STRUCTURED ASSET INVESTMENT LOAN TRUST ......PROSPECTUS SUPPLEMENT (To Prospectus dated January 25,...

PROSPECTUS SUPPLEMENT(To Prospectus dated January 25, 2005)

$2,485,384,000 (Approximate)

STRUCTURED ASSET INVESTMENT LOAN TRUSTMortgage Pass-Through Certificates, Series 2005-5

Aurora Loan Services LLCMaster Servicer

CIFG Assurance North America, Inc.Class A8 and Class A9 Certificate Insurer

Lehman Brothers Holdings Inc.Sponsor and Seller

Structured Asset Securities CorporationDepositor

The trust will issue certificates including the following classes offeredhereby:

s Eight classes of senior certificates

s One class of subordinate senior certificates

s Ten classes of subordinate certificates

The classes of certificates offered by this prospectus supplement arelisted, together with their initial class principal amounts and interest rates, inthe table under ‘‘The Offered Certificates’’ on page S-1 of this prospectussupplement. This prospectus supplement and the accompanying prospectusrelate only to the offering of the certificates listed in the table on page S-1and not to the other classes of certificates that will be issued by the trustfund as described in this prospectus supplement.

Principal and interest will be payable monthly, as described in thisprospectus supplement. The first expected distribution date will be June 27,2005. Credit enhancement for the offered certificates includes excess interest,overcollateralization, subordination, loss allocation and limited cross-collateralization features and primary mortgage insurance, and, in the case ofthe Class A8 and Class A9 Certificates only, two certificate guaranty

insurance policies issued by CIFG Assurance North America, Inc., which will guarantee certain payments of interestand principal to the holders of the Class A8 and Class A9 Certificates, to the extent described in this prospectussupplement. Amounts payable under an interest rate swap agreement provided by ABN AMRO Bank N.V. will beapplied to pay certain interest shortfalls, maintain overcollateralization and cover certain losses.

The assets of the trust fund will primarily consist of four pools of conventional, first and second lien,adjustable and fixed rate, fully amortizing and balloon, residential mortgage loans. The mortgage loans wereoriginated in accordance with underwriting guidelines that are not as strict as Fannie Mae and Freddie Macguidelines. As a result, the mortgage loans may experience higher rates of delinquency, foreclosure and bankruptcythan if they had been underwritten in accordance with higher standards.

Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved the certificates or determined that this prospectus supplement or the accompanying prospectus isaccurate or complete. Any representation to the contrary is a criminal offense.

The certificates offered by this prospectus supplement will be purchased by Lehman Brothers Inc., asunderwriter, from Structured Asset Securities Corporation, and are being offered from time to time for sale to thepublic in negotiated transactions or otherwise at varying prices to be determined at the time of sale. Theunderwriter has the right to reject any order. Proceeds to Structured Asset Securities Corporation from the sale ofthese certificates will be approximately 99.91% of their initial total class principal amount before deductingexpenses.

On or about May 27, 2005, delivery of the certificates offered by this prospectus supplement will be madethrough the book-entry facilities of The Depository Trust Company, Clearstream Banking Luxembourg and theEuroclear System.

Underwriter:

LEHMAN BROTHERSThe date of this prospectus supplement is May 26, 2005

Consider carefully the riskfactors beginning on page S-18 ofthis prospectus supplement.

For a list of capitalized terms usedin this prospectus supplement andthe prospectus, see the glossary ofdefined terms beginning on pageS-107 in this prospectus supplementand the index of principal terms onpage 126 in the prospectus.

The certificates will representinterests in the trust fund only andwill not represent interests in orobligations of any other entity.

This prospectus supplement maybe used to offer and sell thecertificates offered hereby only ifaccompanied by the prospectus.

Important notice about information presented in thisprospectus supplement and the accompanying prospectus:

We provide information to you about the certificates offered by this prospectus supplement in two

separate documents that progressively provide more detail: (1) the accompanying prospectus, which provides

general information, some of which may not apply to your certificates and (2) this prospectus supplement,

which describes the specific terms of your certificates.

If information varies between this prospectus supplement and the accompanying prospectus, you should

rely on the information in this prospectus supplement.

You should rely only on the information contained or incorporated by reference in this prospectus

supplement and the accompanying prospectus. We have not authorized anyone to provide you with different

information.

We are not offering the certificates in any state where the offer is not permitted. We do not claim that the

information in this prospectus supplement and prospectus is accurate as of any date other than the dates stated

on their respective covers.

Dealers will deliver a prospectus supplement and prospectus when acting as underwriters of the

certificates and with respect to their unsold allotments or subscriptions. In addition, all dealers selling the

certificates will be required to deliver a prospectus supplement and prospectus for ninety days following the

date of this prospectus supplement.

We include cross-references in this prospectus supplement and the accompanying prospectus to captions in

these materials where you can find further related discussions. The following tables of contents provide the

pages on which these captions are located.

S-ii

Tables of ContentsProspectus Supplement

Page

The Offered Certificates ;;;;;;;; S-1Summary of Terms ;;;;;;;;;; S-3Risk Factors ;;;;;;;;;;;;; S-18Glossary ;;;;;;;;;;;;;;; S-33Description of the Certificates ;;;;;; S-33

General ;;;;;;;;;;;;;; S-33Book-Entry Registration ;;;;;;; S-34Distributions of Interest ;;;;;;;; S-35Determination of LIBOR ;;;;;;; S-39Distributions of Principal ;;;;;;; S-39Credit Enhancement ;;;;;;;;; S-46Supplemental Interest Trust ;;;;;; S-50Optional Purchase of the Mortgage Loans S-53

Fees and Expenses of the Trust Fund ;;;Description of the Mortgage Pools ;;;; S-55

General ;;;;;;;;;;;;;; S-55Adjustable Rate Mortgage Loans ;;;; S-58The Index ;;;;;;;;;;;;; S-58Primary Mortgage Insurance ;;;;;; S-58Pool 1 Mortgage Loans ;;;;;;;; S-64Pool 2 Mortgage Loans ;;;;;;;; S-64Pool 3 Mortgage Loans ;;;;;;;; S-64Pool 4 Mortgage Loans ;;;;;;;; S-65

Additional Information ;;;;;;;;; S-65Underwriting Guidelines ;;;;;;;; S-65

BNC Underwriting Guidelines ;;;;; S-66Option One Underwriting Guidelines ;;General Underwriting Guidelines ;;;; S-72

The Master Servicer ;;;;;;;;;; S-75The Servicers ;;;;;;;;;;;;; S-76

General ;;;;;;;;;;;;;; S-76Option One Mortgage Corporation ;;; S-77

Servicing of the Mortgage Loans ;;;;; S-79General ;;;;;;;;;;;;;; S-79Servicing Accounts ;;;;;;;;; S-80Servicing Compensation and Payment of

Expenses;;;;;;;;;;;;; S-80Waiver or Modification of Mortgage Loan

Terms ;;;;;;;;;;;;;; S-80Prepayment Interest Shortfalls ;;;;; S-81Advances ;;;;;;;;;;;;; S-81Primary Mortgage Insurance ;;;;;; S-81Collection of Taxes, Assessments and

Similar Items ;;;;;;;;;;; S-81Insurance Coverage ;;;;;;;;; S-82Evidence as to Compliance ;;;;;; S-82Master Servicer Default; Servicer Default S-82Amendment of the Servicing

Agreements;;;;;;;;;;;; S-82

Page

Custody of the Mortgage Files ;;; S-83The Credit Risk Manager;;;;;; S-83Optional Purchase of Defaulted

Mortgage Loans ;;;;;;;; S-83Special Servicer for Distressed

Mortgage Loans ;;;;;;;; S-83Pledge of Servicing Rights ;;;;; S-84

The Trust Agreement ;;;;;;;; S-84General ;;;;;;;;;;;;; S-84The Issuing Entity ;;;;;;;; S-84The Trustee ;;;;;;;;;;; S-85The Securities Administrator ;;;; S-85Assignment of Mortgage Loans ;;; S-85Representations and Warranties ;;; S-86Certain Matters Under the Trust

Agreement;;;;;;;;;;; S-87Voting Rights ;;;;;;;;;; S-91

Yield, Prepayment and Weighted AverageLife ;;;;;;;;;;;;; S-91

General ;;;;;;;;;;;;; S-91Overcollateralization;;;;;;;; S-95Weighted Average Life ;;;;;; S-95

The Certificate Insurance Policies ;;; S-97The Policies ;;;;;;;;;;; S-97The Certificate Insurer ;;;;;;; S-99

Material Federal Income TaxConsiderations ;;;;;;;;; S-101

General ;;;;;;;;;;;;; S-101Tax Treatment of the Offered

Certificates ;;;;;;;;;; S-101Legal Investment Considerations;;;; S-103ERISA Considerations ;;;;;;;; S-103

ERISA Considerations With Respect tothe Swap Agreement ;;;;;; S-104

Use of Proceeds ;;;;;;;;;; S-105Underwriting ;;;;;;;;;;;; S-105Experts ;;;;;;;;;;;;;; S-106Legal Matters ;;;;;;;;;;; S-106Ratings ;;;;;;;;;;;;;; S-106Glossary of Defined Terms ;;;;;; S-107Annex A Global Clearance, Settlement

and Tax Documentation Procedures ; S-A-1Annex B Certain Characteristics of the

Mortgage Loans ;;;;;;;;; S-B-1Annex C-1 Assumed Mortgage Loan

Characteristics ;;;;;;;;;; S-C-1-1Annex C-2 Principal Amount Decrement

Tables ;;;;;;;;;;;;; S-C-2-1Annex D Swap Agreement Scheduled

Notional Amounts and Rates ofPayment;;;;;;;;;;;;; S-D-1

S-iii

S-54

S-67

Prospectus

Page

Description of the Securities ;;;;;;; 2General;;;;;;;;;;;;;;; 2Distributions on the Securities ;;;;; 2Optional Termination ;;;;;;;;; 4Optional Purchase of Securities ;;;;; 5Other Purchases ;;;;;;;;;;; 5Exchangeable Securities ;;;;;;;; 5Yield, Prepayment and Maturity

Considerations ;;;;;;;;;;; 12Payment Delays ;;;;;;;;;;; 12Principal Prepayments;;;;;;;;; 12Timing of Reduction of PrincipalAmount ; 12Interest or Principal Weighted ;;;;;Securities ;;;;;;;;;;;;;; 12Final Scheduled Distribution Date ;;;; 12Prepayments and Weighted Average Life ; 13Other Factors Affecting Weighted Average

Life ;;;;;;;;;;;;;;; 14The Trust Funds ;;;;;;;;;;;; 15

General;;;;;;;;;;;;;;; 15Ginnie Mae Certificates ;;;;;;;; 17Fannie Mae Certificates ;;;;;;;; 18Freddie Mac Certificates ;;;;;;;; 20Private Mortgage-Backed Securities ;;; 22The Mortgage Loans ;;;;;;;;; 24The Manufactured Home Loans ;;;;; 30Pre Funding Arrangements ;;;;;;; 33Collection Account and Distribution

Account ;;;;;;;;;;;;; 33Other Funds or Accounts ;;;;;;; 34

Loan Underwriting Procedures and Standards 34

Underwriting Standards ;;;;;;;; 34Loss Experience ;;;;;;;;;;; 36Representations and Warranties ;;;;; 37Substitution of Primary Assets ;;;;; 38

Servicing of Loans ;;;;;;;;;;; 38General;;;;;;;;;;;;;;; 38Collection Procedures; Escrow Accounts ; 39Deposits to and Withdrawals from the

Collection Account ;;;;;;;;; 40Servicing Accounts ;;;;;;;;;; 41Buy-Down Loans, GPM Loans and Other

Subsidized Loans;;;;;;;;;; 41Advances and Other Payments and

Limitations Thereon ;;;;;;;; 43Maintenance of Insurance Policies and Other

Servicing Procedures ;;;;;;;; 43

Page

Presentation of Claims; Realization Upon

Defaulted Loans ;;;;;;;;;; 46Enforcement of Due-On-Sale Clauses ;;; 47Certain Rights Related to Foreclosure ;;; 47Servicing Compensation and Payment of

Expenses ;;;;;;;;;;;;; 47Evidence as to Compliance;;;;;;;; 48Certain Matters Regarding the Master Servicer 49

Certain Risks ;;;;;;;;;;;;; 50Credit Support ;;;;;;;;;;;;; 50

General;;;;;;;;;;;;;;; 50Subordinate Securities; Subordination

Reserve Fund ;;;;;;;;;;; 51Cross-Support Features ;;;;;;;; 52Insurance ;;;;;;;;;;;;;; 52Letter of Credit ;;;;;;;;;;; 52Financial Guaranty Insurance Policy ;;; 53Reserve Funds ;;;;;;;;;;;; 53

Description of Mortgage and Other Insurance 53

Mortgage Insurance on the Loans ;;;; 54Hazard Insurance on the Loans ;;;;; 59Bankruptcy Bond;;;;;;;;;;; 61Repurchase Bond;;;;;;;;;;; 61

The Agreements ;;;;;;;;;;;; 61Issuance of Securities ;;;;;;;;; 62Assignment of Primary Assets ;;;;; 62Repurchase and Substitution of Non-

Conforming Loans ;;;;;;;;; 64Reports to Securityholders ;;;;;;; 65Investment of Funds ;;;;;;;;; 66Event of Default; Rights Upon Event of

Default ;;;;;;;;;;;;;; 67The Trustee ;;;;;;;;;;;;; 69Duties of the Trustee ;;;;;;;;; 69Resignation of Trustee ;;;;;;;; 70Distribution Account ;;;;;;;;; 70Expense Reserve Fund ;;;;;;;; 71Amendment of Agreement ;;;;;;; 71Voting Rights ;;;;;;;;;;;; 71REMIC Administrator ;;;;;;;;; 71Administration Agreement ;;;;;;; 71Periodic Reports ;;;;;;;;;;; 72Termination ;;;;;;;;;;;;; 72

Legal Aspects of Loans ;;;;;;;;; 73Mortgages ;;;;;;;;;;;;; 73Junior Mortgages; Rights of Senior

Mortgages ;;;;;;;;;;;; 73

S-iv

Prospectus (continued)

Page

Cooperative Loans ;;;;;;;;;; 75Foreclosure on Mortgages ;;;;;;; 77Realizing Upon Cooperative Loan Security 78

Rights of Redemption ;;;;;;;;; 79Anti-Deficiency Legislation and Other

Limitations on Lenders ;;;;;;; 79Servicemembers Civil Relief Act ;;;; 81Environmental Considerations ;;;;; 82Due-on-Sale Clauses in Mortgage Loans ; 83Enforceability of Prepayment and Late

Payment Fees ;;;;;;;;;;; 84Equitable Limitations on Remedies ;;; 84Applicability of Usury Laws ;;;;;; 85Multifamily and Mixed Use Loans;;;; 85Leases and Rents ;;;;;;;;;;; 86Default Interest and Limitations on ;;;Payment ;;;;;;;;;;;;;; 86Secondary Financing; Due-on-Encumbrance

Provisions;;;;;;;;;;;;; 86Certain Laws and Regulations ;;;;; 87Americans with Disabilities Act;;;;; 87Personal Property;;;;;;;;;;; 87Adjustable Interest Rate Loans ;;;;; 87Manufactured Home Loans;;;;;;; 88Material Federal Income Tax ;;;;;Considerations ;;;;;;;;;;;; 91

Types of Securities ;;;;;;;;;;; 91

Page

Taxation of Securities Treated as Debt

Instruments ;;;;;;;;;;;; 94Exchangeable Securities ;;;;;;;; 100REMIC Residual Certificates ;;;;;; 102Grantor Trust Certificates ;;;;;;; 108Partner Certificates ;;;;;;;;;; 111Special Tax Attributes;;;;;;;;; 113Backup Withholding ;;;;;;;;; 115Reportable Transactions ;;;;;;;; 115

State and Local Tax Considerations ;;;; 116ERISA Considerations;;;;;;;;;; 116

General;;;;;;;;;;;;;;; 116The Underwriter Exemption ;;;;;; 117Additional Considerations for Securities

which are Notes ;;;;;;;;;; 121Additional Fiduciary Considerations ;;;; 121Legal Investment Considerations ;;;;; 121Legal Matters ;;;;;;;;;;;;; 122The Depositor ;;;;;;;;;;;;; 122Use of Proceeds ;;;;;;;;;;;; 123Plan of Distribution;;;;;;;;;;; 123Additional Information ;;;;;;;;; 124Incorporation of Certain Documents by

Reference ;;;;;;;;;;;;;; 125Reports to Securityholders ;;;;;;;; 125Index of Principal Terms ;;;;;;;; 126

S-v

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S-2

Summary of Termss This summary highlights selected information from this document and does not contain all of the

information that you need to consider in making your investment decision. To understand all ofthe terms of the offering of the certificates, it is necessary that you read carefully this entiredocument and the accompanying prospectus.

s While this summary contains an overview of certain calculations, cash flow priorities and otherinformation to aid your understanding, you should read carefully the full description of thesecalculations, cash flow priorities and other information in this prospectus supplement and theaccompanying prospectus before making any investment decision.

s Some of the information that follows consists of forward-looking statements relating to futureeconomic performance or projections and other financial items. Forward-looking statements aresubject to a variety of risks and uncertainties, such as general economic and business conditionsand regulatory initiatives and compliance, many of which are beyond the control of the partiesparticipating in this transaction. Accordingly, what actually happens may be very different fromthe projections included in this prospectus supplement.

s Whenever we refer to a percentage of some or all of the mortgage loans in the trust fund, thatpercentage has been calculated on the basis of the total scheduled principal balance of thosemortgage loans as of May 1, 2005, unless we specify otherwise. We explain in this prospectussupplement under ‘‘Glossary of Defined Terms’’ how the scheduled principal balance of amortgage loan is determined. Whenever we refer in this Summary of Terms or in the RiskFactors section of this prospectus supplement to the total principal balance of any mortgage loans,we mean the total of their scheduled principal balances unless we specify otherwise.

Parties

Sponsor and Seller

Lehman Brothers Holdings Inc. will sell the

mortgage loans to the depositor.

Depositor

Structured Asset Securities Corporation, a

Delaware special purpose corporation, will sell the

mortgage loans to the issuing entity. The depositor’s

address is 745 Seventh Avenue, New York, New

York 10019, and its telephone number is (212) 526-

7000.

Issuing Entity

Structured Asset Investment Loan Trust 2005-5,

a common law trust formed under the laws of the

state of New York.

Trustee

U.S. Bank National Association.

Securities Administrator

Wells Fargo Bank, N.A., will be responsible for

preparing monthly distribution statements and

certain tax information for investors and certain tax

filings for the trust fund.

Master Servicer

Aurora Loan Services LLC, an affiliate of the

seller, the depositor, one of the servicers and

Lehman Brothers Inc., will oversee the servicing of

the mortgage loans by the servicers.

Primary Servicers

On the closing date, Option One Mortgage

Corporation, Aurora Loan Services LLC and various

other servicers will service approximately 79.49%,

13.22% and 7.29%, respectively, of the mortgage

loans. It is anticipated that servicing of

approximately 68.40% of the mortgage loans

initially serviced by Option One Mortgage

Corporation will be transferred to one or more other

servicers as described under ‘‘—The Mortgage

Loans—Servicing of the Mortgage Loans’’ below.

S-3

Credit Risk Manager

The Murrayhill Company will monitor and

advise the servicers with respect to default

management of the mortgage loans and also prepare

certain loan-level reports for the trust fund which

will be available for review by certificateholders.

Originators

BNC Mortgage, Inc., Option One Mortgage

Corporation and various other banks, savings and

loans and other mortgage lending institutions

originated the mortgage loans to be included in the

trust fund.

Swap Counterparty

ABN AMRO Bank N.V.

Certificate Insurer

CIFG Assurance North America, Inc. will

provide certificate guaranty insurance policies for

the Class A8 and Class A9 Certificates, which will

guarantee certain payments of interest and principal

to holders of the Class A8 and Class A9 Certificates,

to the extent described in this prospectus

supplement.

LPMI Insurers

On the closing date, Mortgage Guaranty

Insurance Corporation, PMI Mortgage Insurance Co.

and Republic Mortgage Insurance Company will

provide primary mortgage insurance for certain of

the first lien mortgage loans with original loan-to-

value ratios in excess of 80%.

The Certificates

The certificates offered by this prospectus

supplement will be issued with the initial

approximate characteristics set forth under ‘‘The

Offered Certificates’’ in the table on page S-1.

The offered certificates will be issued in book-

entry form. The minimum denominations and the

incremental denominations of each class of offered

certificates are set forth in the table on page S-2.

The certificates represent ownership interests in

a trust fund, the assets of which will consist

primarily of conventional, first and second lien,

adjustable and fixed rate, fully amortizing and

balloon, residential mortgage loans having a total

principal balance as of the cut-off date, which is

May 1, 2005, of approximately $2,497,873,627. In

addition, the supplemental interest trust will hold an

interest rate swap agreement for the benefit of the

certificateholders.

The mortgage loans to be included in the trust

fund will be divided into four mortgage pools: ‘‘pool

1,’’ ‘‘pool 2,’’ ‘‘pool 3’’ and ‘‘pool 4.’’ Pool 1 will

consist of those mortgage loans in the trust fund

with original principal balances that do not exceed

the applicable Fannie Mae maximum original loan

amount limitations for one- to four- family

residential mortgaged properties. Pool 2 and pool 3

will consist of those mortgage loans in the trust fund

with original principal balances that do not exceed

the applicable Freddie Mac maximum original loan

amount limitations for one- to four-family

residential mortgaged properties. Pool 4 will consist

of mortgage loans with original principal balances

that may be less than, equal to, or in excess of,

Fannie Mae or Freddie Mac original loan amount

limitations.

Payments of principal and interest on the Class

A1 Certificates will be based primarily on

collections from the pool 1 mortgage loans.

Payments of principal and interest on the Class A2

and A3 Certificates will be based primarily on



and A5 Certificates will be based primarily on


Payments of principal and interest on the Class A6,

A7 and A8 Certificates will be based primarily on


Payments of principal and interest on the Class A9,

M1, M2, M3, M4, M5, M6, M7, M8, M9 and B

Certificates will be based on collections from all

four mortgage pools as described herein.

The rights of holders of the Class A9, M1, M2,

M3, M4, M5, M6, M7, M8, M9 and B Certificates

to receive payments of principal and interest will be

subordinate to the rights of the holders of certificates

having a senior priority of payment, as described in

this Summary of Terms under ‘‘—Enhancement of

Likelihood of Payment on the Certificates—

Subordination of Payments’’ below. We refer to the

S-4

Class M1, M2, M3, M4, M5, M6, M7, M8, M9 and

B Certificates collectively as ‘‘subordinate’’

certificates. We refer to the Class A9 Certificates as

‘‘subordinate senior’’ certificates. We refer to the

Class A1, A2, A3, A4, A5, A6, A7 and A8

Certificates collectively as ‘‘senior’’ certificates.

The Class P Certificates will be entitled to

receive all the cash flow from the mortgage pools

solely arising from prepayment premiums paid by

the borrowers on certain voluntary, full and partial

prepayments of the mortgage loans. Accordingly,

these amounts will not be available for payments to

the servicers or to holders of other classes of

certificates.

The Class X Certificates will be entitled to

receive any monthly excess cashflow remaining after

required distributions are made to the offered

certificates.

The Class X, Class P and Class R Certificates

are not offered by this prospectus supplement.

The offered certificates will have an

approximate total initial principal amount of

$2,485,384,000. Any difference between the total

principal amount of the offered certificates on the

date they are issued and the approximate total

principal amount of the offered certificates as

reflected in this prospectus supplement will not

exceed 5%.

Payments on the Certificates

Principal and interest on the certificates will be

paid on the 25th day of each month, beginning in

June 2005. However, if the 25th day is not a

business day, payments will be made on the next

business day after the 25th day of the month.

Interest Payments

Interest will accrue on each class of offered

certificates at the applicable annual rates described

below:

s Class A1 Certificates: the lesser of (1) theapplicable annual rate as described in the

table on page S-1 and (2) with respect to any

distribution date on which any of the Class

A2, A3, A4, A5, A6, A7 or A8 Certificates

are outstanding, the pool 1 net funds cap, and

after the distribution date on which the class

principal amounts of the Class A2, A3, A4,

A5, A6, A7 and A8 Certificates have each

been reduced to zero, the subordinate net

funds cap.




A1, A4, A5, A6, A7 or A8 Certificates are

outstanding, the pool 2 net funds cap, and



A6, A7 and A8 Certificates have each been

reduced to zero, the subordinate net funds

cap.










cap.










cap.









S-5


cap.




A1, A2, A3, A4 or A5 Certificates are




A4 and A5 Certificates have each been


cap.










cap.










cap.

Interest will accrue on each class of the Class

A9, M1, M2, M3, M4, M5, M6, M7, M8, M9 and B

Certificates at an annual rate equal to the lesser of

(1) the applicable annual rate as described in the

table on page S-1 and (2) the subordinate net funds

cap.

If the option to purchase the mortgage loans is

not exercised by the master servicer on the initial

optional termination date as described under ‘‘—The

Mortgage Loans—Optional Purchase of the

Mortgage Loans’’ below, then with respect to the

next distribution date and each distribution date

thereafter, the annual rate in clause (1) of each

interest rate formula set forth above will be

increased for each class of certificates to the

applicable annual rate as described in the table on

page S-1, subject in each case to the applicable net

funds cap.

See ‘‘—The Mortgage Loans—OptionalPurchase of the Mortgage Loans’’ below.

The pool 1 net funds cap is a limitation

generally based on the weighted average mortgage

rates of the pool 1 mortgage loans during the

applicable collection period, net of certain fees and

expenses of the trust fund and any swap payments

owed to the swap counterparty allocable to pool 1.

The pool 2 net funds cap is a limitation generally

based on the weighted average mortgage rates of the

pool 2 mortgage loans during the applicable

collection period, net of certain fees and expenses of

the trust fund and any swap payments owed to the

swap counterparty allocable to pool 2. The pool 3

net funds cap is a limitation generally based on the

weighted average mortgage rates of the pool 3

mortgage loans during the applicable collection

period, net of certain fees and expenses of the trust

fund and any swap payments owed to the swap

counterparty allocable to pool 3. The pool 4 net

funds cap is a limitation generally based on the

weighted average mortgage rates of the pool 4

mortgage loans during the applicable collection

period, net of certain fees and expenses of the trust

fund, any swap payments owed to the swap

counterparty allocable to pool 4 and the monthly

premium due to the certificate insurer for the

certificate guaranty insurance policy benefiting the

Class A8 Certificates for that distribution date. The

subordinate net funds cap is generally the weighted

average of the pool 1 net funds cap, the pool 2 net

funds cap, the pool 3 net funds cap and the pool 4

net funds cap, net of the monthly premium due to

the certificate insurer for the certificate guaranty

insurance policy benefiting the Class A9 Certificates

for that distribution date.

See ‘‘Description of the Certificates—Distributions of Interest’’ in this prospectussupplement for the priority of payment of interestand ‘‘Glossary of Defined Terms’’ in this prospectussupplement for a description of the defined termsrelevant to the payment of interest.

S-6

The Interest Rate Swap Agreement

The trustee, on behalf of the supplemental

interest trust, will enter into an interest rate swap

agreement with ABN AMRO Bank N.V., as swap

counterparty. Under the interest rate swap

agreement, on each distribution date, beginning on

the distribution date in July 2005 and ending on the

distribution date in May 2010, the supplemental

interest trust will be obligated to make fixed

payments at the applicable rate of payment owed by

the trust fund, which will range from 3.38% to

4.75% annually, as described in this prospectus

supplement, and the swap counterparty will be

obligated to make floating payments at LIBOR (as

determined under the interest rate swap agreement),

in each case calculated on a scheduled notional

amount. To the extent that a fixed payment exceeds

the floating payment on any distribution date,

amounts otherwise available to certificateholders

will be applied to make a net swap payment to the

swap counterparty, and to the extent that a floating

payment exceeds the fixed payment on any

distribution date, the swap counterparty will owe a

net swap payment to the supplemental interest trust.

Any net amounts received under the interest rate

swap agreement will be paid by the supplemental

interest trust and applied to pay interest shortfalls,

maintain overcollateralization and cover losses, as

described in this prospectus supplement.

See ‘‘Description of the Certificates—Supplemental Interest Trust—Interest Rate SwapAgreement’’ and ‘‘—Application of Deposits andPayments Received by the Supplemental InterestTrust’’ in this prospectus supplement.

Principal Payments

The amount of principal payable to the offered

certificates will be determined by (1) formulas that

allocate portions of principal payments received on

the mortgage loans among the mortgage pools and

the different certificate classes, (2) funds received on

the mortgage loans that are available to make

principal payments on the certificates and (3) the

application of excess interest from each mortgage

pool to pay principal on the certificates. Funds

received on the mortgage loans may consist of (1)

expected monthly scheduled payments or (2)

unexpected payments resulting from prepayments or

defaults by borrowers, liquidation of defaulted

mortgage loans or repurchases of mortgage loans

under the circumstances described in this prospectus

supplement.

The manner of allocating payments of principal

on the mortgage loans will differ, as described in

this prospectus supplement, depending upon the

occurrence of several different events or triggers:

s whether a distribution date occurs before oron or after the ‘‘stepdown date,’’ which is the

later of (1) the distribution date in June 2008

and (2) the first distribution date on which

the ratio of (a) the total principal balance of

the subordinate senior certificates and

subordinate certificates plus any

overcollateralization amount to (b) the total

principal balance of the mortgage loans in the

trust fund equals or exceeds the percentage

specified in this prospectus supplement;

s a ‘‘cumulative loss trigger event’’ occurswhen cumulative losses on the mortgage

loans are higher than certain levels specified

in this prospectus supplement;

s a ‘‘delinquency event’’ occurs when the rateof delinquencies of the mortgage loans over

any three-month period is higher than certain

levels set forth in this prospectus supplement;

and

s in the case of pool 3, a ‘‘sequential triggerevent’’ occurs if (a) before the distribution

date in June 2008, a cumulative loss trigger

event occurs or (b) on or after the

distribution date in June 2008, a cumulative

loss trigger event or a delinquency event

occurs.

See ‘‘Description of the Certificates—Distributions of Principal’’ in this prospectussupplement for the priority of payment of principaland ‘‘Glossary of Defined Terms’’ in this prospectussupplement for a description of the defined termsrelevant to the payment of principal.

Limited Recourse

The only source of cash available to make

interest and principal payments on the certificates

will be the assets of the trust fund and the

S-7

supplemental interest trust. The trust fund will have

no source of cash other than collections and

recoveries of the mortgage loans through insurance

or otherwise. No other entity will be required or

expected to make any payments on the certificates,

other than the Class A8 and Class A9 Certificates,

which will have the benefit of certificate guaranty

insurance policies issued by CIFG Assurance North

America, Inc.

Enhancement of Likelihood of Payment on theCertificates

In order to enhance the likelihood that holders

of more senior classes of certificates will receive

regular distributions of interest and principal, the

payment structure of this securitization includes

excess interest, overcollateralization, subordination,

loss allocation and limited cross-collateralization

features, primary mortgage insurance and an interest

rate swap agreement, and, for the benefit of the

Class A8 and Class A9 Certificates only, certificate

guaranty insurance policies. The certificates, other

than the Class A8 and Class A9 Certificates, will

not be insured by any financial guaranty insurance

policy.

The Class B Certificates are more likely to

experience losses than the Class M9, M8, M7, M6,

M5, M4, M3, M2, M1 and A9 Certificates and the

senior certificates. The Class M9 Certificates are

more likely to experience losses than the Class M8,

M7, M6, M5, M4, M3, M2, M1 and A9 Certificates

and the senior certificates. The Class M8 Certificates

are more likely to experience losses than the Class

M7, M6, M5, M4, M3, M2, M1 and A9 Certificates

and the senior certificates. The Class M7 Certificates

are more likely to experience losses than the Class

M6, M5, M4, M3, M2, M1 and A9 Certificates and

the senior certificates. The Class M6 Certificates are

more likely to experience losses than the Class M5,

M4, M3, M2, M1 and A9 Certificates and the senior

certificates. The Class M5 Certificates are more

likely to experience losses than the Class M4, M3,

M2, M1 and A9 Certificates and the senior


likely to experience losses than the Class M3, M2,

M1 and A9 Certificates and the senior certificates.

The Class M3 Certificates are more likely to

experience losses than the Class M2, M1 and A9

Certificates and the senior certificates. The Class M2

Certificates are more likely to experience losses than

the Class M1 and A9 Certificates and the senior


likely to experience losses than the Class A9

Certificates and the senior certificates. The Class A9

Certificates are more likely to experience losses than

the senior certificates.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement,’’ ‘‘Description of theCertificates—Credit Enhancement’’and‘‘—Supplemental Interest Trust’’ in this prospectussupplement for a more detailed description of excessinterest, overcollateralization, subordination, lossallocation, primary mortgage insurance, limitedcross-collateralization and the interest rate swapagreement.

Subordination of Payments

Certificates with an ‘‘A’’ in their class

designation (other than the Class A9 Certificates)

will have a payment priority as a group over all

other certificates. The Class A9 Certificates will

have a payment priority over the Class M1, M2,

M3, M4, M5, M6, M7, M8, M9 and B Certificates;

the Class M1 Certificates will have a payment

priority over the Class M2, M3, M4, M5, M6, M7,

M8, M9 and B Certificates; the Class M2

Certificates will have a payment priority over the

Class M3, M4, M5, M6, M7, M8, M9 and B

Certificates; the Class M3 Certificates will have a

payment priority over the Class M4, M5, M6, M7,

M8, M9 and B Certificates; the Class M4

Certificates will have a payment priority over the

Class M5, M6, M7, M8, M9 and B Certificates; the

Class M5 Certificates will have a payment priority

over the Class M6, M7, M8, M9 and B Certificates;

the Class M6 Certificates will have a payment

priority over the Class M7, M8, M9 and B


payment priority over the Class M8, M9 and B


payment priority over the Class M9 and B

Certificates; and the Class M9 Certificates will have

a payment priority over the Class B Certificates.

Each class of offered certificates will have a

payment priority over the Class X and Class R

Certificates.

S-8

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement’’ and ‘‘Description of theCertificates—Credit Enhancement—Subordination’’in this prospectus supplement.

Allocation of Losses

As described in this prospectus supplement,

amounts representing losses on the mortgage loans

(to the extent that those losses exceed excess

interest and any overcollateralization, as described in

this prospectus supplement) will be applied to

reduce the principal amount of the subordinate or

subordinate senior class of certificates still

outstanding that has the lowest payment priority,

until the principal amount of that class of certificates

has been reduced to zero. For example, losses in

excess of overcollateralization and excess interest

will first be allocated in reduction of the principal

amount of the Class B Certificates until it is reduced

to zero, then in reduction of the principal amount of

the Class M9 Certificates until it is reduced to zero,

then in reduction of the principal amount of the

Class M8 Certificates until it is reduced to zero,














Class M1 Certificates until it is reduced to zero and

finally in reduction of the principal amount of the

Class A9 Certificates until it is reduced to zero. If a

loss has been allocated to reduce the principal

amount of a subordinate certificate, it is unlikely

that investors will receive any payment in respect of

that reduction. If a loss has been allocated to reduce

the principal amount of a subordinate senior

certificate, that certificate will have the benefit of

the Class A9 certificate guaranty insurance policy

and will be entitled to reimbursement of any losses

allocated to it on the final scheduled distribution

date (to the extent not previously reimbursed). If the

applicable subordination is insufficient to absorb

losses, then holders of senior certificates (other than

the Class A8 Certificates, which have the benefit of

the Class A8 certificate guaranty insurance policy)

will incur losses and may never receive all of their

principal payments.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement’’ and ‘‘Description of theCertificates—Credit Enhancement—Application ofRealized Losses’’ in this prospectus supplement.

Excess Interest

The mortgage loans bear interest each month

that in the aggregate is expected to exceed the

amount needed to pay monthly interest on the

offered certificates, certain fees and expenses of the

trust fund, any swap payments owed to the swap

counterparty and the premiums payable under the

Class A8 and Class A9 certificate guaranty

insurance policies. This ‘‘excess interest’’ received

from the mortgage loans each month will be

available to absorb realized losses on the mortgage

loans and to maintain the required level of

overcollateralization.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement’’ and ‘‘Description of theCertificates—Credit Enhancement—Excess Interest’’in this prospectus supplement.

Overcollateralization

On the closing date, the total principal balance

of the mortgage loans in the trust fund is expected

to exceed the total principal amount of the offered

certificates by approximately $12,489,627, which

represents approximately 0.50% of the total

principal balance of the mortgage loans in the trust

fund as of May 1, 2005. This condition is referred

to in this prospectus supplement as

‘‘overcollateralization.’’ Thereafter, to the extent

described in this prospectus supplement, a portion of

excess interest may be applied to pay principal on

the certificates to the extent needed to maintain the

required level of overcollateralization. We cannot,

however, assure you that sufficient interest will be

generated by the mortgage loans to maintain any

level of overcollateralization.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement’’ and ‘‘Description of the

S-9

Certificates—Credit Enhancement—Overcollateralization’’ in this prospectussupplement.

Limited Cross-Collateralization

Under certain limited circumstances, principal

payments on the mortgage loans in a mortgage pool

may be distributed as principal to holders of the

senior certificates corresponding to the other

mortgage pools.

If the senior certificates relating to one

mortgage pool have been retired, then principal

payments on the mortgage loans relating to the

retired senior certificates will be distributed to the

remaining senior certificates of the other mortgage

pools, if any, before being distributed to the

subordinate classes of certificates.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement’’ and ‘‘Description of theCertificates—Distributions of Principal’’ in thisprospectus supplement.

Primary Mortgage Insurance

Approximately 0.27% of the first lien mortgage

loans with original loan-to-value ratios in excess of

80% are covered by existing borrower-paid primary

mortgage insurance policies. In addition, on the

closing date, loan-level primary mortgage insurance

policies will be obtained on behalf of the trust fund

from Mortgage Guaranty Insurance Corporation,

PMI Mortgage Insurance Co. and Republic

Mortgage Insurance Company in order to provide

initial primary mortgage insurance coverage for

approximately 81.59% of those first lien mortgage

loans with original loan-to-value ratios in excess of

80%. However, these primary mortgage insurance

policies will provide only limited protection against

losses on defaulted mortgage loans.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement—Primary Mortgage Insurance’’and ‘‘Description of the Mortgage Pools—PrimaryMortgage Insurance’’ in this prospectus supplement.

The Interest Rate Swap Agreement

Any net swap payment received under the

interest rate swap agreement will be applied to pay

interest shortfalls, maintain overcollateralization and

cover losses, as described in this prospectus

supplement.

See ‘‘Risk Factors—Potential Inadequacy ofCredit Enhancement—The Interest Rate SwapAgreement,’’ ‘‘Description of the Certificates—Supplemental Interest Trust—Interest Rate SwapAgreement’’ and ‘‘—Application of Deposits andPayments Received by the Supplemental InterestTrust’’ in this prospectus supplement.

The Class A8 and Class A9 Certificate GuarantyInsurance Policies

The CIFG Assurance North America, Inc.

certificate guaranty insurance policies will guarantee

certain interest and principal payments to holders of

the Class A8 and Class A9 Certificates under the

circumstances described in this prospectus

supplement. No other classes of certificates will

benefit from the certificate guaranty insurance

policies.

For information about CIFG Assurance NorthAmerica, Inc. and for a more detailed discussion ofthe CIFG Assurance North America, Inc. certificateguaranty insurance policies, see ‘‘The CertificateInsurance Policies’’ in this prospectus supplement.

Fees and Expenses

Before payments are made on the certificates,

the servicers will be paid a monthly fee calculated

either as 0.50% annually, or in the case of some of

the mortgage loans serviced by Option One,

calculated starting at 0.30% annually and gradually

increasing to up to 0.65% annually, on the principal

balance of the mortgage loans serviced by that

servicer (subject to reduction as described in this

prospectus supplement).

In addition, the providers of the loan-level

primary mortgage insurance policies will be paid a

monthly fee calculated as an annual percentage on

the principal balance of each mortgage loan insured

by that primary mortgage insurance provider. These

fees will be 0.950% annually for Mortgage Guaranty

Insurance Corporation, 1.510% annually for

Republic Mortgage Insurance Company and between

0.263% and 2.224% annually (with a weighted

average as of the cut-off date of approximately

0.970% annually) for PMI Mortgage Insurance Co.

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The master servicer will receive as

compensation the investment income on funds held

in the collection account. The trustee will be paid a

fixed annual fee from investment earnings on funds

held in the securities administration account. The

securities administrator will receive as compensation

the investment income on funds held in the

securities administration account after payment of

the trustee fee. After payments of interest on the

certificates have been made, the credit risk manager

will be paid a monthly fee calculated as 0.011%

annually on the total principal balance of the

mortgage loans.

Expenses of the servicers, the custodians, the

master servicer and the securities administrator will

be reimbursed before payments are made on the

certificates. Expenses of the trustee will be

reimbursed up to a specified amount annually before

payments are made on the certificates; any

additional unpaid expenses will be paid to the

trustee after payments of interest on the certificates

have been made.

See ‘‘Fees and Expenses of the Trust Fund’’ inthis prospectus supplement.

Final Scheduled Distribution Date

The final scheduled distribution date for the

offered certificates will be the applicable distribution

date specified in the table on page S-2. The final

scheduled distribution date for the offered

certificates is based upon the second distribution

date after the date of the last scheduled payment of

the latest maturing mortgage loan. The actual final

distribution date for each class of offered certificates

may be earlier or later (other than the Class A8 and

A9 Certificates, whose final distribution date will be

no later than the distribution date specified in the

table on page S-2), and could be substantially

earlier, than the applicable final scheduled

distribution date.

The NIMS Insurer

One or more insurance companies, referred to

herein collectively as the NIMS Insurer, may issue a

financial guaranty insurance policy covering certain

payments to be made on net interest margin

securities to be issued by a separate trust or other

special purpose entity and secured by all or a

portion of the Class P and Class X Certificates. In

that event, the NIMS Insurer will be able to exercise

rights which could adversely affect

certificateholders.

We refer you to ‘‘Risk Factors—Rights of theNIMS Insurer May Affect Certificates’’ in thisprospectus supplement for additional informationconcerning the NIMS Insurer.

The Mortgage Loans

On the closing date, which is expected to be on

or about May 27, 2005, the assets of the trust fund

will consist primarily of four mortgage pools of

conventional, first and second lien, adjustable and

fixed rate, fully amortizing and balloon, residential

mortgage loans with a total principal balance as of

the cut-off date of approximately $2,497,873,627.


Certificates will be based primarily on collections

from the pool 1 mortgage loans. Payments of

principal and interest on the Class A2 and A3



principal and interest on the Class A4 and A5



principal and interest on the Class A6, A7 and A8



principal and interest on the subordinate senior and

subordinate certificates will be based on collections

from all of the mortgage pools as described herein.

The mortgage loans will be secured by mortgages,

deeds of trust or other security instruments, all of

which are referred to in this prospectus supplement

as mortgages.

The depositor expects that the mortgage loans

will have the following approximate characteristics

as of the cut-off date:

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Pool 1 Mortgage Loan Summary

Range or TotalWeightedAverage Total Percentage

Number of Mortgage Loans ;;;;;;;;;; 3,831 — —Number of Fixed Rate Mortgage Loans ;;;;; 1,084 — 17.73%Number of Adjustable Rate Mortgage Loans ;;; 2,747 — 82.27%Total Scheduled Principal Balance ;;;;;;; $569,793,654 — —Scheduled Principal Balances ;;;;;;;;; $14,805 to $332,726 $148,732 —Mortgage Rates ;;;;;;;;;;;;;;; 4.850% to 12.850% 7.203% —Original Terms to Maturity (in months) ;;;;; 180 to 360 351 —Remaining Terms to Maturity (in months) ;;;; 176 to 360 349 —Original Combined Loan-to-Value Ratios ;;;; 10.25% to 100.00% 80.39% —Number of Second Lien Mortgage Loans ;;;; 570 — 4.72%Number of Interest-Only Mortgage Loans ;;;; 525 — 19.11%Number of Balloon Mortgage Loans ;;;;;; 462 — 3.95%Geographic Distribution in Excess of 10% of the

Total Scheduled Principal Balance:

Number of Mortgage Loans in California ;;;; 900 — 30.08%Number of Mortgage Loans in the Maximum Single

Zip Code Concentration ;;;;;;;;;; 20 — 0.51%Credit Scores ;;;;;;;;;;;;;;;; 500 to 814 633 —Number of Mortgage Loans with Prepayment

Penalties at Origination ;;;;;;;;;;; 2,785 — 74.20%Gross Margins ;;;;;;;;;;;;;;; 2.890% to 7.990% 5.574%(1) —Maximum Mortgage Rates ;;;;;;;;;; 10.850% to 18.750% 13.668%(1) —Minimum Mortgage Rates ;;;;;;;;;; 4.850% to 11.750% 7.059%(1) —Months to Next Mortgage Rate Adjustment ;;; 17 to 59 24(1) —Initial Caps;;;;;;;;;;;;;;;;; 1.500% to 3.000% 2.958%(1) —Periodic Caps;;;;;;;;;;;;;;;; 1.000% to 1.000% 1.000%(1) —

(1) The weighted average is based only on the adjustable rate mortgage loans in pool 1.

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Number of Mortgage Loans ;;;;;;;;;; 4,188 — —Number of Fixed Rate Mortgage Loans ;;;;; 993 — 14.43%Number of Adjustable Rate Mortgage Loans ;;; 3,195 — 85.57%Total Scheduled Principal Balance ;;;;;;; $674,170,588 — —Scheduled Principal Balances ;;;;;;;;; $14,795 to $682,499 $160,976 —Mortgage Rates ;;;;;;;;;;;;;;; 4.875% to 12.250% 7.363% —Original Terms to Maturity (in months) ;;;;; 120 to 360 353 —Remaining Terms to Maturity (in months) ;;;; 117 to 360 352 —Original Combined Loan-to-Value Ratios ;;;; 13.51% to 100.00% 81.35% —Number of Second Lien Mortgage Loans ;;;; 523 — 3.34%Number of Interest-Only Mortgage Loans ;;;; 1,161 — 37.48%Number of Balloon Mortgage Loans ;;;;;; 383 — 2.49%Geographic Distribution in Excess of 10% of the






S-13



Number of Mortgage Loans ;;;;;;;;;; 3,481 — —Number of Fixed Rate Mortgage Loans ;;;;; 978 — 17.89%Number of Adjustable Rate Mortgage Loans ;;; 2,503 — 82.11%Total Scheduled Principal Balance ;;;;;;; $565,403,692 — —Scheduled Principal Balances ;;;;;;;;; $14,482 to $622,741 $162,425 —Mortgage Rates ;;;;;;;;;;;;;;; 4.850% to 13.200% 7.207% —Original Terms to Maturity (in months) ;;;;; 120 to 360 352 —Remaining Terms to Maturity (in months) ;;;; 93 to 360 350 —Original Combined Loan-to-Value Ratios ;;;; 8.33% to 100.00% 80.69% —Number of Second Lien Mortgage Loans ;;;; 489 — 3.76%Number of Interest-Only Mortgage Loans ;;;; 642 — 24.71%Number of Balloon Mortgage Loans ;;;;;; 346 — 2.75%Geographic Distribution in Excess of 10% of the






S-14



Number of Mortgage Loans ;;;;;;;;;; 2,313 — —Number of Fixed Rate Mortgage Loans ;;;;; 669 — 14.66%Number of Adjustable Rate Mortgage Loans ;;; 1,644 — 85.34%Total Scheduled Principal Balance ;;;;;;; $688,505,692 — —Scheduled Principal Balances ;;;;;;;;; $14,863 to $2,000,000 $297,667 —Mortgage Rates ;;;;;;;;;;;;;;; 4.850% to 12.694% 7.067% —Original Terms to Maturity (in months) ;;;;; 180 to 360 352 —Remaining Terms to Maturity (in months) ;;;; 175 to 360 350 —Original Combined Loan-to-Value Ratios ;;;; 20.00% to 100.00% 82.32% —Number of Second Lien Mortgage Loans ;;;; 415 — 4.88%Number of Interest-Only Mortgage Loans ;;;; 651 — 44.36%Number of Balloon Mortgage Loans ;;;;;; 312 — 3.78%Geographic Distribution in Excess of 10% of the


Number of Mortgage Loans in California ;;;; 1,033 — 55.47%Number of Mortgage Loans in the Maximum Single




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The mortgage loans were generally originated

or acquired in accordance with underwriting

guidelines that are less strict than Fannie Mae and

Freddie Mac guidelines. As a result, the mortgage

loans are likely to experience higher rates of

delinquency, foreclosure and bankruptcy than

mortgage loans underwritten in accordance with

higher standards.

The mortgage loans in the trust fund will not be

insured or guaranteed by any government agency.

None of the mortgage loans in the trust fund

will be ‘‘high cost’’ loans under applicable federal,

state or local anti-predatory or anti-abusive lending

laws.

Servicing of the Mortgage Loans

The mortgage loans will be master serviced by

Aurora Loan Services LLC. The master servicer will

oversee the servicing of the mortgage loans by the

servicers. It is anticipated that servicing of

approximately 68.40% of the mortgage loans

initially serviced by Option One Mortgage

Corporation will be transferred to another servicer

on or about July 1, 2005. Primary servicing also

may subsequently be transferred to servicers other

than the initial servicers, in accordance with the

trust agreement and the applicable servicing

agreement, as described in this prospectus

supplement.

Lehman Brothers Holdings Inc. will retain

certain rights relating to the servicing of the

mortgage loans, including the right to terminate and

replace any servicer, at any time, without cause, in

accordance with the terms of the trust agreement

and the applicable servicing agreement, which,

among other things, generally requires payment of a

termination fee.

See ‘‘The Master Servicer,’’ ‘‘The Servicers’’and ‘‘Servicing of the Mortgage Loans’’ in thisprospectus supplement.

Optional Purchase of the Mortgage Loans

The master servicer, with the prior written

consent of the seller and the NIMS Insurer, which

consent may not be unreasonably withheld, may

purchase the mortgage loans on or after the initial

optional termination date, which is the distribution

date following the month in which the total

principal balance of the mortgage loans (determined

in the aggregate rather than by mortgage pool)

declines to less than 10% of the initial total

principal balance of the mortgage loans as of the

cut-off date. If the master servicer fails to exercise

this option, the NIMS Insurer will have the right to

direct the master servicer to exercise this option so

long as it is insuring the net interest margin

securities or any amounts payable to the NIMS

Insurer in respect of the insurance remain unpaid.

If the mortgage loans are purchased, the

certificateholders will be paid accrued interest and

principal in an amount not to exceed the purchase

price.

If the option to purchase the mortgage loans is

not exercised on the initial optional termination date,

then, beginning with the next distribution date and

thereafter, the interest rates on the offered

certificates will be increased as described in the

table on page S-1.

See ‘‘Description of the Certificates—OptionalPurchase of the Mortgage Loans’’ in this prospectussupplement for a description of the purchase priceto be paid for the mortgage loans upon an optionalpurchase. See ‘‘Summary of Terms—TheCertificates—Payments on the Certificates—InterestPayments’’ in this prospectus supplement for adescription of the increased interest rates to be paidon the certificates after the initial optionaltermination date.

Financing

An affiliate of Lehman Brothers Inc. has

provided financing for certain of the mortgage loans.

A portion of the proceeds of the sale of the

certificates will be used to repay the financing.

Tax Status

The trustee will elect to treat a portion of the

trust fund as multiple REMICs for federal income

tax purposes. Each of the offered certificates will

represent ownership of ‘‘regular interests’’ in a

REMIC. The Class R Certificate will be designated

as the sole class of ‘‘residual interest’’ in each of the

REMICs.

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See ‘‘Material Federal Income TaxConsiderations’’ in this prospectus supplement andin the accompanying prospectus for additionalinformation concerning the application of federalincome tax laws to the certificates.

ERISA Considerations

Generally, all of the certificates offered by this

prospectus supplement may be purchased by

employee benefit plans or other retirement

arrangements subject to the Employee Retirement

Income Security Act of 1974 or Section 4975 of the

Internal Revenue Code of 1986. Offered certificates

may not be acquired or held by a person investing

assets of any such plans or arrangements before the

termination of the interest rate swap agreement,

unless such acquisition or holding is eligible for the

exemptive relief available under one of the class

exemptions described in this prospectus supplement

under ‘‘ERISA Considerations—ERISA

Considerations With Respect to the Swap

Agreement.’’

See ‘‘ERISA Considerations’’ in this prospectussupplement and in the prospectus for a morecomplete discussion of these issues.

Legal Investment Considerations

None of the certificates will constitute

‘‘mortgage related securities’’ for purposes of the

Secondary Mortgage Market Enhancement Act of

1984.

There are other restrictions on the ability of

certain types of investors to purchase the certificates

that prospective investors should also consider.

See ‘‘Legal Investment Considerations’’ in thisprospectus supplement and in the prospectus.

Ratings of the Certificates

The certificates offered by this prospectus

supplement will initially have the ratings from

Moody’s Investors Service, Inc., Standard and

Poor’s Ratings Services, a division of The McGraw-

Hill Companies, Inc. and Fitch Ratings set forth in

the table on page S-1.

These ratings are not recommendations to buy,

sell or hold these certificates. A rating may be

changed or withdrawn at any time by the assigning

rating agency.

s The ratings do not address the possibilitythat, as a result of principal prepayments, the

yield on your certificates may be lower than

anticipated.

s The ratings do not address the payment ofany basis risk shortfalls with respect to the

certificates.

s The ratings on the Class A8 Certificates areassigned without regard to the Class A8

certificate guaranty insurance policy.

See ‘‘Ratings’’ in this prospectus supplement fora more complete discussion of the certificate ratings.

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Risk Factors

The following information, which you should carefully consider, identifies certain significant sourcesof risk associated with an investment in the offered certificates.

Higher Expected Delinquenciesof the Mortgage Loans . . . . . . . The mortgage loans, in general, were originated according to

underwriting guidelines that are not as strict as Fannie Mae or Freddie

Mac guidelines, so the mortgage loans are likely to experience rates of

delinquency, foreclosure and bankruptcy that are higher, and that may

be substantially higher, than those experienced by mortgage loans

underwritten in accordance with higher standards. In particular, a

significant portion of the mortgage loans in the trust fund were classified

in relatively low (i.e., relatively higher risk) credit categories.

Changes in the values of mortgaged properties related to the mortgage

loans may have a greater effect on the delinquency, foreclosure,

bankruptcy and loss experience of the mortgage loans in the trust fund

than on mortgage loans originated under stricter guidelines. We cannot

assure you that the values of the mortgaged properties have remained

or will remain at levels in effect on the dates of origination of the

related mortgage loans.

See ‘‘Description of the Mortgage Pools—General’’ in this prospectussupplement for a description of the characteristics of the mo

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