<PAGE>
                                                                               .
                                                                               .
                                                                               .

                                                                    Exhibit 99.1

                           (UBS INVESTMENT BANK LOGO)
                    Collateral Stratification Report Fremont

<TABLE>
<CAPTION>
Pool Summary     count          UPB            %      WAC     LTV     CLTV   FICO    DTI
------------     -----   ----------------   ------   -----   -----   -----   ----   -----
<S>              <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
Conforming        3481     787,577,787.14    69.76   8.059   80.73   99.40    643   43.15
Non-Conforming     590     341,451,180.38    30.24   7.833   80.60   98.44    658   42.85
                  ----   ----------------   ------   -----   -----   -----    ---   -----
Total:            4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                  ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

UPB: 1,129,028,967.52
AVG UPB: $277,334.55
WA WAC: 7.990%
WA NET RATE: 7.490%
WA CLTV: 80.692%
WA CLTV w/ Simult 2nds: 99.110%
Balloon Pct: 40.55%
WA OTERM: 360
WA AGE: 2.353
WA RTERM: 358
1st Lien Pct: 100.00%
WA FICO: 647
ARM %: 94.28%
WA MARGIN: 5.854%
WA ROLL TERM: 22
WA MAXRATE: 14.022%
WA MINRATE: 8.022%
GSE ELIGIBLE: 69.76%
% PREPAY PENALTY: 56.33%
Loan Count: 4,071
% GA loans: 0.00%
% Odd-Due Dates: 0.00%
% IO: 21.85%
% Simultaneous 2nd: 99.29%

<TABLE>
<CAPTION>
PRODUCT                                 count          UPB            %      WAC     LTV     CLTV    FICO    DTI
-------                                 -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                                     <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
15YR FXD                                    1         190,915.74     0.02   8.300   80.00   100.00    640   44.25
20YR FXD                                    2         281,530.75     0.02   7.999   80.00   100.00    636   32.24
2/6 MONTH LIBOR                          1664     384,338,244.21    34.04   8.236   80.78    99.17    643   42.59
2/6 MONTH LIBOR - 40 YR AMTERM           1377     423,929,955.70    37.55   8.066   80.78    98.93    651   43.93
2/6 MONTH LIBOR -0 MONTHS IO MONTH IO     761     244,742,719.40    21.68   7.619   80.42    99.50    644   42.99
30YR FXD                                  144      35,165,393.72     3.11   7.560   80.30    98.72    662   39.94
3/6 MONTH LIBOR                            15       4,116,927.32     0.36   8.381   82.31    99.09    633   45.77
3/6 MONTH LIBOR - 40 YR AMTERM             12       3,644,056.71     0.32   7.590   81.45   100.00    672   38.67
3/6 MONTH LIBOR -0 MONTHS IO MONTH IO       6       1,921,070.00     0.17   7.242   83.05    99.46    696   44.72
5/6 MONTH LIBOR                             1         423,732.39     0.04   8.300   80.00   100.00    637   42.76
5/6 MONTH LIBOR - 40 YR AMTERM              5       1,324,247.17     0.12   7.391   80.00   100.00    650   45.29
BALLOON OTHER - 40 YR AMTERM               83      28,950,174.41     2.56   7.352   80.67    97.88    672   40.84
                                         ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                                   4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                                         ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

<TABLE>
<CAPTION>
Original($)                 count          UPB            %      WAC     LTV     CLTV    FICO    DTI
-----------                 -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                         <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
50,000.01 - 100,000.00        250      20,878,643.86     1.85   8.599   80.27    99.89    619   41.06
100,000.01 - 150,000.00       685      84,770,124.16     7.51   8.368   80.29    99.78    625   41.62
150,000.01 - 200,000.00       717     125,310,761.10    11.10   8.011   80.56    99.60    635   42.80
200,000.01 - 250,000.00       550     123,371,676.69    10.93   8.110   80.41    99.72    635   43.48
250,000.01 - 300,000.00       390     107,390,451.74     9.51   8.083   80.67    99.38    645   43.49
300,000.01 - 350,000.00       406     131,305,915.97    11.63   7.943   81.07    99.16    649   43.74
350,000.01 - 400,000.00       308     115,008,007.86    10.19   7.936   80.81    99.12    653   42.97
400,000.01 - 450,000.00       185      78,690,972.79     6.97   7.857   80.93    99.17    659   43.26
450,000.01 - 500,000.00       167      78,982,065.02     7.00   7.914   80.63    99.38    661   44.04
500,000.01 - 550,000.00       115      60,163,885.93     5.33   7.749   81.36    99.27    656   44.82
550,000.01 - 600,000.00        91      52,448,155.93     4.65   7.940   81.74    98.82    662   43.38
600,000.01 - 650,000.00        47      29,419,466.80     2.61   7.862   81.59    98.69    658   42.02
650,000.01 - 700,000.00        47      31,771,196.98     2.81   7.927   81.72    99.25    646   41.74
700,000.01 - 750,000.00        42      30,511,451.95     2.70   7.815   80.25    97.60    665   41.54
750,000.01 - 800,000.00        47      36,971,239.72     3.27   8.075   78.17    94.77    649   40.74
800,000.01 - 850,000.00         6       4,949,811.50     0.44   7.758   81.75    99.19    703   41.45
850,000.01 - 900,000.00         5       4,430,909.42     0.39   7.107   80.00   100.00    675   40.67
900,000.01 - 950,000.00         1         919,122.76     0.08   6.200   80.00    95.00    718   43.40
950,000.01 - 1,000,000.00      12      11,735,107.34     1.04   7.053   78.17    94.67    682   45.05
                             ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                       4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                             ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: $54,750.00
Maximum: $1,000,000.00
Average: $277,517.65

<TABLE>
<CAPTION>
Currbal($)                  count          UPB            %      WAC     LTV     CLTV    FICO    DTI
----------                  -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                         <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
50,000.01 - 100,000.00        250      20,878,643.86     1.85   8.599   80.27    99.89    619   41.06
100,000.01 - 150,000.00       686      84,920,082.35     7.52   8.366   80.29    99.78    625   41.63
150,000.01 - 200,000.00       718     125,558,282.06    11.12   8.014   80.57    99.60    635   42.80
200,000.01 - 250,000.00       549     123,224,164.46    10.91   8.110   80.40    99.72    635   43.48
250,000.01 - 300,000.00       389     107,140,484.82     9.49   8.080   80.67    99.37    645   43.48
300,000.01 - 350,000.00       406     131,305,915.97    11.63   7.943   81.07    99.16    649   43.74
350,000.01 - 400,000.00       308     115,008,007.86    10.19   7.936   80.81    99.12    653   42.97
400,000.01 - 450,000.00       185      78,690,972.79     6.97   7.857   80.93    99.17    659   43.26
450,000.01 - 500,000.00       167      78,982,065.02     7.00   7.914   80.63    99.38    661   44.04
500,000.01 - 550,000.00       115      60,163,885.93     5.33   7.749   81.36    99.27    656   44.82
550,000.01 - 600,000.00        91      52,448,155.93     4.65   7.940   81.74    98.82    662   43.38
600,000.01 - 650,000.00        47      29,419,466.80     2.61   7.862   81.59    98.69    658   42.02
650,000.01 - 700,000.00        47      31,771,196.98     2.81   7.927   81.72    99.25    646   41.74
700,000.01 - 750,000.00        42      30,511,451.95     2.70   7.815   80.25    97.60    665   41.54
750,000.01 - 800,000.00        47      36,971,239.72     3.27   8.075   78.17    94.77    649   40.74
800,000.01 - 850,000.00         6       4,949,811.50     0.44   7.758   81.75    99.19    703   41.45
850,000.01 - 900,000.00         5       4,430,909.42     0.39   7.107   80.00   100.00    675   40.67
900,000.01 - 950,000.00         1         919,122.76     0.08   6.200   80.00    95.00    718   43.40
950,000.01 - 1,000,000.00      12      11,735,107.34     1.04   7.053   78.17    94.67    682   45.05
                             ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                       4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                             ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: $54,623.90
Maximum: $1,000,000.00
Average: $277,334.55

<TABLE>
<CAPTION>
Gross Rate (%)    count          UPB            %       WAC     LTV     CLTV    FICO    DTI
--------------    -----   ----------------   ------   ------   -----   ------   ----   -----
<S>               <C>     <C>                <C>      <C>      <C>     <C>      <C>    <C>
5.500 - 5.999        12       5,156,912.10     0.46    5.870   77.93    96.87    685   38.43
6.000 - 6.499        76      30,345,048.22     2.69    6.292   80.23    98.72    686   43.45
6.500 - 6.999       328     111,789,698.46     9.90    6.811   80.41    98.98    669   42.12
7.000 - 7.499       446     135,713,942.32    12.02    7.272   80.52    99.13    648   42.79
7.500 - 7.999      1046     297,633,376.97    26.36    7.770   80.59    99.17    643   42.95
8.000 - 8.499       834     222,397,998.67    19.70    8.253   80.73    99.14    638   43.47
8.500 - 8.999       896     227,040,271.39    20.11    8.722   81.04    99.13    646   43.33
9.000 - 9.499       297      75,205,883.08     6.66    9.201   81.00    99.13    648   43.39
9.500 - 9.999       115      21,165,568.65     1.87    9.691   80.81    99.46    635   43.57
10.000 - 10.499      16       1,834,852.31     0.16   10.172   79.83    99.83    636   41.37
10.500 - 10.999       5         745,415.35     0.07   10.668   77.73    90.94    622   37.51
                   ----   ----------------   ------    -----   -----    -----    ---   -----
Total:             4071   1,129,028,967.52   100.00    7.990   80.69    99.11    647   43.06
                   ====   ================   ======    =====   =====    =====    ===   =====
</TABLE>

Minimum: 5.550%
Maximum: 10.800%
Weighted Average: 7.990%

<TABLE>
<CAPTION>
Margin (%)        count          UPB            %       WAC     LTV     CLTV    FICO    DTI
----------        -----   ----------------   ------   ------   -----   ------   ----   -----
<S>               <C>     <C>                <C>      <C>      <C>     <C>      <C>    <C>
3.001 - 3.500         2         753,620.52     0.07    5.550   80.00    98.62    626   50.92
3.501 - 4.000        18       9,325,675.42     0.88    6.038   79.88    97.40    687   43.47
4.001 - 4.500       111      38,785,365.80     3.64    6.508   80.05    99.48    674   44.66
4.501 - 5.000       315     102,035,353.23     9.59    6.957   80.53    99.00    662   42.79
5.001 - 5.500       575     169,122,717.80    15.89    7.457   80.43    99.26    643   42.82
5.501 - 6.000       965     270,583,438.06    25.42    7.906   80.63    99.19    641   43.09
6.001 - 6.500       897     243,811,855.34    22.91    8.393   80.99    99.22    642   43.19
6.501 - 7.000       958     230,022,926.73    21.61    8.997   80.92    99.06    646   43.63
                   ----   ----------------   ------    -----   -----    -----    ---   -----
Total:             3841   1,064,440,952.90   100.00    8.022   80.71    99.16    646   43.22
                   ====   ================   ======    =====   =====    =====    ===   =====
</TABLE>

Minimum: 3.329%
Maximum: 6.990%
Weighted Average: 5.854%

<TABLE>
<CAPTION>
Initial Rate Cap (%)   count          UPB            %       WAC     LTV     CLTV    FICO    DTI
--------------------   -----   ----------------   ------   ------   -----   ------   ----   -----
<S>                    <C>     <C>                <C>      <C>      <C>     <C>      <C>    <C>
 0.000                     1         140,583.98     0.01    7.350   80.00   100.00    607   27.57
 2.000                  1487     431,966,867.79    40.58    8.003   80.91    98.93    643   43.20
 3.000                  2352     631,605,829.24    59.34    8.035   80.56    99.32    648   43.24
11.250                     1         727,671.89     0.07    8.250   80.00    95.00    614   41.13
                        ----   ----------------   ------    -----   -----    -----    ---   -----
Total:                  3841   1,064,440,952.90   100.00    8.022   80.71    99.16    646   43.22
                        ====   ================   ======    =====   =====    =====    ===   =====
</TABLE>

Minimum: 0.000%
Maximum: 11.250%
Weighted Average: 2.600%

The information herein has been provided solely by UBS Investment Bank. Neither
the issuer of certificates nor any of its affiliates makes any representation as
to the accuracy or completeness of the information herein. The information
herein is preliminary, and will be superseded by the applicable prospectus
supplement and by any other information subsequently fil Securities and Exchange
Commission. The information contained herein will be superseded by the
description of the mortgage loans contained and/or incorporated by reference in
the Prospectus Supplement relating to the Certificates and supersedes all
information contained in any collateral term sheets relating to the mortgage
pool previously provided by UBS Invest


                                                                     PAGE 1 OF 3

<PAGE>

                           (UBS INVESTMENT BANK LOGO)
                    Collateral Stratification Report Fremont

<TABLE>
<CAPTION>
Periodic Rate Cap(%)   count          UPB            %      WAC     LTV     CLTV    FICO    DTI
--------------------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                    <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
0.000                      1         140,583.98     0.01   7.350   80.00   100.00    607   27.57
1.500                   3840   1,064,300,368.92    99.99   8.022   80.71    99.16    646   43.23
                        ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                  3841   1,064,440,952.90   100.00   8.022   80.71    99.16    646   43.22
                        ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: 0.000%
Maximum: 1.500%
Weighted Average: 1.500%

<TABLE>
<CAPTION>
FICO Scores   count          UPB            %      WAC     LTV     CLTV    FICO    DTI
-----------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>           <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
550 - 574        23       5,917,826.13     0.52   8.274   89.78    94.58    561   46.52
575 - 599       815     172,238,026.49    15.26   8.024   80.91    99.23    589   43.06
600 - 624       877     217,333,845.53    19.25   8.008   80.94    99.18    613   43.08
625 - 649       928     263,056,778.96    23.30   8.226   80.47    99.27    637   43.25
650 - 674       583     183,094,237.17    16.22   7.986   80.40    98.98    662   43.12
675 - 699       377     128,419,920.66    11.37   7.737   80.81    99.01    686   42.67
700 - 724       218      75,305,577.30     6.67   7.741   80.44    98.75    711   42.84
725 - 749       148      49,837,807.45     4.41   7.776   80.10    99.35    736   43.07
750 - 774        72      24,097,371.36     2.13   7.625   80.76    98.96    759   41.73
775 - 799        26       8,689,804.01     0.77   7.867   80.32    99.45    784   44.73
800 - 824         4       1,037,772.46     0.09   7.534   80.00   100.00    805   40.60
               ----   ----------------   ------   -----   -----    -----    ---   -----
Total:         4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
               ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: 550
Maximum: 807
Weighted Average: 647
Pct Fico <= 575: 0.55%
Pct Fico < 575: 0.52%
Pct Fico < 500: 0.00%

<TABLE>
<CAPTION>
CLTV (%)        count          UPB            %      WAC     LTV     CLTV    FICO    DTI
--------        -----   ----------------   ------   -----   -----   ------   ----   -----
<S>             <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
0.01 - 50.00        1         799,779.96     0.07   8.140   50.00    62.00    592   41.19
60.01 - 65.00       4       3,089,463.91     0.27   7.536   63.85    77.09    705   39.11
65.01 - 70.00       3       2,397,135.12     0.21   8.300   69.52    86.29    651   35.75
70.01 - 75.00       6       3,155,400.63     0.28   7.622   72.89    88.62    663   45.19
75.01 - 80.00    3713   1,009,104,594.58    89.38   7.979   79.98    99.49    648   43.17
80.01 - 85.00     138      34,486,760.11     3.05   7.724   84.81    99.07    635   42.30
85.01 - 90.00     206      75,995,833.21     6.73   8.285   89.94    96.23    637   42.20
                 ----   ----------------   ------   -----   -----    -----    ---   -----
Total:           4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                 ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: 50.00%
Maximum: 90.00%
Weighted Average: 80.69%

<TABLE>
<CAPTION>
CLTV(%) - including
Simultaneous 2nds     count          UPB            %      WAC     LTV     CLTV    FICO    DTI
-------------------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                   <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
60.01 - 65.00             1         799,779.96     0.07   8.140   50.00    62.00    592   41.19
70.01 - 75.00             2       1,578,575.28     0.14   8.197   63.25    73.68    693   40.13
75.01 - 80.00            23       8,775,624.24     0.78   7.883   78.35    80.00    668   35.85
80.01 - 85.00             5       2,580,105.67     0.23   7.463   72.94    83.98    653   31.07
85.01 - 90.00            33      17,252,314.88     1.53   7.724   78.68    89.39    662   42.35
90.01 - 95.00           263      97,017,288.15     8.59   8.064   85.61    94.81    639   42.80
95.01 - 100.00         3741   1,000,078,895.52    88.58   7.990   80.34    99.97    648   43.20
100.01 >=                 3         946,383.82     0.08   7.334   80.34   100.47    638   41.28
                       ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                 4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                       ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

Minimum: 62.00%
Maximum: 100.82%
> 80: 99.01%
= 100: 86.95%
Weighted Average: 99.11%

<TABLE>
<CAPTION>
Geographic Concentration   count          UPB            %      WAC     LTV     CLTV    FICO    DTI
------------------------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                        <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
CALIFORNIA                   692     288,247,741.31    25.53   7.718   80.64    99.25    656   43.27
FLORIDA                      718     174,851,187.13    15.49   8.101   80.74    98.95    641   42.53
NEW YORK                     336     134,503,984.98    11.91   7.895   80.68    98.69    667   44.03
MARYLAND                     229      66,849,107.03     5.92   8.065   81.00    99.28    642   44.60
NEW JERSEY                   223      66,223,182.95     5.87   8.227   80.48    99.30    652   43.65
ILLINOIS                     313      66,031,815.31     5.85   8.553   81.08    98.97    643   43.65
VIRGINIA                     144      44,267,596.31     3.92   7.863   80.14    99.27    636   43.49
MASSACHUSETTS                132      39,026,693.82     3.46   8.097   81.13    99.01    642   43.82
GEORGIA                      219      36,599,934.40     3.24   8.165   81.29    99.64    628   40.90
ARIZONA                       85      19,984,856.96     1.77   7.911   80.43    99.75    643   42.37
NEVADA                        63      18,019,192.07     1.60   7.947   80.56    97.73    641   41.55
TEXAS                         86      15,534,463.64     1.38   8.460   80.13    99.86    635   42.26
CONNECTICUT                   62      14,505,053.10     1.28   7.956   80.87    99.34    638   41.78
COLORADO                      66      13,447,150.70     1.19   7.666   79.60    98.43    635   41.77
MINNESOTA                     66      13,057,642.66     1.16   7.700   80.75    98.93    646   42.40
WASHINGTON                    54      12,691,335.93     1.12   7.703   79.19    98.20    644   43.40
HAWAII                        31      11,556,843.32     1.02   7.985   81.08    99.01    664   41.48
NORTH CAROLINA                74      11,123,114.40     0.99   7.958   80.12    98.58    624   41.62
MICHIGAN                      68      10,616,723.32     0.94   8.398   81.37    99.76    616   43.49
PENNSYLVANIA                  51      10,069,253.89     0.89   8.120   80.10    99.51    639   41.84
WISCONSIN                     59       9,727,983.54     0.86   8.224   82.09    99.00    627   39.24
OHIO                          41       7,480,455.25     0.66   8.054   80.09    98.66    629   39.93
DISTRICT OF COLUMBIA          22       6,673,736.39     0.59   7.997   80.71    99.64    662   44.34
MISSOURI                      32       4,458,045.96     0.39   8.452   80.49    99.72    622   41.65
SOUTH CAROLINA                26       4,061,829.51     0.36   8.499   79.93    99.93    638   41.85
OREGON                        19       3,948,361.40     0.35   7.836   80.19    99.44    637   35.66
TENNESSEE                     29       3,845,504.17     0.34   8.330   81.53   100.00    622   40.06
UTAH                          20       3,802,030.19     0.34   7.820   80.83   100.00    624   44.29
INDIANA                       26       3,644,825.46     0.32   8.239   81.34    99.87    613   40.13
RHODE ISLAND                  15       3,067,386.85     0.27   8.201   80.00   100.00    661   43.78
NEW HAMPSHIRE                  9       1,985,003.44     0.18   8.305   81.21   100.00    617   42.92
NEW MEXICO                    10       1,793,193.52     0.16   8.862   80.69    99.66    631   42.20
IDAHO                         12       1,699,917.01     0.15   7.954   80.46    98.62    630   41.43
DELAWARE                       9       1,364,879.95     0.12   8.021   81.85   100.00    627   38.61
OKLAHOMA                       6       1,299,026.78     0.12   8.207   80.82    99.59    617   45.33
KENTUCKY                       8         842,484.48     0.07   8.213   80.60   100.00    596   39.63
KANSAS                         5         640,661.42     0.06   8.459   80.00    98.94    627   42.55
ARKANSAS                       4         520,028.92     0.05   7.749   79.41    99.26    629   45.69
VERMONT                        2         469,550.30     0.04   7.638   82.62   100.00    624   38.62
MAINE                          2         241,904.15     0.02   7.999   80.00   100.00    608   45.84
NEBRASKA                       1         108,258.42     0.01   8.150   80.00   100.00    609   49.48
IOWA                           1          80,710.45     0.01   8.950   80.00   100.00    597   47.81
WEST VIRGINIA                  1          66,316.73     0.01   8.350   80.00   100.00    597   48.49
                            ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                      4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                            ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

<TABLE>
<CAPTION>
California Concentration   count          UPB            %      WAC     LTV     CLTV    FICO    DTI
------------------------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>                        <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
North CA                     273     112,800,943.90     9.99   7.667   80.74    99.19    655   43.12
South CA                     419     175,446,797.41    15.54   7.751   80.58    99.28    657   43.37
States Not CA               3379     840,781,226.21    74.47   8.084   80.71    99.06    644   42.98
                            ----   ----------------   ------   -----   -----    -----    ---   -----
Total:                      4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
                            ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

<TABLE>
<CAPTION>
Zip Code   count          UPB            %      WAC     LTV     CLTV    FICO    DTI
--------   -----   ----------------   ------   -----   -----   ------   ----   -----
<S>        <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
 11208        11       4,879,094.56     0.43   8.095   81.04    99.48    681   45.84
 11207         9       3,952,041.30     0.35   7.626   80.59   100.00    648   43.39
 33971        18       3,513,120.65     0.31   8.265   80.30    99.67    627   43.10
 11233         7       3,469,188.37     0.31   7.604   84.57    98.56    698   42.20
 11236         7       3,228,125.22     0.29   8.151   80.00    99.46    642   45.23
 Other      4019   1,109,987,397.42    98.31   7.991   80.68    99.10    647   43.04
            ----   ----------------   ------   -----   -----    -----    ---   -----
Total:      4071   1,129,028,967.52   100.00   7.990   80.69    99.11    647   43.06
            ====   ================   ======   =====   =====    =====    ===   =====
</TABLE>

<TABLE>
<CAPTION>
Loan Purpose             count          UPB            %      WAC     LTV     CLTV   FICO    DTI
------------             -----   ----------------   ------   -----   -----   -----   ----   -----
<S>                      <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
Cash Out Refi              549     173,417,651.82    15.36   7.843   80.70   97.93    642   42.32
Debt Consolidation         161      50,774,852.71     4.50   7.649   80.88   98.49    636   43.70
Home Improvement            54      20,847,395.70     1.85   7.741   81.25   98.60    641   42.69
Purchase                  3289     879,784,111.94    77.92   8.046   80.66   99.41    649   43.20
Rate & Term Refi            15       3,619,242.28     0.32   7.772   81.30   96.19    647   36.22
Purchase Miscellaneous       3         585,713.07     0.05   7.514   90.00   95.00    612   43.23
                          ----   ----------------   ------   -----   -----   -----    ---   -----
Total:                    4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                          ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

The information herein has been provided solely by UBS Investment Bank. Neither
the issuer of certificates nor any of its affiliates makes any representation as
to the accuracy or completeness of the information herein. The information
herein is preliminary, and will be superseded by the applicable prospectus
supplement and by any other information subsequently fil Securities and Exchange
Commission. The information contained herein will be superseded by the
description of the mortgage loans contained and/or incorporated by reference in
the Prospectus Supplement relating to the Certificates and supersedes all
information contained in any collateral term sheets relating to the mortgage
pool previously provided by UBS Invest


                                                                     PAGE 2 OF 3

<PAGE>

                           (UBS INVESTMENT BANK LOGO)
                    Collateral Stratification Report Fremont

<TABLE>
<CAPTION>
Document Type   count          UPB            %      WAC     LTV     CLTV   FICO    DTI
-------------   -----   ----------------   ------   -----   -----   -----   ----   -----
<S>             <C>     <C>                <C>      <C>     <C>     <C>      <C>    <C>
Easy Doc            3         541,542.49     0.05   8.057   87.37    92.37   604   44.28
Full             2446     637,276,050.94    56.44   7.628   81.30    98.85   635   42.08
Stated Doc       1621     491,070,790.11    43.49   8.461   79.89    99.45   664   44.34
                    1         140,583.98     0.01   7.350   80.00   100.00   607   27.57
                 ----   ----------------   ------   -----   -----   ------   ---   -----
Total:           4071   1,129,028,967.52   100.00   7.990   80.69    99.11   647   43.06
                 ====   ================   ======   =====   =====   ======   ===   =====
</TABLE>

<TABLE>
<CAPTION>
Property Type   count          UPB            %      WAC     LTV     CLTV   FICO    DTI
-------------   -----   ----------------   ------   -----   -----   -----   ----   -----
<S>             <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
Condominium       335      77,103,667.73     6.83   8.196   80.77    99.39   649   42.78
Four Family        10       4,744,343.52     0.42   8.423   89.04    94.04   665   48.19
Single Family    3316     902,070,136.74    79.90   7.960   80.59    99.12   645   42.88
Three Family       21       9,127,283.66     0.81   7.995   87.11    95.02   651   43.29
Two Family        388     135,842,951.89    12.03   8.061   80.57    99.32   665   44.21
Not Provided        1         140,583.98     0.01   7.350   80.00   100.00   607   27.57
                 ----   ----------------   ------   -----   -----    -----   ---   -----
Total:           4071   1,129,028,967.52   100.00   7.990   80.69    99.11   647   43.06
                 ====   ================   ======   =====   =====    =====   ===   =====
</TABLE>

<TABLE>
<CAPTION>
Occupancy           count          UPB            %      WAC     LTV     CLTV   FICO    DTI
---------           -----   ----------------   ------   -----   -----   -----   ----   -----
<S>                 <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
Investor Occupied      59      24,110,145.43     2.14   8.568   88.95   93.97    657   38.64
Owner Occupied       4004   1,101,243,380.83    97.54   7.979   80.48   99.24    647   43.18
Second Home             8       3,675,441.26     0.33   7.588   89.18   95.00    658   36.35
                     ----   ----------------   ------   -----   -----   -----    ---   -----
Total:               4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                     ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

<TABLE>
<CAPTION>
Prepayment Penalty   count          UPB            %      WAC     LTV     CLTV   FICO    DTI
------------------   -----   ----------------   ------   -----   -----   -----   ----   -----
<S>                  <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
 0                    1756     493,025,709.64    43.67   8.205   80.76   99.04    652   43.53
12                     172      61,516,506.16     5.45   8.015   80.84   98.32    659   41.41
24                    1802     477,842,907.51    42.32   7.890   80.65   99.34    640   42.86
30                       3         536,548.54     0.05   7.236   80.00   98.64    665   43.28
36                     338      96,107,295.67     8.51   7.375   80.48   98.83    652   42.69
                      ----   ----------------   ------   -----   -----   -----    ---   -----
Total                 4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                      ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

wa TERM: 24.658

<TABLE>
<CAPTION>
DTI(%)               count          UPB            %      WAC     LTV     CLTV   FICO    DTI
------               -----   ----------------   ------   -----   -----   -----   ----   -----
<S>                  <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
5.01 - 10.00            16       6,241,914.41     0.55   7.366   81.57   96.05    677    8.14
10.01 - 15.00           18       4,413,683.94     0.39   7.707   81.39   99.40    636   12.68
15.01 - 20.00           31       8,711,655.81     0.77   7.569   81.24   98.67    637   17.59
20.01 - 25.00           74      18,576,846.20     1.65   7.856   81.77   98.63    642   22.64
25.01 - 30.00          130      32,378,213.40     2.87   7.940   80.08   98.07    644   27.55
30.01 - 35.00          279      68,213,596.96     6.04   7.999   81.07   98.86    643   32.77
35.01 - 40.00          510     136,857,192.95    12.12   7.996   80.71   98.85    650   37.65
40.01 - 45.00          949     263,892,693.84    23.37   8.018   80.55   99.17    652   42.80
45.01 - 50.00         1976     565,072,277.26    50.05   8.008   80.60   99.33    646   47.94
50.01 - 55.00           88      24,670,892.75     2.19   7.753   82.67   98.27    636   51.30
                      ----   ----------------   ------   -----   -----   -----    ---   -----
Total:                4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                      ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

Wtd Ave: 43.06

<TABLE>
<CAPTION>
Interest Only         count          UPB            %      WAC     LTV     CLTV   FICO    DTI
-------------         -----   ----------------   ------   -----   -----   -----   ----   -----
<S>                   <C>     <C>                <C>      <C>     <C>     <C>     <C>    <C>
Interest in Arrears    3304     882,365,178.12    78.15   8.095   80.76   99.00    648   43.07
Interest Only           767     246,663,789.40    21.85   7.616   80.44   99.50    644   43.01
                       ----   ----------------   ------   -----   -----   -----    ---   -----
Total:                 4071   1,129,028,967.52   100.00   7.990   80.69   99.11    647   43.06
                       ====   ================   ======   =====   =====   =====    ===   =====
</TABLE>

The information herein has been provided solely by UBS Investment Bank. Neither
the issuer of certificates nor any of its affiliates makes any representation as
to the accuracy or completeness of the information herein. The information
herein is preliminary, and will be superseded by the applicable prospectus
supplement and by any other information subsequently fil Securities and Exchange
Commission. The information contained herein will be superseded by the
description of the mortgage loans contained and/or incorporated by reference in
the Prospectus Supplement relating to the Certificates and supersedes all
information contained in any collateral term sheets relating to the mortgage
pool previously provided by UBS Invest


                                                                     PAGE 3 OF 3