SUBJECT TO COMPLETION DATED MAY 20, 2008
(To Prospectus Dated , 20 )
[WELLS FARGO LOGO]
Wells Fargo Asset Securities Corporation
Wells Fargo Bank, N.A.
Sponsor and Master Servicer
Wells Fargo Alternative Loan 20 - Trust
Mortgage Asset-Backed Pass-Through Certificates, Series 20 -
Principal and interest payable monthly, commencing in [_____] 20
You should carefully consider the risk factors beginning on page S- of this
prospectus supplement. Neither the offered certificates nor the underlying
mortgage loans are insured or guaranteed by any governmental agency or
instrumentality or any other entity.
The offered certificates will represent interests in the assets deposited with
the issuing entity only and will not represent interests in or obligations of
the depositor, the sponsor or any other entity.
This prospectus supplement may be used to offer and sell the offered
certificates only if accompanied by the prospectus.
The Issuing Entity Will Issue--
o Seventeen classes of senior certificates.
o Six classes of subordinated certificates, all of which are subordinated
to, and provide credit enhancement for, the senior certificates. Each
class of subordinated certificates is also subordinated to each class of
subordinated certificates, if any, with a lower number.
The classes of offered certificates are listed and their sizes and basic payment
characteristics are described under the heading "Offered Certificates" in the
table beginning on page S-6.
The Assets of the Issuing Entity Will Include--
o A pool of fully amortizing, one- to four-family, fixed interest rate,
residential first mortgage loans (excluding the fixed retained yield
described in this prospectus supplement), substantially all of which have
original terms to stated maturity of approximately 30 years.
Credit Enhancement Will Consist Of--
o Subordination of the subordinated certificates to the senior certificates
for the distributions of principal and interest and the allocation of
o Shifting interest in prepayments through the allocation, subject to
certain exceptions, of most principal collections to the senior
certificates for the first five years and a lesser, but still
disproportionately large, allocation of these collections to the senior
certificates during the following four years.
o In the case of each class of super senior certificates, the subordination
of the related class of super senior support certificates for losses if
the subordinated certificates are no longer outstanding.
Neither the SEC nor any state securities commission has approved the
certificates offered by this prospectus supplement or determined that this
prospectus supplement or the prospectus is accurate or complete. Any
representation to the contrary is a criminal offense.
The underwriter will purchase the offered certificates from the depositor and
offer them to investors at varying prices to be determined at the time of sale.
The offered certificates will be available for delivery to investors on or about
[_____], 20 . Classes in book entry form will be made available through The
Depository Trust Company, Clearstream International or the Euroclear System.
Total proceeds to the depositor for the offered certificates will be
approximately $[_____] before deducting expenses estimated at $[_____] plus
accrued interest from [_____], 20 to [_____], 20 .
The date of this prospectus supplement is [_____], 20