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

FORM 8-K /A

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

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

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

Delaware
(State or other jurisdiction
of incorporation)

333-120575
(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 /A 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 /A relates to the monthly distribution reported to the holders of Structured Asset Securities Corporation Mortgage Pass-Through Certificates, Series 2005-4XS, which was made on April 25, 2005.

Section 9 - Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits.

99.1 Monthly distribution report pursuant to section 5.02 of the Trust Agreement for the distribution on April 25, 2005.

(Exhibit No. Description)

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 SECURITIES ADMINISTRATOR UNDER THE TRUST AGREEMENT ON BEHALF OF STRUCTURED ASSET SECURITIES CORPORATION, REGISTRANT

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

Date: May 26, 2005

Structured Asset Securities Corporation

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Reporting Package Table of Contents

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Administrator:
Amanda Hellyer 312.904.6299
amanda.hellyer@abnamro.com

Analyst:
Vamsi Kaipa 714.259.6252
vamsi.kaipa@abnamro.com

Revised 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
Asset-Backed Facts ~ 15 Month Loan Payoff/Loss Summary
Realized Loss Detail

Page 2-4
Page 5-8
Page 9
Page 10-11

Page 12-13

Page 14
Page 15-18

Page 19-22
Page 23-26

Page 27-30

Substitution Detail History

Page 31

Page(s)

Information is available for this issue from the following sources

Issue Id:

Monthly Data File
Name:

SASC54XS

SASC54XS_200504_3.ZIP

Closing Date:

First Payment Date:

Rated Final Payment: Date:

28-Feb-05
25-Mar-05

26-Mar-40

Parties to The Transaction

Depositor: Structured Asset Securities Corporation

Underwriter: Lehman Brothers Inc./Lehman Brothers Inc.

Master Servicer: Aurora Loan Services LLC

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

800.246.5761

LaSalle Factor Line

LaSalle Web Site

www.etrustee.net

Page 1 of 31

Class

CUSIP

Original

Opening

Principal

Negative

Closing

Interest

Pass-Through

Per $ 1000

Next Rate(3)

WAC:
WAMM:
Current Index:
Next Index:

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

6.295336%

2.850000%
3.020000%

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Structured Asset Securities Corporation

Mortgage Pass-Through Certificates

Series 2005-4XS

Face Value (1)

Balance

Payment

Adj. or Loss

Amortization

Balance

Payment (2)

Adjustment

Rate

353

Bond Payments - Pools 1&2

Revised Date:

ABN AMRO Acct: 722414.2

950.902811462

67.300859449

0.000000000

883.601952013

2.431933907

3.140000000%

0.00

0.000000000

2.97000000%

0.000000000

86359B4Q1

1-A1

136,413,000.00

9,180,712.14

0.00

120,534,793.08

331,747.40

129,715,505.22

1000.000000000

0.000000000

1000.000000000

4.183333333

5.020000000%

0.00

0.000000000

5.02000000%

0.000000000

86359B4R9

1-A2A

15,000,000.00

0.00

15,000,000.00

62,750.00

15,000,000.00

1000.000000000

0.000000000

1000.000000000

3.891666693

4.670000000%

0.00

0.000000000

4.67000000%

0.000000000

86359B4S7

1-A2B

62,645,000.00

0.00

62,645,000.00

243,793.46

62,645,000.00

1000.000000000

0.000000000

1000.000000000

4.166666798

5.000000000%

0.00

0.000000000

5.00000000%

0.000000000

86359B4T5

1-A3

25,312,000.00

0.00

25,312,000.00

105,466.67

25,312,000.00

1000.000000000

0.000000000

1000.000000000

4.441667000

5.330000000%

0.00

0.000000000

5.33000000%

0.000000000

86359B4U2

1-A4A

10,000,000.00

0.00

10,000,000.00

44,416.67

10,000,000.00

1000.000000000

0.000000000

1000.000000000

4.375000000

5.250000000%

0.00

0.000000000

5.25000000%

0.000000000

86359B4V0

1-A4B

27,648,000.00

0.00

27,648,000.00

120,960.00

27,648,000.00

1000.000000000

0.000000000

1000.000000000

4.041666667

4.850000000%

0.00

0.000000000

4.85000000%

0.000000000

86359B4W8

1-A5A

9,900,000.00

0.00

9,900,000.00

40,012.50

9,900,000.00

1000.000000000

0.000000000

1000.000000000

4.158333333

4.990000000%

0.00

0.000000000

4.99000000%

0.000000000

86359B4X6

1-A5B

20,880,000.00

0.00

20,880,000.00

86,826.00

20,880,000.00

980.744693944

19.861341581

0.000000000

960.883352363

4.143646314

5.070000000%

0.00

0.000000000

5.07000000%

0.000000000

86359B4Y4

2-A1A

116,482,000.00

2,313,488.79

0.00

111,925,614.65

482,660.21

114,239,103.44

980.744693756

19.861341923

0.000000000

960.883351833

4.143646515

5.070000000%

0.00

0.000000000

5.07000000%

0.000000000

86359B4Z1

2-A1B

15,135,000.00

300,601.41

0.00

14,542,969.53

62,714.09

14,843,570.94

1000.000000000

0.000000000

1000.000000000

2.858889102

3.490000000%

0.00

0.000000000

3.32000000%

0.000000000

86359B5A5

10,451,000.00

0.00

10,451,000.00

29,878.25

10,451,000.00

1000.000000000

0.000000000

1000.000000000

3.074166564

3.740000000%

0.00

0.000000000

3.57000000%

0.000000000

86359B5B3

8,129,000.00

0.00

8,129,000.00

24,989.90

8,129,000.00

1000.000000000

0.000000000

1000.000000000

3.573610641

4.320000000%

0.00

0.000000000

4.15000000%

0.000000000

86359B5C1

6,503,000.00

0.00

6,503,000.00

23,239.19

6,503,000.00

1000.000000000

0.000000000

1000.000000000

72774.800000000

0.00

7,277.48

72774.800000000

N/A

0.000000000

9ABSU1522

100.00

0.00

100.00

7,277.48

100.00

981.992207437

0.000000000

958.203355426

0.000000000

0.00

)

(744,915.45

)

(1.603698172

1.95972819%

0.000000000

9ABSU1530

464,498,534.22

0.00

445,084,054.08

0.00

456,133,940.97

Page 2 of 31

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:
Current Index:
Next Index:

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

6.295336%

2.850000%
3.020000%

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Structured Asset Securities Corporation

Mortgage Pass-Through Certificates

Series 2005-4XS

Face Value (1)

Balance

Payment

Adj. or Loss

Amortization

Balance

Payment (2)

Adjustment

Rate

353

Bond Payments - Pools 1&2

Revised Date:

ABN AMRO Acct: 722414.2

0.000000000

0.00

0.000000000

N/A

0.000000000

9ABSU1548

0.00

Total P&I Payment

0.00

)

(737,637.97

464,498,100.00

455,266,279.60

13,461,534.16

Total

443,471,477.26

11,794,802.34

0.00

1,666,731.82

Page 3 of 31

Class

CUSIP

Original

Opening

Principal

Negative

Closing

Interest

Pass-Through

Per $ 1000

Next Rate(3)

WAC:
WAMM:
Current Index:
Next Index:

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

6.295336%

2.850000%
3.020000%

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Structured Asset Securities Corporation

Mortgage Pass-Through Certificates

Series 2005-4XS

Face Value (1)

Balance

Payment

Adj. or Loss

Amortization

Balance

Payment (2)

Adjustment

Rate

353

Bond Payments - Pool 3

Revised Date:

ABN AMRO Acct: 722414.2

964.768177860

30.641776222

0.000000000

934.126401637

4.164582582

5.180000000%

0.00

0.000000000

5.18000000%

0.000000000

86359B5D9

3-A1

84,280,000.00

2,582,488.90

0.00

78,728,173.13

350,991.02

81,310,662.03

1000.000000000

0.000000000

1000.000000000

3.558333333

4.270000000%

0.00

0.000000000

4.27000000%

0.000000000

86359B5E7

3-A2

24,186,000.00

0.00

24,186,000.00

86,061.85

24,186,000.00

1000.000000000

0.000000000

1000.000000000

3.725000000

4.470000000%

0.00

0.000000000

4.47000000%

0.000000000

86359B5F4

3-A3

81,922,000.00

0.00

81,922,000.00

305,159.45

81,922,000.00

1000.000000000

0.000000000

1000.000000000

3.991666789

4.790000000%

0.00

0.000000000

4.79000000%

0.000000000

86359B5G2

3-A4

40,971,000.00

0.00

40,971,000.00

163,542.58

40,971,000.00

1000.000000000

0.000000000

1000.000000000

4.450000000

5.340000000%

0.00

0.000000000

5.34000000%

0.000000000

86359B5H0

3-A5

55,379,000.00

0.00

55,379,000.00

246,436.55

55,379,000.00

1000.000000000

0.000000000

1000.000000000

4.500000000

5.400000000%

0.00

0.000000000

5.40000000%

0.000000000

86359B5J6

3-M1

2,953,000.00

0.00

2,953,000.00

13,288.50

2,953,000.00

1000.000000000

0.000000000

1000.000000000

4.583332393

5.500000000%

0.00

0.000000000

5.50000000%

0.000000000

86359B5K3

3-M2

3,544,000.00

0.00

3,544,000.00

16,243.33

3,544,000.00

1000.000000000

0.000000000

1000.000000000

4.583333333

5.500000000%

0.00

0.000000000

5.50000000%

0.000000000

86359B5L1

3-M3

2,067,000.00

0.00

2,067,000.00

9,473.75

2,067,000.00

1000.000000000

0.000000000

1000.000000000

0.000000000

0.00

0.000000000

N/A

0.000000000

9ABSU1647

3-P

100.00

0.00

100.00

0.00

100.00

990.722967256

0.000000000

982.548931212

0.000000000

0.00

)

(168,676.16

)

(0.571198001

0.69185597%

0.000000000

9ABSU1654

3-X

295,302,434.05

0.00

290,149,090.96

0.00

292,562,903.70

0.000000000

0.00

0.000000000

N/A

0.000000000

9ABSU1662

3-R

0.00

Total P&I Payment

0.00

)

(168,676.16

295,302,100.00

292,332,762.03

3,773,685.93

Total

289,750,273.13

2,582,488.90

0.00

1,191,197.03

Page 4 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Revised Date:

Cash Reconciliation Summary

Overcollateralization Deficiency

Overcollateralization Amount

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

1,183,440.80

0.00

)

(10,957.71

Less Other Adjustment

0.00

Total

3,807,915.09

Unscheduled Interest:

Prepayment Penalties

7,277.45

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

7,277.45

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

PMI Amounts
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
Credit Risk Manager's Fees

Misc. Fees

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

3,778,715.56

0.00
0.00
0.00

0.00

126,757.74
310,142.21
436,899.95

928,406.62

12,098,393.06

0.00
0.00
0.00

13,026,799.68
13,463,699.63

17,242,415.19

748,696,844.67

2,722

436,899.95

13,026,799.68

0.00
0.00

0.00

735,233,145.04

2,677

325,270.64

2,941,781.60

310,142.21

2,635,432.00

316,459.78

2,694,231.87

47,434.68

0.00

)

(10,957.71

108,875.47

145,352.44

15,002.08

)

(4,044.37

0.00
0.00

10,957.71
10,957.71

0.00

Advance Summary (Advance Made by Servicer)

)

(36,476.97

3,778,715.56

Interest Not Advanced (

Current Period

)

0.00

2,635,432.00

Less Non Recovered

)

(2,882,981.73

)

(318,953.07

0.00

Other Principal Information

Principal Remittance Amount
Overcollateralization Release Amount

0.00

Principal Distribution Amount

0.00

Page 5 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Revised Date:

Cash Reconciliation Summary Pool 1

Pool 1-2 Overcollateralization Deficiency

Pool 1-2 Overcollateralization Amount

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

505,986.64

0.00

)

(7,681.21

Less Other Adjustment

0.00

Total

1,719,613.13

Unscheduled Interest:

Prepayment Penalties

2,591.08

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

2,591.08

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

PMI Amounts
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
Credit Risk Manager's Fees

Misc. Fees

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

1,710,802.15

0.00
0.00
0.00

0.00

52,886.76

135,201.53
188,088.29

430,378.30

8,042,499.84

0.00
0.00
0.00

8,472,878.14
8,660,966.43

10,371,768.58

319,248,436.26

1,212

188,088.29

8,472,878.14

0.00
0.00

0.00

310,587,469.83

1,185

141,628.77

1,363,091.68

135,201.53

1,221,307.70

139,006.57

1,257,196.11

19,083.27

0.00

)

(7,681.21

47,710.36

59,112.43

10,878.57

)

(3,197.36

0.00
0.00

7,681.21
7,681.21

0.00

Advance Summary (Advance Made by Servicer)

)

(11,402.07

1,710,802.15

Interest Not Advanced (

Current Period

)

0.00

1,221,307.70

Less Non Recovered

)

(1,327,203.27

)

(137,823.73

0.00

1,612,676.82

13,068.18

Other Principal Information

Principal Remittance Amount
Overcollateralization Release Amount

8,660,966.43

0.00

8,660,966.43

Principal Distribution Amount

0.00

Page 6 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Revised Date:

Cash Reconciliation Summary Pool 2

Pool 1-2 Overcollateralization Deficiency

Pool 1-2 Overcollateralization Amount

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

213,923.81

0.00

)

(181.36

Less Other Adjustment

0.00

Total

707,930.36

Unscheduled Interest:

Prepayment Penalties

4,686.40

Yield Maintenance Penalties

0.00

Other Interest Proceeds

0.00

Total

4,686.40

Less Fees & Expenses Paid By/To Servicer

Less Fee Paid To Servicer
Less Fee Strips Paid by Servicer

PMI Amounts
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
Credit Risk Manager's Fees

Misc. Fees

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

704,348.32

0.00
0.00
0.00

0.00

5,847.43

15,088.83
20,936.26

15,118.80

2,352,865.40

0.00
0.00
0.00

2,367,984.20
2,388,920.46

3,093,268.78

136,885,504.71

740

20,936.26

2,367,984.20

0.00
0.00

0.00

134,496,584.25

727

16,130.95

548,303.37

15,088.83

494,187.91

15,451.21

507,165.48

8,449.80

0.00

)

(181.36

20,116.11

28,384.54

1,028.37

)

(847.01

0.00
0.00

181.36
181.36

0.00

Advance Summary (Advance Made by Servicer)

)

(8,268.44

704,348.32

Interest Not Advanced (

Current Period

)

0.00

494,187.91

Less Non Recovered

)

(535,325.81

)

(15,768.57

0.00

1,612,676.82

13,068.18

Other Principal Information

Principal Remittance Amount
Overcollateralization Release Amount

2,388,920.46

0.00

2,388,920.46

Principal Distribution Amount

0.00

Page 7 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Revised Date:

Cash Reconciliation Summary Pool 3

Pool 3 Overcollateralization Deficiency

Pool 3 Overcollateralization Amount

Current Scheduled Interest

Interest Summary

Less Deferred Interest

Plus Gross Advance Interest

Less PPIS Reducing Scheduled Int

463,530.36

0.00

)

(3,095.14

Less Other Adjustment

0.00

Total

1,380,371.60

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

PMI Amounts
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
Credit Risk Manager's Fees

Misc. Fees

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

1,363,565.13

0.00
0.00
0.00

0.00

68,023.55

159,851.85
227,875.40

482,909.52

1,703,027.82

0.00
0.00
0.00

2,185,937.34
2,413,812.74

3,777,377.87

292,562,903.70

770

227,875.40

2,185,937.34

0.00
0.00

0.00

290,149,090.96

765

167,510.92

1,030,386.55

159,851.85

919,936.38

162,002.00

929,870.28

19,901.61

0.00

)

(3,095.14

41,049.00

57,855.46

3,095.14

0.00
0.00
0.00

3,095.14
3,095.14

0.00

Advance Summary (Advance Made by Servicer)

)

(16,806.47

1,363,565.13

Interest Not Advanced (

Current Period

)

0.00

919,936.38

Less Non Recovered

)

(1,020,452.65

)

(165,360.77

0.00

398,917.83

634,641.17

Other Principal Information

Principal Remittance Amount
Overcollateralization Release Amount

2,413,812.74

0.00

2,413,812.74

Principal Distribution Amount

0.00

Page 8 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Interest Adjustments Summary

Revised 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

7,277.45

7,277.45

Total Excess Allocated to the Bonds

7,277.45

0.00

Aggregate Interest Adjustment Allocated to the Bonds

0.00

7,277.45

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 9 of 31

Structured Asset Securities Corporation

Class

Payment Date:

Prior Payment:

Next Payment:

Record Date:

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Bond Interest Reconciliation

Additions

Accrual

Method Days

Revised Date:

Accrued

Certificate

Interest

Prior

Int Carry-Fwd

Shortfall

Prior

Shortfall

Reimbursement

Other

Int erest

Proceeds

Other

Int erest

Losses

Current

Int Carry-Fwd

Shortfall

Current Basis

Risk Carry-Fwd

Shortfall

Remaining

Int Carry-Fwd

Shortfall

Remaining Basis
Risk Carry-Fwd

Shortfall

Net Cap Rate

in Effect

Y/ N

Distributable

Certificate

Int erest

Payment

Amount

Deductions

Outstanding

Deposits from

Agreement

0.00

1-A1

331,747.40

Act/360

0.00

331,747.40

0.00

1-A2A

62,750.00

30/360

0.00

62,750.00

0.00

1-A2B

243,793.46

30/360

0.00

243,793.46

0.00

1-A3

105,466.67

30/360

0.00

105,466.67

0.00

1-A4A

44,416.67

30/360

0.00

44,416.67

0.00

1-A4B

120,960.00

30/360

0.00

120,960.00

0.00

1-A5A

40,012.50

30/360

0.00

40,012.50

0.00

1-A5B

86,826.00

30/360

0.00

86,826.00

0.00

2-A1A

482,660.21

30/360

0.00

482,660.21

0.00

2-A1B

62,714.09

30/360

0.00

62,714.09

0.00

29,878.25

Act/360

0.00

29,878.25

0.00

24,989.90

Act/360

0.00

24,989.90

0.00

23,239.19

Act/360

0.00

23,239.19

0.00

7,277.48

0.00

1,612,142.60

0.00

30/360

867,227.15

0.00

744,915.45

0.00

744,915.45

1,612,142.60

0.00

3-A1

350,991.02

30/360

0.00

350,991.02

0.00

3-A2

86,061.85

30/360

0.00

86,061.85

0.00

3-A3

305,159.45

30/360

0.00

305,159.45

0.00

3-A4

163,542.58

30/360

0.00

163,542.58

0.00

3-A5

246,436.55

30/360

0.00

246,436.55

0.00

3-M1

13,288.50

30/360

0.00

13,288.50

0.00

3-M2

16,243.33

30/360

0.00

16,243.33

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 10 of 31

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

Structured Asset Securities Corporation

Class

Payment Date:

Prior Payment:

Next Payment:

Record Date:

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Bond Interest Reconciliation

Additions

Accrual

Method Days

Revised Date:

Accrued

Certificate

Interest

Prior

Int Carry-Fwd

Shortfall

Prior

Shortfall

Reimbursement

Other

Int erest

Proceeds

Other

Int erest

Losses

Current

Int Carry-Fwd

Shortfall

Current Basis

Risk Carry-Fwd

Shortfall

Remaining

Int Carry-Fwd

Shortfall

Remaining Basis
Risk Carry-Fwd

Shortfall

Net Cap Rate

in Effect

Y/ N

Distributable

Certificate

Int erest

Payment

Amount

Deductions

Outstanding

Deposits from

Agreement

0.00

3-M3

9,473.75

30/360

0.00

9,473.75

0.00

3-P

0.00

3-X

398,483.78

0.00

30/360

229,807.62

0.00

168,676.16

0.00

168,676.16

398,483.78

0.00

1,097,034.77

3,764,242.98

4,868,555.23

2,857,928.85

0.00

913,591.61

2,010,626.38

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 11 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Bond Principal Reconciliation

Credit Support

Original

Current(4)

Revised 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

2.00
1.00

1-A1

4.43%

4.59%

3/26/2040

120,534,793.08

0.00

129,715,505.22

136,413,000.00

188,088.29

0.00

519,745.71

8,472,878.14

1-A2A

4.43%

4.59%

3/26/2040

15,000,000.00

0.00

15,000,000.00

0.00

1-A2B

4.43%

4.59%

3/26/2040

62,645,000.00

0.00

62,645,000.00

0.00

1-A3

4.43%

4.59%

3/26/2040

25,312,000.00

0.00

25,312,000.00

0.00

1-A4A

4.43%

4.59%

3/26/2040

10,000,000.00

0.00

10,000,000.00

0.00

1-A4B

4.43%

4.59%

3/26/2040

27,648,000.00

0.00

27,648,000.00

0.00

1-A5A

4.43%

4.59%

3/26/2040

9,900,000.00

0.00

9,900,000.00

0.00

1-A5B

4.43%

4.59%

3/26/2040

20,880,000.00

0.00

20,880,000.00

0.00

2-A1A

4.43%

4.59%

3/26/2040

111,925,614.65

0.00

114,239,103.44

116,482,000.00

18,528.74

0.00

199,276.85

2,095,683.20

2-A1B

4.43%

4.59%

3/26/2040

14,542,969.53

0.00

14,843,570.94

15,135,000.00

2,407.52

0.00

25,892.89

272,301.00

2.66%

2.76%

3/26/2040

10,451,000.00

0.00

10,451,000.00

0.00

1.13%

1.17%

3/26/2040

8,129,000.00

0.00

8,129,000.00

0.00

0.00%

3/26/2040

6,503,000.00

0.00

6,503,000.00

0.00

3/26/2040

100.00

0.00

100.00

0.00

3/26/2040

445,084,054.08

0.00

456,133,940.97

464,498,534.22

0.00

3-A1

4.43%

4.59%

3/26/2040

78,728,173.13

0.00

81,310,662.03

84,280,000.00

227,875.40

0.00

168,676.16

2,185,937.34

3-A2

4.43%

4.59%

3/26/2040

24,186,000.00

0.00

24,186,000.00

0.00

3-A3

4.43%

4.59%

3/26/2040

81,922,000.00

0.00

81,922,000.00

0.00

3-A4

4.43%

4.59%

3/26/2040

40,971,000.00

0.00

40,971,000.00

0.00

3-A5

4.43%

4.59%

3/26/2040

55,379,000.00

0.00

55,379,000.00

0.00

3-M1

2.66%

2.76%

3/26/2040

2,953,000.00

0.00

2,953,000.00

0.00

3-M2

1.13%

1.17%

3/26/2040

3,544,000.00

0.00

3,544,000.00

0.00

3-M3

0.00%

3/26/2040

2,067,000.00

0.00

2,067,000.00

0.00

Page 12 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Bond Principal Reconciliation

Credit Support

Original

Current(4)

Revised 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

4.00
9.00

3-P

3/26/2040

100.00

0.00

100.00

0.00

3-X

3/26/2040

290,149,090.96

0.00

292,562,903.70

295,302,434.05

0.00

436,899.95

0.00

13,026,799.68

913,591.61

759,800,200.00

733,221,750.39

747,599,041.63

Page 13 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Other Related Information

Revised Date:

$7,195.13

Insurance

Insured Payments to Class:

0.00

1-A2A

1-A4B

1-A5A

3-A5

Page 14 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Distribution

Date

REO

Balance

Revised Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

1.34%

1.35%

0.11%

0.13%

0.00%

25-Apr-05

9,949,826

941,824

2,638

724,341,494

98.54%

98.52%

0.18%

0.35%

0.00%

25-Mar-05

2,644,401

2,717

746,052,443

99.82%

99.65%

Page 15 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Distribution

Date

REO

Balance

Revised Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

Pool 1

1.77%

1.84%

0.17%

0.26%

0.00%

25-Apr-05

5,719,850

801,904

1,162

304,065,715

98.06%

97.90%

0.25%

0.53%

0.00%

25-Mar-05

1,707,894

1,209

317,540,543

99.75%

99.47%

Page 16 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Distribution

Date

REO

Balance

Revised Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

Pool 2

1.38%

1.59%

0.14%

0.10%

0.00%

25-Apr-05

2,134,755

139,920

716

132,221,909

98.49%

98.31%

0.00%

25-Mar-05

740

136,885,505

100.00%

Page 17 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Distribution

Date

REO

Balance

Revised Date:

Foreclosure

Delinq 3+ Months

Delinq 2 Months

Delinq 1 Month

Current

Balance

Delinquency Aging Categories

Pool 3

0.65%

0.72%

0.00%

25-Apr-05

2,095,221

760

288,053,870

99.35%

99.28%

0.26%

0.32%

0.00%

25-Mar-05

936,508

768

291,626,396

99.74%

99.68%

Page 18 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Distribution

Date

Revised 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-Apr-05

0.00%

0.00% 0.00%

0.00%

25-Mar-05

0.00%

0.00% 0.00%

0.00%

Page 19 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Distribution

Date

Revised 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-Apr-05

0.00%

0.00% 0.00%

0.00%

25-Mar-05

0.00%

0.00% 0.00%

0.00%

Page 20 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Distribution

Date

Revised 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-Apr-05

0.00%

0.00% 0.00%

0.00%

25-Mar-05

0.00%

0.00% 0.00%

0.00%

Page 21 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Distribution

Date

Revised 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 3

Current

31 - 60 Days

61 - 90 Days

90 + Days

Balance

25-Apr-05

0.00%

0.00% 0.00%

0.00%

25-Mar-05

0.00%

0.00% 0.00%

0.00%

Page 22 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Asset-Backed Facts ~ 15 Month Historical Payoff/Loss Summary

Distribution

Date

Ending Pool (1)

Payoffs(2)

Realized Losses (2)

Remaining Term

Curr Weighted Avg.

# Balance

# Amount

Life

Coupon Remit

Revised Date:

Ending Arrearage (1)

Balance

Insurance

Substitution

Liquidation

Proceeds

Pool 3

25-Apr-05

2,677

97.31%

735,233,145

96.77%

1.65%

1.62%

0.00%

353

6.30%

6.04%

12,098,393

0.00

25-Mar-05

2,722

98.95%

748,696,845

98.54%

1.05%

1.39%

0.00%

354

6.30%

6.05%

10,583,275

0.00

(1) Percentage based on pool as of cutoff. (2) Percentage based on pool as of beginning of period.

Page 23 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Asset-Backed Facts ~ 15 Month Historical Payoff/Loss Summary

Distribution

Date

Ending Pool (1)

Payoffs(2)

Realized Losses (2)

Remaining Term

Curr Weighted Avg.

# Balance

# Amount

Life

Coupon Remit

Revised Date:

Ending Arrearage (1)

Balance

Insurance

Substitution

Liquidation

Proceeds

Pool 1

25-Apr-05

1,185

43.08%

310,587,470

40.88%

2.23%

2.52%

0.00%

350

6.67%

6.42%

8,042,500

0.00

25-Mar-05

1,212

44.06%

319,248,436

42.02%

1.14%

1.81%

0.00%

351

6.67%

6.42%

5,874,252

0.00

(1) Percentage based on pool as of cutoff. (2) Percentage based on pool as of beginning of period.

Page 24 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Asset-Backed Facts ~ 15 Month Historical Payoff/Loss Summary

Distribution

Date

Ending Pool (1)

Payoffs(2)

Realized Losses (2)

Remaining Term

Curr Weighted Avg.

# Balance

# Amount

Life

Coupon Remit

Revised Date:

Ending Arrearage (1)

Balance

Insurance

Substitution

Liquidation

Proceeds

Pool 2

25-Apr-05

727

26.43%

134,496,584

17.70%

1.76%

1.72%

0.00%

357

6.38%

6.13%

2,352,865

0.00

25-Mar-05

740

26.90%

136,885,505

18.02%

1.46%

1.62%

0.00%

358

6.39%

6.14%

2,254,028

0.00

(1) Percentage based on pool as of cutoff. (2) Percentage based on pool as of beginning of period.

Page 25 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

Asset-Backed Facts ~ 15 Month Historical Payoff/Loss Summary

Distribution

Date

Ending Pool (1)

Payoffs(2)

Realized Losses (2)

Remaining Term

Curr Weighted Avg.

# Balance

# Amount

Life

Coupon Remit

Revised Date:

Ending Arrearage (1)

Balance

Insurance

Substitution

Liquidation

Proceeds

Pool 3

25-Apr-05

765

27.81%

290,149,091

38.19%

0.65%

0.58%

0.00%

355

5.84%

5.59%

1,703,028

0.00

25-Mar-05

770

27.99%

292,562,904

38.51%

0.52%

0.83%

0.00%

356

5.85%

5.60%

2,454,995

0.00

(1) Percentage based on pool as of cutoff. (2) Percentage based on pool as of beginning of period.

Page 26 of 31

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Revised Date:

Current Total

Cumulative

Page 27 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Revised Date:

Pool 1

Current Total

Cumulative

Page 28 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Revised Date:

Pool 2

Current Total

Cumulative

Page 29 of 31

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

Structured Asset Securities Corporation

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

22-May-05

25-Apr-05

25-Mar-05

25-May-05

22-Apr-05

Mortgage Pass-Through Certificates

Series 2005-4XS

ABN AMRO Acct: 722414.2

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

Revised Date:

Pool 3

Current Total

Cumulative

Page 30 of 31

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

Structured Asset Securities Corporation

Substitution Detail History

ABN AMRO Acct: 722414.2

Series 2005-4XS

Mortgage Pass-Through Certificates

22-Apr-05

25-May-05

25-Mar-05

25-Apr-05

22-May-05

Record Date:

Next Payment:

Prior Payment:

Payment Date:

Revised Date:

Property ID

Deleted Loan

Qualified Substitute

Scheduled Prin Bal

Page 31 of 31

Original Property

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)

Structured Asset Securities Corp Trust 2005-4XS 8-K/A