Copyright Office.
           ----------------

          "PTO" means the United States Patent and Trademark Office.
           ---

          "Security Agreement" means the Security Agreement dated as of March
           ------------------
__, 2001 between Borrower and Lender.

          (c)   Terms Defined in the UCC.  Where applicable and except as
                ------------------------
otherwise defined herein, terms used in this Agreement shall have the meanings
assigned to them in the UCC.

          (d)   Interpretation.  In this Agreement, (i) the meaning of defined
                --------------
terms shall be equally applicable to both the singular and plural forms of the
terms defined; and (ii) the captions and headings are for convenience of
reference only and shall not affect the construction of this Agreement.

          SECTION 2.   Security Interest.
                       ------------------
          (a)   As security for the payment and performance of the Obligations,
Borrower hereby pledges, assigns, transfers, hypothecates and sets over to
Lender, and hereby grants to Lender a security interest in, all of Borrower's
right, title and interest in, to and under the following property, wherever
located and whether now existing or owned or hereafter acquired or arising
(collectively, the "Collateral"):

          (i)   All of Borrower's present and future United States registered
copyrights and copyright registrations, including Borrower's United States
registered copyrights and copyright registrations, all of Borrower's present and
future United States applications for copyright registrations, including
Borrower's United States applications for copyright

                                       1.
<PAGE>

registrations and all of Borrower's present and future copyrights which are not
registered in the United States Copyright Office (collectively, the
"Copyrights"), and any and all royalties, payments, and other amounts payable to
Borrower in connection with the Copyrights, together with all renewals and
extensions of the Copyrights, the right to recover for all past, present, and
future infringements of the Copyrights, and all computer programs, computer
databases, computer program flow diagrams, source codes, object codes and all
tangible property embodying or incorporating the Copyrights, and all other
rights of every kind whatsoever accruing thereunder or pertaining thereto;

          (ii)    All of Borrower's right, title and interest in and to any and
all present and future license agreements with respect to the Copyrights;

          (iii)   All present and future accounts, accounts receivable and other
rights to payment arising from, in connection with or relating to the
Copyrights;

          (iv)    All patents and patent applications, domestic or foreign, all
licenses relating to any of the foregoing and all income and royalties with
respect to any licenses, all rights to sue for past, present or future
infringement thereof, all rights arising therefrom and pertaining thereto and
all reissues, divisions, continuations, renewals, extensions and continuations-
in-part thereof;

          (v)     All state (including common law), federal and foreign
trademarks, service marks and trade names, and applications for registration of
such trademarks, service marks and trade names, all licenses relating to any of
the foregoing and all income and royalties with respect to any licenses, whether
registered or unregistered and wherever registered, all rights to sue for past,
present or future infringement or unconsented use thereof, all rights arising
therefrom and pertaining thereto and all reissues, extensions and renewals
thereof;

          (vi)    The entire goodwill of or associated with the businesses now
or hereafter conducted by Borrower connected with and symbolized by any of the
aforementioned properties and assets;

          (vii)   All general intangibles and all intangible intellectual or
other similar property of Borrower of any kind or nature, associated with or
arising out of any of the aforementioned properties and assets and not otherwise
described above; and

          (viii)  All cash and noncash proceeds of any and all of the foregoing
Collateral (including license royalties, rights to payment, accounts receivable
and proceeds of infringement suits) and, to the extent not otherwise included,
all payments under insurance or any indemnity, warranty or guaranty payable by
reason of loss or damage to or otherwise with respect to the foregoing
Collateral.

          (b)    Continuing Security Interest.  This Agreement shall create a
                 ----------------------------
continuing security interest in the Collateral which shall remain in effect
until terminated in accordance with Section 9 hereof.

                                       2.
<PAGE>

          (c)   Notwithstanding the foregoing provisions of this Section 2, the
grant of a security interest as provided herein shall not extend to, and the
term "Collateral" shall not include, any general intangibles of Borrower
(whether owned or held as licensee or lessee, or otherwise), to the extent that
(i) such general intangibles are not assignable or capable of being encumbered
as a matter of law or under the terms of the license, lease or other agreement
applicable thereto (but solely to the extent that any such restriction shall be
enforceable under applicable law), without the consent of the licensor or lessor
thereof or other applicable party thereto and (ii) such consent has not been
obtained; provided, however, that the foregoing grant of security interest shall
extend to, and the term "Collateral" shall include, (A) any general intangible
which is an account receivable or a proceed of, or otherwise related to the
enforcement or collection of, any account receivable, or goods which are the
subject of any account receivable, (B) any and all proceeds of any general
intangibles which are otherwise excluded to the extent that the assignment or
encumbrance of such proceeds is not so restricted, and (C) upon obtaining the
consent of any such licensor, lessor or other applicable party with respect to
any such otherwise excluded general intangibles, such general intangibles as
well as any and all proceeds thereof that might have theretofore have been
excluded from such grant of a security interest and the term "Collateral".

          (d)   The security interest granted by Borrower to Lender hereby shall
be junior and subordinate in all respects to the security interest granted by
Borrower to Senior Lender in respect of the Senior Debt for however long such
security interest granted by Borrower to Senior Lender in respect of the Senior
Debt shall remain in effect. Borrower agrees not to contest the validity,
perfection or enforceability of the Senior Debt or Senior Lender's security
interest in any of the Collateral.

          SECTION 3.   Supplement to Security Agreement.  This Agreement has
                       --------------------------------
been granted in conjunction with the security interests granted to Lender under
the Security Agreement. The rights and remedies of Lender with respect to the
security interests granted herein are without prejudice to, and are in addition
to those set forth in the Security Agreement, all terms and provisions of which
are incorporated herein by reference.

          SECTION 4.   Representations and Warranties.  Borrower represents and
                       ------------------------------
warrants to Lender that:

          (a)   A true and correct list of all of Borrower's United States
registered copyrights and copyright registrations is set forth in Schedule A.
                                                                  ----------

          (b)   A true and correct list of all of Borrower's United States
applications for copyright registrations is set forth in Schedule B.
                                                         -----------

          (c)   A true and correct list of all of the existing Collateral
consisting of U.S. patents and patent applications and/or registrations owned by
Borrower, in whole or in part, is set forth in Schedule C.
                                               ----------

                                       3.
<PAGE>

          (d)   A true and correct list of all of the existing Collateral
consisting of U.S. trademarks, trademark registrations and/or applications owned
by Borrower, in whole or in part, is set forth in Schedule D.
                                                  -----------

          SECTION 5.   Binding Effect.  This Agreement shall be binding upon,
                       --------------
inure to the benefit of and be enforceable by Borrower, Lender and their
respective successors and assigns.

          SECTION 6.   Governing Law.  This Agreement shall be governed by, and
                       -------------
construed in accordance with, the law of the State of California, except as
required by mandatory provisions of law and to the extent the validity or
perfection of the security interests hereunder, or the remedies hereunder, in
respect of any Collateral are governed by the law of a jurisdiction other than
California.

          SECTION 7.   Amendment.  This Agreement is subject to modification
                       ---------
only by a writing signed by the parties, except as provided herein. To the
extent that any provision of this Agreement conflicts with any provision of the
Security Agreement, the provision giving Lender greater rights or remedies shall
govern, it being understood that the purpose of this Agreement is to add to, and
not detract from, the rights granted to Lender under the Security Agreement.

          SECTION 8.   Counterparts.  This Agreement may be executed in any
                       ------------
number of counterparts and by different parties hereto in separate counterparts,
each of which when so executed shall be deemed to be an original and all of
which taken together shall constitute but one and the same agreement.

          SECTION 9.   Termination.  Upon payment and performance in full of all
                       -----------
Obligations, the security interests created by this Agreement shall terminate
and Lender shall promptly execute and deliver to Borrower such documents and
instruments reasonably requested by Borrower as shall be necessary to evidence
termination of all such security interests given by Borrower to Lender
hereunder.

          SECTION 10.   Further Acts.  On a continuing basis, Borrower shall
                        ------------
make, execute, acknowledge and deliver, and file and record in the proper filing
and recording places, all such instruments and documents, and take all such
action as may be necessary or advisable or may be requested by Lender to carry
out the intent and purposes of this Agreement, or for assuring, confirming or
protecting the grant or perfection of the security interest granted or purported
to be granted hereby, to ensure Borrower's compliance with this Agreement or to
enable Lender to exercise and enforce its rights and remedies hereunder with
respect to the Collateral, including any documents for filing with the Copyright
Office, the PTO and/or any applicable state office. Lender may record this
Agreement, an abstract thereof, or any other document describing Lender's
interest in the Copyrights with the Copyright Office, at the expense of
Borrower. Lender may record this Agreement, an abstract thereof, or any other
document describing Lender's interest in the Collateral with the PTO, at the
expense of Borrower.

          SECTION 11.   Authorization to Supplement.
                        ---------------------------

                                       4.
<PAGE>

          (a)   Borrower shall give Lender prompt notice of any additional
United States copyright registrations or applications therefor after the date
hereof. Borrower authorizes Lender to modify this Agreement by amending Schedule
A or B to include any future United States registered copyrights or applications
therefor of Borrower. Notwithstanding the foregoing, no failure to so modify
this Agreement or amend Schedules A or B shall in any way affect, invalidate or
detract from Lender's continuing security interest in all Collateral, whether or
not listed on Schedule A or B.

          (b)   If Borrower shall obtain rights to any new trademarks, any new
patentable inventions or become entitled to the benefit of any patent
application or patent for any reissue, division, or continuation, of any patent,
the provisions of this Agreement shall automatically apply thereto. Borrower
shall give prompt notice in writing to Lender with respect to any such new
trademarks or patents, or renewal or extension of any trademark registration.
Without limiting Borrower's obligations under this Section 11, Borrower
authorizes Lender to modify this Agreement by amending Schedules C or D to
include any such new patent or trademark rights. Notwithstanding the foregoing,
no failure to so modify this Agreement or amend Schedules C or D shall in any
way affect, invalidate or detract from Lender's continuing security interest in
all Collateral, whether or not listed on Schedule C or D.

                  [remainder of page intentionally left blank]

                                       5.
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement, as of the date first above written.

                              ARIEL CORPORATION

                              By:
                                 --------------------------------------
                                   Title:

                              2540 Route 130
                              Cranbury, NJ 08512
                              Attn:  Dennis Schneider, President
                              Fax:  (     ) _________________

                              MAYAN NETWORKS CORPORATION

                              By:
                                 --------------------------------------
                                   Title:

                              2115 O'Nel Drive
                              San Jose
                              Attn:  John Tingleff, Chief Financial Officer

                              Fax:  (     ) _________________

                                       6.
<PAGE>

                                   SCHEDULE A
                to the Intellectual Property Security Agreement

                               Ariel Corporation

                             Registered Copyrights

        TITLE OF WORK         REGISTRATION NUMBER         DATE OF ISSUANCE
        -------------         -------------------         ----------------

                                     A-1.
<PAGE>

                                   SCHEDULE B
                to the Intellectual Property Security Agreement

                               Ariel Corporation

                  Applications for Registration of Copyrights

            TITLE OF WORK                             DATE OF APPLICATION
            -------------                             -------------------

                                      2.
<PAGE>

                                   SCHEDULE C
                 to the Patent and Trademark Security Agreement

                               Ariel Corporation

                        Issued U.S. Patents of Borrower
                        -------------------------------

    Patent No.          Issue Date             Inventor              Title
    ----------          ----------             --------              -----

                  Pending U.S. Patent Applications of Borrower
                  --------------------------------------------

    Serial No.          Filing Date            Inventor              Title
    ----------          -----------            --------              -----

                                     A-1.
<PAGE>

                                   SCHEDULE D
                 to the Patent and Trademark Security Agreement

                               Ariel Corporation

                          U.S. Trademarks of Borrower
                          ---------------------------

  Registration       Registration                         Registered
      No.                Date          Filing Date          Owner         Mark
  ------------       ------------      -----------        ----------      ----

                Pending U.S. Trademark Applications of Borrower
                -----------------------------------------------

   Application No.           Filing Date             Applicant            Mark
   ---------------           -----------             ---------            ----

                                     S-1.SERIES SUPPLEMENT

                      CORPORATE BACKED TRUST CERTIFICATES

                             SERIES 2001-20 TRUST

                                    between

                            LEHMAN ABS CORPORATION,

                                 as Depositor

                                      and

                     U.S. BANK TRUST NATIONAL ASSOCIATION,

                                  as Trustee

                      CORPORATE BACKED TRUST CERTIFICATES

                           Dated as of May 22, 2001

<PAGE>

                               Table of Contents

                                                                           Page

Section 1.      Incorporation of Standard Terms..............................3

Section 2.      Definitions..................................................3

Section 3.      Designation of Trust and Certificates........................9

Section 4.      Trust Certificates..........................................10

Section 5.      Distributions...............................................10

Section 6.      Trustee's Fees..............................................12

Section 7.      Optional Exchange; Optional Redemption......................13

Section 8.      Notices of Events of Default................................15

Section 9.      Miscellaneous...............................................15

Section 10.     Governing Law...............................................18

Section 11.     Counterparts................................................18

Section 12.     Termination of the Trust....................................18

Section 13.     Sale of Underlying Securities...............................18

Section 14.     Amendments..................................................18

Section 15.     Voting of Underlying Securities, Modification of Indenture..19

SCHEDULE I        SERIES 2001-20 UNDERLYING SECURITIES SCHEDULE
SCHEDULE II       CLASS A-2 CERTIFICATE CALL SCHEDULE
EXHIBIT A-1       FORM OF TRUST CERTIFICATE CLASS A-1
EXHIBIT A-2       FORM OF TRUST CERTIFICATE CLASS A-2
EXHIBIT B         FORM OF WARRANT AGENT AGREEMENT
EXHIBIT C         FORM OF INVESTMENT LETTER

<PAGE>

                               SERIES SUPPLEMENT

                      CORPORATE BACKED TRUST CERTIFICATES

                             Series 2001-20 TRUST

          SERIES SUPPLEMENT, Series 2001-20, dated as of May 22, 2001
(the "Series Supplement"), by and between LEHMAN ABS CORPORATION, as Depositor
(the "Depositor"), and U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee (the
"Trustee").

                             W I T N E S S E T H:

               WHEREAS, the Depositor desires to create the Trust designated
herein (the "Trust") by executing and delivering this Series Supplement, which
shall incorporate the terms of the Standard Terms for Trust Agreements, dated
as of January 16, 2001 (the "Standard Terms"; together with this Series
Supplement, the "Trust Agreement"), by and between the Depositor and the
Trustee, as modified by this Series Supplement;

               WHEREAS, the Depositor desires to deposit into the Trust the
Underlying Securities set forth on Schedule I attached hereto (the "Underlying
Securities Schedule") the general terms of which are described in the
Prospectus Supplement under the heading "Description of the Deposited Assets -
Underlying Securities;"

               WHEREAS, in connection with the creation of the Trust and the
deposit therein of the Underlying Securities, it is desired to provide for the
issuance of trust certificates (the "Certificates") evidencing undivided
interests in the Trust; and

               WHEREAS, the Trustee has joined in the execution of the
Standard Terms and this Series Supplement to evidence the acceptance by the
Trustee of the Trust;

               NOW, THEREFORE, in consideration of the foregoing premises and
the mutual covenants expressed herein, it is hereby agreed by and between the
Depositor and the Trustee as follows:

          Section 1. Incorporation of Standard Terms. Except as otherwise
provided herein, all of the provisions of the Standard Terms are hereby
incorporated herein by reference in their entirety, and this Series Supplement
and the Standard Terms shall form a single agreement between the parties. In
the event of any inconsistency between the provisions of this Series
Supplement and the provisions of the Standard Terms, the provisions of this
Series Supplement will control with respect to the Series 2001-20 Certificates
and the transactions described herein.

          Section 2. Definitions. (a) Except as otherwise specified herein or
as the context may otherwise require, the following terms shall have the
respective meanings set forth below for all purposes under this Series
Supplement. (Section 2(b) below sets forth terms listed in the Standard Terms
which are not applicable to this Series.) Capitalized terms used but not
defined herein shall have the meanings assigned to them in the Standard Terms.

               "Available Funds" shall have the meaning specified in the
Standard Terms, except that proceeds of any redemption of the Underlying
Securities and investment income earned on funds invested pursuant to Section
3.05 of the Standard Terms shall be included in Available Funds.

               "Business Day" shall mean any day other than (i) Saturday and
Sunday or (ii) a day on which banking institutions in New York City, New York
are authorized or obligated by law or executive order to be closed for
business or (iii) a day that is not a business day for the purposes of the
Declaration of Trust.

               "Call Date" shall mean any Business Day on or after May 22,
2006, or after the announcement of any redemption or other unscheduled payment
on the Underlying Securities on which the Call Warrants are exercised and the
proceeds of an Optional Call are distributed to holders of the Certificates
pursuant to Section 7 hereof.

               "Call Notice" shall have the meaning specified in Section 1.1
of the Warrant Agent Agreement.

               "Call Price" shall mean, for each related Call Date, (i) in the
case of the Class A-1 Certificates, the par value of the Class A-1
Certificates being purchased pursuant to the exercise of the Call Warrants,
plus any accrued and unpaid interest on such amount (including any deferred
distributions with interest thereon) to but excluding the Call Date and (ii)
in the case of the Class A-2 Certificates, any accrued and unpaid interest on
the notional amount of the Class A-2 Certificates being purchased pursuant to
the exercise of the Call Warrants to but excluding the Call Date, plus the
additional amount (or portion thereof, in the case of a partial call) set
forth under the heading "Value" in Schedule II hereof for such Call Date or,
if such Call Date is not a Distribution Date, the immediately following
Distribution Date.

               "Call Warrants" shall have the meaning specified in Section 3
hereof.

               "Certificate Account" shall have the meaning specified in the
Standard Terms.

               "Certificates" shall have the meaning specified in Section 3
hereof.

               "Class A-1 Allocation" means the sum of the present values
(discounted at the rate of 7.75% per annum) of (i) any unpaid interest due or
to become due on the Class A-1 Certificates and (ii) the outstanding principal
amount of the Certificates (in each case assuming that the Class A-1
Certificates were paid when due and were not redeemed prior to their stated
maturity).

               "Class A-2 Allocation" means the present value (discounted at
the rate of 7.75% per annum) of any unpaid amounts due or to become due on the
Class A-2 Certificates (assuming that the Class A-2 Certificates were paid
when due and were not redeemed prior to their stated maturity).

               "Class A-1 Certificates" shall mean the Certificates, in the
form attached hereto as Exhibit A-1, to be issued by the Trust representing a
proportionate undivided beneficial ownership interest in certain distributions
to be made by the Trust and having the characteristics described herein and in
the Certificates.

               "Class A-2 Certificates" shall mean the Certificates, in the
form attached hereto as Exhibit A-2, to be issued by the Trust representing a
proportionate undivided beneficial ownership interest in certain distributions
to be made by the Trust and having the characteristics described herein and in
the Certificates.

               "Closing Date" shall mean May 22, 2001.

               "Collection Period" shall mean, (i) with respect to each
December Distribution Date, the period beginning on the day after the June
Distribution Date and ending on such December Distribution Date, inclusive
and, (ii) with respect to each June Distribution Date, the period beginning on
the day after the December Distribution Date of a given year and ending on the
June Distribution Date of the following year, inclusive; provided, however,
that clauses (i) and (ii) shall be subject to Section 9(f) hereof.

               "Corporate Trust Office" shall mean the office of U.S. Bank
Trust National Association located at 100 Wall Street, New York, New York
10005.

               "Currency" shall mean United States Dollars.

               "Declaration of Trust" shall mean the declaration of trust
pursuant to which the Underlying Securities were issued.

               "Deferral Period" shall have the meaning specified in Section
5(b).

               "Depository" shall mean The Depository Trust Company.

               "Distribution Date" shall mean June 1st and December 1st of
each year (or if such date is not a Business Day, the next succeeding Business
Day), commencing on June 1, 2001 and ending on the earlier of the Final
Scheduled Distribution Date and any date on which Underlying Securities are
redeemed pursuant to the Declaration of Trust.

               "Eligible Account" shall have the meaning specified in the
Standard Terms.

               "Eligible Investments" shall be as defined in the Standard
Terms; provided, however, that (i) the minimum required rating for long-term
instruments will be equal to the rating of the Underlying Securities, and (ii)
the rating of any short-term instruments will be A-1+ by S&P and P1 by
Moody's; and provided, further, that any such investment matures no later than
the Business Day prior to any related Distribution Date and that any such
investment be denominated in U.S. dollars.

               "Event of Default" shall mean (i) a default in the payment of
any interest on any Underlying Security after the same becomes due and payable
(subject to any permitted deferrals and applicable grace period), (ii) a
default in the payment of the principal of or any installment of principal of
any Underlying Security when the same becomes due and payable, and (iii) any
other event specified as an "Event of Default" in the Declaration of Trust for
the Underlying Securities.

               "Exchange Act" shall mean the Securities and Exchange Act of
1934, as amended, and the rules and regulations promulgated thereunder.

               "Extraordinary Trust Expenses" shall have the meaning specified
in the Standard Terms.

               "Final Scheduled Distribution Date" shall mean June 1, 2027.

               "Interest Accrual Period" shall mean for any Distribution Date,
the period from and including the preceding Distribution Date (or in the case
of the first Interest Accrual Period, from and including May 22, 2001) to but
excluding the current Distribution Date.

               "Liquidation Price" shall mean the price at which the Trustee
sells the Underlying Securities.

               "Liquidation Proceeds" shall have the meaning specified in the
Standard Terms.

               "Maturity Date" shall have the meaning specified in Schedule I
hereto.

               "Moody's" shall mean Moody's Investors Service, Inc.

               "Optional Call" shall mean the call of the Certificates by the
Warrant Holder, in whole or in part, resulting from the exercise of Call
Warrants by the Warrant Holder, pursuant to Section 7(b) hereof.

               "Optional Exchange" shall mean the exchange of the Certificates
by the Trust for the Underlying Securities pursuant to Section 7(a) hereof.

               "Optional Exchange Date" shall mean any Distribution Date on
which Underlying Securities subject to Optional Exchange are distributed to a
Certificateholder.

               "Ordinary Expenses" shall mean the Trustee's ordinary expenses
and overhead in connection with its services as Trustee, including the items
referred to in the definition of Ordinary Expenses in the Standard Terms.

               "Prepaid Ordinary Expenses" shall be zero for this Series.

               "Prospectus Supplement" shall mean the Prospectus Supplement,
dated May 11, 2001, relating to the Certificates.

               "Rating Agency" shall mean Moody's and S&P.

               "Rating Agency Condition" shall have the meaning specified in
the Standard Terms.

               "Record Date" shall mean, with respect to each Distribution
Date, the day immediately preceding the related Distribution Date.

               "Required Interest" shall have the meaning specified in the
Standard Terms.

               "Required Percentage-Amendment" shall be 66-2/3% of the
aggregate Voting Rights, unless the subject amendment requires the vote of
holders of only one Class of Certificates pursuant to the Standard Terms, in
which case 66-2/3% of the Certificate Principal Amount of such Class.

               "Required Percentage-Direction of Trustee" shall be 66-2/3% of
the aggregate Voting Rights.

               "Required Percentage-Remedies" shall be 66-2/3% of the
aggregate Voting Rights.

               "Required Percentage-Removal" shall be 66-2/3% of the aggregate
Voting Rights.

               "Required Rating" shall mean, in the case of Moody's, the
rating assigned to the Underlying Securities by Moody's as of the Closing
Date, and, in the case of S&P, the rating assigned to the Underlying
Securities by S&P as of the Closing Date.

               "S&P" shall mean Standard & Poor's Ratings Services, a division
of The McGraw-Hill Companies, Inc.

               "Series" shall mean Series 2001-20.

               "Special Event" shall have the meaning specified in the
Prospectus Supplement.

               "Trustee Fee" shall mean the amount paid to the Trustee by the
Depositor on the Closing Date.

               "Trust Property" shall mean the Underlying Securities described
on Schedule I hereto and the Certificate Account.

               "Underlying Securities" shall mean $40,220,000 aggregate
principal amount of 8.375% Subordinated Capital Income Securities due June 1,
2027 issued by the Underlying Securities Issuer, as set forth in Schedule I
attached hereto (subject to Section 3(d) hereof).

               "Underlying Securities Issuer" shall mean Washington Mutual
Capital I.

               "Underlying Securities Trustee" shall mean The Bank of New
York.

               "Underwriters" shall mean Lehman Brothers Inc., an affiliate of
the Depositor, A.G. Edwards & Sons, Inc., Dain Rauscher Incorporated, and
Prudential Securities Incorporated.

               "Voting Rights" shall, in the entirety, be allocated among all
Class A-1 Certificateholders in proportion to the then unpaid principal
amounts of their respective Certificates. The Class A-2 Certificateholders
will have no Voting Rights.

               "Warrant Agent" shall mean initially, U.S. Bank Trust National
Association.

               "Warrant Agent Agreement" shall mean that certain Warrant Agent
Agreement, dated as of the date hereof, between the Depositor and U.S. Bank
Trust National Association, as Warrant Agent and as Trustee, as the same may
be amended from time to time.

               "Warrant Holder" shall mean the holder of a Call Warrant.

          (b) The terms listed below are not applicable to this Series.

                     "Accounting Date"

                     "Administrative Fees"

                     "Advance"

                     "Allowable Expense Amounts"

                     "Basic Documents"

                     "Calculation Agent"

                     "Call Premium Percentage"

                     "Credit Support"

                     "Credit Support Instrument"

                     "Credit Support Provider"

                     "Cut-off Date"

                     "Eligible Expense"

                     "Exchange Rate Agent"

                     "Fixed Pass-Through Rate"

                     "Floating Pass-Through Rate"

                     "Guaranteed Investment Contract"

                     "Letter of Credit"

                     "Limited Guarantor"

                     "Limited Guaranty"

                     "Minimum Wire Denomination"

                     "Notional Amount"

                     "Pass-Through Rate"

                     "Place of Distribution"

                     "Purchase Price"

                     "Required Premium"

                     "Required Principal"

                     "Requisite Reserve Amount"

                     "Retained Interest"

                     "Sale Procedures"

                     "Sub-Administration Account"

                     "Sub-Administration Agreement"

                     "Sub-Administration Agent"

                     "Surety Bond"

                     "Swap Agreement"

                     "Swap Counterparty"

                     "Swap Distribution Amount"

                     "Swap Guarantee"

                     "Swap Guarantor"

                     "Swap Receipt Amount"

                     "Swap Termination Payment"

          Section 3. Designation of Trust and Certificates. The Trust created
hereby shall be known as the "Corporate-Backed Trust Certificates, Series
2001-20 Trust." The Certificates evidencing certain undivided ownership
interests therein shall be known as "Corporate Backed Trust Certificates,
Series 2001-20." The Certificates shall consist of the Class A-1 Certificates
and the Class A-2 Certificates (together, the "Certificates"). The Trust is
also issuing call warrants with respect to the Certificates ("Call Warrants").

          (a) The Certificates shall be held through the Depository in
book-entry form and shall be substantially in the forms attached hereto as
Exhibits A-1 and A-2. The Class A-1 Certificates shall be issued in
denominations of $25. The Class A-2 Certificates shall be issued in minimum
notional denominations of $1,000 and integral multiples of $1 in excess
thereof. Except as provided in the Standard Terms and in paragraph (d) in this
Section, the Trust shall not issue additional Certificates or incur any
indebtedness.

          (b) The Class A-1 Certificates have an initial aggregate certificate
principal amount (the "Certificate Principal Amount") of $40,220,000. The
Class A-2 Certificates are interest-only Certificates, and have a notional
amount equal to the Certificate Principal Amount of the Class A-1
Certificates.

          (c) The holders of the Class A-1 Certificates will be entitled to
receive on each Distribution Date the interest, if any, received on the
Underlying Securities, to the extent necessary to pay interest at a rate of
7.75% per annum on the outstanding Certificate Principal Amount of the Class
A-1 Certificates. The holders of the Class A-2 Certificates will be entitled
to receive on each Distribution Date the interest, if any, received on the
Underlying Securities, to the extent necessary to pay interest at a rate of
0.625% per annum on the outstanding notional amount of the Class A-2
Certificates. On June 1, 2001, the Trustee will pay to the Depositor the
amount of interest accrued and paid on the Underlying Securities from December
1, 2000 to but not including the Closing Date. If Available Funds are
insufficient to pay such amount, the Trustee will pay the Depositor its pro
rata share, based on the ratio the amount owed to the Depositor bears to all
amounts owed on the Class A-1 Certificates in respect of accrued interest, of
any proceeds from the recovery on the Underlying Securities.

          (d) The Depositor may sell to the Trustee additional Underlying
Securities on any date hereafter upon at least 3 Business Days notice to the
Trustee and upon (i) satisfaction of the Rating Agency Condition and (ii)
delivery of an Opinion of Counsel to the effect that the sale of such
additional Underlying Securities will not materially increase the likelihood
that the Trust would fail to qualify as a grantor trust under the Code. Upon
such sale to the Trustee, the Trustee shall deposit such additional Underlying
Securities in the Certificate Account, and shall authenticate and deliver to
the Depositor, on its order, Class A-1 Certificates in a Certificate Principal
Amount, and Class A-2 Certificates in a notional amount, equal to the
principal amount of such additional Underlying Securities and the Call
Warrants related thereto. Any such additional Class A-1 Certificates and Class
A-2 Certificates authenticated and delivered shall have the same terms and
rank pari passu with the corresponding classes of Certificates previously
issued in accordance with this Series Supplement.

          (e) As a condition precedent for transferring the Call Warrants, the
prospective transferee shall be required to deliver to the Trustee and the
Depositor an executed copy of the Investment Letter (set forth in Exhibit C
hereto).

          Section 4. Trust Certificates. The Trustee hereby acknowledges
receipt, on or prior to the Closing Date, of:

               (i)  the Underlying Securities set forth on the Underlying
                    Securities Schedule; and

               (ii) all documents required to be delivered to the Trustee
                    pursuant to Section 2.01 of the Standard Terms.

          Section 5. Distributions.

                    (a) Except as otherwise provided in Section 3(c), on each
               applicable Distribution Date, the Trustee shall apply Available
               Funds in the Certificate Account as follows in the following
               order of priority:

               (i)  the Trustee will pay the interest portion of Available
                    Funds (subject to Section 5(c) and Section 5(d) below):

                    (a) first, to the Trustee, as reimbursement for any
                    Extraordinary Trust Expenses incurred by the Trustee in
                    accordance with Section 6(b) below and approved by 100% of
                    the Certificateholders; and

                    (b) second, to the holders of the Class A-1 Certificates
                    and to the holders of the Class A-2 Certificates, interest
                    accrued and unpaid on each such Class pro rata in
                    proportion to their entitlements thereto.

               (ii) the Trustee will pay the principal portion of Available
                    Funds:

                    (a) first, to the Trustee, as reimbursement for any
               remaining Extraordinary Trust Expenses incurred by the Trustee
               in accordance with Section 6(b) below and approved by 100% of
               the Certificateholders; and

                    (b) second, to the holders of the Class A-1 Certificates,
               the Certificate Principal Amount.

          (b) Distributions of interest on the Class A-1 Certificates and
Class A-2 Certificates may be deferred as a result of the deferral of payment
on the Underlying Securities. Distributions on the Underlying Securities may
be deferred pursuant to the Underlying Securities Trust Agreement for up to
ten consecutive semiannual interest periods (each, a "Deferral Period")
provided that no Deferral Period may extend beyond the Final Scheduled
Distribution Date. During any Deferral Period, interest on the Underlying
Securities will continue to accrue at the applicable rate per annum compounded
semi-annually. Interest on deferred and compounded interest on the Class A-1
Certificates and Class A-2 Certificates will be owing only to the extent that
such interest is actually received by the Trustee on the Underlying
Securities.

          (c) Notwithstanding the foregoing, if the Underlying Securities are
redeemed, prepaid or liquidated in whole or in part for any reason (including
a Special Event) other than due to the occurrence of an Event of Default or at
their maturity, the Trustee shall apply Available Funds in the following order
of priority:

               (i)  first, to the Trustee, as reimbursement for any
                    Extraordinary Trust Expenses incurred by the Trustee in
                    accordance with Section 6(b) below and approved by 100% of
                    the Certificateholders;

               (ii) second, to the holders of the Class A-1 Certificates, an
                    amount equal to the outstanding principal amount thereof
                    plus accrued and unpaid interest thereon;

              (iii) third, to the holders of the Class A-2 Certificates, the
                    present value of all amounts that would otherwise have
                    been payable on the Class A-2 Certificates for the period
                    from the date of such redemption or prepayment to the
                    Final Scheduled Distribution Date using a discount rate of
                    8.375% per annum, assuming no delinquencies, deferrals,
                    redemptions or prepayments on the Underlying Securities;
                    and

               (iv) fourth, any remainder to the holders of the Class A-1
                    Certificates and the Class A-2 Certificates pro rata in
                    proportion to the ratio of the Class A-1 Allocation to the
                    Class A-2 Allocation.

          (d) Notwithstanding the foregoing, if the Underlying Securities are
redeemed, prepaid or liquidated in whole or in part due to the occurrence of
an Event of Default, the Trustee shall apply Available Funds to the holders of
the Class A-1 Certificates and the holders of the Class A-2 Certificates in
accordance with the ratio of the Class A-1 Allocation to the Class A-2
Allocation.

          (e) Unless otherwise instructed by holders of Certificates
representing a majority of the Voting Rights, thirty (30) days after giving
notice pursuant to Section 8 hereof, the Trustee shall sell the Underlying
Securities pursuant to Section 13 hereof and deposit the Liquidation Proceeds,
if any, into the Certificate Account for distribution not later than two (2)
Business Days after the receipt of immediately available funds in accordance
with Section 5(d) hereof.

          (f) If the Trustee receives non-cash property in respect of the
Underlying Securities as a result of a payment default on the Underlying
Securities (including from the sale thereof), the Trustee will promptly give
notice to the Depository, or for any Certificates which are not then held by
DTC or any other depository, directly to the registered holders of the
Certificates then outstanding and unpaid. Such notice shall state that the
Trustee shall and the Trustee shall, not later than 30 days after the receipt
of such property, allocate and distribute such property to the holders of
Class A-1 Certificates and Class A-2 Certificates then outstanding and unpaid
(after deducting the costs incurred in connection therewith) in accordance
with Section 5(d) hereof. Property other than cash will be liquidated by the
Trustee, and the proceeds thereof distributed in cash, only to the extent
necessary to avoid distribution of fractional securities to
Certificateholders. In-kind distribution of such property to
Certificateholders will be deemed to reduce the principal amount of
Certificates on a dollar-for-dollar basis.

          (g) Subject to Section 9(f) hereof, to the extent Available Funds
are insufficient to make any required distributions due to any Class of
Certificates on any Distribution Date, any shortfall will be carried over and
will be distributed on the next Distribution Date (or date referred to in
Section 5(h) hereof) on which sufficient funds are available to pay such
shortfall.

          (h) If a payment with respect to the Underlying Securities is made
to the Trustee after the payment date of the Underlying Securities on which
such payment was due, then the Trustee will distribute any such amounts
received on the next occurring Business Day (a "Special Distribution Date") as
if the funds had constituted Available Funds on the Distribution Date
immediately preceding such Special Distribution Date; provided, however, that
the Record Date for such Special Distribution Date shall be five Business Days
prior to the day on which the related payment was received from the Underlying
Securities Trustee.

          (i) Notwithstanding Section 3.12 of the Standard Terms, if the
Underlying Securities Issuer ceases to file periodic reports as required under
the Exchange Act, the Depositor shall within a reasonable time instruct the
Trustee to distribute the Underlying Securities in-kind to the Class A-1
Certificateholders or sell the Underlying Securities and distribute the
proceeds of such sale to the certificateholders in accordance with Section
5(c); provided, however, the Trustee shall not sell the Underlying Securities
unless the proceeds of such sale would exceed the sum of the amounts to be
distributed pursuant to clauses 5(c)(i) and 5(c)(ii) above; and provided,
further, the Depositor shall not instruct the Trustee to distribute or sell
the Underlying Securities pursuant to this clause unless the Underlying
Securities Issuer has either (x) stated in writing that it intends permanently
to cease filing reports required under the Exchange Act or (y) failed to file
any required reports for one full calendar year.

          Section 6. Trustee's Fees.

          (a) As compensation for its services hereunder, the Trustee shall be
entitled to the Trustee Fee. The Trustee Fee shall be paid by the Depositor
and not from Trust Property. The Trustee shall bear all Ordinary Expenses.
Failure by the Depositor to pay such amount shall not entitle the Trustee to
any payment or reimbursement from the Trust, nor shall such failure release
the Trustee from the duties it is required to perform under the Trust
Agreement.

          (b) Extraordinary Expenses shall not be paid out of the Trust
Property unless all the holders of the Class A-1 Certificates and Class A-2
Certificates then outstanding have directed the Trustee to incur such
Extraordinary Expenses. The Trustee may incur other Extraordinary Expenses if
any lesser percentage of the Certificateholders requesting such action
pursuant hereto reimburse the Trustee for the cost thereof from their own
funds in advance. If Extraordinary Expenses are not approved unanimously as
set forth in the first sentence of this Section 6(b), such Extraordinary
Expenses shall not be an obligation of the Trust, and the Trustee shall not
file any claim against the Trust therefor notwithstanding failure of
Certificateholders to reimburse the Trustee.

          Section 7. Optional Exchange; Optional Call.

          (a) (i) On any Distribution Date, any holder of Class A-1
Certificates and Class A-2 Certificates and the related Call Warrants, if Call
Warrants related to such Certificates are outstanding, may exchange such
Certificates and, if applicable, Call Warrants, for a distribution of
Underlying Securities representing the same percentage of the Underlying
Securities as such Certificates represent of all outstanding Certificates.

               (ii) The following conditions shall apply to any Optional
                    Exchange.

                    (a) A notice specifying the number of Certificates being
                    surrendered and the Optional Exchange Date shall be
                    delivered to the Trustee no less than 5 days (or such
                    shorter period acceptable to the Trustee) but not more
                    than 30 days before the Optional Exchange Date.

                    (b) Certificates and, if applicable, the Call Warrants,
                    shall be surrendered to the Trustee no later than 10:00
                    a.m. (New York City time) on the Optional Exchange Date.

                    (c) Class A-1 Certificates and Class A-2 Certificates
                    representing a like percentage of all Class A-1
                    Certificates and Class A-2 Certificates shall be
                    surrendered.

                    (d) The Trustee shall have received an opinion of counsel
                    stating that the Optional Exchange would not affect the
                    characterization of the Trust as a "grantor trust" for
                    federal income tax purposes.

                    (e) If the Certificateholder is the Depositor or any
                    Affiliate of the Depositor, (1) the Trustee shall have
                    received a certification from the Certificateholder that
                    any Certificates being surrendered have been held for at
                    least six months, and (2) the Certificates being
                    surrendered may represent no more than 5% (or 25% in the
                    case of Certificates acquired by the Underwriter but never
                    distributed to investors) of the then outstanding
                    Certificates.

              (iii) The Trustee shall not be obligated to determine whether
                    an Optional Exchange complies with the applicable
                    provisions for exemption under Rule 3a-7 of the Investment
                    Company Act of 1940, as amended, or the rules or
                    regulations promulgated thereunder.

               (iv) The provisions of Section 4.07 of the Standard Terms shall
                    not apply to an Optional Exchange pursuant to this Section
                    7(a). This Section 7(a) shall not provide any person with
                    a lien against, an interest in or a right to specific
                    performance with respect to the Underlying Securities.

          (b) (i) Concurrently with the execution of this Series Supplement,
the Trustee, on behalf of the Trust, shall execute the Warrant Agent Agreement
and the Call Warrants, dated as of the date hereof and substantially in the
form of Exhibit B hereto, initially evidencing all of the Call Warrants. The
Trustee shall perform the Trust's obligations under the Warrant Agent
Agreement and the Call Warrants in accordance with their respective terms.

               (ii) Call Warrants may be exercised by the Warrant Holder in
                    whole or in part on any Call Date. In addition to the
                    conditions set forth in Section 1.1 of the Warrant Agent
                    Agreement, the following conditions shall apply to any
                    Optional Call.

                    (a) An opinion of counsel to the Warrant Holder shall have
                    been delivered to the Rating Agencies, in form
                    satisfactory to the Rating Agencies, indicating that
                    payment of the Call Price shall not be recoverable as a
                    preferential transfer or fraudulent conveyance under the
                    United States Bankruptcy Code. Such opinion may contain
                    customary assumptions and qualifications.

                    (b) The Warrant Holder shall have provided a certificate
                    of solvency to the Trustee.

              (iii) Upon receipt of a Call Notice, the Trustee shall provide
                    a conditional call notice to the Depository not less than
                    3 Business Days prior to the Call Date.

               (iv) Delivery of a Call Notice does not give rise to an
                    obligation on part of the Warrant Holder to pay the Call
                    Price. If, by 10:00 a.m. (New York City time) on the Call
                    Date, the Warrant Holder has not paid the Call Price, then
                    the Call Notice shall automatically expire and none of the
                    Warrant Holder, the Warrant Agent or the Trustee shall
                    have any obligation with respect to the Call Notice. The
                    expiration of a Call Notice shall in no way affect the
                    Warrant Holder's right to deliver a Call Notice at a later
                    date.

               (v)  Subject to receipt of the Call Price, the Trustee shall
                    pay the Call Price to the Certificateholders on the Call
                    Date. The Call Price for Class of Certificates in respect
                    of partial calls shall be allocated pro rata to the
                    Certificateholders of such Class.

               (vi) The Trustee shall not consent to any amendment or
                    modification of this Agreement (including the Standard
                    Terms) which would alter the timing or amount of any
                    payment of the Call Price without the prior written
                    consent of 100% of the Warrant Holders.

              (vii) The Trustee shall not be obligated to determine whether
                    an Optional Call complies with the applicable provisions
                    for exemption under Rule 3a-7 of the Investment Company
                    Act of 1940, as amended, or the rules or regulations
                    promulgated thereunder.

              (viii) This Section 7 shall not provide the Warrant Holder with
                    a lien against, an interest in or a right to specific
                    performance with respect to the Underlying Securities.

               (ix) The Warrant Holder shall initially be the Depositor.

          Section 8. Notices of Events of Default.

          As promptly as practicable after, and in any event within 30 days
after, the occurrence of any Event of Default actually known to the Trustee,
the Trustee shall give notice of such Event of Default to the Depository, or,
if any Certificates are not then held by DTC or any other depository, directly
to the registered holders of such Certificates. However, except in the case of
an Event of Default relating to the payment of principal of or interest on any
of the Underlying Securities, the Trustee will be protected in withholding
such notice if in good faith it determines that the withholding of such notice
is in the interest of the Certificateholders.

          Section 9. Miscellaneous.

          (a) The provisions of Section 4.04, Advances, of the Standard Terms
shall not apply to the Series 2001-20 Certificates.

          (b) The provisions of Section 4.07, Optional Exchange, of the
Standard Terms shall not apply to the Series 2001-20 Certificates.

          (c) The Trustee shall simultaneously forward reports to
Certificateholders pursuant to Section 4.03 of the Standard Terms and to the
New York Stock Exchange.

          (d) Except as expressly provided herein, the Certificateholders
shall not be entitled to terminate the Trust or cause the sale or other
disposition of the Underlying Securities.

          (e) The provisions of Section 3.07(d) of the Standard Terms shall
not apply to the Series 2001-20 Certificates.

          (f) If the Trustee has not received payment with respect to a
Collection Period on the Underlying Securities on or prior to the related
Distribution Date, such distribution will be made promptly upon receipt of
such payment. No additional amounts shall accrue on the Certificates or be
owed to Certificateholders as a result of such delay; provided, however, that
any additional interest owed and paid by the Underlying Securities Issuer as a
result of such delay shall be paid to the Class A-1 Certificateholders pro
rata in proportion to their respective entitlements to interest.

          (g) The outstanding principal balance of the Certificates shall not
be reduced by the amount of any Realized Losses (as defined in the Standard
Terms).

          (h) The Trust may not engage in any business or activities other
than in connection with, or relating to, the holding, protecting and
preserving of the Trust Property and the issuance of the Certificates, and
other than those required or authorized by the Trust Agreement or incidental
and necessary to accomplish such activities. The Trust may not issue or sell
any certificates or other obligations other than the Certificates or otherwise
incur, assume or guarantee any indebtedness for money borrowed.

          (i) Notwithstanding anything in the Trust Agreement to the contrary,
the Trustee may be removed upon 60 days prior written notice delivered by the
holders of Class A-1 Certificates and Class A-2 Certificates representing the
Required Percentage-Removal.

          (j) In the event that the Internal Revenue Service challenges the
characterization of the Trust as a grantor trust, the Trustee shall then file
such forms as the Depositor may specify to establish the Trust's election
pursuant to Section 761 of the Code to exclude the Trust from the application
of Subchapter K of the Code and is hereby empowered to execute such forms on
behalf of the Certificateholders.

          (k) Notwithstanding anything in the Standard Terms to the contrary,
the Trustee, upon written direction by the Depositor, will execute the
Certificates.

          (l) In relation to Section 7.01(f) of the Standard Terms, any
periodic reports filed by the Trustee pursuant to the Exchange Act in
accordance with the customary practices of the Depositor, need not contain any
independent reports.

          (m) Notwithstanding anything in the Trust Agreement to the contrary,
the Trustee will have no recourse to the Underlying Securities.

          (n) The Trustee shall promptly notify each Rating Agency upon its
obtaining actual knowledge of the occurrence of a Defeasance (as defined in
the Declaration of Trust) with respect to the Underlying Securities Issuer.

         (o) The Trust will not merge or consolidate with any other entity
without confirmation from each Rating Agency that such merger or consolidation
will not result in the qualification, reduction or withdrawal of its
then-current rating on the Certificates.

          (p) Notices. All directions, demands and notices hereunder or under
the Standard Terms shall be in writing and shall be delivered as set forth
below (unless written notice is otherwise provided to the Trustee).

                  If to the Depositor, to:

                           Lehman ABS Corporation
                           3 World Financial Center
                           New York, New York 10285
                           Attention: Structured Credit Trading
                           Telephone: (212) 526-6570
                           Facsimile: (212) 526-1546

                  If to the Trustee, to:

                           U.S. Bank Trust National Association
                           100 Wall Street
                           New York, New York 10005
                           Attention: Corporate Trust
                           Telephone: (212) 361-2500
                           Facsimile: (212) 809-5459

                  If to the Rating Agencies, to:

                           Moody's Investors Service, Inc.
                           99 Church Street 21W
                           New York, New York 10007
                           Attention: CBO/CLO Monitoring Department
                           Telephone: (212) 553-1494
                           Facsimile: (212) 553-0355

         and to:

                           Standard & Poor's
                           55 Water Street
                           New York, New York 10041
                           Attention: Structured Finance Surveillance Group
                           Telephone: (212) 438-2482
                           Facsimile: (212) 438-2664

                  If to the New York Stock Exchange, to:

                           New York Stock Exchange, Inc.
                           20 Broad Street
                           New York, New York 10005
                           Attention: Michael Hyland
                           Telephone: (212) 656-5868
                           Facsimile: (212) 656-6919

          Section 10. Governing Law. THIS SERIES SUPPLEMENT AND THE
TRANSACTIONS DESCRIBED HEREIN SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK APPLICABLE TO CONTRACTS
MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO THE
CHOICE OF LAWS PROVISIONS THEREOF.

          Section 11. Counterparts. This Series Supplement may be executed in
any number of counterparts, each of which shall be deemed to be an original,
and all such counterparts shall constitute but one and the same instrument.

          Section 12. Termination of the Trust. The Trust shall terminate upon
the earliest to occur of (i) the payment in full at maturity or sale by the
Trust after a payment default or an acceleration or other early payment of the
Underlying Securities and the distribution in full of all amounts due to the
Class A-1 Certificateholders and Class A-2 Certificateholders; (ii) the
exercise of all outstanding Call Warrants by the Warrant Holder; (iii) the
Final Scheduled Distribution Date and (iv) the expiration of 21 years from the
death of the last survivor of the descendants of Joseph P. Kennedy, the late
Ambassador of the United States to the Court of St. James, living on the date
hereof.

          Section 13. Sale of Underlying Securities; Optional Exchange. In the
event of a sale of the Underlying Securities pursuant to Section 5(e) hereof
or pursuant to the instructions of the Warrant Agent under Section 1.2 of the
Warrant Agent Agreement, the Trustee shall solicit bids for the sale of the
Underlying Securities with settlement thereof on or before the third (3rd)
Business Day after such sale from three leading dealers in the relevant
market. Any of the following dealers (or their successors) shall be deemed to
qualify as leading dealers: (1) Credit Suisse First Boston Corporation, (2)
Goldman, Sachs & Co., (3) Merrill Lynch, Pierce, Fenner & Smith Incorporated,
(4) UBS Warburg LLC, (5) Salomon Smith Barney Inc., and (6) except in the case
of a sale following an Optional Exchange under Section 7(a) hereof, Lehman
Brothers Inc. The Trustee shall not be responsible for the failure to obtain a
bid so long as it has made reasonable efforts to obtain bids. If a bid for the
sale of the Underlying Securities has been accepted by the Trustee but the
sale has failed to settle on the proposed settlement date, the Trustee shall
request new bids from such leading dealers. to the Class A-1 and Class A-2
Certificateholders. In the event of an Optional Exchange, the Trustee shall
only deliver the Underlying Securities to the purchaser of such Underlying
Securities or sell the Underlying Securities pursuant to this Section 13, as
the case may be, against payment in same day funds deposited into the
Certificate Account.

          Section 14. Amendments. Notwithstanding anything in the Trust
Agreement to the contrary, in addition to the other restrictions on
modification and amendment contained therein, the Trustee shall not enter into
any amendment or modification of the Trust Agreement which would adversely
affect in any material respect the interests of the holders of any class of
Certificates without the consent of the holders of 100% of such class of
Certificates; provided, however, that no such amendment or modification will
be permitted which would alter the status of the Trust as a grantor trust for
federal income tax purposes. Further, no amendment shall be permitted which
would adversely affect in any material respect the interests of any Class of
Certificateholders without confirmation by each Rating Agency that such
amendment will not result in a downgrading or withdrawal of its rating of such
Class of Certificates.

          Section 15. Voting of Underlying Securities, Modification of
Indenture. The Trustee, as holder of the Underlying Securities, has the right
to vote and give consents and waivers in respect of the Underlying Securities
as permitted by the Depository and except as otherwise limited by the Trust
Agreement. In the event that the Trustee receives a request from the
Depository, the Underlying Securities Trustee or the Underlying Securities
Issuer for its consent to any amendment, modification or waiver of the
Underlying Securities, the Declaration of Trust or any other document
thereunder or relating thereto, or receives any other solicitation for any
action with respect to the Underlying Securities, the Trustee shall mail a
notice of such proposed amendment, modification, waiver or solicitation to
each Certificateholder of record as of such date. The Trustee shall request
instructions from the Certificateholders as to whether or not to consent to or
vote to accept such amendment, modification, waiver or solicitation. The
Trustee shall consent or vote, or refrain from consenting or voting, in the
same proportion (based on the relative outstanding principal balances of the
Class A-1 Certificates) as the Certificates of the Trust were actually voted
or not voted by the Certificateholders thereof as of a date determined by the
Trustee prior to the date on which such consent or vote is required; provided,
however, that, notwithstanding anything in the Trust Agreement to the
contrary, the Trustee shall at no time vote on or consent to any matter (i)
unless such vote or consent would not (based on an opinion of counsel) alter
the status of the Trust as a grantor trust for federal income tax purposes or
result in the imposition of tax upon the Certificateholders, (ii) which would
alter the timing or amount of any payment on the Underlying Securities,
including, without limitation, any demand to accelerate the Underlying
Securities, except in the event of a default under the Underlying Securities
or an event which with the passage of time would become an event of default
under the Underlying Securities and with the unanimous consent of all
outstanding Class A-1 Certificateholders and the Class A-2 Certificateholders,
or (iii) which would result in the exchange or substitution of any of the
outstanding Underlying Securities pursuant to a plan for the refunding or
refinancing of such Underlying Securities except in the event of a default
under the Declaration of Trust and only with the consent of Certificateholders
representing 100% of the Class A-1 Certificates and 100% of the Class A-2
Certificates. The Trustee shall have no liability for any failure to act
resulting from Certificateholders' late return of, or failure to return,
directions requested by the Trustee from the Certificateholders.

          In the event that an offer is made by the Underlying Securities
Issuer to issue new obligations in exchange and substitution for any of the
Underlying Securities, pursuant to a plan for the refunding or refinancing of
the outstanding Underlying Securities or any other offer is made for the
Underlying Securities, the Trustee shall notify the Class A-1
Certificateholders and Class A-2 Certificateholders of such offer promptly.
The Trustee must reject any such offer unless the Trustee is directed by the
affirmative vote of the holders of 100% of the Class A-1 Certificates and
Class A-2 Certificates to accept such offer and the Trustee has received the
tax opinion described above. If pursuant to the preceding sentence, the
Trustee accepts any such offer the Trustee shall promptly notify the Rating
Agencies.

          If an event of default under the Declaration of Trust occurs and is
continuing, and if directed by a majority of the outstanding Class A-1
Certificateholders and Class A-2 Certificateholders, the Trustee shall vote
the Underlying Securities in favor of directing, or take such other action as
may be appropriate to direct, the Underlying Securities Trustee to declare the
unpaid principal amount of the Underlying Securities and any accrued and
unpaid interest thereon to be due and payable.

          IN WITNESS WHEREOF, the parties hereto have caused this Series
Supplement to be duly executed by their respective authorized officers as of
the date first written above.

                                     LEHMAN ABS CORPORATION,
                                         as Depositor

                                     By:  /s/  Rene Canezin
                                         ----------------------------------
                                          Name:  Rene Canezin
                                          Title: Senior Vice President

                                     U.S. BANK TRUST NATIONAL ASSOCIATION,
                                        not in its individual capacity
                                        but solely as Trustee on behalf
                                        of the Corporate Backed Trust
                                        Certificates Series, 2001-20
                                        Trust

                                     By:  /s/ Marlene Fahey
                                          ----------------------------------
                                          Name:  Marlene Fahey
                                          Title: Vice President and
                                                 Assistant Secretary

<PAGE>

                                                                    SCHEDULE I

                                SERIES 2001-20

                        UNDERLYING SECURITIES SCHEDULE

Underlying Securities:                       8.375% Subordinated Capital Income
                                             Securities due 2027.

Underlying Securities Issuer:                Washington Mutual Capital I

CUSIP Number:                                939318AA9

Principal Amount Deposited:                  $40,220,000

Original Issue Date:                         June 1, 1997.

Principal Amount of
Underlying Securities
Originally Issued:                           $400,000,000

Maturity Date:                               June 1, 2027.

Principal Payment Date:                      June 1, 2027.

Interest Rate:                               8.375% per annum.

Interest Payment Dates:                      June 1st and December 1st.

Underlying Securities Record Dates:          The day immediately preceding each
                                             Distribution Date.

<PAGE>

                                                                   SCHEDULE II

                      CLASS A-2 CERTIFICATE CALL SCHEDULE

          Distribution Date                Value

              06/01/2001                $2,314,922
              12/01/2001                $2,304,980
              06/01/2002                $2,294,542
              12/01/2002                $2,283,581
              06/01/2003                $2,272,073
              12/01/2003                $2,259,989
              06/01/2004                $2,247,301
              12/01/2004                $2,233,978
              06/01/2005                $2,219,990
              12/01/2005                $2,205,302
              06/01/2006                $2,189,879
              12/01/2006                $2,173,686
              06/01/2007                $2,156,683
              12/01/2007                $2,138,829
              06/01/2008                $2,120,083
              12/01/2008                $2,100,400
              06/01/2009                $2,079,732
              12/01/2009                $2,058,032
              06/01/2010                $2,035,246
              12/01/2010                $2,011,320
              06/01/2011                $1,986,199
              12/01/2011                $1,959,821
              06/01/2012                $1,932,125
              12/01/2012                $1,903,044
              06/01/2013                $1,872,508
              12/01/2013                $1,840,446
              06/01/2014                $1,806,781
              12/01/2014                $1,771,433
              06/01/2015                $1,734,317
              12/01/2015                $1,695,345
              06/01/2016                $1,654,425
              12/01/2016                $1,611,459
              06/01/2017                $1,566,344
              12/01/2017                $1,518,974
              06/01/2018                $1,469,235
              12/01/2018                $1,417,009
              06/01/2019                $1,362,172
              12/01/2019                $1,304,593
              06/01/2020                $1,244,135
              12/01/2020                $1,180,655
              06/01/2021                $1,114,000
              12/01/2021                $1,044,012
              06/01/2022                $  970,526
              12/01/2022                $  893,364
              06/01/2023                $  812,345
              12/01/2023                $  727,275
              06/01/2024                $  637,951
              12/01/2024                $  544,161
              06/01/2025                $  445,682
              12/01/2025                $  342,278
              06/01/2026                $  233,705
              12/01/2026                $  119,702
              06/01/2027                     --

<PAGE>

EXHIBIT A-1
                           FORM OF TRUST CERTIFICATE

                             CLASS A-1 CERTIFICATE

NUMBER 1                                        1,608,800 $25 PAR CERTIFICATES
                                                         CUSIP NO. 21988G 73 4

                      SEE REVERSE FOR CERTAIN DEFINITIONS

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUER OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

THIS CERTIFICATE REPRESENTS A PROPORTIONATE UNDIVIDED BENEFICIAL OWNERSHIP
INTEREST IN THE TRUST AND DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, AND IS NOT GUARANTEED BY THE DEPOSITOR OR THE TRUSTEE OR ANY OF THEIR
RESPECTIVE AFFILIATES. NEITHER THIS CERTIFICATE OR THE TRUST ASSETS ARE
INSURED OR GUARANTEED BY ANY GOVERNMENTAL AGENCY OR ANY OTHER PERSON.

                            LEHMAN ABS CORPORATION.

                               1,608,800 $25 PAR

                     CORPORATE BACKED TRUST CERTIFICATES,

                                SERIES 2001-20

7.75% INTEREST RATE

evidencing a proportionate undivided beneficial ownership interest in the
Trust, as defined below, the property of which consists principally of
$40,220,000 aggregate principal amount of 8.375% Subordinated Capital Income
Securities due June 1, 2027, issued by Washington Mutual Capital I and all
payments received thereon (the "Trust Property"), deposited in trust by Lehman
ABS Corporation (the "Depositor").

THIS CERTIFIES THAT CEDE & CO. is the registered owner of $40,220,000 DOLLARS
nonassessable, fully-paid, proportionate undivided beneficial ownership
interest in the Corporate Backed Trust Certificates, Series 2001-20 Trust,
formed by the Depositor.

<PAGE>

The Trust was created pursuant to a Standard Terms for Trust Agreements, dated
as of January 16, 2001 (the "Standard Terms"), between the Depositor and U.S.
Bank Trust National Association, a national banking association, not in its
individual capacity but solely as Trustee (the "Trustee"), as supplemented by
the Series Supplement, Series 2001-20, dated as of May 22, 2001 (the "Series
Supplement" and, together with the Standard Terms, the "Trust Agreement"),
between the Depositor and the Trustee. This Certificate does not purport to
summarize the Trust Agreement and reference is hereby made to the Trust
Agreement for information with respect to the interests, rights, benefits,
obligations, proceeds and duties evidenced hereby and the rights, duties and
obligations of the Trustee with respect hereto. A copy of the Trust Agreement
may be obtained from the Trustee by written request sent to the Corporate
Trust Office. Capitalized terms used but not defined herein have the meanings
assigned to them in the Trust Agreement.

This Certificate is one of the duly authorized Certificates designated as the
"Corporate Backed Trust Certificates, Series 2001-20, Class A-1" (herein
called the "Certificates"). This Certificate is issued under and is subject to
the terms, provisions and conditions of the Trust Agreement, to which Trust
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound. The Trust Property consists of: (i)
Underlying Securities described in the Trust Agreement; (ii) all payments on
or collections in respect of the Underlying Securities accrued on or after May
22, 2001 together with any proceeds thereof; and (iii) all funds from time to
time deposited with the Trustee relating to the Certificates, together with
any and all income, proceeds and payments with respect thereto; provided,
however, that any income from the investment of Trust funds in certain
permitted investments ("Eligible Investments") does not constitute Trust
Property.

Subject to the terms and conditions of the Trust Agreement (including the
availability of funds for distributions) and until the obligation created by
the Trust Agreement shall have terminated in accordance therewith,
distributions will be made on each Distribution Date, to the Person in whose
name this Certificate is registered on the applicable Record Date, in an
amount equal to such Certificateholder's proportionate undivided beneficial
ownership interest in the amount required to be distributed to the Holders of
the Certificates on such Distribution Date. The Record Date applicable to any
Distribution Date is the close of business on the day immediately preceding
such Distribution Date (whether or not a Business Day). If a payment with
respect to the Underlying Securities is made to the Trustee after the date on
which such payment was due, then the Trustee will distribute any such amounts
received on the next occurring Business Day (a "Special Distribution Date").

Each Certificateholder, by its acceptance of a Certificate, covenants and
agrees that such Certificateholder will not at any time institute against the
Trust, or join in any institution against the Trust of, any bankruptcy
proceedings under any United States Federal or state bankruptcy or similar law
in connection with any obligations relating to the Certificates or the Trust
Agreement.

Distributions made on this Certificate will be made as provided in the Trust
Agreement by the Trustee by wire transfer in immediately available funds, or
check mailed to the Certificateholder of record in the Certificate Register
without the presentation or surrender of this Certificate or the making of any
notation hereon, except that with respect to Certificates registered on the
Record Date in the name of the nominee of the Clearing Agency (initially, such
nominee shall be Cede & Co.), payments will be made by wire transfer in
immediately available funds to the account designated by such nominee. Except
as otherwise provided in the Trust Agreement and notwithstanding the above,
the final distribution on this Certificate will be made after due notice by
the Trustee of the pendency of such distribution and only upon presentation
and surrender of this Certificate at the Corporate Trust Office or such other
location as may be specified in such notice.

Reference is hereby made to the further provisions of this Certificate 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 or on
behalf of the Trustee, by manual signature, this Certificate shall not entitle
the Holder hereof to any benefit under the Trust Agreement or be valid for any
purpose.

THIS CERTIFICATE SHALL BE CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE
OF NEW YORK, WITHOUT REFERENCE TO ITS CONFLICT OF LAW PROVISIONS, AND THE
OBLIGATIONS, RIGHTS AND REMEDIES OF THE HOLDER HEREOF SHALL BE DETERMINED IN
ACCORDANCE WITH SUCH LAWS.

<PAGE>

IN WITNESS WHEREOF, the Trustee has caused this Certificate to be duly
executed as of the date set forth below.

                              CORPORATE BACKED TRUST CERTIFICATES,
                              SERIES 2001-20 TRUST

                              By: U.S. BANK TRUST NATIONAL ASSOCIATION
                              not in its individual capacity but solely as
                              Trustee,

                              By:
                                  -----------------------------------------
                                  Authorized Signatory

Dated: May 22, 2001

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is on one of the Corporate Backed Trust Certificates, Series 2001-20,
described in the Trust Agreement referred to herein.

U.S. BANK TRUST NATIONAL ASSOCIATION
not in its individual capacity but solely as
Trustee,

By:
    ---------------------------------
    Authorized Signatory

<PAGE>

                           (REVERSE OF CERTIFICATE)

The Certificates are limited in right of distribution to certain payments and
collections respecting the Underlying Securities, all as more specifically set
forth herein and in the Trust Agreement. The registered Holder hereof, by its
acceptance hereof, agrees that it will look solely to the Trust Property (to
the extent of its rights therein) for distributions hereunder.

The Trust Agreement permits, with certain exceptions therein provided, the
amendment thereof and the modification of the rights and obligations of the
Depositor and the Trustee and the rights of the Certificateholders under the
Trust Agreement at any time by the Depositor and the Trustee with the consent
of the holders of Class A-1 Certificates in the manner set forth in the Series
Supplement and the Standard Terms. Any such consent by the Holder of this
Certificate (or any predecessor Certificate) shall be conclusive and binding
on such Holder and upon all future Holders of this Certificate and of any
Certificate issued upon the transfer hereof or in exchange hereof or in lieu
hereof whether or not notation of such consent is made upon this Certificate.
The Trust Agreement also permits the amendment thereof, in certain limited
circumstances, without the consent of the Holders of any of the Certificates.

The Certificates are issuable in fully registered form only in denominations
of $25.

As provided in the Trust Agreement and subject to certain limitations therein
set forth, the transfer of this Certificate is registerable in the Certificate
Register upon surrender of this Certificate for registration of transfer at
the offices or agencies of the Certificate Registrar maintained by the Trustee
in the Borough of Manhattan, the City of New York, duly endorsed by or
accompanied by an assignment in the form below and by such other documents as
required by the Trust Agreement, and thereupon one or more new Certificates of
the same class in authorized denominations evidencing the same principal
amount will be issued to the designated transferee or transferees. The initial
Certificate Registrar appointed under the Trust Agreement is U.S. Bank Trust
National Association.

No service charge will be made for any registration of transfer or exchange,
but the Trustee may require exchange of a sum sufficient to cover any tax or
other governmental charge that may be imposed in connection with any transfer
or exchange of Certificates.

The Depositor and the Trustee and any agent of the Depositor or the Trustee
may treat the Person in whose name this Certificate is registered as the owner
hereof for all purposes, and neither the Depositor, the Trustee, nor any such
agent shall be affected by any notice to the contrary.

It is the intention of the parties to the Trust Agreement that the Trust
created thereunder shall constitute a fixed investment trust for federal
income tax purposes under Treasury Regulation Section 301.7701-4, and the
Certificateholder agrees to treat the Trust, any distributions therefrom and
its beneficial interest in the Certificates consistently with such
characterization.

The Trust and the obligations of the Depositor and the Trustee created by the
Trust Agreement with respect to the Certificates shall terminate upon the
earliest to occur of (i) the payment in full at maturity or sale by the Trust
after a payment default on or an acceleration or other early payment of the
Underlying Securities and the distribution in full of all amounts due to the
Class A-1 and Class A-2 Certificateholders; (ii) the exercise of all
outstanding Call Warrants by the Warrant Holder; (iii) the Final Scheduled
Distribution Date and (iv) the expiration of 21 years from the death of the
last survivor of the descendants of Joseph P. Kennedy, the late Ambassador of
the United States to the Court of St. James, living on the date hereof.

An employee benefit plan subject to the Employee Retirement Income Security
Act of 1974, as amended ("ERISA"), a plan described in Section 4975(e) of the
Code, an entity whose underlying assets include plan assets by reason of any
such plan's investment in the entity, including an individual retirement
account or Keogh plan (any such, a "Plan") may purchase and hold Certificates
if the Plan can represent and warrant that its purchase and holding of the
Certificates would not be prohibited under ERISA or the Code.

<PAGE>

                                  ASSIGNMENT

FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto

PLEASE INSERT SOCIAL SECURITY
OR OTHER IDENTIFYING NUMBER
OF ASSIGNEE

(Please print or type name and address, including postal zip code, of
assignee) the within Certificate, and all rights thereunder, hereby
irrevocably constituting and appointing _________________________ Attorney to
transfer said Certificate on the books of the Certificate Register, with full
power of substitution in the premises.

Dated:

                                                           *
                                                       Signature Guaranteed:

                                                           *

*NOTICE: The signature to this assignment must correspond with the name as it
appears upon the face of the within Certificate in every particular, without
alteration, enlargement or any change whatever. Signatures must be guaranteed
by an "eligible guarantor institution" meeting the requirements of the
Certificate Registrar, which requirements include membership or participation
in the Security Transfer Agent Medallion Program ("STAMP") or such other
"signature guarantee program" as may be determined by the Certificate
Registrar in addition to, or in substitution for, STAMP, all in accordance
with the Securities Exchange Act of 1934, as amended

<PAGE>

EXHIBIT A-2
                           FORM OF TRUST CERTIFICATE

                             CLASS A-2 CERTIFICATE

NUMBER 1                                                 CUSIP NO. 21988G AS 5

                      SEE REVERSE FOR CERTAIN DEFINITIONS

         THIS CLASS A-2 CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE TRANSFERRED, SOLD OR
OTHERWISE DISPOSED OF EXCEPT WHILE A REGISTRATION UNDER SUCH ACT IS IN EFFECT
OR PURSUANT TO AN EXEMPTION THEREFROM UNDER SUCH ACT. THE CLASS A-2
CERTIFICATE REPRESENTED HEREBY MAY BE TRANSFERRED ONLY IN ACCORDANCE WITH THE
TERMS OF THE SERIES SUPPLEMENT.

         THE NOTIONAL PRINCIPAL AMOUNT OF THIS CLASS A-2 CERTIFICATE IS AS SET
FORTH HEREIN. ACCORDINGLY, THE OUTSTANDING NOTIONAL PRINCIPAL AMOUNT OF THIS
CLASS A-2 CERTIFICATE AT ANY TIME MAY BE LESS THAN THE AMOUNT SHOWN ON THE
FACE HEREOF.

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUER
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER
NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT
IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         THIS CERTIFICATE REPRESENTS A PROPORTIONATE UNDIVIDED BENEFICIAL
OWNERSHIP INTEREST IN THE TRUST AND DOES NOT EVIDENCE AN OBLIGATION OF, OR AN
INTEREST IN, AND IS NOT GUARANTEED BY THE DEPOSITOR OR THE TRUSTEE OR ANY OF
THEIR RESPECTIVE AFFILIATES. NEITHER THIS CERTIFICATE OR THE TRUST ASSETS ARE
INSURED OR GUARANTEED BY ANY GOVERNMENTAL AGENCY OR ANY OTHER PERSON.

<PAGE>

                            LEHMAN ABS CORPORATION

                     CORPORATE BACKED TRUST CERTIFICATES,

                                SERIES 2001-20

                     $40,220,000 NOTIONAL PRINCIPAL AMOUNT

0.625% INTEREST RATE

         evidencing a proportionate undivided beneficial ownership interest in
the Trust, as defined below, the property of which consists principally of
$40,220,000 aggregate notional principal amount of 8.375% Subordinated Capital
Income Securities due June 1, 2027, issued by Washington Mutual Capital I and
all payments received thereon (the "Trust Property"), deposited in trust by
Lehman ABS Corporation (the "Depositor").

         THIS CERTIFIES THAT CEDE & CO. is the registered owner of an
aggregate principal amount of $40,220,000 notional principal amount
nonassessable, fully-paid, proportionate undivided beneficial ownership
interest in the Corporate Backed Trust Certificates, Series 2001-20 Trust,
formed by the Depositor.

         The Trust was created pursuant to a Standard Terms for Trust
Agreements, dated as of January 16, 2001 (the "Standard Terms"), between the
Depositor and U.S. Bank Trust National Association , a national banking
association, not in its individual capacity but solely as Trustee (the
"Trustee"), as supplemented by the Series Supplement, Series 2001-20, dated as
of May 22, 2001 (the "Series Supplement" and, together with the Standard
Terms, the "Trust Agreement"), between the Depositor and the Trustee. This
Certificate does not purport to summarize the Trust Agreement and reference is
hereby made to the Trust Agreement for information with respect to the
interests, rights, benefits, obligations, proceeds and duties evidenced hereby
and the rights, duties and obligations of the Trustee with respect hereto. A
copy of the Trust Agreement may be obtained from the Trustee by written
request sent to the Corporate Trust Office. Capitalized terms used but not
defined herein have the meanings assigned to them in the Trust Agreement.

         This Certificate is one of the duly authorized Certificates
designated as the "Corporate Backed Trust Certificates, Series 2001-20, Class
A-2" (herein called the "Certificates"). This Certificate is issued under and
is subject to the terms, provisions and conditions of the Trust Agreement, to
which Trust Agreement the Holder of this Certificate by virtue of the
acceptance hereof assents and by which such Holder is bound. The Trust
Property consists of: (i) Underlying Securities described in the Trust
Agreement; (ii) all payments on or collections in respect of the Underlying
Securities accrued on or after May 22, 2001 together with any proceeds
thereof; and (iii) all funds from time to time deposited with the Trustee
relating to the Certificates, together with any and all income, proceeds and
payments with respect thereto; provided, however, that any income from the
investment of Trust funds in certain permitted investments ("Eligible
Investments") does not constitute Trust Property.

         Subject to the terms and conditions of the Trust Agreement (including
the availability of funds for distributions) and until the obligation created
by the Trust Agreement shall have terminated in accordance therewith,
distributions of interest will be made on this Certificate on each
Distribution Date.

         Subject to the terms and conditions of the Trust Agreement (including
the availability of funds for distributions) and until the obligation created
by the Trust Agreement shall have terminated in accordance therewith,
distributions will be made on each Distribution Date, to the Person in whose
name this Certificate is registered on the applicable Record Date, in an
amount equal to such Certificateholder's proportionate undivided beneficial
ownership interest in the amount required to be distributed to the Holders of
the Certificates on such Distribution Date. The Record Date applicable to any
Distribution Date is the close of business on the day immediately preceding
such Distribution Date (whether or not a Business Day). If a payment with
respect to the Underlying Securities is made to the Trustee after the date on
which such payment was due, then the Trustee will distribute any such amounts
received on the next occurring Business Day (a "Special Distribution Date").

         Each Certificateholder, by its acceptance of a Certificate, covenants
and agrees that such Certificateholder will not at any time institute against
the Trust, or join in any institution against the Trust of, any bankruptcy
proceedings under any United States Federal or state bankruptcy or similar law
in connection with any obligations relating to the Certificates or the Trust
Agreement.

         Distributions made on this Certificate will be made as provided in
the Trust Agreement by the Trustee by wire transfer in immediately available
funds, or check mailed to the Certificateholder of record in the Certificate
Register without the presentation or surrender of this Certificate or the
making of any notation hereon, except that with respect to Certificates
registered on the Record Date in the name of the nominee of the Clearing
Agency (initially, such nominee shall be Cede & Co.), payments will be made by
wire transfer in immediately available funds to the account designated by such
nominee. Except as otherwise provided in the Trust Agreement and
notwithstanding the above, the final distribution on this Certificate will be
made after due notice by the Trustee of the pendency of such distribution and
only upon presentation and surrender of this Certificate at the Corporate
Trust Office or such other location as may be specified in such notice.

         Reference is hereby made to the further provisions of this
Certificate 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
or on behalf of the Trustee, by manual signature, this Certificate shall not
entitle the Holder hereof to any benefit under the Trust Agreement or be valid
for any purpose.

         THIS CERTIFICATE SHALL BE CONSTRUED IN ACCORDANCE WITH THE LAWS OF
THE STATE OF NEW YORK, WITHOUT REFERENCE TO ITS CONFLICT OF LAW PROVISIONS,
AND THE OBLIGATIONS, RIGHTS AND REMEDIES OF THE HOLDER HEREOF SHALL BE
DETERMINED IN ACCORDANCE WITH SUCH LAWS.

<PAGE>

         IN WITNESS WHEREOF, the Trustee has caused this Certificate to be
duly executed as of the date set forth below.

                        CORPORATE BACKED TRUST CERTIFICATES,
                        SERIES 2001- 20 TRUST

                        By: U.S. BANK TRUST NATIONAL ASSOCIATION
                        not in its individual capacity but solely as
                        Trustee,

                        By:
                            ------------------------------------------
                            Authorized Signatory

Dated: May 22, 2001

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

         This is on one of the Corporate Backed Trust Certificates, Series
2001-20, described in the Trust Agreement referred to herein.

U.S. BANK TRUST NATIONAL ASSOCIATION
not in its individual capacity but solely as
Trustee,

By:
    ---------------------------------
    Authorized Signatory

<PAGE>

                           (REVERSE OF CERTIFICATE)

The Certificates are limited in right of distribution to certain payments and
collections respecting the Underlying Securities, all as more specifically set
forth herein and in the Trust Agreement. The registered Holder hereof, by its
acceptance hereof, agrees that it will look solely to the Trust Property (to
the extent of its rights therein) for distributions hereunder.

The Trust Agreement permits, with certain exceptions therein provided, the
amendment thereof and the modification of the rights and obligations of the
Depositor and the Trustee and the rights of the Certificateholders under the
Trust Agreement at any time by the Depositor and the Trustee with the consent
of the holders of Class A-2 Certificates in the manner set forth in the Series
Supplement and the Standard Terms. Any such consent by the Holder of this
Certificate (or any predecessor Certificate) shall be conclusive and binding
on such Holder and upon all future Holders of this Certificate and of any
Certificate issued upon the transfer hereof or in exchange hereof or in lieu
hereof whether or not notation of such consent is made upon this Certificate.
The Trust Agreement also permits the amendment thereof, in certain limited
circumstances, without the consent of the Holders of any of the Certificates.

The Certificates are issuable in fully registered form only in denominations
of $1,000 and in integral multiples of $1 in excess thereof.

As provided in the Trust Agreement and subject to certain limitations therein
set forth, the transfer of this Certificate is registerable in the Certificate
Register upon surrender of this Certificate for registration of transfer at
the offices or agencies of the Certificate Registrar maintained by the Trustee
in the Borough of Manhattan, the City of New York, duly endorsed by or
accompanied by an assignment in the form below and by such other documents as
required by the Trust Agreement, and thereupon one or more new Certificates of
the same class in authorized denominations evidencing the same notional
principal amount will be issued to the designated transferee or transferees.
The initial Certificate Registrar appointed under the Trust Agreement is U.S.
Bank Trust National Association.

No service charge will be made for any registration of transfer or exchange,
but the Trustee may require exchange of a sum sufficient to cover any tax or
other governmental charge that may be imposed in connection with any transfer
or exchange of Certificates.

The Depositor and the Trustee and any agent of the Depositor or the Trustee
may treat the Person in whose name this Certificate is registered as the owner
hereof for all purposes, and neither the Depositor, the Trustee, nor any such
agent shall be affected by any notice to the contrary.

It is the intention of the parties to the Trust Agreement that the Trust
created thereunder shall constitute a fixed investment trust for federal
income tax purposes under Treasury Regulation Section 301.7701-4, and the
Certificateholder agrees to treat the Trust, any distributions therefrom and
its beneficial interest in the Certificates consistently with such
characterization.

The Trust and the obligations of the Depositor and the Trustee created by the
Trust Agreement with respect to the Certificates shall terminate upon the
earliest to occur of (i) the payment in full at maturity or sale by the Trust
after a payment default on or an acceleration or other early payment of the
Underlying Securities and the distribution in full of all amounts due to the
Class A-1 and Class A-2 Certificateholders; (ii) the exercise of all
outstanding Call Warrants by the Warrant Holder; (iii) the Final Scheduled
Distribution Date and (iv) the expiration of 21 years from the death of the
last survivor of the descendants of Joseph P. Kennedy, the late Ambassador of
the United States to the Court of St. James, living on the date hereof.

An employee benefit plan subject to the Employee Retirement Income Security
Act of 1974, as amended ("ERISA"), a plan described in Section 4975(e) of the
Code, an entity whose underlying assets include plan assets by reason of any
such plan's investment in the entity, including an individual retirement
account or Keogh plan (any such, a "Plan") may purchase and hold Certificates
if the Plan can represent and warrant that its purchase and holding of the
Certificates would not be prohibited under ERISA or the Code.

<PAGE>

                                  ASSIGNMENT

FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto

PLEASE INSERT SOCIAL SECURITY
OR OTHER IDENTIFYING NUMBER
OF ASSIGNEE

(Please print or type name and address, including postal zip code, of
assignee) the within Certificate, and all rights thereunder, hereby
irrevocably constituting and appointing Attorney to transfer said Certificate
on the books of the Certificate Register, with full power of substitution in
the premises.

Dated:

                                                           *
                                                   Signature Guaranteed:

                                                           *

*NOTICE: The signature to this assignment must correspond with the name as it
appears upon the face of the within Certificate in every particular, without
alteration, enlargement or any change whatever. Signatures must be guaranteed
by an "eligible guarantor institution" meeting the requirements of the
Certificate Registrar, which requirements include membership or participation
in the Security Transfer Agent Medallion Program ("STAMP") or such other
"signature guarantee program" as may be determined by the Certificate
Registrar in addition to, or in substitution for, STAMP, all in accordance
with the Securities Exchange Act of 1934, as amended.

<PAGE>

EXHIBIT B

                        FORM OF WARRANT AGENT AGREEMENT

                      CORPORATE BACKED TRUST CERTIFICATES

                             Series 2001-20 TRUST

         WARRANT AGENT AGREEMENT, dated as of May 22, 2001 (the "Warrant Agent
Agreement"), by and between LEHMAN ABS CORPORATION, as Depositor (the
"Depositor"), and U.S. BANK TRUST NATIONAL ASSOCIATION, as Warrant Agent (the
"Warrant Agent").

                             W I T N E S S E T H:

         WHEREAS, the Depositor created Corporate Backed Trust Certificates,
Series 2001-20 Trust (the "Trust"), a trust created under the laws of the
State of New York pursuant to a Standard Terms for Trust Agreements, dated as
of January 16, 2001 (the "Agreement"), between Lehman ABS Corporation (the
"Depositor") and U.S. Bank Trust National Association, a national banking
association, not in its individual capacity but solely as Trustee (the
"Trustee"), as supplemented by the Series Supplement 2001-20, dated as of May
22, 2001 (the "Series Supplement" and, together with the Agreement, the "Trust
Agreement"), between the Depositor and the Trustee; and

         WHEREAS, in connection with the creation of the Trust and the deposit
therein of the Underlying Securities, it is desired to provide for the
issuance of trust certificates (the "Certificates") evidencing undivided
interests in the Trust and call warrants with respect to the Certificates
("Call Warrants").

         NOW, THEREFORE, in consideration of the foregoing premises and the
mutual covenants expressed herein, it is hereby agreed by and between the
Depositor and the Trustee as follows:

         Section 1. Definitions. Except as otherwise specified herein or as
the context may otherwise require, capitalized terms used herein but not
defined herein shall have the respective meanings set forth below for all
purposes under the Series Supplement.

                                   ARTICLE I

                           Exercise of Call Warrants

     Section 1.1 Manner of Exercise. (a) Call Warrants may be exercised by any
holder thereof (each, a "Warrant Holder") in whole or in part on any Call
Date. The following conditions shall apply to any exercise of Call Warrants:

          (i) A notice (each, a "Call Notice") specifying the number of Call
     Warrants being exercised and the Call Date shall be delivered to the
     Warrant Agent and the Trustee at least 5 Business Days before such Call
     Date.

          (ii) The Warrant Holder shall surrender the Call Warrants to the
     Warrant Agent at its office specified in Section 6.3 hereof no later than
     10:00 a.m. (New York City time) on such Call Date.

          (iii) The Warrant Holder shall have made payment to the Warrant
     Agent, by wire transfer or other immediately available funds acceptable
     to the Warrant Agent, in the amount of the Call Price, no later than
     10:00 a.m. (New York City time) on the Call Date.

          (iv) The Warrant Holder shall exercise Call Warrants relating to
     Class A-1 Certificates and Call Warrants relating to Class A-2
     Certificates which represent a like percentage of all Class A-1
     Certificates and Class A-2 Certificates.

          (v) The Warrant Holder may not exercise the Call Warrants at any
     time when such Warrant Holder is insolvent, and such Warrant Holder shall
     be required to certify that it is solvent at the time of exercise, by
     completing the Form of Subscription attached to the Call Warrants and
     delivering such completed Form of Subscription to the Trustee on or prior
     to the Call Date and by delivering to the Trustee a form reasonably
     satisfactory to the Trustee of the opinion and the solvency certificate
     required pursuant to Section 7(b)(ii) of the Series Supplement.

          (vi) The Warrant Holder shall have satisfied any other conditions to
     the exercise of Call Warrants set forth in Section 7(b) of the Series
     Supplement.

          (b) Upon exercise of Call Warrants, any Warrant Holder other than
the Depositor or any Affiliate of the Depositor shall be entitled to delivery
of the Called Certificates. The "Called Certificates" shall be Certificates
having a Certificate Principal Amount or notional amount, as applicable, equal
to $25 per Call Warrant. Unless otherwise specified therein, such Call Notice
shall be deemed to be notice of an Optional Exchange pursuant to Section 7(a)
of the Series Supplement. Any Warrant Holder which is the Depositor or any
Affiliate of the Depositor shall receive the proceeds of the sale of the
Called Underlying Securities and shall not be entitled to receive the related
Called Certificates. "Called Underlying Securities" are Underlying Securities
which represent the same percentage of the Underlying Securities as the Called
Certificates represent of the Class A-1 Certificates and Class A-2
Certificates.

          (c) The Warrant Agent shall notify the Trustee immediately upon its
receipt of a Call Notice and upon receipt of payment of the Call Price. The
Warrant Agent shall transfer the amount any paid Call Price to the Trustee in
immediately available funds, for application pursuant to the Trust Agreement
on the applicable Call Date (and, pending such transfer, shall hold such
amount for the benefit of the Warrant Holder in a segregated trust account).

          (d) Delivery of a Call Notice does not give rise to an obligation on
part of the Warrant Holder to pay the Call Price. If, by 10:00 a.m. (New York
City time) on the Call Date, the Warrant Holder has not paid the Call Price,
then the Call Notice shall automatically expire and none of the Warrant
Holder, the Warrant Agent or the Trustee shall have any obligation with
respect to the Call Notice. The expiration of a Call Notice shall in no way
affect the Warrant Holder's right to deliver a Call Notice at a later date.

     Section 1.2 Transfer of Certificates. As soon as practicable after
each surrender of Call Warrants in whole or in part on the Call Date and upon
satisfaction of all other requirements described in the Call Warrants and in
Section 1.1 hereof, the Warrant Agent shall instruct the Trustee as follows:

          (a) if Call Warrants are being exercised by any Warrant Holder other
than the Depositor or any Affiliate of the Depositor, to cause the Called
Certificates to reflect the holder's beneficial ownership of such
Certificates, or

          (b) if the Call Warrants are being exercised by the Depositor or any
Affiliate of the Depositor, to cause the Called Underlying Securities to be
sold pursuant to Section 13 of the Series Supplement and to distribute the
proceeds of such sale to the Warrant Holder.

          If such exercise is in part only, the Warrant Agent shall instruct
the Trustee to authenticate new Call Warrants of like tenor, representing the
outstanding Call Warrants of the Warrant Holder and the Warrant Agent shall
deliver such Call Warrants to the Warrant Holder.

     Section 1.3 Cancellation and Destruction of Call Warrants. All Call
Warrants surrendered to the Warrant Agent for the purpose of exercise (in
whole or in part) pursuant to Section 1.1 and actually exercised, or for the
purpose of transfer or exchange pursuant to Article III, shall be cancelled by
the Warrant Agent, and no Call Warrant shall be issued in lieu thereof. The
Warrant Agent shall destroy all cancelled Call Warrants.

     Section 1.4 No Rights as Holder of Certificates Conferred by Call
Warrants. Prior to the exercise thereof, Call Warrants shall not entitle the
Warrant Holder to any of the rights of a holder of the Certificates,
including, without limitation, the right to receive the payment of any amount
on or in respect of the Certificates or to enforce any of the covenants of the
Trust Agreement.

                                  ARTICLE II

                           Restrictions on Transfer

     Section 2.1 Restrictive Legends. Except as otherwise permitted by
this Article II, each Call Warrant (including each Call Warrant issued upon
the transfer of any Call Warrant) shall be issued with a legend in
substantially the following form:

     "This Call Warrant has not been registered under the Securities Act
of 1933, as amended, and may not be transferred, sold or otherwise disposed of
except while a registration under such Act is in effect or pursuant to an
exemption therefrom under such Act. The Call Warrant represented hereby may be
transferred only in compliance with the conditions specified in the Call
Warrants."

    Section 2.2 Notice of Proposed Transfer; Opinions of Counsel. Prior
to any transfer of any Call Warrant or portion thereof, the Warrant Holder
will give 5 Business Days (or such lesser period acceptable to the Warrant
Agent) prior written notice to the Warrant Agent of such Warrant Holder's
intention to effect such transfer.

                                  ARTICLE III

               Registration and Transfer of Call Warrants, etc.

     Section 3.1 Warrant Register; Ownership of Call Warrants. The Warrant
Agent will keep a register in which the Warrant Agent will provide for the
registration of Call Warrants and the registration of transfers of Call
Warrants representing whole numbers of Call Warrants. The Trustee and the
Warrant Agent may treat the Person in whose name any Call Warrant is
registered on such register as the owner thereof for all purposes, and the
Trustee and the Warrant Agent shall not be affected by any notice to the
contrary.

     Section 3.2 Transfer and Exchange of Call Warrants. Upon surrender of any
Call Warrant for registration of transfer or for exchange to the Warrant
Agent, the Warrant Agent shall (subject to compliance with Article II) execute
and deliver, and cause the Trustee, on behalf of the Trust, to execute and
deliver, in exchange therefor, a new Call Warrant of like tenor and evidencing
a like whole number of Call Warrants, in the name of such Warrant Holder or as
such Warrant Holder (upon payment by such Warrant Holder of any applicable
transfer taxes or government charges) may direct; provided that as a condition
precedent for transferring the Call Warrants, the prospective transferee shall
be required to deliver to the Trustee and the Depositor an executed copy of
the Investment Letter (set forth as Exhibit C to the Series Supplement).

     Section 3.3 Replacement of Call Warrants. Upon receipt of evidence
reasonably satisfactory to the Warrant Agent of the loss, theft, destruction
or mutilation of any Call Warrant and, in the case of any such loss, theft or
destruction of any Call Warrant, upon delivery of an indemnity bond in such
reasonable amount as the Warrant Agent may determine, or, in the case of any
such mutilation, upon the surrender of such Call Warrant for cancellation to
the Warrant Agent, the Warrant Agent shall execute and deliver, and cause the
Trustee, on behalf of the Trust, to execute and deliver, in lieu thereof, a
new Call Warrant of like tenor bearing a number not contemporaneously
outstanding.

     Section 3.4 Execution and Delivery of Call Warrants by Trustee. The
Trustee, on behalf of the Trust, hereby agrees (subject to compliance with
Article II) to execute and deliver such new Call Warrants issued in accordance
with Section 1.2 or this Article III as the Warrant Agent shall request in
accordance herewith.

                                  ARTICLE IV

                                  Definitions

     As used herein, unless the context otherwise requires, the following
terms have the following respective meanings:

     "Business Day": As defined in the Trust Agreement.

     "Call Date": Any Business Day on or after May 22, 2006 or after the
announcement of any redemption or other unscheduled payment or sale of the
Underlying Securities on which the Call Warrants are exercised and the
proceeds of an Optional Call (as defined in the Series Supplement) are
distributed to the holders of the Certificates pursuant to Section 7 of the
Series Supplement.

     "Call Price": (i) in the case of the Class A-1 Certificates, the par
value of the Class A-1 Certificates being purchased pursuant to the exercise
of the Call Warrants, plus any accrued and unpaid interest on such amount to
but excluding the Call Date and (ii) in the case of the Class A-2
Certificates, any accrued and unpaid interest on the notional amount of the
Class A-2 Certificates being purchased pursuant to the exercise of the Call
Warrants to but excluding the Call Date, plus the additional amount (or
portion thereof, in the case of a partial call) set forth under the heading
"Value" in Schedule II to Series Supplement for such Call Date or, if such
Call Date is not a distribution date, the immediately following Distribution
Date.

     "Call Warrant": As defined in the recitals.

     "Closing Date": May 22, 2001.

     "Depositor": As defined in the recitals.

     "Depositor Order": As defined in the Trust Agreement.

     "Person": Any individual, corporation, partnership, joint venture,
association, joint stock company, trust (including any beneficiary thereof),
unincorporated organization or government or any agency or political
subdivision thereof.

     "Rating Agencies": Standard & Poor's Ratings Services and Moody's
Investors Service, Inc. and any successor thereto.

     "Responsible Officer": As defined in the Trust Agreement.

     "Securities Act": The Securities Act of 1933, or any similar federal
statute, and the rules and regulations of the Commission thereunder, all as
the same shall be in effect at the time.

     "Trust": As defined in the recitals.

     "Trust Agreement": As defined in the recitals.

     "Trustee": As defined in the introduction to this Warrant, or any
successor thereto under the Trust Agreement.

     "Warrant Agent": U.S. Bank Trust National Association, a national banking
association, in its capacity as warrant agent hereunder, or any successor
thereto.

                                   ARTICLE V

                                 Warrant Agent

     Section 5.1 Limitation on Liability. The Warrant Agent shall be protected
and shall incur no liability for or in respect of any action taken, suffered
or omitted by it in connection with its administration of the Call Warrants in
reliance upon any instrument of assignment or transfer, power of attorney,
endorsement, affidavit, letter, notice, direction, consent, certificate,
statement or other paper or document in good faith believed by it to be
genuine and to be signed, executed and, where necessary, verified and
acknowledged, by the proper Person or Persons.

     Section 5.2 Duties of Warrant Agent. The Warrant Agent undertakes only
the specific duties and obligations imposed hereunder upon the following terms
and conditions, by all of which the Depositor, the Trust, the Trustee and each
Warrant Holder shall be bound:

          (a) The Warrant Agent may consult with legal counsel (who may be
legal counsel for the Depositor), and the opinion of such counsel shall be
full and complete authorization and protection to the Warrant Agent as to any
action taken or omitted by it in good faith and in accordance with such
opinion, provided the Warrant Agent shall have exercised reasonable care in
the selection by it of such counsel.

          (b) Whenever in the performance of its duties hereunder, the Warrant
Agent shall deem it necessary or desirable that any fact or matter be proved
or established by the Depositor or the Trustee prior to taking or suffering
any action hereunder, such fact or matter may be deemed to be conclusively
proved and established by a Depositor Order or a certificate signed by a
Responsible Officer of the Trustee and delivered to the Warrant Agent; and
such certificate shall be full authorization to the Warrant Agent for any
action taken or suffered in good faith by it hereunder in reliance upon such
certificate.

          (c) The Warrant Agent shall be liable hereunder only for its own
negligence, willful misconduct or bad faith.

          (d) The Warrant Agent shall not be liable for or by reason of any of
the statements of fact or recitals contained herein or be required to verify
the same, but all such statements and recitals are and shall be deemed to have
been made by the Trust and the Depositor only.

          (e) The Warrant Agent shall not have any responsibility in respect
of and makes no representation as to the validity of the Call Warrants or the
execution and delivery thereof (except the due execution hereof by the Warrant
Agent); nor shall it be responsible for any breach by the Trust of any
covenant or condition contained in the Call Warrants; nor shall it by any act
thereunder be deemed to make any representation or warranty as to the
Certificates to be purchased thereunder.

          (f) The Warrant Agent is hereby authorized and directed to accept
instructions with respect to the performance of its duties hereunder from the
Chairman of the Board, the Chief Executive Officer, Chief Financial Officer,
Chief Operating Officer, President, a Vice President, a Senior Vice President,
a Managing Director, its Treasurer, an Assistant Treasurer, its Secretary or
an Assistant Secretary of the Depositor, and any Responsible Officer of the
Trustee, and to apply to such officers for advice or instructions in
connection with its duties, and it shall not be liable for any action taken or
suffered to be taken by it in good faith in accordance with instructions of
any such officer.

          (g) The Warrant Agent and any shareholder, director, officer or
employee of the Warrant Agent may buy, sell or deal in any of the Call
Warrants or other securities of the Trust or otherwise act as fully and freely
as though it were not Warrant Agent hereunder, so long as such persons do so
in full compliance with all applicable laws. Nothing herein shall preclude the
Warrant Agent from acting in any other capacity for the Trust, the Depositor
or for any other legal entity.

          (h) The Warrant Agent may execute and exercise any of the rights or
powers hereby vested in it or perform any duty hereunder either itself or by
or through its attorneys or agents.

          (i) The Warrant Agent shall act solely as the agent of the Trust
hereunder. The Warrant Agent shall not be liable except for the failure to
perform such duties as are specifically set forth herein, and no implied
covenants or obligations shall be read into the Call Warrants against the
Warrant Agent, whose duties shall be determined solely by the express
provisions thereof. The Warrant Agent shall not be deemed to be a fiduciary.

          (j) The Warrant Agent shall not be responsible for any failure on
the part of the Trustee to comply with any of its covenants and obligations
contained herein.

          (k) The Warrant Agent shall not be under any obligation or duty to
institute, appear in or defend any action, suit or legal proceeding in respect
hereof, unless first indemnified to its satisfaction, but this provision shall
not affect the power of the Warrant Agent to take such action as the Warrant
Agent may consider proper, whether with or without such indemnity. The Warrant
Agent shall promptly notify the Depositor and the Trustee in writing of any
claim made or action, suit or proceeding instituted against it arising out of
or in connection with the Call Warrants.

          (l) The Trustee will perform, execute, acknowledge and deliver or
cause to be performed, executed, acknowledged and delivered all such further
acts, instruments and assurances as may be required by the Warrant Agent in
order to enable it to carry out or perform its duties hereunder.

     Section 5.3 Change of Warrant Agent. The Warrant Agent may resign
and be discharged from its duties hereunder upon thirty (30) days notice in
writing mailed to the Depositor and the Trustee by registered or certified
mail, and to the Warrant Holders by first-class mail at the expense of the
Depositor; provided that no such resignation or discharge shall become
effective until a successor Warrant Agent shall have been appointed hereunder.
The Depositor may remove the Warrant Agent or any successor Warrant Agent upon
thirty (30) days notice in writing, mailed to the Warrant Agent or successor
Warrant Agent, as the case may be, and to the Warrant Holders by first-class
mail; provided further that no such removal shall become effective until a
successor Warrant Agent shall have been appointed hereunder. If the Warrant
Agent shall resign or be removed or shall otherwise become incapable of
acting, the Depositor shall promptly appoint a successor to the Warrant Agent,
which may be designated as an interim Warrant Agent. If an interim Warrant
Agent is designated, the Depositor shall then appoint a permanent successor to
the Warrant Agent, which may be the interim Warrant Agent. If the Depositor
shall fail to make such appointment of a permanent successor within a period
of thirty (30) days after such removal or within sixty (60) days after
notification in writing of such resignation or incapacity by the resigning or
incapacitated Warrant Agent or by the Warrant Holder, then the Warrant Agent
or registered Warrant Holder may apply to any court of competent jurisdiction
for the appointment of such a successor. Any successor to the Warrant Agent
appointed hereunder must be rated in one of the four highest rating categories
by the Rating Agencies. Any entity which may be merged or consolidated with or
which shall otherwise succeed to substantially all of the trust or agency
business of the Warrant Agent shall be deemed to be the successor Warrant
Agent without any further action.

                                  ARTICLE VI

                                 Miscellaneous

     Section 6.1 Remedies. The remedies at law of the Warrant Holder in
the event of any default or threatened default by the Warrant Agent in the
performance of or compliance with any of the terms of the Call Warrants are
not and will not be adequate and, to the full extent permitted by law, such
terms may be specifically enforced by a decree for the specific performance of
any agreement contained herein or by an injunction against a violation of any
of the terms thereof or otherwise.

     Section 6.2 Limitation on Liabilities of Warrant Holder. Nothing
contained in this Warrant Agent Agreement shall be construed as imposing any
obligation on the Warrant Holder to purchase any of the Certificates except in
accordance with the terms thereof.

    Section 6.3 Notices. All notices and other communications under this
Warrant Agent Agreement shall be in writing and shall be delivered, or mailed
by registered or certified mail, return receipt requested, by a nationally
recognized overnight courier, postage prepaid, addressed (a) if to any Warrant
Holder, at the registered address of such Warrant Holder as set forth in the
register kept by the Warrant Agent or (b) if to the Warrant Agent, to 100 Wall
Street, Suite 1600, New York, New York 10005, Attention: Corporate Trust or to
such other address notice of which the Warrant Agent shall have given to the
Warrant Holder and the Trustee or (c) if to the Trust or the Trustee, to the
Corporate Trust Office (as set forth in the Trust Agreement); provided that
the exercise of any Call Warrants shall be effective in the manner provided in
Article I.

    Section 6.4 Amendment. (a) This Warrant Agent Agreement may be
amended from time to time by the Depositor, the Trustee and the Warrant Agent
without the consent of any Warrant Holder, upon receipt of an opinion of
counsel satisfactory to the Warrant Agent that the provisions hereof have been
satisfied and that such amendment would not alter the status of the Trust as a
grantor trust under the Code, for any of the following purposes: (i) to cure
any ambiguity or to correct or supplement any provision herein which may be
defective or inconsistent with any other provision herein or to provide for
any other terms or modify any other provisions with respect to matters or
questions arising under the Call Warrant which shall not adversely affect in
any material respect the interests of the Warrant Holder or any holder of a
Certificate or (ii) to evidence and provide for the acceptance of appointment
hereunder of a Warrant Agent other than U.S. Bank Trust National Association.

          (a) Without limiting the generality of the foregoing, the Call
Warrants may also be modified or amended from time to time by the Depositor,
the Trustee and the Warrant Agent with the consent of Warrant Holders of
66-2/3% of each of the Call Warrants related to the Class A-1 Certificates and
the Call Warrants related to the Class A-2 Certificates, upon receipt of an
opinion of counsel satisfactory to the Warrant Agent that the provisions
hereof (including, without limitation, the following proviso) have seen
satisfied, for the purpose of adding any provisions to or changing in any
manner or eliminating any of the provisions of the Call Warrants or of
modifying in any manner the rights of the Warrant Holders; provided, however,
that no such amendment shall (i) adversely affect in any material respect the
interests of holders of Certificates without the consent of the holders of
Certificates evidencing not less than the Required Percentage-Amendment of the
aggregate Voting Rights of such affected Certificates (as such terms are
defined in the Trust Agreement) and without written confirmation from the
Rating Agencies that such amendment will not result in a downgrading or
withdrawal of its rating of the Certificates; (ii) alter the terms on which
Call Warrants are exercisable or the amounts payable upon exercise of a
Warrant without the consent of the holders of Certificates evidencing not less
than 100% of the aggregate Voting Rights of such affected Certificates and
100% of the affected Warrant Holders or (iii) reduce the percentage of
aggregate Voting Rights required by (i) or (ii) without the consent of the
holders of all such affected Certificates. Notwithstanding any other provision
of this Warrant, this Section 6.4(b) shall not be amended without the consent
of 100% of the affected Warrant Holders.

          (b) Promptly after the execution of any such amendment or
modification, the Warrant Agent shall furnish a copy of such amendment or
modification to each Warrant Holder, to the Trustee and to the Rating
Agencies. It shall not be necessary for the consent of Warrant Holders or
holders of Certificates under this Section to approve the particular form of
any proposed amendment, but it shall be sufficient if such consent shall
approve the substance thereof. The manner of obtaining such consents and of
evidencing the authorization of the execution thereof shall be subject to such
reasonable regulations as the Warrant Agent may prescribe.

    Section 6.5 Expiration. The right to exercise the Call Warrants shall
expire on the earliest to occur of (a) the cancellation thereof, (b) the
termination of the Trust Agreement, (c) the liquidation, disposition, or
maturity of all of the Certificates, or (d) the occurrence of an Event of
Default under the Trust Agreement.

    Section 6.6 Descriptive Headings. The headings in this Warrant Agent
Agreement are for purposes of reference only and shall not limit or otherwise
affect the meaning hereof.

    Section 6.7 GOVERNING LAW. THIS CALL WARRANT SHALL BE CONSTRUED AND
ENFORCED IN ACCORDANCE WITH, AND THE RIGHTS OF THE PARTIES SHALL BE GOVERNED
BY, THE LAW OF THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICT
OF LAWS.

    Section 6.8 Judicial Proceedings; Waiver of Jury. Any judicial
proceeding brought against the Trust, the Trustee or the Warrant Agent with
respect to this Warrant Agent Agreement may be brought in any court of
competent jurisdiction in the County of New York, State of New York or of the
United States of America for the Southern District of New York and, by
execution and delivery of the Call Warrants, the Trustee on behalf of the
Trust and the Warrant Agent (a) accept, generally and unconditionally, the
nonexclusive jurisdiction of such courts and any related appellate court, and
irrevocably agree that the Trust, the Trustee and the Warrant Agent shall be
bound by any judgment rendered thereby in connection with this Warrant Agent
Agreement or the Call Warrants, subject to any rights of appeal, and (b)
irrevocably waive any objection that the Trust, the Trustee or the Warrant
Agent may now or hereafter have as to the venue of any such suit, action or
proceeding brought in such a court or that such court is an inconvenient
forum.

     Section 6.9 Nonpetition Covenant; No Recourse. Each of (i) the
Warrant Holder by its acceptance thereof, and (ii) the Warrant Agent agrees,
that it shall not (and, in the case of the Warrant Holder, that it shall not
direct the Warrant Agent to), until the date which is one year and one day
after the payment in full of the Certificates and all other securities issued
by the Trust, the Depositor or entities formed, established or settled by the
Depositor, acquiesce, petition or otherwise invoke or cause the Trust, the
Depositor, or any such other entity to invoke the process of the United States
of America, any State or other political subdivision thereof or any entity
exercising executive, legislative, judicial, regulatory or administrative
functions of or pertaining to government for the purpose of commencing or
sustaining a case by or against the Trust, the Depositor or any such other
entity under a federal or state bankruptcy, insolvency or similar law or
appointing a receiver, liquidator, assignee, trustee, custodian, sequestrator
or other similar official of the Trust, the Depositor or any such other entity
or all or any part of the property or assets of Trust, the Depositor or any
such other entity or ordering the winding up or liquidation of the affairs of
the Trust, the Depositor or any such other entity.

     Each of (i) the Warrant Holder, by its acceptance thereof, and (ii) the
Warrant Agent agrees, that it shall not have any recourse to the Certificates.

<PAGE>

                                   U.S. BANK TRUST NATIONAL ASSOCIATION,
                                         not in its individual
                                         capacity but solely as
                                         Trustee and Authenticating Agent

                                   By:
                                       --------------------------------------
                                       Authorized Signatory

                                   U.S. BANK TRUST NATIONAL ASSOCIATION,
                                         as Warrant Agent

                                   By:
                                       --------------------------------------
                                       Authorized Signatory

<PAGE>

EXHIBIT C

                           FORM OF INVESTMENT LETTER

                         QUALIFIED INSTITUTIONAL BUYER

                                                    Date: [_______________]

U.S. Bank Trust National Association,
100 Wall Street
New York, New York 10005

Lehman Brothers Inc.
 as initial Warrant Holder
3 World Financial Center
New York, New York 10285

Lehman ABS Corporation
3 World Financial Center
New York, New York 10285

Ladies and Gentlemen:

         In connection with our proposed purchase of ___________ Call Warrants
(the "Call Warrants") representing an interest in the Corporate Backed Trust
Certificates Series 2001-20 Trust (the "Trust"), the investor on whose behalf
the undersigned is executing this letter (the "Purchaser") confirms that:

         (1) Reference is made to the Prospectus Supplement, dated May 11,
2001 (the "Prospectus Supplement"), with respect to the Certificates to which
the Call Warrants relate. Capitalized terms used herein that are not otherwise
defined shall have the meanings ascribed thereto in the Prospectus Supplement.
The Purchaser has received a copy of the Prospectus Supplement and such other
information as the Purchaser deems necessary in order to make its investment
decision and the Purchaser has been provided the opportunity to ask questions
of, and receive answers from, the Depositor and the Underwriters, concerning
the terms and conditions of the Call Warrants. The Purchaser has received and
understands the above, and understands that substantial risks are involved in
an investment in the Call Warrants. The Purchaser represents that in making
its investment decision to acquire the Call Warrants, the Purchaser has not
relied on representations, warranties, opinions, projections, financial or
other information or analysis, if any, supplied to it by any person, including
you, the Depositor or the Trustee or any of your or their affiliates, except
as expressly contained in the Prospectus Supplement and in the other written
information, if any, discussed above. The Purchaser has such knowledge and
experience in financial and business matters as to be capable of evaluating
the merits and risks of an investment in the Call Warrants, and the Purchaser
is able to bear the substantial economic risks of such an investment. The
Purchaser has relied upon its own tax, legal and financial advisors in
connection with its decision to purchase the Call Warrants.

         (2) The Purchaser is (A) a "Qualified Institutional Buyer" (as
defined in Rule 144A under the Securities Act of 1933, as amended (the "1933
Act")) and (B) acquiring the Call Warrants for its own account or for the
account of an investor of the type described in clause (A) above as to each of
which the Purchaser exercises sole investment discretion. The Purchaser is
purchasing the Call Warrants for investment purposes and not with a view to,
or for, the offer or sale in connection with, a public distribution or in any
other manner that would violate the 1933 Act or the securities or blue sky
laws of any state.

         (3) The Purchaser understands that the Call Warrants have not been
and will not be registered under the 1933 Act or under the securities or blue
sky laws of any state, and that (i) if it decides to resell, pledge or
otherwise transfer any Call Warrant, such Call Warrant may be resold, pledged
or transferred without registration only to an entity that has delivered to
the Depositor and the Trustee a certification that it is a Qualified
Institutional Buyer that purchases (1) for its own account or (2) for the
account of such a Qualified Institutional Buyer, that is, in either case,
aware that the resale, pledge or transfer is being made in reliance on said
Rule 144A and (ii) it will, and each subsequent holder will be required to,
notify any purchaser of any Call Warrant from it of the resale restrictions
referred to in clause (i) above.

         (4) The Purchaser understands that each of the Call Warrants will
bear a legend to the following effect, unless otherwise agreed by the
Depositor and the Trustee:

         "THIS CALL WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT
OF 1933, AS AMENDED, AND MAY NOT BE TRANSFERRED, SOLD OR OTHERWISE DISPOSED OF
EXCEPT WHILE A REGISTRATION UNDER SUCH ACT IS IN EFFECT OR PURSUANT TO AN
EXEMPTION THEREFROM UNDER SUCH ACT. THIS CALL WARRANT REPRESENTED HEREBY MAY
BE TRANSFERRED ONLY IN COMPLIANCE WITH THE CONDITIONS SPECIFIED IN THIS CALL
WARRANT."

         (5) The Purchaser understands that no subsequent transfer of the Call
Warrants is permitted unless it causes its proposed transferee to provide to
the Depositor and the initial Warrant Holder a letter substantially in the
form of Exhibit C to the Series Supplement, as applicable, or such other
written statement as the Depositor shall prescribe.

         (6) The Purchaser agrees that if at some time in the future it wishes
to transfer or exchange any of the Call Warrants, it will not transfer or
exchange any of the Call Warrants unless such transfer or exchange is in
accordance with Section 3.2 of the Warrant Agent Agreement. The Purchaser
understands that any purported transfer of the Call Warrants (or any interest
therein) in contravention of any of the restrictions and conditions in the
Trust Agreement, as applicable, shall be void, and the purported transferee in
such transfer shall not be recognized by the Trust or any other Person as a
Warrant Holder.

         You and the Trustee are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any
interested party in any administrative or legal proceeding or official inquiry
with respect to the matters covered hereby.

                                 Very truly yours,

                                 By:
                                    ----------------------------------
                                 Name:
                                 Title:

                                 [Medallion Stamp to be affixed here]

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00026-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00026-of-00352.parquet"}]]