8-K 1 mabs04wmc1.txt AUGUST 8K 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): August 25, 2004 MASTR ASSET BACKED SECURITIES TRUST Mortgage Pass-Through Certificates, Series 2004-WMC1 Trust (Exact name of registrant as specified in its charter) New York (governing law of 54-2150435 Pooling and Servicing Agreement) 54-2150436 (State or other 333-106982-20 54-2150437 jurisdiction (Commission 54-2150438 of Incorporation) File Number) IRS EIN c/o Wells Fargo Bank, N.A. 9062 Old Annapolis Road Columbia, MD 21045 (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code: (410) 884-2000 (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)) ITEM 8.01 Other Events On August 25, 2004 a distribution was made to holders of MASTR ASSET BACKED SECURITIES TRUST, Mortgage Pass-Through Certificates, Series 2004-WMC1 Trust. ITEM 9.01 Financial Statements and Exhibits (c) Exhibits Exhibit Number Description EX-99.1 Monthly report distributed to holders of Mortgage Pass-Through Certificates, Series 2004-WMC1 Trust, relating to the August 25, 2004 distribution. 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. MASTR ASSET BACKED SECURITIES TRUST Mortgage Pass-Through Certificates, Series 2004-WMC1 Trust (Registrant) By: Wells Fargo Bank, N.A. as Master Servicer By: /s/ Beth Belfield as Assistant Vice President By: Beth Belfield as Assistant Vice President Date: 8/30/04 INDEX TO EXHIBITS Exhibit Number Description EX-99.1 Monthly report distributed to holders of Mortgage Pass-Through Certificates, Series 2004-WMC1 Trust, relating to the August 25, 2004 distribution. EX-99.1

MASTR Asset Backed Securitizations Mortgage Pass-Through Certificates Record Date: 67/3031/04 Distribution Date: 78/2625/04 MABS Series: 2004-WMC1 Contact: Customer Service - CTSLink Wells Fargo Bank, N.A. Securities Administration Services 7485 New Horizon Way Frederick, MD 21703 Telephone: (301) 815-6600 Fax: (301) 815-6660 Certificateholder Distribution Summary Certificate Certificate Beginning Class Pass-Through Certificate Interest Principal Class CUSIP Description Rate Balance Distribution Distribution A1 57643LCQ7 SEN 1.~~52000~~67000% ~~226~~216,~~121~~630,~~386~~934.6248 ~~277~~301,~~955~~478.7305 912,~~490~~556,~~452~~104.1488 A2 57643LCR5 SEN 1.~~68000~~83000% 28,170,000.00 4042,~~752~~959.6025 0.00 A3 57643LCS3 SEN 1.~~53000~~68000% ~~134~~129,~~905~~653,~~384~~577.4403 ~~177~~181,~~737~~515.8401 56,~~251~~165,~~807~~993.4100 A4 57643LCT1 SEN 1.~~40000~~55000% 6254,~~687~~988,~~569~~433.6958 7571,~~573~~026.3573 78,~~699~~272,~~136~~610.1139 A5 57643LCU8 SEN 1.~~52000~~67000% 79,850,000.00 ~~104~~111,~~514~~124.7858 0.00 A6 57643LCV6 SEN 1.~~70000~~85000% 17,315,000.00 2526,~~347~~693.2496 0.00 M1 57643LCW4 MEZ 1.~~82000~~97000% 52,644,000.00 8286,~~504~~423.8590 0.00 M2 57643LCX2 MEZ 2.~~45000~~60000% 42,653,000.00 8992,~~985~~414.9883 0.00 M3 57643LCY0 MEZ 2.~~65000~~80000% 13,065,000.00 2930,~~813~~485.6000 0.00 M4 57643LCZ7 MEZ 3.~~10000~~25000% 11,912,000.00 3132,~~798~~261.4267 0.00 M5 57643LDA1 MEZ 3.~~25000~~40000% 9,222,000.00 2526,~~808~~129.7900 0.00 M6 57643LDB9 MEZ 4.~~55000~~70000% 11,528,000.00 45,~~167~~151.3433 0.00 M7 57643LDC7 MEZ 6.00000% 8,454,000.00 42,270.00 0.00 CE MAB4WM1CE OC 0.00000% 8,069,453.80 32,~~027~~923,~~665~~413.5497 0.00 R MAB4WM1R1 RES 0.00000% 0.00 0.00 0.00 R-X MAB4WM1RX RES 0.00000% 0.00 0.00 0.00 P MAB04WM1P Pre_Pay 0.00000% 100.00 ~~353~~552,~~435~~403.2584 0.00 Totals ~~706~~684,~~596~~155,~~894~~498.5589 4,~~430~~565,~~331~~751.3112 2226,~~441~~994,~~395~~708.6627

Certificateholder Distribution Summary (continued) Current Ending Cumulative Realized Certificate Total Realized Class Loss Balance Distribution Losses A1 0.00 ~~216~~204,~~630~~074,~~934~~829.4860 912,~~768~~857,~~407~~582.8793 0.00 A2 0.00 28,170,000.00 4042,~~752~~959.6025 0.00 A3 0.00 ~~129~~123,~~653~~487,~~577~~584.03 56,~~429~~347,~~545~~508.2501 0.00 A4 0.00 5446,~~988~~715,~~433~~823.5819 78,~~774~~343,~~709~~637.4612 0.00 A5 0.00 79,850,000.00 ~~104~~111,~~514~~124.7858 0.00 A6 0.00 17,315,000.00 2526,~~347~~693.2496 0.00 M1 0.00 52,644,000.00 8286,~~504~~423.8590 0.00 M2 0.00 42,653,000.00 8992,~~985~~414.9883 0.00 M3 0.00 13,065,000.00 2930,~~813~~485.6000 0.00 M4 0.00 11,912,000.00 3132,~~798~~261.4267 0.00 M5 0.00 9,222,000.00 2526,~~808~~129.7900 0.00 M6 0.00 11,528,000.00 45,~~167~~151.3433 0.00 M7 0.00 8,454,000.00 42,270.00 0.00 CE 0.00 8,069,453.80 32,~~027~~923,~~665~~413.5497 0.00 R 0.00 0.00 0.00 0.00 R-X 0.00 0.00 0.00 0.00 P 0.00 100.00 ~~353~~552,~~435~~403.2584 0.00 Totals 0.00 ~~684~~657,~~155~~160,~~498~~790.8962 2631,~~871~~560,~~726~~459.9739 0.00 All distributions required by the Pooling and Servicing Agreement have been calculated by the Certificate Administrator on behalf of the Trustee.

Principal Distribution Statement Original Beginning Scheduled Unscheduled Face Certificate Principal Principal Realized Class Amount Balance Distribution Distribution Accretion Loss (1) A1 253,534,000.00 ~~226~~216,~~121~~630,~~386~~934.6248 0.00 912,~~490~~556,~~452~~104.1488 0.00 0.00 A2 28,170,000.00 28,170,000.00 0.00 0.00 0.00 0.00 A3 151,682,000.00 ~~134~~129,~~905~~653,~~384~~577.4403 0.00 56,~~251~~165,~~807~~993.4100 0.00 0.00 A4 80,421,000.00 6254,~~687~~988,~~569~~433.6958 0.00 78,~~699~~272,~~136~~610.1139 0.00 0.00 A5 79,850,000.00 79,850,000.00 0.00 0.00 0.00 0.00 A6 17,315,000.00 17,315,000.00 0.00 0.00 0.00 0.00 M1 52,644,000.00 52,644,000.00 0.00 0.00 0.00 0.00 M2 42,653,000.00 42,653,000.00 0.00 0.00 0.00 0.00 M3 13,065,000.00 13,065,000.00 0.00 0.00 0.00 0.00 M4 11,912,000.00 11,912,000.00 0.00 0.00 0.00 0.00 M5 9,222,000.00 9,222,000.00 0.00 0.00 0.00 0.00 M6 11,528,000.00 11,528,000.00 0.00 0.00 0.00 0.00 M7 8,454,000.00 8,454,000.00 0.00 0.00 0.00 0.00 CE 8,069,309.07 8,069,453.80 0.00 0.00 0.00 0.00 R 0.00 0.00 0.00 0.00 0.00 0.00 R-X 0.00 0.00 0.00 0.00 0.00 0.00 P 100.00 100.00 0.00 0.00 0.00 0.00 Totals 768,519,409.07 ~~706~~684,~~596~~155,~~894~~498.5589 0.00 2226,~~441~~994,~~395~~708.6627 0.00 0.00 (1) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

Principal Distribution Statement (continued) Total Ending Ending Total Principal Certificate Certificate Principal Class Reduction Balance Percentage Distribution A1 912,~~490~~556,~~452~~104.1488 ~~216~~204,~~630~~074,~~934~~829.4860 0.~~85444530~~80492096 912,~~490~~556,~~452~~104.1488 A2 0.00 28,170,000.00 1.00000000 0.00 A3 56,~~251~~165,~~807~~993.4100 ~~129~~123,~~653~~487,~~577~~584.03 0.~~85477233~~81412154 56,~~251~~165,~~807~~993.4100 A4 78,~~699~~272,~~136~~610.1139 5446,~~988~~715,~~433~~823.5819 0.~~68375715~~58089085 78,~~699~~272,~~136~~610.1139 A5 0.00 79,850,000.00 1.00000000 0.00 A6 0.00 17,315,000.00 1.00000000 0.00 M1 0.00 52,644,000.00 1.00000000 0.00 M2 0.00 42,653,000.00 1.00000000 0.00 M3 0.00 13,065,000.00 1.00000000 0.00 M4 0.00 11,912,000.00 1.00000000 0.00 M5 0.00 9,222,000.00 1.00000000 0.00 M6 0.00 11,528,000.00 1.00000000 0.00 M7 0.00 8,454,000.00 1.00000000 0.00 CE 0.00 8,069,453.80 1.00001794 0.00 R 0.00 0.00 0.00000000 0.00 R-X 0.00 0.00 0.00000000 0.00 P 0.00 100.00 1.00000000 0.00 Totals 2226,~~441~~994,~~395~~708.6627 ~~684~~657,~~155~~160,~~498~~790.8962 0.~~89022540~~85509980 2226,~~441~~994,~~395~~708.6627

Principal Distribution Factors Statement Original Beginning Scheduled Unscheduled Face Certificate Principal Principal Class (2) Amount Balance Distribution Distribution Accretion A1 253,534,000.00 ~~891~~854.~~87795964~~44529917 0.00000000 3749.~~43266047~~52434340 0.00000000 A2 28,170,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 A3 151,682,000.00 ~~889~~854.~~39613428~~77233310 0.00000000 3440.~~62380118~~65078915 0.00000000 A4 80,421,000.00 ~~779~~683.~~49254162~~75714776 0.00000000 95102.~~73539386~~86629599 0.00000000 A5 79,850,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 A6 17,315,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M1 52,644,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M2 42,653,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M3 13,065,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M4 11,912,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M5 9,222,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M6 11,528,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 M7 8,454,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 CE 8,069,309.07 1000.01793586 0.00000000 0.00000000 0.00000000 R 0.00 0.00000000 0.00000000 0.00000000 0.00000000 R-X 0.00 0.00000000 0.00000000 0.00000000 0.00000000 P 100.00 1000.00000000 0.00000000 0.00000000 0.00000000 (2) All Classes are per $1000 denomination.

Principal Distribution Factors Statement (continued) Total Ending Ending Total Realized Principal Certificate Certificate Principal Class Loss (3) Reduction Balance Percentage Distribution A1 0.00000000 3749.~~43266047~~52434340 ~~854~~804.~~44529917~~92095577 0.~~85444530~~80492096 3749.~~43266047~~52434340 A2 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 A3 0.00000000 3440.~~62380118~~65078915 ~~854~~814.~~77233310~~12154395 0.~~85477233~~81412154 3440.~~62380118~~65078915 A4 0.00000000 95102.~~73539386~~86629599 ~~683~~580.~~75714776~~89085177 0.~~68375715~~58089085 95102.~~73539386~~86629599 A5 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 A6 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M1 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M2 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M3 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M4 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M5 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M6 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 M7 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 CE 0.00000000 0.00000000 1,000.01793586 1.00001794 0.00000000 R 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 R-X 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 P 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 (3) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

Interest Distribution Statement Beginning Payment of Original Current Certificate/ Current Unpaid Current Face Certificate Notional Accrued Interest Interest Class Amount Rate Balance Interest Shortfall Shortfall A1 253,534,000.00 1.~~52000~~67000% ~~226~~216,~~121~~630,~~386~~934.6248 ~~295~~301,~~967~~478.7705 0.00 0.00 A2 28,170,000.00 1.~~68000~~83000% 28,170,000.00 4042,~~752~~959.6025 0.00 0.00 A3 151,682,000.00 1.~~53000~~68000% ~~134~~129,~~905~~653,~~384~~577.4403 ~~177~~181,~~737~~515.8401 0.00 0.00 A4 80,421,000.00 1.~~40000~~55000% 6254,~~687~~988,~~569~~433.6958 7571,~~573~~026.3573 0.00 0.00 A5 79,850,000.00 1.~~52000~~67000% 79,850,000.00 ~~104~~111,~~514~~124.7858 0.00 0.00 A6 17,315,000.00 1.~~70000~~85000% 17,315,000.00 2526,~~347~~693.2496 0.00 0.00 M1 52,644,000.00 1.~~82000~~97000% 52,644,000.00 8286,~~504~~423.8590 0.00 0.00 M2 42,653,000.00 2.~~45000~~60000% 42,653,000.00 8992,~~985~~414.9883 0.00 0.00 M3 13,065,000.00 2.~~65000~~80000% 13,065,000.00 2930,~~813~~485.6000 0.00 0.00 M4 11,912,000.00 3.~~10000~~25000% 11,912,000.00 3132,~~798~~261.4267 0.00 0.00 M5 9,222,000.00 3.~~25000~~40000% 9,222,000.00 2526,~~808~~129.7900 0.00 0.00 M6 11,528,000.00 4.~~55000~~70000% 11,528,000.00 45,~~167~~151.3433 0.00 0.00 M7 8,454,000.00 6.00000% 8,454,000.00 42,270.00 0.00 0.00 CE 8,069,309.07 0.00000% 8,069,453.80 0.00 0.00 0.00 R 0.00 0.00000% 0.00 0.00 0.00 0.00 R-X 0.00 0.00000% 0.00 0.00 0.00 0.00 P 100.00 0.00000% 100.00 0.00 0.00 0.00 Totals 768,519,409.07 1,~~067~~089,~~242~~933.5631 0.00 0.00

Interest Distribution Statement (continued) Remaining Ending Non-Supported Total Unpaid Certificate/ Interest Realized Interest Interest Notional Class Shortfall Losses (4) Distribution Shortfall Balance A1 0.00 0.00 ~~277~~301,~~955~~478.7305 0.00 ~~216~~204,~~630~~074,~~934~~829.4860 A2 0.00 0.00 4042,~~752~~959.6025 0.00 28,170,000.00 A3 0.00 0.00 ~~177~~181,~~737~~515.8401 0.00 ~~129~~123,~~653~~487,~~577~~584.03 A4 0.00 0.00 7571,~~573~~026.3573 0.00 5446,~~988~~715,~~433~~823.5819 A5 0.00 0.00 ~~104~~111,~~514~~124.7858 0.00 79,850,000.00 A6 0.00 0.00 2526,~~347~~693.2496 0.00 17,315,000.00 M1 0.00 0.00 8286,~~504~~423.8590 0.00 52,644,000.00 M2 0.00 0.00 8992,~~985~~414.9883 0.00 42,653,000.00 M3 0.00 0.00 2930,~~813~~485.6000 0.00 13,065,000.00 M4 0.00 0.00 3132,~~798~~261.4267 0.00 11,912,000.00 M5 0.00 0.00 2526,~~808~~129.7900 0.00 9,222,000.00 M6 0.00 0.00 45,~~167~~151.3433 0.00 11,528,000.00 M7 0.00 0.00 42,270.00 0.00 8,454,000.00 CE 0.00 0.00 32,~~027~~923,~~665~~413.5497 0.00 8,069,453.80 R 0.00 0.00 0.00 0.00 0.00 R-X 0.00 0.00 0.00 0.00 0.00 P 0.00 0.00 ~~353~~552,~~435~~403.2584 0.00 100.00 Totals 0.00 0.00 4,~~430~~565,~~331~~751.3112 0.00 (4) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

Interest Distribution Factors Statement Beginning Payment of Original Current Certificate/ Current Unpaid Current Face Certificate Notional Accrued Interest Interest Class (5) Amount Rate Balance Interest Shortfall Shortfall A1 253,534,000.00 1.~~52000~~67000% ~~891~~854.~~87795964~~44529917 1.~~16736915~~18910304 0.00000000 0.00000000 A2 28,170,000.00 1.~~68000~~83000% 1000.00000000 1.~~44666667~~52500000 0.00000000 0.00000000 A3 151,682,000.00 1.~~53000~~68000% ~~889~~854.~~39613428~~77233310 1.~~17177938~~19668128 0.00000000 0.00000000 A4 80,421,000.00 1.~~40000~~55000% ~~779~~683.~~49254162~~75714776 0.~~93972159~~88318636 0.00000000 0.00000000 A5 79,850,000.00 1.~~52000~~67000% 1000.00000000 1.~~30888892~~39166662 0.00000000 0.00000000 A6 17,315,000.00 1.~~70000~~85000% 1000.00000000 1.~~46388911~~54166676 0.00000000 0.00000000 M1 52,644,000.00 1.~~82000~~97000% 1000.00000000 1.~~56722229~~64166667 0.00000000 0.00000000 M2 42,653,000.00 2.~~45000~~60000% 1000.00000000 2.~~10972218~~16666659 0.00000000 0.00000000 M3 13,065,000.00 2.~~65000~~80000% 1000.00000000 2.~~28194413~~33333333 0.00000000 0.00000000 M4 11,912,000.00 3.~~10000~~25000% 1000.00000000 2.~~66944426~~70833361 0.00000000 0.00000000 M5 9,222,000.00 3.~~25000~~40000% 1000.00000000 2.~~79861093~~83333333 0.00000000 0.00000000 M6 11,528,000.00 4.~~55000~~70000% 1000.00000000 3.~~91805517~~91666638 0.00000000 0.00000000 M7 8,454,000.00 6.00000% 1000.00000000 5.00000000 0.00000000 0.00000000 CE 8,069,309.07 0.00000% 1000.01793586 0.00000000 0.00000000 0.00000000 R 0.00 0.00000% 0.00000000 0.00000000 0.00000000 0.00000000 R-X 0.00 0.00000% 0.00000000 0.00000000 0.00000000 0.00000000 P 100.00 0.00000% 1000.00000000 0.00000000 0.00000000 0.00000000 (5) All Classes are per $1000 denomination.

Interest Distribution Factors Statement (continued) Remaining Ending Non-Supported Total Unpaid Certificate/ Interest Realized Interest Interest Notional Class Shortfall Losses (6) Distribution Shortfall Balance A1 0.00000000 0.00000000 1.~~09632527~~18910304 0.00000000 ~~854~~804.~~44529917~~92095577 A2 0.00000000 0.00000000 1.~~44666667~~52500000 0.00000000 1000.00000000 A3 0.00000000 0.00000000 1.~~17177938~~19668128 0.00000000 ~~854~~814.~~77233310~~12154395 A4 0.00000000 0.00000000 0.~~93972159~~88318636 0.00000000 ~~683~~580.~~75714776~~89085177 A5 0.00000000 0.00000000 1.~~30888892~~39166662 0.00000000 1000.00000000 A6 0.00000000 0.00000000 1.~~46388911~~54166676 0.00000000 1000.00000000 M1 0.00000000 0.00000000 1.~~56722229~~64166667 0.00000000 1000.00000000 M2 0.00000000 0.00000000 2.~~10972218~~16666659 0.00000000 1000.00000000 M3 0.00000000 0.00000000 2.~~28194413~~33333333 0.00000000 1000.00000000 M4 0.00000000 0.00000000 2.~~66944426~~70833361 0.00000000 1000.00000000 M5 0.00000000 0.00000000 2.~~79861093~~83333333 0.00000000 1000.00000000 M6 0.00000000 0.00000000 3.~~91805517~~91666638 0.00000000 1000.00000000 M7 0.00000000 0.00000000 5.00000000 0.00000000 1000.00000000 CE 0.00000000 0.00000000 ~~375~~362.~~20753186~~28801557 0.00000000 1000.01793586 R 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 R-X 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 P 0.00000000 0.00000000 ~~3534352~~5524038.~~50000000~~40000000 0.00000000 1000.00000000 (6) Amount Does Not Include Excess Special Hazard, Bankruptcy,or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

CERTIFICATEHOLDER ACCOUNT STATEMENT CERTIFICATE ACCOUNT Beginning Balance 0.00 Deposits Payments of Interest and Principal 2631,~~815~~295,~~651~~970.2099 Liquidations, Insurance Proceeds, Reserve Funds 0.00 Proceeds from Repurchased Loans 0.00 Other Amounts (Servicer Advances) 0.00 Realized Loss (Gains, Subsequent Expenses & Recoveries) 0.00 Prepayment Penalties ~~353~~552,~~435~~403.2584 Total Deposits 2731,~~169~~848,~~086~~374.4583 Withdrawals Reimbursement for Servicer Advances 0.00 Payment of Service Fee ~~297~~287,~~359~~915.4844 Payment of Interest and Principal 2631,~~871~~560,~~726~~459.9739 Total Withdrawals (Pool Distribution Amount) 2731,~~169~~848,~~086~~374.4583 Ending Balance 0.00

SERVICING FEES Gross Servicing Fee ~~294~~285,~~415~~064.3580 Administrator fee 2,~~944~~850.1364 Supported Prepayment/Curtailment Interest Shortfall 0.00 Net Servicing Fee ~~297~~287,~~359~~915.4844

LOAN STATUS STRATIFICATION/CREDIT ENHANCEMENT STATEMENT DELINQUENCY STATUS DELINQUENT BANKRUPTCY FORECLOSURE REO Total No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 0 0 0 0 0.00 0.00 0.00 0.00 30 Days 5156 0 0 0 5156 9,~~632~~610,~~017~~759.3372 0.00 0.00 0.00 9,~~632~~610,~~017~~759.3372 60 Days 2028 0 0 0 2028 36,~~437~~735,~~281~~498.5199 0.00 0.00 0.00 36,~~437~~735,~~281~~498.5199 90 Days 15 0 0 0 15 32,~~664~~091,~~093~~666.5553 0.00 0.00 0.00 32,~~664~~091,~~093~~666.5553 120 Days 711 0 0 0 711 ~~618~~2,~~489~~175,751.1565 0.00 0.00 0.00 ~~618~~2,~~489~~175,751.1565 150 Days 25 0 0 0 25 ~~344~~501,~~749~~908.9147 0.00 0.00 0.00 ~~344~~501,~~749~~908.9147 180+ Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 Totals 95115 0 0 0 95115 1721,~~696~~115,~~631~~585.4536 0.00 0.00 0.00 1721,~~696~~115,~~631~~585.4536 No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 30 Days 1.~~178646~~340996% 0.000000% 0.000000% 0.000000% 1.~~178646~~340996% 1.~~406820~~461338% 0.000000% 0.000000% 0.000000% 1.~~406820~~461338% 60 Days 0.~~462214~~670498% 0.000000% 0.000000% 0.000000% 0.~~462214~~670498% 01.~~502038~~024148% 0.000000% 0.000000% 0.000000% 01.~~502038~~024148% 90 Days 0.~~346661~~359195% 0.000000% 0.000000% 0.000000% 0.~~346661~~359195% 0.~~535165~~318043% 0.000000% 0.000000% 0.000000% 0.~~535165~~318043% 120 Days 0.~~161775~~263410% 0.000000% 0.000000% 0.000000% 0.~~161775~~263410% 0.~~090334~~330828% 0.000000% 0.000000% 0.000000% 0.~~090334~~330828% 150 Days 0.~~046221~~119732% 0.000000% 0.000000% 0.000000% 0.~~046221~~119732% 0.~~050353~~076316% 0.000000% 0.000000% 0.000000% 0.~~050353~~076316% 180+ Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% Totals 2.~~195517~~753831% 0.000000% 0.000000% 0.000000% 2.~~195517~~753831% 23.~~584711~~210674% 0.000000% 0.000000% 0.000000% 23.~~584711~~210674%

OTHER INFORMATION Current Period Class A Insufficient Funds 0.00 Principal Balance of Contaminated Properties 0.00 Periodic Advance ~~126~~151,~~114~~616.1244 Class A-6 157,547,309.07 20.50010803% 157,547,453.80 23.~~02801835~~97395828% 2.~~530857~~634819% 0.000000% Class M-1 104,903,309.07 13.65005331% 104,903,453.80 15.~~33327642~~96313342% 78.~~694742~~010825% 0.000000% Class M-2 62,250,309.07 8.10003083% 62,250,453.80 9.~~09887502~~47263663% 6.~~234401~~490497% 0.000000% Class M-3 49,185,309.07 6.40000870% 49,185,453.80 7.~~18922144~~48453872% 1.~~909654~~988098% 0.000000% Class M-4 37,273,309.07 4.85001532% 37,273,453.80 5.~~44809679~~67189253% 1.~~741125~~812646% 0.000000% Class CE 0.00 0.00000000% 0.00 0.00000000% 1.~~179477~~227927% 0.000000% Class R-I 0.00 0.00000000% 0.00 0.00000000% 0.000000% 0.000000% Please Refer to the Prospectus Supplement for a Full Description of Loss Exposure

COLLATERAL STATEMENT Collateral Description Mixed Fixed & Arm Weighted Average Gross Coupon 7.~~432382~~430051% Weighted Average Net Coupon 6.~~932382~~925051% Weighted Average Pass-Through Rate 6.~~927382~~930051% Weighted Average Maturity(Stepdown Calculation ) ~~333~~332 Beginning Scheduled Collateral Loan Count 4,~~449~~327 Number Of Loans Paid In Full ~~122~~151 Ending Scheduled Collateral Loan Count 4,~~327~~176 Beginning Scheduled Collateral Balance ~~706~~684,~~596~~155,~~894~~498.5589 Ending Scheduled Collateral Balance ~~684~~657,~~155~~160,~~498~~790.8962 Ending Actual Collateral Balance at 3031-~~Jun~~Jul-2004 ~~684~~657,~~665~~668,~~756~~364.0771 Monthly P &I Constant 4,~~929~~776,~~808~~093.5170 Special Servicing Fee 0.00 Prepayment Penalties ~~353~~552,~~435~~403.2584 Realized Loss Amount 0.00 Cumulative Realized Loss 0.00 Ending Scheduled Balance for Premium Loans ~~684~~657,~~155~~160,~~498~~790.8962 Scheduled Principal ~~553~~540,~~393~~002.7401 Unscheduled Principal 2126,~~888~~454,~~001~~706.9226

Other Income (265,~~159~~171.~~37)~~01

Miscellaneous Reporting Net Monthly Excess Cashflow 32,~~009~~923,~~653~~413.3195 Extra Prinicpal Distribution Amount 0.00 OC Amount 8,069,453.80 OC Deficiency Amount 0.00 OC Release Amount 0.00 OC Target Amount 8,069,453.80 Stepdown 0.00 Trigger Event 0.00 Credit Enhancement Percentage 23.~~028018~~973958%

Group Level Collateral Statement Group Group 1 Group 2 Group 3 Collateral Description Fixed 15/30 & ARM Fixed 15/30 & ARM Fixed 15/30 & ARM Weighted Average Coupon Rate 8.~~260733~~249887 7.~~207524~~209697 8.~~225979~~219793 Weighted Average Net Rate 7.~~760732~~749887 6.~~707525~~709697 7.~~725982~~719794 Weighted Average Maturity ~~290~~289 ~~352~~351 ~~292~~291 Beginning Loan Count 1,~~039~~014 1,~~408~~369 ~~529~~524 Loans Paid In Full 2533 3947 512 Ending Loan Count ~~1,014~~981 1,~~369~~322 ~~524~~512 Beginning Scheduled Balance 8583,~~446~~596,~~576~~274.8081 ~~241~~233,~~333~~693,~~554~~403.0590 44,~~965~~638,~~920~~487.7403 Ending scheduled Balance 8380,~~596~~693,~~274~~597.8196 ~~233~~224,~~693~~039,~~403~~975.9087 4443,~~638~~672,~~487~~139.0380 Record Date 0607/3031/2004 0607/3031/2004 0607/3031/2004 Principal And Interest Constant ~~661~~647,~~700~~587.7569 1,~~639~~588,~~494~~855.77 ~~347~~344,~~330~~971.1157 Scheduled Principal 7372,~~491~~871.3119 ~~189~~184,~~980~~806.2496 39,~~089~~205.5264 Unscheduled Principal 12,~~776~~829,~~810~~805.6866 79,~~450~~468,~~169~~621.9107 ~~288~~927,~~344~~141.1959 Scheduled Interest ~~588~~574,~~209~~716.4450 1,~~449~~404,~~514~~048.5381 ~~308~~305,~~240~~765.5993 Servicing Fees 3534,~~602~~831.7477 ~~100~~97,~~555~~372.6224 18,~~735~~599.8136 Master Servicing Fees 0.00 0.00 0.00 Trustee Fee 0.00 0.00 0.00 FRY Amount 0.00 0.00 0.00 Special Hazard Fee 0.00 0.00 0.00 Other Fee ~~356~~348.0332 ~~1,005~~973.5774 ~~187~~185.3698 Pool Insurance Fee 0.00 0.00 0.00 Spread Fee 1 0.00 0.00 0.00 Spread Fee 2 0.00 0.00 0.00 Spread Fee 3 0.00 0.00 0.00 Net Interest ~~552~~539,~~606~~884.6576 1,~~348~~306,~~958~~676.9557 ~~289~~287,~~504~~166.9059 Realized Loss Amount 0.00 0.00 0.00 Cumulative Realized Loss 0.00 0.00 0.00 Percentage of Cumulative Losses 0.0000 0.0000 0.0000 Prepayment Penalties ~~48,432~~0.1300 ~~116,553~~0.0200 ~~4,800~~0.8100 Special Servicing Fee 0.00 0.00 0.00 Pass-Through Rate 7.~~755732~~744888 6.~~702524~~704696 7.~~720981~~714793

Group Level Collateral Statement Group Group 4 Group 5 Group 6 Collateral Description Fixed 15/30 & ARM Fixed 15/30 & ARM Fixed 15/30 & ARM Weighted Average Coupon Rate 7.~~166546~~166642 8.~~697913~~648741 6.~~853108~~843266 Weighted Average Net Rate 6.~~666546~~666641 98.~~197913~~148739 6.~~353109~~343266 Weighted Average Maturity ~~352~~351 ~~251~~250 ~~352~~351 Beginning Loan Count ~~734~~710 ~~387~~371 ~~352~~339 Loans Paid In Full 2426 1619 1314 Ending Loan Count ~~710~~684 ~~371~~352 ~~339~~325 Beginning Scheduled Balance ~~128~~124,~~963~~039,~~855~~481.0434 5453,~~937~~544,~~542~~857.2513 ~~150~~144,~~949~~642,~~445~~994.6768 Ending scheduled Balance ~~124~~118,~~039~~839,~~481~~835.3457 5351,~~544~~168,~~857~~247.1357 ~~144~~138,~~642~~746,~~994~~993.6885 Record Date 0607/3031/2004 0607/3031/2004 0607/3031/2004 Principal And Interest Constant ~~872~~840,~~993~~248.3382 ~~435~~422,~~336~~734.0478 ~~972~~931,~~953~~695.5107 Scheduled Principal ~~102~~99,~~805~~460.5007 3736,~~134~~821.4078 ~~110~~106,~~892~~836.7737 Unscheduled Principal 45,~~821~~100,~~568~~185.2070 12,~~355~~339,~~550~~787.7278 65,~~195~~789,~~558~~164.2246 Scheduled Interest ~~770~~740,~~187~~788.8375 ~~398~~385,~~201~~913.6400 ~~862~~824,~~060~~858.7470 Servicing Fees 5351,~~734~~683.9514 22,~~890~~310.6336 6260,~~895~~267.6093 Master Servicing Fees 0.00 0.00 0.00 Trustee Fee 0.00 0.00 0.00 FRY Amount 0.00 0.00 0.00 Special Hazard Fee 0.00 0.00 0.00 Other Fee ~~537~~516.3484 ~~228~~223.9010 ~~628~~602.9366 Pool Insurance Fee 0.00 0.00 0.00 Spread Fee 1 0.00 0.00 0.00 Spread Fee 2 0.00 0.00 0.00 Spread Fee 3 0.00 0.00 0.00 Net Interest ~~716~~689,~~452~~105.8957 ~~375~~363,~~310~~602.9956 ~~799~~764,~~165~~590.2182 Realized Loss Amount 0.00 0.00 0.00 Cumulative Realized Loss 0.00 0.00 0.00 Percentage of Cumulative Losses 0.0000 0.0000 0.0000 Prepayment Penalties ~~103,941~~0.9900 ~~20,686~~0.9800 ~~59,020~~0.3200 Special Servicing Fee 0.00 0.00 0.00 Pass-Through Rate 6.~~661546~~661641 8.~~192914~~143741 6.~~348108~~338266

Group Level Collateral Statement Group Total Collateral Description Mixed Fixed & Arm Weighted Average Coupon Rate 7.~~432382~~430051 Weighted Average Net Rate 6.~~932382~~925051 Weighted Average Maturity ~~333~~332.00 Record Date 0607/3031/2004 Principal And Interest Constant 4,~~929~~776,~~808~~093.5170 Beginning Loan Count 4,~~449~~327 Loans Paid In Full ~~122~~151 Ending Loan Count 4,~~327~~176 Beginning Scheduled Balance ~~706~~684,~~596~~155,~~894~~498.5589 Ending Scheduled Balance ~~684~~657,~~155~~160,~~498~~790.8962 Scheduled Principal ~~553~~540,~~393~~002.7401 Unscheduled Principal 2126,~~888~~454,~~001~~706.9226 Scheduled Interest 4,~~376~~236,~~414~~091.7769 Servicing Fee ~~294~~285,~~415~~064.3580 Master Servicing Fee 0.00 Trustee Fee 0.00 Fry Amount 0.00 Special Hazard Fee 0.00 Other Fee 2,~~944~~850.1364 Pool Insurance Fee 0.00 Spread 1 0.00 Spread 2 0.00 Spread 3 0.00 Net Interest 43,~~081~~951,~~999~~026.5987 Realized Loss Amount 0.00 Cumulative Realized Loss 0.00 Percentage of Cumulative Losses 0.0000 Prepayment Penalties ~~353,435~~0.2500 Special Servicing Fee 0.00 Pass-Through Rate 6.~~927382~~930051

Filing Compare · MORTGAGE ASSET SEC TRANS INC MASTR AS BK SEC TR 2004 WMC1