UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) October 25, 2005

Structured Asset Securities Corporation (as Depositor under the Trust Agreement dated as of September 1, 2005, providing for the issuance of Lehman XS Trust Mortgage Pass-Through Certificates, Series 2005-4)
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction
of incorporation)

333-127589
(Commission
File Number)

74-2440850
(IRS Employer
Identification No.)

745 Seventh Avenue, 7th Floor, New York, NY
(Address of principal executive offices)

10019
(Zip Code)

Registrant's telephone number, including area code 212-526-7000

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

[ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Section 8 - Other Events

Item 8.01. Other Events.

This current report on Form 8-K relates to the monthly distribution reported to the holders of Lehman XS Trust Mortgage Pass-Through Certificates, Series 2005-4, which was made on October 25, 2005.

Section 9 - Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits.

(Exhibit No. Description)
99.1 Monthly distribution report pursuant to section 4.03 of the Trust Agreement for the distribution on October 25, 2005.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

LASALLE BANK NATIONAL ASSOCIATION, IN ITS CAPACITY AS TRUSTEE UNDER THE TRUST AGREEMENT ON BEHALF OF STRUCTURED ASSET SECURITIES CORPORATION, REGISTRANT

By: /s/ Russell Goldenberg
Russell Goldenberg
Group Senior Vice President

Date: October 28, 2005

Lehman XS Trust

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Reporting Package Table of Contents

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Administrator:
Kim Sturm 312.904.4373
kimberly.sturm@abnamro.com

Analyst:
Chris Suh 714.259.6266
chris.k.suh@abnamro.com

Statement Date:

135 S. LaSalle Street, Suite 1625
Chicago, IL 60603
USA

Statements to Certificateholders
Cash Reconciliation Summary
Shortfall Summary Report
Bond Interest Reconciliation

Bond Principal Reconciliation

Other Related Information
Asset-Backed Facts ~ 15 Month Loan Status Summary Part I

Asset-Backed Facts ~ 15 Month Loan Status Summary Part II
Realized Loss Detail
Substitution Detail History

Page 2-3
Page 4-6
Page 7
Page 8

Page 9

Page 10
Page 11-13

Page 14-16
Page 17-19

Page 20

Page(s)

Information is available for this issue from the following sources

Issue Id:

Monthly Data File
Name:

LHXS0504

LHXS0504_200510_3.ZIP

Closing Date:

First Payment Date:

Rated Final Payment: Date:

30-Sep-05
25-Oct-05

25-Oct-35

Parties to The Transaction

Issuer: Lehman Brothers Inc.

Underwriter: Lehman Brothers Inc.

Master Servicer: Aurora Loan Services LLC

Rating Agency: Standard & Poor's Ratings Services/Moody's Investors Service, Inc.

800.246.5761

LaSalle Factor Line

LaSalle Web Site

www.etrustee.net

Page 1 of 20

Class

CUSIP

Original

Opening

Principal

Negative

Closing

Interest

Pass-Through

Per $ 1000

Next Rate(3)

WAC:
WAMM:

Next Index:

Payment Date:
Prior Payment:
Next Payment:
Record Date:

6.563602%

4.037500%

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Lehman XS Trust

Mortgage Pass-Through Certificates

Series 2005-4

Face Value (1)

Balance

Payment

Adj. or Loss

Amortization

Balance

Payment (2)

Adjustment

Rate

357

Bond Payments

Statement Date:

ABN AMRO Acct: 723026.1

1000.000000000

58.402117869

0.000000000

941.597882131

3.291666667

4.1475000000%

0.00

0.000000000

3.9500000000%

0.000000000

525221BY2

1-A1

208,842,000.00

12,196,815.10

0.00

196,645,184.90

687,438.25

208,842,000.00

1000.000000000

0.000000000

1000.000000000

3.425000000

4.3075000000%

0.00

0.000000000

4.1100000000%

0.000000000

525221BZ9

1-A2

141,082,000.00

0.00

141,082,000.00

483,205.85

141,082,000.00

1000.000000000

0.000000000

1000.000000000

3.533333388

4.4375000000%

0.00

0.000000000

4.2400000000%

0.000000000

525221CA4

1-A3

61,532,000.00

0.00

61,532,000.00

217,413.07

61,532,000.00

1000.000000000

0.000000000

1000.000000000

3.433333406

4.3175000000%

0.00

0.000000000

4.1200000000%

0.000000000

525221CB1

1-A4

45,716,000.00

0.00

45,716,000.00

156,958.27

45,716,000.00

1000.000000000

0.000000000

976.875866778

0.625000007

0.00

0.000000000

0.7500000000%

0.000000000

525221CC9

1-AX

174,189,582.00

0.00

170,161,598.90

108,868.49

174,189,582.00

1000.000000000

23.969580837

0.000000000

976.030419163

2.791666610

4.2175000000%

0.00

0.000000000

4.0200000000%

0.000000000

525221CG0

2-A1A

88,629,000.00

2,124,399.98

0.00

86,504,600.02

247,422.62

88,629,000.00

1000.000000000

23.969580800

0.000000000

976.030419200

3.590277733

5.1700000000%

0.00

0.000000000

5.1700000000%

0.000000000

525221CH8

2-A1B

75,000,000.00

1,797,718.56

0.00

73,202,281.44

269,270.83

75,000,000.00

1000.000000000

0.000000000

1000.000000000

4.366666667

5.2400000000%

0.00

0.000000000

5.2400000000%

0.000000000

525221CJ4

2-A2

48,534,000.00

0.00

48,534,000.00

211,931.80

48,534,000.00

1000.000000000

0.000000000

1000.000000000

4.166666500

5.0000000000%

0.00

0.000000000

5.0000000000%

0.000000000

525221CK1

2-A3A

20,000,000.00

0.00

20,000,000.00

83,333.33

20,000,000.00

1000.000000000

0.000000000

1000.000000000

4.491666808

5.3900000000%

0.00

0.000000000

5.3900000000%

0.000000000

525221CL9

2-A3B

23,656,000.00

0.00

23,656,000.00

106,254.87

23,656,000.00

1000.000000000

0.000000000

1000.000000000

4.425000177

5.3100000000%

0.00

0.000000000

5.3100000000%

0.000000000

525221CM7

2-A4

28,303,000.00

0.00

28,303,000.00

125,240.78

28,303,000.00

1000.000000000

0.000000000

1000.000000000

4.275000000

5.1300000000%

0.00

0.000000000

5.1300000000%

0.000000000

525221CN5

2-A5A

29,116,000.00

0.00

29,116,000.00

124,470.90

29,116,000.00

1000.000000000

0.000000000

1000.000000000

4.275002038

5.1300000000%

0.00

0.000000000

5.1300000000%

0.000000000

525221CP0

2-A5B

2,453,000.00

0.00

2,453,000.00

10,486.58

2,453,000.00

1000.000000000

0.000000000

1000.000000000

3.616666813

4.5375000000%

0.00

0.000000000

4.3400000000%

0.000000000

525221CD7

1-M1

22,843,000.00

0.00

22,843,000.00

82,615.52

22,843,000.00

1000.000000000

0.000000000

1000.000000000

3.783333660

4.7375000000%

0.00

0.000000000

4.5400000000%

0.000000000

525221CE5

1-M2

10,202,000.00

0.00

10,202,000.00

38,597.57

10,202,000.00

1000.000000000

0.000000000

1000.000000000

4.658333557

5.7875000000%

0.00

0.000000000

5.5900000000%

0.000000000

525221CF2

1-M3

7,465,000.00

0.00

7,465,000.00

34,774.46

7,465,000.00

1000.000000000

0.000000000

1000.000000000

4.458333455

5.3500000000%

0.00

0.000000000

5.3500000000%

0.000000000

525221CQ8

2-M1

13,651,000.00

0.00

13,651,000.00

60,860.71

13,651,000.00

Page 2 of 20

Notes: (1) N denotes notional balance not included in total (2) Accrued Interest Plus/Minus Interest Adjustment Minus Deferred Interest equals Interest Payment (3) Estimated. * Denotes Controlling Class

Class

CUSIP

Original

Opening

Principal

Negative

Closing

Interest

Pass-Through

Per $ 1000

Next Rate(3)

WAC:
WAMM:

Next Index:

Payment Date:
Prior Payment:
Next Payment:
Record Date:

6.563602%

4.037500%

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Lehman XS Trust

Mortgage Pass-Through Certificates

Series 2005-4

Face Value (1)

Balance

Payment

Adj. or Loss

Amortization

Balance

Payment (2)

Adjustment

Rate

357

Bond Payments

Statement Date:

ABN AMRO Acct: 723026.1

1000.000000000

0.000000000

1000.000000000

4.666667318

5.6000000000%

0.00

0.000000000

5.6000000000%

0.000000000

525221CR6

2-M2

5,119,000.00

0.00

5,119,000.00

23,888.67

5,119,000.00

1000.000000000

0.000000000

1000.000000000

5.150000000

6.1800000000%

0.00

0.000000000

6.1800000000%

0.000000000

525221CS4

2-M3

5,118,000.00

0.00

5,118,000.00

26,357.70

5,118,000.00

1000.000000000

0.000000000

1000.000000000

0.000000000

0.00

0.000000000

N/A

0.000000000

525221

1-P

100.00

0.00

100.00

0.00

100.00

1000.000000000

0.000000000

1000.000000000

362874.000000000

0.00

36,287.40

362874.000000000

N/A

0.000000000

525221

2-P

100.00

0.00

100.00

36,287.40

100.00

1000.000000000

0.000000000

976.875865823

0.000000000

0.00

)

(688,291.47

)

(1.382987498

1.6595849992%

0.000000000

525221

1-X

497,684,520.50

0.00

486,175,996.87

0.00

497,684,520.50

1000.000000000

0.000000000

990.322964876

0.000000000

0.00

)

(619,481.67

)

(1.815139265

2.1781671042%

0.000000000

525221

2-X

341,286,027.98

0.00

337,983,391.10

0.00

341,286,027.98

0.000000000

0.00

0.000000000

N/A

0.000000000

R-1

0.00

0.000000000

0.00

0.000000000

N/A

0.000000000

9ABSX930

R-2

0.00

0.000000000

0.00

0.000000000

N/A

0.000000000

LT1-R

0.00

0.000000000

0.00

0.000000000

N/A

0.000000000

LT2-R

0.00

0.000000000

0.00

0.000000000

N/A

0.000000000

LT3-R

0.00

Total P&I Payment

0.00

)

(1,271,485.74

837,261,200.00

19,254,611.31

Total

821,142,266.36

16,118,933.64

0.00

3,135,677.67

Page 3 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Statement Date:

Cash Reconciliation Summary

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

1,437,544.28

0.00

)

(9,001.85

Less ASER Interest Adv Reduction

0.00

Less Other Adjustment

0.00

Total

4,459,974.30

Unscheduled Interest:
Prepayment Penalties

36,287.40

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

36,287.40

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

Special Servicing Fees

Interest Due Serv on Advances

Recoup of Prior Advances

Misc. Fees & Expenses

Total Unscheduled Fees & Expenses
Total Interest Due Trust

Less Fees & Expenses Paid By/To Trust
Trustee Fee
Fee Strips
Misc. Fees
Interest Reserve Withholding

Plus Interest Reserve Deposit
Total

Total Interest Due Certs

Principal Summary

Scheduled Principal:
Current Scheduled Principal
Advanced Scheduled Principal
Scheduled Principal
Unscheduled Principal:
Curtailments
Prepayments in Full
Liquidation Proceeds
Repurchase Proceeds
Other Principal Proceeds
Total Unscheduled Principal
Remittance Principal

Remittance P&I Due Trust

Remittance P&I Due Certs

Pool Balance Summary

Beginning Pool
Scheduled Principal
Unscheduled Principal
Deferred Interest
Liquidations
Repurchases

Ending Pool

Balance

Count

Principal

Interest

Prior Outstanding
Plus Current Period
Less Recovered

Ending Outstanding

Servicing Fee Summary

Current Servicing Fees
Plus Fees Advanced for PPIS
Less Reduction for PPIS
Plus Delinquent Servicing Fees

Total Servicing Fees

Overcollateralization Summary

PPIS Summary

Gross PPIS
Reduced by PPIE
Reduced by Shortfalls in Fees
Reduced by Other Amounts

PPIS Reducing Scheduled
Interest

PPIS Reducing Servicing Fee
PPIS Due Certificate

0.00

0.00
0.00

0.00

4,449,092.96

0.00
0.00
0.00
0.00

0.00

74,312.93

160,642.92
234,955.85

135,725.56

14,440,479.10

0.00
0.00
0.00

14,576,204.66
14,811,160.51

19,260,253.47

838,970,548.48

3,849

234,955.85

14,576,204.66

0.00
0.00

0.00

824,159,387.97

3,798

0.00

160,642.92

3,031,431.87

160,642.92

3,031,431.87

56,170.59

0.00

)

(9,001.85

119,914.37

167,083.11

9,001.85

0.00
0.00
0.00

9,001.85
9,001.85

0.00

Advance Summary (Advance Made by Servicer)

)

(47,168.75

4,449,092.96

Interest Not Advanced (

Current Period

)

0.00

3,031,431.87

Workout Fees
Liquidation Fees

0.00
0.00

Less Non Recovered

0.00

0.00
0.00

0.00

Overcollateralization Amount

Overcollateralization Deficiency

3,017,321.62

1,352,476.75

Other Principal Information

Principal Remittance Amount

Overcollateralization Release Amount

14,811,160.51

0.00

14,811,160.51

Principal Distribution Amount

Page 4 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Statement Date:

Cash Reconciliation Summary Pool 1

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

866,715.56

0.00

)

(6,996.26

Less ASER Interest Adv Reduction

0.00

Less Other Adjustment

0.00

Total

2,529,444.36

Unscheduled Interest:
Prepayment Penalties

0.00

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

0.00

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

Special Servicing Fees

Interest Due Serv on Advances

Recoup of Prior Advances

Misc. Fees & Expenses

Total Unscheduled Fees & Expenses
Total Interest Due Trust

Less Fees & Expenses Paid By/To Trust
Trustee Fee
Fee Strips
Misc. Fees
Interest Reserve Withholding

Plus Interest Reserve Deposit
Total

Total Interest Due Certs

Principal Summary

Remittance P&I Due Trust

Remittance P&I Due Certs

Pool Balance Summary

Beginning Pool
Scheduled Principal
Unscheduled Principal
Deferred Interest
Liquidations
Repurchases

Ending Pool

Balance

Count

Principal

Interest

Prior Outstanding
Plus Current Period
Less Recovered

Ending Outstanding

Servicing Fee Summary

Current Servicing Fees
Plus Fees Advanced for PPIS
Less Reduction for PPIS
Plus Delinquent Servicing Fees

Total Servicing Fees

Overcollateralization Summary

PPIS Summary

Gross PPIS
Reduced by PPIE
Reduced by Shortfalls in Fees
Reduced by Other Amounts

PPIS Reducing Scheduled
Interest

PPIS Reducing Servicing Fee
PPIS Due Certificate

0.00

0.00
0.00

0.00

2,501,210.67

0.00
0.00
0.00
0.00

0.00

28,646.53
56,339.08
84,985.61

68,362.72

11,355,175.30

0.00
0.00
0.00

11,423,538.02
11,508,523.63

14,009,734.30

497,684,520.50

1,899

84,985.61

11,423,538.02

0.00
0.00

0.00

486,175,996.87

1,858

0.00

56,339.08

1,669,725.06

56,339.08

1,669,725.06

35,229.95

0.00

)

(6,996.26

68,826.49

97,060.18

6,996.26

0.00
0.00
0.00

6,996.26
6,996.26

0.00

Advance Summary (Advance Made by Servicer)

)

(28,233.69

2,501,210.67

Interest Not Advanced (

Current Period

)

0.00

1,669,725.06

Workout Fees
Liquidation Fees

0.00
0.00

Less Non Recovered

0.00

0.00
0.00

0.00

Overcollateralization Amount

Overcollateralization Deficiency

690,811.97

1,051,084.40

Other Principal Information

Principal Remittance Amount

Overcollateralization Release Amount

11,508,523.63

0.00

11,508,523.63

Principal Distribution Amount

Page 5 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Statement Date:

Cash Reconciliation Summary Pool 2

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

570,828.72

0.00

)

(2,005.59

Less ASER Interest Adv Reduction

0.00

Less Other Adjustment

0.00

Total

1,930,529.95

Unscheduled Interest:
Prepayment Penalties

36,287.40

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

36,287.40

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

Special Servicing Fees

Interest Due Serv on Advances

Recoup of Prior Advances

Misc. Fees & Expenses

Total Unscheduled Fees & Expenses
Total Interest Due Trust

Less Fees & Expenses Paid By/To Trust
Trustee Fee
Fee Strips
Misc. Fees
Interest Reserve Withholding

Plus Interest Reserve Deposit
Total

Total Interest Due Certs

Principal Summary

Remittance P&I Due Trust

Remittance P&I Due Certs

Pool Balance Summary

Beginning Pool
Scheduled Principal
Unscheduled Principal
Deferred Interest
Liquidations
Repurchases

Ending Pool

Balance

Count

Principal

Interest

Prior Outstanding
Plus Current Period
Less Recovered

Ending Outstanding

Servicing Fee Summary

Current Servicing Fees
Plus Fees Advanced for PPIS
Less Reduction for PPIS
Plus Delinquent Servicing Fees

Total Servicing Fees

Overcollateralization Summary

PPIS Summary

Gross PPIS
Reduced by PPIE
Reduced by Shortfalls in Fees
Reduced by Other Amounts

PPIS Reducing Scheduled
Interest

PPIS Reducing Servicing Fee
PPIS Due Certificate

0.00

0.00
0.00

0.00

1,947,882.29

0.00
0.00
0.00
0.00

0.00

45,666.40

104,303.84
149,970.24

67,362.84

3,085,303.80

0.00
0.00
0.00

3,152,666.64
3,302,636.88

5,250,519.17

341,286,027.98

1,950

149,970.24

3,152,666.64

0.00
0.00

0.00

337,983,391.10

1,940

0.00

104,303.84

1,361,706.81

104,303.84

1,361,706.81

20,940.64

0.00

)

(2,005.59

51,087.87

70,022.93

2,005.59

0.00
0.00
0.00

2,005.59
2,005.59

0.00

Advance Summary (Advance Made by Servicer)

)

(18,935.06

1,947,882.29

Interest Not Advanced (

Current Period

)

0.00

1,361,706.81

Workout Fees
Liquidation Fees

0.00
0.00

Less Non Recovered

0.00

0.00
0.00

0.00

Overcollateralization Amount

Overcollateralization Deficiency

2,326,509.65

301,392.35

Other Principal Information

Principal Remittance Amount

Overcollateralization Release Amount

3,302,636.88

0.00

3,302,636.88

Principal Distribution Amount

Page 6 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Interest Adjustments Summary

Statement Date:

0.00

Special Servicing Fees

Workout Fees

Liquidation Fees

Legal Fees

0.00

Misc. Fees & Expenses Paid by/to Servicer

Interest Paid to Servicer on Outstanding Advances

0.00

ASER Interest Advance Reduction

Interest Not Advanced (Current Period)

Recoup of Prior Advances by Servicer

0.00

Servicing Fees Paid Servicer on Loans Not Advanced

Misc. Fees & Expenses Paid by Trust

0.00

Shortfall Due to Rate Modification

Total Shortfall Allocated to the Bonds

Total Interest Adjustment to the Bonds

0.00

Shortfall Allocated to the Bonds:

Excess Allocated to the Bonds:

Other Interest Proceeds Due the Bonds

Yield Maintenance Penalties Due the Bonds

Prepayment Penalties Due the Bonds

Recovered ASER Interest Due the Bonds

Recovered Interest Due the Bonds

Less Total Shortfall Allocated to the Bonds

Total Excess Allocated to the Bonds

36,287.40

36,287.40

Total Excess Allocated to the Bonds

36,287.40

0.00

Aggregate Interest Adjustment Allocated to the Bonds

0.00

36,287.40

0.00

Prepayment Interest Excess Due the Bonds

0.00

ARD Excess Interest

0.00

Net Prepayment Int. Shortfalls Allocated to the Bonds

Other Interest Loss

Interest Income

0.00

Page 7 of 20

Lehman XS Trust

Class

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Bond Interest Reconciliation

Additions

Accrual

Method Days

Statement Date:

Accrued

Certificate

Interest

Prior

Int Carry-Fwd

Shortfall

Prior

Shortfall

Reimbursement

Other

Int ere st

Proceeds

Other

Int ere st

Losses

Current

Int Carry-Fwd

Shortfall

Remaining

Int Carry-Fwd

Shortfall

Net Cap Rate

in Effect

Y/ N

Distributable

Certificate

Int ere st

Payment

Amount

Deductions

Outstanding

Deposits from YM

Agreement

Remaining Basis Risk

Carry-Fwd Shortfall

Current Basis Risk

Carry-Fwd Shortfall

0.00

687,438.25

Act/360

0.00

687,438.25

0.00

1-A1

0.00

483,205.85

Act/360

0.00

483,205.85

0.00

1-A2

0.00

217,413.07

Act/360

0.00

217,413.07

0.00

1-A3

0.00

156,958.27

Act/360

0.00

156,958.27

0.00

1-A4

0.00

108,868.49

30/360

0.00

108,868.49

0.00

1-AX

0.00

247,422.62

Act/360

0.00

247,422.62

0.00

2-A1A

0.00

269,270.83

30/360

0.00

269,270.83

0.00

2-A1B

0.00

211,931.80

30/360

0.00

211,931.80

0.00

2-A2

0.00

83,333.33

30/360

0.00

83,333.33

0.00

2-A3A

0.00

106,254.87

30/360

0.00

106,254.87

0.00

2-A3B

0.00

125,240.78

30/360

0.00

125,240.78

0.00

2-A4

0.00

124,470.90

30/360

0.00

124,470.90

0.00

2-A5A

0.00

10,486.58

30/360

0.00

10,486.58

0.00

2-A5B

0.00

82,615.52

Act/360

0.00

82,615.52

0.00

1-M1

0.00

38,597.57

Act/360

0.00

38,597.57

0.00

1-M2

0.00

34,774.46

Act/360

0.00

34,774.46

0.00

1-M3

0.00

60,860.71

30/360

0.00

60,860.71

0.00

2-M1

0.00

23,888.67

30/360

0.00

23,888.67

0.00

2-M2

0.00

26,357.70

30/360

0.00

26,357.70

0.00

2-M3

0.00

688,291.47

0.00

30/360

0.00

688,291.47

0.00

688,291.47

0.00

1-X

0.00

619,481.67

0.00

30/360

0.00

619,481.67

0.00

619,481.67

0.00

2-X

0.00

4,407,163.41

3,099,390.27

0.00

1,307,773.14

0.00

(2) Interest Carry-Forward Shortfall is unpaid interest with interest thereon
(3) Basis Risk Carry-Forward Shortfall - difference between LIBOR plus margin and the Net Rate Cap.

Page 8 of 20

(1) Other Interest Proceeds are additional interest amounts specifically allocated to the bond(s) and used in determining the bonds Distributable Interest.

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Bond Principal Reconciliation

Credit Support

Original

Current(4)

Statement Date:

Beginning

Class Balance

Unscheduled

Principal

Payment

Extra

Principal

Payment Amt

Prior

Loss

Reimburs.

Rated

Final

Maturity

Class

Current

Losses

Original

Class Balance

Scheduled

Principal

Payment

Ending

Class Balance

Cumulative

Losses

Interest on

Losses

Additions

Losses

6.00
1.00

1-A1

10/25/2035

196,645,184.90

0.00

208,842,000.00

11,508,523.63

0.00

688,291.47

0.00

1-A2

10/25/2035

141,082,000.00

0.00

141,082,000.00

0.00

1-A3

10/25/2035

61,532,000.00

0.00

61,532,000.00

0.00

1-A4

10/25/2035

45,716,000.00

0.00

45,716,000.00

0.00

1-AX

9/25/2008

170,161,598.90

0.00

174,189,582.00

0.00

2-A1A

10/25/2035

86,504,600.02

0.00

88,629,000.00

1,788,860.19

0.00

335,539.79

0.00

2-A1B

10/25/2035

73,202,281.44

0.00

75,000,000.00

1,513,776.69

0.00

283,941.87

0.00

2-A2

10/25/2035

48,534,000.00

0.00

48,534,000.00

0.00

2-A3A

10/25/2035

20,000,000.00

0.00

20,000,000.00

0.00

2-A3B

10/25/2035

23,656,000.00

0.00

23,656,000.00

0.00

2-A4

10/25/2035

28,303,000.00

0.00

28,303,000.00

0.00

2-A5A

10/25/2035

29,116,000.00

0.00

29,116,000.00

0.00

2-A5B

10/25/2035

2,453,000.00

0.00

2,453,000.00

0.00

1-M1

10/25/2035

22,843,000.00

0.00

22,843,000.00

0.00

1-M2

10/25/2035

10,202,000.00

0.00

10,202,000.00

0.00

1-M3

10/25/2035

7,465,000.00

0.00

7,465,000.00

0.00

2-M1

10/25/2035

13,651,000.00

0.00

13,651,000.00

0.00

2-M2

10/25/2035

5,119,000.00

0.00

5,119,000.00

0.00

2-M3

10/25/2035

5,118,000.00

0.00

5,118,000.00

0.00

1-X

10/25/2035

486,175,996.87

0.00

497,684,520.50

0.00

2-X

10/25/2035

337,983,391.10

0.00

341,286,027.98

0.00

14,811,160.51

0.00

-0.01

1,307,773.14

837,261,000.00

821,142,066.36

837,261,000.00

Page 9 of 20

(1) Extra Principal Amounts: the lessor of (i) the excess, if any, of the overcollateralization Target Amount over the Overcollateralization Amount.

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Other Related Information

Statement Date:

$3,047.73

Insurance Premium 1-A4

Insured Payments to Class:

0.00

1-A4

Insurance Premium 2-A4

$2,594.44

2-4A

0.00

Page 10 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part I

Distribution

Date

REO

Balance

Statement Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

0.13%

0.00%

25-Oct-05

1,091,350

3,793

823,068,038

99.87%

Page 11 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part I

Distribution

Date

REO

Balance

Statement Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

Pool 1

0.16%

0.15%

0.00%

25-Oct-05

743,752

1,855

485,432,245

99.84%

99.85%

Page 12 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part I

Distribution

Date

REO

Balance

Statement Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

Pool 2

0.10%

0.00%

25-Oct-05

347,598

1,938

337,635,793

99.90%

Page 13 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Distribution

Date

Statement Date:

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance # Balance

# Balance

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance

# Balance

In Foreclosure and Delinquent

In Bankruptcy and Delinquent

In REO and Delinquent

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part II

Current

31 - 60 Days

61 - 90 Days

90 + Days

Balance

25-Oct-05

0.00%

0.00% 0.00%

0.00%

Page 14 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Distribution

Date

Statement Date:

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance # Balance

# Balance

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance

# Balance

In Foreclosure and Delinquent

In Bankruptcy and Delinquent

In REO and Delinquent

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part II - Pool 1

Current

31 - 60 Days

61 - 90 Days

90 + Days

Balance

25-Oct-05

0.00%

0.00% 0.00%

0.00%

Page 15 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Distribution

Date

Statement Date:

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance # Balance

# Balance

Current 31 - 60 Days 61 - 90 Days

90 + Days

# Balance # Balance

# Balance

In Foreclosure and Delinquent

In Bankruptcy and Delinquent

In REO and Delinquent

Asset-Backed Facts ~ 15 Month Historical Loan Status Summary Part II - Pool 2

Current

31 - 60 Days

61 - 90 Days

90 + Days

Balance

25-Oct-05

0.00%

0.00% 0.00%

0.00%

Page 16 of 20

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Realized Loss Detail

Period

Disclosure

Control #

Appraisal

Date

Appraisal

Value

Beginning

Scheduled

Balance

Gross

Proceeds

Gross Proceeds

as a % of

Sched. Balance

Aggregate

Liquidation

Expenses *

Net

Liquidation

Proceeds

Net Proceeds

as a % of

Sched. Balance

Realized

Loss

Statement Date:

Current Total

Cumulative

Page 17 of 20

* Aggregate liquidation expenses also include outstanding P&I advances and unpaid servicing fees, unpaid trustee fees, etc..

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Realized Loss Detail

Period

Disclosure

Control #

Appraisal

Date

Appraisal

Value

Beginning

Scheduled

Balance

Gross

Proceeds

Gross Proceeds

as a % of

Sched. Balance

Aggregate

Liquidation

Expenses *

Net

Liquidation

Proceeds

Net Proceeds

as a % of

Sched. Balance

Realized

Loss

Statement Date:

Pool 1

Current Total

Cumulative

Page 18 of 20

* Aggregate liquidation expenses also include outstanding P&I advances and unpaid servicing fees, unpaid trustee fees, etc..

Lehman XS Trust

Payment Date:
Prior Payment:
Next Payment:
Record Date:

25-Oct-05
25-Oct-05

N/A

25-Nov-05

24-Oct-05

Mortgage Pass-Through Certificates

Series 2005-4

ABN AMRO Acct: 723026.1

Realized Loss Detail

Period

Disclosure

Control #

Appraisal

Date

Appraisal

Value

Beginning

Scheduled

Balance

Gross

Proceeds

Gross Proceeds

as a % of

Sched. Balance

Aggregate

Liquidation

Expenses *

Net

Liquidation

Proceeds

Net Proceeds

as a % of

Sched. Balance

Realized

Loss

Statement Date:

Pool 2

Current Total

Cumulative

Page 19 of 20

* Aggregate liquidation expenses also include outstanding P&I advances and unpaid servicing fees, unpaid trustee fees, etc..

Lehman XS Trust

Substitution Detail History

ABN AMRO Acct: 723026.1

Series 2005-4

Mortgage Pass-Through Certificates

24-Oct-05

25-Nov-05

N/A

25-Oct-05

Record Date:

Next Payment:

Prior Payment:

Payment Date:

Statement Date:

Property ID

Deleted Loan

Qualified Substitute

Scheduled Prin Bal

Per Section 7.01(a)(i) of the Property Management and Lease Servicing Agreement, aggregate Appraised Value of the Qualified Substitute Mortgaged Properties acquired by the
Issuer since the Closing Date in connection with the substitution or exchange pursuant to Section 7.01 is not to exceed 25% of the aggregate Initial Appraised Value of the
Mortgaged Properties.

(A)

Page 20 of 20

Original Property

Lehman XS Trust, Series 2005-4 8-K