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EXHIBIT 4.1



EXECUTION VERSION



 


WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.,



as Depositor and Master Servicer



and



LASALLE BANK NATIONAL ASSOCIATION,



as Trustee



and



CHRISTIANA BANK & TRUST COMPANY,



as Delaware Trustee







POOLING AND SERVICING AGREEMENT



$750,412,008.71



Washington Mutual Mortgage Securities Corp.



WaMu Mortgage Pass-Through Certificates



Series 2005-AR3



Cut-Off Date: February 1, 2005


 






 TABLE OF
CONTENTS

 


	
 	
Page
	
ARTICLE I

	
3


	
Section 1.01.  Definitions

	
3


	
Adjustment Date

	
3


	
Aggregate Certificate Principal Balance

	
4


	
Appraised Value

	
4


	
Assignment of Proprietary Lease

	
4


	
Authenticating Agent

	
4


	
Authorized Denomination

	
4


	
Available Distribution Amount

	
4


	
Bankruptcy Loss

	
5


	
Beneficial Holder

	
5


	
Benefit Plan Opinion

	
5


	
Book-Entry Certificates

	
6


	
Business Day

	
6


	
Buydown Agreement

	
6


	
Buydown Fund

	
6


	
Buydown Fund Account

	
6


	
Buydown Loan

	
6


	
Carry-Forward Subsequent Recoveries Amount

	
6


	
Certificate

	
6


	
Certificate Account

	
7


	
Certificateholder or Holder

	
7


	
Certificate Interest Rate

	
7


	
Certificate of Trust

	
7


	
Certificate Principal Balance

	
7


	
Certificate Register and Certificate Registrar

	
7


	
Class

	
7


	
Class A Certificates

	
7


	
Class A-1 Certificates

	
7


	
Class A-2 Certificates

	
8


	
Class A-3 Certificates

	
8


	
Class B Certificates

	
8


	
Class B-1 Certificates

	
8


	
Class B-2 Certificates

	
8


	
Class B-3 Certificates

	
8


	
Class B-4 Certificates

	
8


	
Class B-5 Certificates

	
8


	
Class B-6 Certificates

	
8


	
Class Principal Balance

	
8


	
Class R Certificates

	
9


	
Clean-Up Call Option Date

	
9


	
Clean-Up Call Percentage

	
9


	
Clearing Agency

	
9


	
Closing Date

	
9


	
Code

	
9


	
Company

	
9


	
Compensating Interest

	
9


	
Cooperative

	
9


	
Cooperative Apartment

	
9


	
Cooperative Lease

	
9


	
Cooperative Loans

	
10


	
Cooperative Stock

	
10


	
Cooperative Stock Certificate

	
10


	
Corporate Trust Office

	
10


	
Corporation

	
10


	
Cumulative Carry-Forward Subsequent Recoveries Amount

	
10


	
Curtailment

	
10


	
Curtailment Shortfall

	
10


	
Custodial Account for P&I

	
10


	
Custodial Account for Reserves

	
11


	
Custodial Agreement

	
11


	
Custodian

	
11


	
Cut-Off Date

	
11


	
Definitive Certificates

	
11


	
Delaware Trustee

	
11


	
Depositary Agreement

	
12


	
Destroyed Mortgage Note

	
12


	
Determination Date

	
12


	
Disqualified Organization

	
12


	
Distribution Amount

	
12


	
Distribution Date

	
14


	
DTC

	
14


	
DTC Participant

	
14


	
Due Date

	
14


	
Eligible Institution

	
14


	
Eligible Investments

	
15


	
ERISA

	
16


	
ERISA Restricted Certificate

	
16


	
Event of Default

	
16


	
Excess Liquidation Proceeds

	
16


	
Excess Subsequent Recoveries

	
16


	
Fannie Mae

	
16


	
FDIC

	
16


	
FHA

	
17


	
Final Maturity Date

	
17


	
Fitch:

	
17


	
Freddie Mac

	
17


	
Index

	
17


	
Indirect DTC Participants

	
17


	
Initial Custodial Agreement

	
17


	
Initial Custodian

	
17


	
Insurance Proceeds

	
17


	
Interest Distribution Amount

	
17


	
Investment Account

	
17


	
Investment Depository

	
18


	
Junior Subordinate Certificates

	
18


	
Last Scheduled Distribution Date

	
18


	
Lender

	
18


	
Liquidated Mortgage Loan

	
18


	
Liquidation Principal

	
18


	
Liquidation Proceeds

	
18


	
Loan-to-Value Ratio

	
18


	
Lowest Class B Owner

	
18


	
Margin

	
18


	
Master Servicer

	
18


	
Master Servicer Business Day

	
18


	
Master Servicing Fee

	
19


	
Master Servicing Fee Rate

	
19


	
MERS

	
19


	
MERS Loan

	
19


	
MERS® System

	
19


	
MIN

	
19


	
MOM Loan

	
19


	
Monthly P&I Advance

	
19


	
Monthly Payment

	
19


	
Moody’s

	
19


	
Mortgage

	
19


	
Mortgage File

	
19


	
Mortgage Interest Rate

	
22


	
Mortgage Loan Schedule

	
22


	
Mortgage Loans

	
23


	
Mortgage Note

	
23


	
Mortgage Pool

	
23


	
Mortgage Pool Assets

	
23


	
Mortgaged Property

	
23


	
Mortgagor

	
23


	
Nonrecoverable Advance

	
23


	
Non-U.S. Person

	
23


	
Notice Addresses

	
24


	
OTS

	
24


	
Officer’s Certificate

	
24


	
One-Year CMT

	
24


	
One-Year LIBOR

	
24


	
Opinion of Counsel

	
24


	
Original Trust Agreement

	
24


	
Original Value

	
24


	
Ownership Interest

	
25


	
Pass-Through Entity

	
25


	
Pass-Through Rate

	
25


	
Paying Agent

	
25


	
Payoff

	
25


	
Payoff Earnings

	
25


	
Payoff Interest

	
25


	
Payoff Period

	
26


	
Percentage Interest

	
26


	
Periodic Cap

	
26


	
Permitted Transferee

	
26


	
Person

	
27


	
Prepaid Monthly Payment

	
27


	
Primary Insurance Policy

	
27


	
Principal Balance

	
27


	
Principal Payment

	
27


	
Principal Payment Amount

	
27


	
Principal Prepayment

	
28


	
Principal Prepayment Amount

	
28


	
Prior Period

	
28


	
Prospectus

	
28


	
Purchase Obligation

	
28


	
Purchase Price

	
28


	
Qualified Insurer

	
28


	
Rate Ceiling

	
29


	
Rate Floor

	
29


	
Rating Agency

	
29


	
Ratings

	
29


	
Realized Loss

	
29


	
Recognition Agreement

	
30


	
Record Date

	
30


	
Relief Act Shortfall

	
30


	
REMIC

	
30


	
REMIC Provisions

	
30


	
REMIC I

	
30


	
REMIC I Assets

	
30


	
REMIC I Regular Interests

	
31


	
Residual Certificates

	
31


	
Residual Distribution Amount

	
31


	
Responsible Officer

	
31


	
S&P

	
31


	
Secretary of State

	
31


	
Securities Act

	
31


	
Security Agreement

	
31


	
Selling and Servicing Contract

	
31


	
Senior Certificates

	
31


	
Senior Liquidation Amount

	
32


	
Senior Percentage

	
32


	
Senior Prepayment Percentage

	
32


	
Senior Principal Distribution Amount

	
34


	
Senior Subordinate Certificates

	
34


	
Servicer

	
34


	
Servicing Fee

	
34


	
Servicing Fee Rate

	
34


	
Servicing Officer

	
34


	
Special Primary Insurance Policy

	
34


	
Special Primary Insurance Premium

	
34


	
Statutory Trust Statute

	
34


	
Subordinate Certificates

	
34


	
Subordinate Liquidation Amount

	
34


	
Subordinate Percentage

	
35


	
Subordinate Prepayment Percentage

	
35


	
Subordinate Principal Distribution Amount

	
35


	
Subordinate Principal Prepayments Distribution Amount

	
35


	
Subordination Level

	
35


	
Subsequent Recoveries

	
35


	
Substitute Mortgage Loan

	
35


	
Tax Matters Person

	
35


	
Termination Date

	
36


	
Termination Payment

	
36


	
Transfer

	
36


	
Transferee

	
36


	
Transferee Affidavit and Agreement

	
36


	
Trust

	
36


	
Trustee

	
36


	
Uncollected Interest

	
36


	
Uncompensated Interest Shortfall

	
36


	
Underwriters

	
37


	
Underwriting Standards

	
37


	
Uninsured Cause

	
37


	
U.S. Person

	
37


	
VA

	
37


	
Weighted Average Pass-Through Rate

	
37


	
Withdrawal Date

	
37


	
 

	
 


	
 

	
 


	
ARTICLE II  Creation of the Trust; Conveyance of the Mortgage Pool
Assets; REMIC Election and Designations; Original Issuance of Certificates

	
37


	
Section 2.01.  Creation of the Trust

	
37


	
Section 2.02.  Restrictions on Activities of the Trust

	
38


	
Section 2.03.  Separateness Requirements

	
39


	
Section 2.04.  Conveyance of Mortgage Pool Assets; Security
Interest

	
41


	
Section 2.05.  Delivery of Mortgage Files

	
42


	
Section 2.06.  REMIC Election for REMIC I

	
43


	
Section 2.07.  Acceptance by Trustee

	
45


	
Section 2.08.  Representations and Warranties of the Company
Concerning the Mortgage Loans

	
47


	
Section 2.09.  Acknowledgment of Transfer of Mortgage Pool
Assets

	
51


	
Section 2.10.  Acknowledgement of Transfer of REMIC I Assets;
Authentication of Certificates

	
52


	
Section 2.11.  Legal Title

	
52


	
Section 2.12.  Compliance with ERISA Requirements

	
52


	
Section 2.13.  Additional Representation of the Company Concerning
the Mortgage Loans

	
52


	
ARTICLE III  Administration and Servicing of Mortgage
Loans

	
52


	
Section 3.01.  The Company to Act as Master Servicer

	
52


	
Section 3.02.  Custodial Accounts and Buydown Fund
Accounts

	
55


	
Section 3.03.  The Investment Account; Eligible
Investments

	
56


	
Section 3.04.  The Certificate Account

	
57


	
Section 3.05.  Permitted Withdrawals from the Certificate Account,
the Investment Account, Custodial Accounts for P&I and Custodial Accounts for Reserves and of Buydown Funds from the
Buydown Fund Accounts

	
58


	
Section 3.06.  Maintenance of Primary Insurance Policies;
Collections Thereunder

	
60


	
Section 3.07.  Maintenance of Hazard Insurance

	
60


	
Section 3.08.  Enforcement of Due-on-Sale Clauses; Assumption
Agreements

	
61


	
Section 3.09.  Realization Upon Defaulted Mortgage Loans

	
62


	
Section 3.10.  Trustee to Cooperate; Release of Mortgage
Files

	
64


	
Section 3.11.  Compensation to the Master Servicer and the
Servicers

	
65


	
Section 3.12.  Reports to the Trustee; Certificate Account
Statement

	
65


	
Section 3.13.  Annual Statement as to Compliance

	
65


	
Section 3.14.  Access to Certain Documentation and Information
Regarding the Mortgage Loans

	
66


	
Section 3.15.  Annual Independent Public Accountants’
Servicing Report

	
66


	
Section 3.16.  [Reserved.]

	
66


	
Section 3.17.  [Reserved.]

	
66


	
Section 3.18.  [Reserved.]

	
66


	
Section 3.19.  [Reserved.]

	
66


	
Section 3.20.  Assumption or Termination of Selling and Servicing
Contracts by Trustee

	
66


	
ARTICLE IV  Payments to Certificateholders; Payment of
Expenses

	
67


	
Section 4.01.  Distributions to Certificateholders; Payment of
Special Primary Insurance Premiums

	
67


	
Section 4.02.  Advances by the Master Servicer; Distribution
Reports to the Trustee

	
68


	
Section 4.03.  Nonrecoverable Advances

	
69


	
Section 4.04.  Statements to Certificateholders

	
70


	
ARTICLE V  The Certificates

	
70


	
Section 5.01.  The Certificates

	
70


	
Section 5.02.  Certificates Issuable in Classes; Distributions of
Principal and Interest; Authorized Denominations

	
77


	
Section 5.03.  Registration of Transfer and Exchange of
Certificates

	
77


	
Section 5.04.  Mutilated, Destroyed, Lost or Stolen
Certificates

	
78


	
Section 5.05.  Persons Deemed Owners

	
78


	
Section 5.06.  Temporary Certificates

	
78


	
Section 5.07.  Book-Entry for Book-Entry Certificates

	
79


	
Section 5.08.  Notices to Clearing Agency

	
80


	
Section 5.09.  Definitive Certificates.

	
80


	
Section 5.10.  Office for Transfer of Certificates.

	
80


	
Section 5.11.  Nature of Certificates.

	
81


	
ARTICLE VI  The Company and the Master Servicer

	
81


	
Section 6.01.  Liability of the Company and the Master
Servicer

	
81


	
Section 6.02.  Merger or Consolidation of the Company, or the
Master Servicer

	
81


	
Section 6.03.  Limitation on Liability of the Company, the Master
Servicer and Others

	
81


	
Section 6.04.  The Company and the Master Servicer not to
Resign

	
82


	
Section 6.05.  Trustee Access.

	
82


	
ARTICLE VII  Default

	
83


	
Section 7.01.  Events of Default

	
83


	
Section 7.02.  Trustee to Act; Appointment of Successor

	
85


	
Section 7.03.  Notification to Certificateholders

	
86


	
ARTICLE VIII  Concerning the Trustees

	
86


	
Section 8.01.  Duties of Trustees

	
86


	
Section 8.02.  Certain Matters Affecting the Trustees

	
88


	
Section 8.03.  Trustees Not Liable for Certificates or Mortgage
Loans

	
89


	
Section 8.04.  Trustees May Own Certificates

	
90


	
Section 8.05.  The Master Servicer to Pay Trustees’ Fees and
Expenses

	
90


	
Section 8.06.  Eligibility Requirements for Trustees

	
90


	
Section 8.07.  Resignation and Removal of Trustees

	
90


	
Section 8.08.  Successor Trustee

	
91


	
Section 8.09.  Merger or Consolidation of Trustee

	
92


	
Section 8.10.  Appointment of Co-Trustee or Separate
Trustee

	
92


	
Section 8.11.  Authenticating Agents

	
93


	
Section 8.12.  Paying Agents

	
94


	
Section 8.13.  Duties of Delaware Trustee

	
95


	
Section 8.14.  Amendment to Certificate of Trust

	
95


	
Section 8.15.  Limitation of Liability

	
95


	
ARTICLE IX  Termination

	
95


	
Section 9.01.  Termination Upon Purchase by the Master Servicer or
Liquidation of All Mortgage Loans

	
95


	
Section 9.02.  Additional Termination Requirements

	
97


	
Section 9.03.  Trust Irrevocable

	
98


	
ARTICLE X  Miscellaneous Provisions

	
98


	
Section 10.01.  Amendment

	
98


	
Section 10.02.  Recordation of Agreement

	
100


	
Section 10.03.  Limitation on Rights of
Certificateholders

	
100


	
Section 10.04.  Access to List of Certificateholders

	
101


	
Section 10.05.  Governing Law

	
101


	
Section 10.06.  Notices

	
101


	
Section 10.07.  Severability of Provisions

	
101


	
Section 10.08.  Counterpart Signatures

	
102


	
Section 10.09.  Benefits of Agreement

	
102


	
Section 10.10.  Notices and Copies to Rating Agencies

	
102







 





 


Exhibit
A  Form of Certificates (other than Class
R Certificates)


Exhibit
B  Form of Class R Certificates


Exhibit
C  Anti-Predatory Lending
Categorization


Exhibit
D  Mortgage Loan Schedule


Exhibit E  Selling And Servicing Contract


Exhibit F  Form of Transferor Certificate For Junior Subordinate
Certificates


Exhibit
G  Form of Transferee’s Agreement
For Junior Subordinate Certificates


Exhibit
H  Form of Additional Matter Incorporated
Into The Certificates


Exhibit I  Transferor Certificate


Exhibit J  Transferee Affidavit And Agreement


Exhibit
K  [Reserved]


Exhibit L  Form of Investment Letter


Exhibit
M  Form of Trustee’s Certification
Pursuant to Section 2.07


Exhibit
N  Officer’s Certificate With
Respect to ERISA Matters Pursuant to Section 5.01(d)


Exhibit O   Officer’s Certificate With
Respect to ERISA Matters Pursuant to Section 5.01(g)


 








This Pooling and Servicing Agreement, dated and effective as of
February 1, 2005 (this “Agreement”), is executed by and among Washington Mutual Mortgage Securities Corp., as
depositor and Master Servicer (the “Company”), LaSalle Bank National Association, a national banking association
with a corporate trust office at 135 South LaSalle Street, Suite 1625, Chicago, Illinois 60603, as Trustee (the
“Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee (the “Delaware
Trustee”).  Capitalized terms used in this Agreement and not otherwise defined have the meanings ascribed to such
terms in Article I hereof.


PRELIMINARY STATEMENT


The Company at the Closing Date is the owner of the Mortgage Loans and
the other property being conveyed by it to the Trust. On the Closing Date, the Company will acquire the Certificates from the Trust
as consideration for its transfer to the Trust of the Mortgage Loans and certain other assets and will be the owner of the
Certificates.  The Company has duly authorized the execution and delivery of this Agreement to provide for (i) the conveyance
to the Trust of the Mortgage Loans and certain other assets and (ii) the issuance to the Company of the Certificates, representing
in the aggregate the entire beneficial interest in REMIC I. The Company is entering into this Agreement, and the Trustee and the
Delaware Trustee are each accepting the trust created hereby, for good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged.


The Certificates issued hereunder, other than the Junior Subordinate
Certificates, have been offered for sale pursuant to a Prospectus, dated February 10, 2004, and a Prospectus Supplement, dated
February 18, 2005, of the Company (together, the “Prospectus”). The Junior Subordinate Certificates have
been offered for sale pursuant to a Private Placement Memorandum, dated February 23, 2005.  The Trust created hereunder
is intended to be the “Trust” described in the Prospectus and the Private Placement Memorandum and the Certificates are
intended to be the “Certificates” described therein. The following table sets forth the designation, type of interest,
Certificate Interest Rate, initial Class Principal Balance and Final Maturity Date for the Certificates:






REMIC I
Interests



	
 

	

Class Designation for
each Class of Certificates


	
 

	
Type of Interest


	
 

	
Certificate Interest Rate (1)


	
 

	
Initial Class Principal Balance


	
 

	
Final Maturity Date*



	
 

	
Class A-1

	

 

	
Regular

	
 

	
Variable (2)

	
 

	

$400,000,000.00

	
 

	
March 2035


	


	
Class A-2

	

 

	
Regular

	
 

	
Variable (2)

	
 

	

304,500,000.00

	
 

	
March 2035


	
 

	
Class A-3

	

 

	
Regular

	
 

	
Variable (2)

	
 

	

14,019,000.00

	
 

	
March 2035


	
 

	
Class B-1

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

17,260,000.00

	
 

	
March 2035


	
 

	
Class B-2

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

5,253,000.00

	
 

	
March 2035


	
 

	
Class B-3

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

3,377,000.00

	
 

	
March 2035


	
 

	
Class B-4

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

2,626,000.00

	
 

	
March 2035


	
 

	
Class B-5

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

1,876,000.00

	
 

	
March 2035


	
 

	
Class B-6

	
 

	
Regular

	
 

	
Variable (2)

	
 

	

1,500,908.71

	
 

	
March 2035


	
 

	
Class R (3)

	
 

	
Residual

	
 

	
4.6608%

	
 

	
100.00

	
 

	
March 2035


	
 

	
 

	
 

	
 

	
 

	
 

	
 

	
 

	
 

	
 


	

*             The Distribution Date in the specified month,
which is the Distribution Date in the month following the month the latest maturing Mortgage Loan matures.  For federal income
tax purposes, for each Class of Certificates, the “latest possible maturity date” shall be the Final Maturity Date.





	
 


	

(1)           Interest distributed on each Distribution Date to the
Certificates will have accrued at the applicable per annum Certificate Interest Rate on the applicable Class Principal Balance
outstanding immediately before such Distribution Date.





	
 


	

(2)           For each Distribution Date, the
Certificate Interest Rate on each Class of Class A Certificates and each Class of Class B Certificates shall equal the Weighted
Average Pass-Through Rate for such Distribution Date.





	
 


	
(3)
          The Class R Certificates shall be entitled to receive the Residual
Distribution Amount and any Excess Liquidation Proceeds.

	
 


											





 


As provided herein, with respect to REMIC I, the Company will cause an
election to be made on behalf of REMIC I to be treated for federal income tax purposes as a REMIC. The Certificates (other than the
Class R Certificates) will be designated regular interests in REMIC I and the Class R Certificates will be designated the sole
class of residual interest in REMIC I, for purposes of the REMIC Provisions.  As of the Cut-Off Date, the Mortgage Loans have
an aggregate Principal Balance of $750,412,008.71 and the Certificates have an Aggregate Certificate Principal Balance of
$750,412,008.71.







W I T N E S S E T H :


WHEREAS, the Company is a corporation duly organized and existing
under and by virtue of the laws of the State of Delaware and has full corporate power and authority to enter into this Agreement
and to undertake the obligations undertaken by it herein;


WHEREAS, the Trustee is a national banking association duly organized
and existing under the laws of the United States of America and has full power and authority to enter into this
Agreement;


WHEREAS, the Delaware Trustee is a banking corporation duly organized
and existing under the laws of the State of Delaware and has full power and authority to enter into this Agreement;


WHEREAS, prior to the execution and delivery hereof, the Company and
the Delaware Trustee have entered into the Original Trust Agreement, and the Delaware Trustee has filed the Certificate of
Trust;


WHEREAS, it is the intention of the Company, the Trustee and the
Delaware Trustee that the Trust created by this Agreement constitute a statutory trust under the Statutory Trust Statute, that this
Agreement constitute the governing instrument of the Trust, and that this Agreement amend and restate the Original Trust
Agreement;


WHEREAS, the Company is the owner of the Mortgage Loans identified in
the Mortgage Loan Schedule hereto having unpaid Principal Balances on the Cut-Off Date as stated therein; and


WHEREAS, the Company has been duly authorized to create the Trust to
(i) hold the Mortgage Loans and certain other property and (ii) issue the Certificates.


NOW, THEREFORE, in order to declare the terms and conditions upon
which the Certificates are to be issued, and in consideration of the premises and of the purchase and acceptance of the
Certificates by the Holders thereof, the Company covenants and agrees with the Trustee and the Delaware Trustee, for the equal and
proportionate benefit of the respective Holders from time to time of the Certificates, as applicable, as follows:



ARTICLE
I






Section 1.01.        Definitions.


Whenever used in this Agreement, the following words and phrases,
unless the context otherwise requires, shall have the following meanings:


Adjustment Date:  As to each Mortgage Loan, a Due Date on or about the fifth anniversary of the first Due Date and annually
thereafter, as set forth in the related Mortgage Note, on which date an adjustment to the Mortgage Interest Rate of such Mortgage
Loan becomes effective.


Aggregate Certificate Principal
Balance:  At any given time, the sum of the then current Class Principal Balances of the Certificates.


Appraised Value:  With respect to any
(i) Mortgage Loan that is not a Streamlined Mortgage Loan or ROV Mortgage Loan, the lesser of (a) the value set forth on the
appraisal made in connection with the origination of the related Mortgage Loan as the value of the related Mortgaged Property and
(b) the purchase price paid for the Mortgaged Property, provided, however, that if such Mortgage Loan was originated in connection
with the refinance of a mortgage loan, such value shall be based solely on the appraisal made in connection with the origination of
such Mortgage Loan; (ii) ROV Mortgage Loan, the lesser of (a) the value set forth on the residential appraisal review made in
connection with the origination of the related Mortgage Loan as the value of the related Mortgaged Property and (b) the purchase
price paid for the Mortgaged Property, provided, however, that if such ROV Mortgage Loan was originated in connection the refinance
of a mortgage loan, such value shall be based solely on the residential appraisal review made in connection with the origination of
such ROV Mortgage Loan; and (iii) Streamlined Mortgage Loan, the value set forth in the appraisal made in connection with the
origination of the mortgage loan being refinanced.


Assignment of Proprietary Lease:  With
respect to a Cooperative Loan, the assignment or mortgage of the related Cooperative Lease from the Mortgagor to the originator of
the Cooperative Loan.


Authenticating Agent:  Any
authenticating agent appointed by the Trustee pursuant to Section 8.11.


Authorized Denomination:  With respect
to each Class of Certificates (other than the Class R Certificates), an initial Certificate Principal Balance equal to $25,000 and
multiples of $1 in excess thereof, except that one Certificate of each Class of the Junior Subordinate Certificates may be issued
in an amount that is not an integral multiple of $1.  With respect to the Class R Certificates, one Certificate with a
Percentage Interest equal to 0.01% and one Certificate with a Percentage Interest equal to 99.99%.


Available Distribution Amount:  For
any Distribution Date, the sum of the following amounts with respect to the Mortgage Loans (together with, for the first
Distribution Date, the amount deposited by the Company in the Certificate Account pursuant to the last paragraph of Section 2.01,
if any such amount is referred to therein):


(1)        the total amount of all
cash received by or on behalf of the Master Servicer with respect to such Mortgage Loans by the Determination Date for such
Distribution Date and not previously distributed, including Monthly P&I Advances made by Servicers, Liquidation Proceeds and
scheduled amounts of distributions from Buydown Funds respecting Buydown Loans, if any, except:



(a)       
all scheduled payments of principal and interest collected but due subsequent to such Distribution Date;



(b)       
all Curtailments received after the Prior Period;



(c)       
all Payoffs received after the Payoff Period immediately preceding such Distribution Date (together with any interest payment
received with such Payoffs to the extent that it represents the payment of interest accrued on the Mortgage Loans for the period
subsequent to the Prior Period), and interest which was accrued and received on Payoffs received during the period from the 1st to
the 14th day of the month of such Distribution Date, which interest shall not be included in the calculation of the Available
Distribution Amount for any Distribution Date;



(d)       
Insurance Proceeds, Liquidation Proceeds and Subsequent Recoveries received on such Mortgage Loans after the Prior
Period;



(e)       
all amounts in the Certificate Account which are due and reimbursable to a Servicer or the Master Servicer pursuant to the terms of
this Agreement;



(f)         the sum of the Master Servicing Fee and the Servicing Fee for each such
Mortgage Loan, and any Special Primary Insurance Premium payable on such Distribution Date with respect to such Mortgage Loan;
and



(g)       
Excess Liquidation Proceeds;


(2)        the sum, to the extent
not previously distributed, of the following amounts, to the extent advanced or received, as applicable, by the Master
Servicer:



(a)       
any Monthly P&I Advance made by the Master Servicer to the Trustee with respect to such Distribution Date relating to such
Mortgage Loans; and



(b)       
Compensating Interest; and


(3)        the total amount of any
cash received during the Prior Period by the Trustee or the Master Servicer in respect of a Purchase Obligation under Section 2.07
and Section 2.08 or any permitted purchase of such a Mortgage Loan.


Bankruptcy Loss:  A loss on a Mortgage
Loan arising out of (i) a reduction in the scheduled Monthly Payment for such Mortgage Loan by a court of competent jurisdiction in
a case under the United States Bankruptcy Code, other than any such reduction that arises out of clause (ii) of this definition of
“Bankruptcy Loss,” including, without limitation, any such reduction that results in a permanent forgiveness of
principal, or (ii) with respect to any Mortgage Loan, a valuation, by a court of competent jurisdiction in a case under such
Bankruptcy Code, of the related Mortgaged Property in an amount less than the then outstanding Principal Balance of such Mortgage
Loan.


Beneficial Holder:  A Person holding a
beneficial interest in any Book-Entry Certificate as or through a DTC Participant or an Indirect DTC Participant or a Person
holding a beneficial interest in any Definitive Certificate.


Benefit Plan Opinion:  With respect to
any Certificate presented for registration in the name of any Person, an Opinion of Counsel acceptable to and in form and substance
satisfactory to the Trustee and the Company to the effect that the purchase or holding of such Certificate is permissible under
applicable law, will not constitute or result in a non-exempt prohibited transaction under Section 406 of ERISA or Section 4975 of
the Code, and will not subject the Trust, the Trustee, the Delaware Trustee, the Master Servicer or the Company to any obligation
or liability (including obligations or liabilities under Section 406 of ERISA or Section 4975 of the Code) in addition to those
undertaken in this Agreement, which Opinion of Counsel shall not be an expense of the Trust, the Trustee, the Delaware Trustee, the
Master Servicer or the Company.


Book-Entry Certificates:  The Class A
and Senior Subordinate Certificates, beneficial ownership and transfers of which shall be made through book entries as described in
Section 5.07.


Business Day:  Any day other than a
Saturday, a Sunday or a day on which banking institutions in Stockton, California, Chicago, Illinois, New York, New York, Seattle,
Washington or any city in which the Corporate Trust Office is located are authorized or obligated by law or executive order to be
closed.


Buydown Agreement:  An agreement
between a Person and a Mortgagor pursuant to which such Person has provided a Buydown Fund.


Buydown Fund:  A fund provided by the
originator of a Mortgage Loan or another Person with respect to a Buydown Loan which provides an amount sufficient to subsidize
regularly scheduled principal and interest payments due on such Buydown Loan for a period. Buydown Funds may be (i) funded at the
par values of future payment subsidies, or (ii) funded in an amount less than the par values of future payment subsidies, and
determined by discounting such par values in accordance with interest accruing on such amounts, in which event they will be
deposited in an account bearing interest. Buydown Funds may be held in a separate Buydown Fund Account or may be held in a
Custodial Account for P&I or a Custodial Account for Reserves and monitored by a Servicer.


Buydown Fund Account:  A separate
account or accounts created and maintained pursuant to Section 3.02 (a) with the corporate trust department of the Trustee or
another financial institution approved by the Master Servicer, (b) within FDIC insured accounts (or other accounts with comparable
insurance coverage acceptable to the Rating Agencies) created, maintained and monitored by a Servicer or (c) in a separate
non-trust account without FDIC or other insurance in an Eligible Institution. Such account or accounts may be non-interest bearing
or may bear interest. In the event that a Buydown Fund Account is established pursuant to clause (b) of the preceding sentence,
amounts held in such Buydown Fund Account shall not exceed the level of deposit insurance coverage on such account; accordingly,
more than one Buydown Fund Account may be established.


Buydown Loan:  A Mortgage Loan for
which the Mortgage Interest Rate has been subsidized through a Buydown Fund provided at the time of origination of such Mortgage
Loan.


Carry-Forward Subsequent Recoveries
Amount:  For any Distribution Date, the excess, if any, of (i) the Subsequent Recoveries for
such Distribution Date over (ii) the amount by which the Class Principal Balance of the Class of Subordinate Certificates with the
lowest priority is increased in respect of Subsequent Recoveries on such Distribution Date pursuant to the definition of
“Class Principal Balance” herein.


Certificate:  Any one of the
Certificates issued pursuant to this Agreement, executed by the Trustee and authenticated by or on behalf of the Trustee hereunder
in substantially one of the forms set forth in Exhibit A and B hereto. The additional matter appearing in Exhibit H shall be deemed
incorporated into Exhibit A as though set forth at the end of such Exhibit.


Certificate Account:  The separate
trust account created and maintained with the Trustee, the Investment Depository or any other bank or trust company acceptable to
the Rating Agencies which is incorporated under the laws of the United States of America or any state thereof pursuant to Section
3.04, which account shall bear a designation clearly indicating that the funds deposited therein are held in trust for the benefit
of the Trust or any other account serving a similar function acceptable to the Rating Agencies. Funds in the Certificate Account
may be invested in Eligible Investments pursuant to Section 3.04(b) and reinvestment earnings thereon shall be paid to the Master
Servicer as additional servicing compensation. Funds deposited in the Certificate Account (exclusive of the Master Servicing Fee)
shall be held in trust for the Certificateholders and for the uses and purposes set forth in Section 2.01, Section 3.04, Section
3.05 and Section 4.01.


Certificateholder or Holder:  With
respect to the Certificates, the Person in whose name a Certificate is registered in the Certificate Register, except that, solely
for the purposes of giving any consent pursuant to this Agreement, any Certificate registered in the name of the Company, the
Master Servicer or any affiliate thereof shall be deemed not to be outstanding and the Percentage Interest evidenced thereby shall
not be taken into account in determining whether the requisite percentage of Percentage Interests necessary to effect any such
consent has been obtained; provided, that the Trustee may conclusively rely upon an Officer’s Certificate to determine
whether any Person is an affiliate of the Company or the Master Servicer.


Certificate Interest Rate:  For each
Class of Certificates, the per annum rate set forth as the Certificate Interest Rate for such Class in the Preliminary Statement
hereto.


Certificate of Trust:  The certificate
of trust filed with respect to the Trust with the Secretary of State in accordance with Section 3810(a) of the Statutory Trust
Statute.


Certificate Principal Balance:  For
each Certificate of any Class, the portion of the related Class Principal Balance, if any, represented by such Certificate.


Certificate Register and Certificate
Registrar:  The register maintained and the registrar appointed, respectively, pursuant to Section 5.03.


Class:  All Certificates having the
same priority and rights to payments on the Mortgage Loans from the Available Distribution Amount, which Certificates shall be
designated as a separate Class, and which shall be set forth in the applicable forms of Certificates attached hereto as Exhibit A.
Each Class of Certificates shall be entitled to receive the amounts allocated to such Class pursuant to the definition of
“Distribution Amount” only to the extent of the Available Distribution Amount for such Distribution Date remaining
after distributions in accordance with prior clauses of the definition of “Distribution Amount.”


Class A Certificates:  The Class A-1,
Class A-2 and Class A-3 Certificates.


Class A-1 Certificates:  The
Certificates designated as “Class A-1” on the face thereof in substantially the form attached hereto as Exhibit A.


Class A-2 Certificates:  The
Certificates designated as “Class A-2” on the face thereof in substantially the form attached hereto as Exhibit A.


Class A-3 Certificates:  The
Certificates designated as “Class A-3” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B Certificates:  The Class B-1,
Class B-2, Class B-3, Class B-4, Class B-5 and Class B-6 Certificates.


Class B-1 Certificates:  The
Certificates designated as “Class B-1” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B-2 Certificates:  The
Certificates designated as “Class B-2” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B-3 Certificates:  The
Certificates designated as “Class B-3” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B-4 Certificates:  The
Certificates designated as “Class B-4” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B-5 Certificates:  The
Certificates designated as “Class B-5” on the face thereof in substantially the form attached hereto as Exhibit A.


Class B-6 Certificates:  The
Certificates designated as “Class B-6” on the face thereof in substantially the form attached hereto as Exhibit A.


Class Principal Balance:  For any
Class of Certificates, the applicable initial Class Principal Balance therefor set forth in the Preliminary Statement hereto,
corresponding to the rights of such Class in payments of principal due to be passed through to the Certificateholders from
principal payments on the Mortgage Loans, as reduced from time to time by (x) distributions of principal to the Certificateholders
of such Class and (y) the portion of Realized Losses allocated to the Class Principal Balance of such Class pursuant to the
definition of “Realized Loss” with respect to a given Distribution Date. For any Distribution Date, the reduction of
the Class Principal Balance of any Class of Certificates pursuant to the definition of “Realized Loss” shall be deemed
effective after the determination and distribution of principal on such Class pursuant to the definition of “Distribution
Amount.”


Notwithstanding the foregoing, any amounts distributed in respect of
principal losses pursuant to paragraph (xxii) of the definition of “Distribution Amount” shall not cause a reduction in
the Class Principal Balances of the Certificates.


In addition to the foregoing, on each Distribution Date, the Class
Principal Balance of the Class of Subordinate Certificates with the lowest priority then outstanding shall be increased by an
amount equal to the lesser of (i) the Subsequent Recoveries for such Distribution Date and (ii) the amount of Realized Losses
allocated to such Class on previous Distribution Dates (the amount in this clause (ii) reduced by the amount, if any, by which such
Class Principal Balance has been increased on prior Distribution Dates pursuant to this paragraph).


The Class Principal Balance for the Class A Certificates shall be
referred to as the “Class A Principal Balance,” the Class Principal Balance for the Class B-1 Certificates shall
be referred to as the “Class B-1 Principal Balance,” and so on.


Class R Certificates:  The
Certificates designated as “Class R” on the face thereof in substantially the form attached hereto as Exhibit A, which
Class has been designated as the sole class of “residual interest” in REMIC I, pursuant to Section 2.06 for purposes of
Section 860G(a)(2) of the Code.


Clean-Up Call Option Date:  The date
on which the aggregate principal balance of the Mortgage Loans has been reduced to less than the Clean-Up Call Percentage of that
balance as of the Cut-Off Date.


Clean-Up Call Percentage:  10%.


Clearing Agency:  An organization
registered as a “clearing agency” pursuant to Section 17A of the Securities Exchange Act of 1934, as amended, which
initially shall be DTC.


Closing Date:  February 23, 2005,
which is the date of settlement of the sale of the Certificates to the original purchasers thereof.


Code:  The Internal Revenue Code of
1986, as amended.


Company:  Washington Mutual Mortgage
Securities Corp., a Delaware corporation, or its successor-in-interest.


Compensating Interest: For any Distribution
Date, the least of (i) the sum of (a) the aggregate Master Servicing Fee payable with respect to the Mortgage Loans on such
Distribution Date, (b) the aggregate Payoff Earnings with respect to the Mortgage Loans for such Distribution Date and (c) the
aggregate Payoff Interest with respect to the Mortgage Loans for such Distribution Date; (ii) the aggregate Uncollected Interest
with respect to the Mortgage Loans for such Distribution Date and (iii) 1/12 of 0.125% of the aggregate Principal Balance of
the Mortgage Loans immediately preceding such Distribution Date.


Cooperative:  A private, cooperative
housing corporation which owns or leases land and all or part of a building or buildings, including apartments, spaces used for
commercial purposes and common areas therein and whose board of directors authorizes, among other things, the sale of Cooperative
Stock.


Cooperative Apartment:  A dwelling
unit in a multi-dwelling building owned or leased by a Cooperative, which unit the Mortgagor has an exclusive right to occupy
pursuant to the terms of a proprietary lease or occupancy agreement.


Cooperative Lease:  With respect to a
Cooperative Loan, the proprietary lease or occupancy agreement with respect to the Cooperative Apartment occupied by the Mortgagor
and relating to the related Cooperative Stock, which lease or agreement confers an exclusive right to the holder of such
Cooperative Stock to occupy such apartment.


Cooperative Loans:  Any of the
Mortgage Loans made in respect of a Cooperative Apartment, evidenced by a Mortgage Note and secured by (i) a Security Agreement,
(ii) the related Cooperative Stock Certificate, (iii) an assignment or mortgage of the Cooperative Lease, (iv) financing statements
and (v) a stock power (or other similar instrument), and ancillary thereto, a Recognition Agreement, each of which was transferred
and assigned to the Trust pursuant to Section 2.04.


Cooperative Stock:  With respect to a
Cooperative Loan, the single outstanding class of stock, partnership interest or other ownership instrument in the related
Cooperative.


Cooperative Stock Certificate:  With
respect to a Cooperative Loan, the stock certificate or other instrument evidencing the related Cooperative Stock.


Corporate Trust Office:  The corporate
trust office of the Trustee, at which at any particular time its corporate trust business with respect to this Agreement shall be
administered, which office at the date of the execution of this Agreement is located at 135 South LaSalle Street, Suite 1625,
Chicago, Illinois 60603, Attention: Global Securitization Trust Services/WaMu Series 2005-AR3.


Corporation:  Any Person (other than
an individual, partnership, joint venture or unincorporated organization) incorporated, associated, organized, chartered or
existing under the laws of any state or under the federal laws of the United States of America; provided, that such Person
have indefinite existence under the law of its domicile.


Cumulative Carry-Forward Subsequent Recoveries
Amount:  For any Distribution Date, the sum of (i) the Carry-Forward
Subsequent Recoveries Amount for such Distribution Date and (ii) the Carry-Forward Subsequent Recoveries Amounts for prior
Distribution Dates to the extent such Carry-Forward Subsequent Recoveries Amounts have not been applied in reduction of Realized
Losses on prior Distribution Dates pursuant to the first paragraph of the definition of “Realized Loss”
herein.


Curtailment:  Any payment of principal
on a Mortgage Loan, made by or on behalf of the related Mortgagor, other than a Monthly Payment, a Prepaid Monthly Payment or a
Payoff, which is applied to reduce the outstanding principal balance of the Mortgage Loan.  (Prepayment penalties are not
payments of principal and hence Curtailments do not include prepayment penalties).


Curtailment Shortfall:  For any
Distribution Date and for any Curtailment applied with a Monthly Payment in the Prior Period other than a Prepaid Monthly Payment,
an amount equal to one month’s interest on such Curtailment at the applicable Pass-Through Rate on such Mortgage Loan.


Custodial Account for P&I:  The
Custodial Account for principal and interest established and maintained by each Servicer pursuant to its Selling and Servicing
Contract and caused by the Master Servicer to be established and maintained pursuant to Section 3.02 (a) with the corporate trust
department of the Trustee or another financial institution approved by the Master Servicer such that the rights of the Master
Servicer, the Trust, the Trustee, the Delaware Trustee and the Certificateholders thereto shall be fully protected against the
claims of any creditors of the applicable Servicer and of any creditors or depositors of the institution in which such account is
maintained, (b) within FDIC insured accounts (or other accounts with comparable insurance coverage acceptable to the Rating
Agencies) created, maintained and monitored by a Servicer or (c) in a separate non-trust account without FDIC or other insurance in
an Eligible Institution. In the event that a Custodial Account for P&I is established pursuant to clause (b) of the preceding
sentence, amounts held in such Custodial Account for P&I shall not exceed the level of deposit insurance coverage on such
account; accordingly, more than one Custodial Account for P&I may be established. Any amount that is at any time not protected
or insured in accordance with the first sentence of this definition of “Custodial Account for P&I” shall promptly
be withdrawn from such Custodial Account for P&I and be remitted to the Investment Account.


Custodial Account for Reserves:  The
Custodial Account for Reserves established and maintained by each Servicer pursuant to its Selling and Servicing Contract and
caused by the Master Servicer to be established and maintained pursuant to Section 3.02 (a) with the corporate trust department of
the Trustee or another financial institution approved by the Master Servicer such that the rights of the Master Servicer, the
Trust, the Trustee, the Delaware Trustee and the Certificateholders thereto shall be fully protected against the claims of any
creditors of the applicable Servicer and of any creditors or depositors of the institution in which such account is maintained, (b)
within FDIC insured accounts (or other accounts with comparable insurance coverage acceptable to the Rating Agencies) created,
maintained and monitored by a Servicer or (c) in a separate non-trust account without FDIC or other insurance in an Eligible
Institution. In the event that a Custodial Account for Reserves is established pursuant to clause (b) of the preceding sentence,
amounts held in such Custodial Account for Reserves shall not exceed the level of deposit insurance coverage on such account;
accordingly, more than one Custodial Account for Reserves may be established. Any amount that is at any time not protected or
insured in accordance with the first sentence of this definition of “Custodial Account for Reserves” shall promptly be
withdrawn from such Custodial Account for Reserves and be remitted to the Investment Account.


Custodial Agreement:  The agreement,
if any, between the Trustee and a Custodian (or the Trustee, a Custodian and the Master Servicer) providing for the safekeeping of
the Mortgage Files on behalf of the Trust.


Custodian:  A custodian which is
appointed by the Trustee with the consent of the Master Servicer, as provided in Article II hereof, pursuant to a Custodial
Agreement. Any Custodian so appointed shall act as agent on behalf of the Trustee.  The reasonable fees and expenses of the
Custodian shall be paid by the Master Servicer.  The Trustee shall remain at all times responsible under the terms of this
Agreement, notwithstanding the fact that certain duties have been assigned to a Custodian.


Cut-Off Date:  February 1, 2005.


Definitive Certificates:  Certificates
in definitive, fully registered and certificated form.


Delaware Trustee:  Christiana Bank
& Trust Company, or its successor-in-interest as provided in Section 8.09, or any successor trustee appointed as herein
provided.


Depositary Agreement:  The Letter of
Representations, dated February 22, 2005 by and among DTC, the Trust and the Trustee. The Trustee is authorized to enter into
the Depositary Agreement on behalf of the Trust. 


Destroyed Mortgage Note:  A Mortgage
Note the original of which (or a portion of the original of which) was permanently lost or destroyed and has not been replaced.


Determination Date:  A day not later
than the 10th day preceding a related Distribution Date, as determined by the Master Servicer.


Disqualified Organization:  Any Person
which is not a Permitted Transferee, but does not include any Pass-Through Entity which owns or holds a Residual Certificate and of
which a Disqualified Organization, directly or indirectly, may be a stockholder, partner or beneficiary.


Distribution Amount: For any Distribution
Date, the Available Distribution Amount for such Distribution Date shall be distributed to the Certificates in the following
amounts and priority, to the extent of the Available Distribution Amount for such Distribution Date:


(i)                  first,
to each Class of Class A and Class R Certificates, concurrently, the sum of the Interest Distribution Amounts for such Classes
remaining unpaid from previous Distribution Dates, pro rata according to their respective shares of such unpaid amounts;


(ii)                second, to each
Class of Class A and Class R Certificates, concurrently, the sum of the Interest Distribution Amounts for such Classes for the
current Distribution Date, pro rata according to their respective Interest Distribution Amounts;


(iii)               third, to each Class of
Class A and Class R Certificates, as principal, the Senior Principal Distribution Amount, sequentially, as follows:



(a) first, to the Class R Certificates,
until the Class R Principal Balance has been reduced to zero; and



(b) second, to each Class of Class A
Certificates, pro rata according to Class Principal Balance until each such Class’ respective Class Principal Balance has
been reduced to zero;


(iv)              fourth, to the Class B-1
Certificates, the Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution
Dates;


(v)                fifth, to the Class
B-1 Certificates, the Interest Distribution Amount for such Class of Certificates for the current Distribution Date;


(vi)              sixth, to the Class B-1
Certificates, the portion of the Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the
definition of “Subordinate Principal Distribution Amount,” until the Class B-1 Principal Balance has been reduced to
zero;


(vii)             seventh, to the Class B-2
Certificates, the Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution
Dates;


(viii)           eighth, to the Class B-2 Certificates, the
Interest Distribution Amount for such Class of Certificates for the current Distribution Date;


(ix)              ninth, to the Class B-2
Certificates, the portion of the Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the
definition of “Subordinate Principal Distribution Amount,” until the Class B-2 Principal Balance has been reduced to
zero;


(x)                tenth, to the Class
B-3 Certificates, the Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution
Dates;


(xi)              eleventh, to the Class B-3
Certificates, the Interest Distribution Amount for such Class of Certificates for the current Distribution Date;


(xii)             twelfth, to the Class B-3
Certificates, the portion of the Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the
definition of “Subordinate Principal Distribution Amount,” until the Class B-3 Principal Balance has been reduced to
zero;


(xiii)           thirteenth, to the Class B-4 Certificates, the
Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution Dates;


(xiv)           fourteenth, to the Class B-4 Certificates, the
Interest Distribution Amount for such Class of Certificates for the current Distribution Date;


(xv)            fifteenth, to the Class B-4 Certificates,
the portion of the Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the definition of
“Subordinate Principal Distribution Amount,” until the Class B-4 Principal Balance has been reduced to zero;


(xvi)           sixteenth, to the Class B-5 Certificates, the
Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution Dates;


(xvii)         seventeenth, to the Class B-5 Certificates, the Interest
Distribution Amount for such Class of Certificates for the current Distribution Date;


(xviii)        eighteenth, to the Class B-5 Certificates, the portion of the
Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the definition of “Subordinate
Principal Distribution Amount,” until the Class B-5 Principal Balance has been reduced to zero;


(xix)           nineteenth, to the Class B-6 Certificates, the
Interest Distribution Amount for such Class of Certificates remaining unpaid from previous Distribution Dates;


(xx)            twentieth, to the Class B-6 Certificates,
the Interest Distribution Amount for such Class of Certificates for the current Distribution Date;


(xxi)           twenty-first, to the Class B-6 Certificates, the
portion of the Subordinate Principal Distribution Amount allocable to such Class of Certificates pursuant to the definition of
“Subordinate Principal Distribution Amount,” until the Class B-6 Principal Balance has been reduced to zero;


(xxii)         twenty-second, to the outstanding Classes of Certificates in
the order of seniority (which, from highest to lowest, shall be as follows: the Class A Certificates, and then Class B-1, Class
B-2, Class B-3, Class B-4, Class B-5 and Class B-6 of decreasing seniority) the remaining portion, if any, of the Available
Distribution Amount, up to the amount of unreimbursed Realized Losses allocable to principal previously allocated to each such
Class, if any; provided, however, that any amounts distributed pursuant to this paragraph (xxii) of this definition of
“Distribution Amount” shall not cause a further reduction in the Class Principal Balances of any of the Classes of
Certificates; and


(xxiii)        twenty-third, to the Class R Certificates, the Residual
Distribution Amount for such Distribution Date.


Distribution Date:  With respect to
distributions on the Certificates, the 25th day (or, if such 25th day is not a Business Day, the Business Day immediately
succeeding such 25th day) of each month, with the first such date being March 25, 2005.  The “related Due
Date” for any Distribution Date is the Due Date immediately preceding such Distribution Date.


DTC:  The Depository Trust
Company.


DTC Participant:  A broker, dealer,
bank, other financial institution or other Person for whom DTC effects book-entry transfers and pledges of securities deposited
with DTC.


Due Date:  The day on which the
Monthly Payment for each Mortgage Loan is due.


Eligible Institution:  An institution
having (i) the highest short-term debt rating, and one of the two highest long-term debt ratings of the Rating Agencies, (ii) with
respect to any Custodial Account for P&I and special Custodial Account for Reserves, an unsecured long-term debt rating of at
least one of the two highest unsecured long-term debt ratings of the Rating Agencies, (iii) with respect to any Buydown Fund
Account or Custodial Account which also serves as a Buydown Fund Account, the highest unsecured long-term debt rating by the Rating
Agencies, or (iv) the approval of the Rating Agencies.  Such institution may be the Servicer if the applicable Selling and
Servicing Contract requires the Servicer to provide the Master Servicer with written notice on the Business Day following the date
on which the Servicer determines that such Servicer’s short-term debt and unsecured long-term debt ratings fail to meet the
requirements of the prior sentence.  Notwithstanding the foregoing, Washington Mutual Bank, FA shall be an “Eligible
Institution” if the following conditions are satisfied: (i) Washington Mutual Bank, FA is acting as Servicer, (ii) if S&P
is a Rating Agency as defined herein, the long-term unsecured debt obligations of Washington Mutual Bank, FA are rated no lower
than “A-” by S&P and the short-term unsecured debt obligations of Washington Mutual Bank, FA are rated no lower
than “A-2” by S&P, (iii) if Fitch is a Rating Agency as defined herein, the long-term unsecured debt obligations of
Washington Mutual Bank, FA are rated no lower than “A” by Fitch and the short-term unsecured debt obligations of
Washington Mutual Bank, FA are rated no lower than “F1” by Fitch and (iv) if Moody’s is a Rating Agency as
defined herein, the long-term unsecured debt obligations of Washington Mutual Bank, FA are rated no lower than “A2” by
Moody’s and the short-term unsecured debt obligations of Washington Mutual Bank, FA are rated no lower than “P-1”
by Moody’s; provided, that if the long-term or short-term unsecured debt obligations of Washington Mutual Bank, FA are
downgraded by any of the Rating Agencies to a rating lower than the applicable rating specified in this sentence, Washington Mutual
Bank, FA shall cease to be an “Eligible Institution” ten Business Days after notification of such downgrade.


Eligible Investments:  Any one or more
of the obligations or securities listed below in which funds deposited in the Investment Account, the Certificate Account, the
Custodial Account for P&I and the Custodial Account for Reserves may be invested:


(xxiv)       Obligations of, or guaranteed as to principal and interest by, the United
States of America or any agency or instrumentality thereof when such obligations are backed by the full faith and credit of the
United States of America;


(xxv)         Repurchase agreements on obligations described in clause (i)
of this definition of “Eligible Investments,” provided that the unsecured obligations of the party (including the
Trustee in its commercial capacity) agreeing to repurchase such obligations have at the time one of the two highest short term debt
ratings  of the Rating Agencies and provided that such repurchaser’s unsecured long term debt has one of the two highest
unsecured long term debt ratings of the Rating Agencies;


(xxvi)       Federal funds, certificates of deposit, time deposits and bankers’
acceptances of any U.S. bank or trust company incorporated under the laws of the United States of America or any state (including
the Trustee in its commercial capacity), provided that the debt obligations of such bank or trust company (or, in the case of the
principal bank in a bank holding company system, debt obligations of the bank holding company) at the date of acquisition thereof
have one of the two highest short term debt ratings of the Rating Agencies and unsecured long term debt has one of the two highest
unsecured long term debt ratings of the Rating Agencies;


(xxvii)      Obligations of, or obligations guaranteed by, any state of the United States of
America or the District of Columbia, provided that such obligations at the date of acquisition thereof shall have the highest
long-term debt ratings available for such securities from the Rating Agencies;


(xxviii)    Commercial paper of any corporation incorporated under the laws of the United States of
America or any state thereof, which on the date of acquisition has the highest commercial paper rating of the Rating Agencies,
provided that the corporation has unsecured long term debt that has one of the two highest unsecured long term debt ratings of the
Rating Agencies;


(xxix)       Securities (other than stripped bonds or stripped coupons) bearing
interest or sold at a discount that are issued by any corporation incorporated under the laws of the United States of America or
any state thereof and have the highest long-term unsecured rating available for such securities from the Rating Agencies; provided,
however, that securities issued by any such corporation will not be investments to the extent that investment therein would cause
the outstanding principal amount of securities issued by such corporation that are then held as part of the Investment Account or
the Certificate Account to exceed 20% of the aggregate principal amount of all Eligible Investments then held in the Investment
Account and the Certificate Account; and


(xxx)         Units of taxable money market funds (which may be 12b-1
funds, as contemplated under the rules promulgated by the Securities and Exchange Commission under the Investment Company Act of
1940), which funds have the highest rating available for such securities from the Rating Agencies or which have been designated in
writing by the Rating Agencies as Eligible Investments;


provided, however, that such obligation or
security is held for a temporary period pursuant to Section 1.860G-2(g)(1) of the Treasury Regulations, and that such period can in
no event exceed thirteen months.


In no event shall an instrument be an Eligible Investment if such
instrument (a) evidences a right to receive only interest payments with respect to the obligations underlying such instrument or
(b) has been purchased at a price greater than the outstanding principal balance of such instrument.


ERISA:  The Employee Retirement Income
Security Act of 1974, as amended.


ERISA Restricted Certificate:  Any
Senior Subordinate Certificate.


Event of Default:  Any event of
default as specified in Section 7.01.


Excess Liquidation Proceeds:  With
respect to any Distribution Date, the sum of (i) the excess, if any, of aggregate Liquidation Proceeds received during the Prior
Period over the amount that would have been received if Payoffs had been made with respect to such Mortgage Loans on the date such
Liquidation Proceeds were received and (ii) any Excess Subsequent Recoveries for such Distribution Date.


Excess Subsequent Recoveries: For any Distribution Date, the excess, if any, of (i) amounts received by the Master
Servicer during the Prior Period (after deduction of amounts reimbursable under Section 3.05(a)(i) and (ii)) in connection with the
liquidation of defaulted Mortgage Loans after such Mortgage Loans became Liquidated Mortgage Loans over (ii) the Subsequent
Recoveries for such Distribution Date.


Fannie Mae:  The entity formerly known
as the Federal National Mortgage Association, or any successor thereto.


FDIC:  Federal Deposit Insurance
Corporation, or any successor thereto.


FHA:  Federal Housing Administration,
or any successor thereto.


Final Maturity Date:  With
respect to each Class of Certificates, the date set forth in the table contained in the Preliminary Statement hereto.


Fitch: Fitch Ratings, provided that at any
time it be a Rating Agency.


Freddie Mac:  The entity formerly
known as the Federal Home Loan Mortgage Corporation, or any successor thereto.


Index:  Initially, either One-Year CMT
or One-Year LIBOR, as set forth on the Mortgage Loan Schedule.  In the event such initial Index is no longer available, the
Master Servicer will select a substitute Index in accordance with the terms of the related Mortgage Note and in compliance with
applicable law.


Indirect DTC Participants:  Entities
such as banks, brokers, dealers or trust companies, that clear through or maintain a custodial relationship with a DTC Participant,
either directly or indirectly.


Initial Custodial Agreement:  The
Custodial Agreement, dated the date hereof, among the Trustee, the Master Servicer and the Initial Custodian.


Initial Custodian:  Washington Mutual
Bank fsb, which has been designated by the Company to be appointed by the Trustee to act as Custodian, and whose appointment has
been approved by the Master Servicer.


Insurance Proceeds:  Amounts paid or
payable by the insurer under any Primary Insurance Policy or any other insurance policy (including any replacement policy permitted
under this Agreement) covering any Mortgage Loan or Mortgaged Property, including, without limitation, any hazard insurance policy
required pursuant to Section 3.07, any title insurance policy required pursuant to Section 2.08 and any FHA insurance policy or VA
guaranty.


Interest Distribution Amount:  For any
Distribution Date, for any Class of Certificates, the amount of interest accrued during the Prior Period, at the related
Certificate Interest Rate for such Class for such Distribution Date, on the respective Class Principal Balance immediately before
such Distribution Date, reduced by Uncompensated Interest Shortfall and the interest portion of Realized Losses allocated to such
Class on such Distribution Date pursuant to the definitions of “Uncompensated Interest Shortfall” and “Realized
Loss,” respectively.


The computation of interest accrued shall be made on the basis of a
360-day year of twelve 30-day months.


Investment Account:  The commingled
account (which shall be commingled only with investment accounts related to series of pass-through certificates with a class of
certificates which has a rating equal to the highest of the Ratings of the Certificates) maintained by the Master Servicer in the
trust department of the Investment Depository pursuant to Section 3.03 and which bears a designation acceptable to the Rating
Agencies.


Investment Depository:  JPMorgan Chase
Bank, or another bank or trust company designated from time to time by the Master Servicer. The Investment Depository shall at all
times be an Eligible Institution.


Junior Subordinate Certificates:  The
Class B-4, Class B-5 and Class B-6 Certificates.


Last Scheduled Distribution
Date:  With respect to any Class of Certificates, the Final Maturity Date for such Class.


Lender:  An institution from which the
Company purchased any Mortgage Loans pursuant to a Selling and Servicing Contract.


Liquidated Mortgage Loan:  A Mortgage
Loan (other than a Mortgage Loan with respect to which a Payoff has been made) for which the Master Servicer or the applicable
Servicer has determined in accordance with its customary servicing practices that it has received all amounts which it expects to
recover from or on account of such Mortgage Loan, whether from Insurance Proceeds, Liquidation Proceeds or otherwise. For purposes
of this definition, acquisition of a Mortgaged Property by the Trust shall not constitute final liquidation of the related Mortgage
Loan.


Liquidation Principal:  The principal
portion of Liquidation Proceeds received with respect to each Mortgage Loan which became a Liquidated Mortgage Loan (but not in
excess of the principal balance thereof) during the Prior Period.


Liquidation Proceeds:  Amounts after
deduction of amounts reimbursable under Section 3.05(a)(i) and (ii) received and retained in connection with the liquidation of
defaulted Mortgage Loans, whether through foreclosure or otherwise, other than any Subsequent Recoveries.


Loan-to-Value Ratio:  The original
principal amount of a Mortgage Loan divided by the Original Value; provided, however, that references to “current
Loan-to-Value Ratio” or “Loan-to-Value Ratio as of the Cut-Off Date” in Section 2.08 shall be deemed to mean the
then current Principal Balance of a Mortgage Loan divided by the Original Value.


Lowest Class B Owner:  An owner
unaffiliated with the Company or the Master Servicer of (i) a 100% interest in the Class of Class B Certificates with the lowest
priority or (ii) a 100% interest in a class of securities representing such interest in such Class specified in clause (i)
above.


Margin:  For each Mortgage Loan, the
applicable fixed per annum percentage rate specified in the applicable Mortgage Note and designated as such in the Mortgage Loan
Schedule.


Master Servicer:  The Company, or any
successor thereto appointed as provided pursuant to Section 7.02, acting to service and administer the Mortgage Loans pursuant to
Section 3.01.


Master Servicer Business Day:  Any day
other than a Saturday, a Sunday, or a day on which banking institutions in Chicago, Illinois are authorized or obligated by law or
executive order to be closed.


Master Servicing Fee:  For each
Mortgage Loan, the fee charged by the Master Servicer for supervising the mortgage servicing and advancing certain expenses, equal
to 1/12 of the product of (i) the Master Servicing Fee Rate for such Mortgage Loan and (ii) the outstanding Principal Balance of
such Mortgage Loan, payable monthly from the Certificate Account, the Investment Account or the Custodial Account for P&I.


Master Servicing Fee Rate:  For each
Mortgage Loan, the per annum rate set forth for such Mortgage Loan in the Mortgage Loan Schedule, equal to 0.050%.


MERS:  Mortgage Electronic
Registration Systems, Inc., a Delaware corporation, or any successor thereto.


MERS Loan:  Any Mortgage Loan
registered on the MERS® System for which MERS appears as the mortgagee of record on the Mortgage or on an assignment
thereof.


MERS® System:  The system of
electronically recording transfers of Mortgages maintained by MERS.


MIN:  The Mortgage Identification
Number for a MERS Loan.


MOM Loan:  A Mortgage Loan that was
registered on the MERS® System at the time of origination thereof and for which MERS appears as the mortgagee of record on the
Mortgage.


Monthly P&I Advance:  An advance
of funds by the Master Servicer pursuant to Section 4.02 or a Servicer pursuant to its Selling and Servicing Contract to cover
delinquent principal and interest installments.


Monthly Payment:  The scheduled
payment of principal (if any) and interest on a Mortgage Loan (including any amounts due from a Buydown Fund, if any) which is due
on the related Due Date for such Mortgage Loan.


Moody’s:  Moody’s
Investors Service, Inc., provided that at any time it be a Rating Agency.


Mortgage:  The mortgage, deed of trust
or other instrument securing a Mortgage Note.


Mortgage File:  The following
documents or instruments with respect to each Mortgage Loan transferred and assigned by the Company pursuant to Section 2.04, (X)
with respect to each Mortgage Loan that is not a Cooperative Loan:


(i)                  The
original Mortgage Note endorsed (A) in blank, without recourse, or (B) to “LaSalle Bank National Association, as Trustee,
without recourse” or to “WaMu Mortgage Pass-Through Certificates Series 2005-AR3 Trust, without recourse” and all
intervening endorsements evidencing a complete chain of endorsements from the originator to the Trustee or the Trust, as
applicable, or, in the event of any Destroyed Mortgage Note, a copy or a duplicate original of the Mortgage Note (or portion
thereof, as applicable), together with an original lost note affidavit from the originator of the Mortgage Loan or the Company (or
any affiliate of the Company from which the Company acquired the Mortgage Loan), as applicable, stating that the original Mortgage
Note (or portion thereof, as applicable) was lost, misplaced or destroyed, together with a copy of the Mortgage Note (or portion
thereof, as applicable); provided, however, that in the event the Company acquired the Mortgage Loan from an affiliate of
the Company, then the Mortgage Note (or portion thereof, as applicable) need not be endorsed in blank or to LaSalle Bank National
Association or the Trust as provided above (but, if not so endorsed, shall be made payable to, or endorsed by the mortgagee named
therein to, such affiliate of the Company);


(ii)        The
Buydown Agreement, if applicable;


(iii)       A Mortgage
that is either



(1)        (x) the original recorded Mortgage with evidence of recording thereon for the
jurisdiction in which the Mortgaged Property is located (which original recorded Mortgage, in the case of a MOM Loan, shall set
forth the MIN and shall indicate that the Mortgage Loan is a MOM Loan), (y) unless the Mortgage Loan is a MERS Loan, an original
Mortgage assignment thereof duly executed and acknowledged in recordable form (A) in blank or (B) to “LaSalle Bank National
Association, as Trustee,” or to “WaMu Mortgage Pass-Through Certificates Series 2005-AR3 Trust,” and (z) unless
the Mortgage Loan is a MOM Loan, recorded originals of all intervening assignments evidencing a complete chain of assignment, from
the originator to the name holder or the payee endorsing the related Mortgage Note (or, in the case of a MERS Loan other than a MOM
Loan, from the originator to MERS); or



(2)        (x) a copy (which may be in electronic form) of the Mortgage (which Mortgage,
in the case of a MOM Loan, shall set forth the MIN and shall indicate that the Mortgage Loan is a MOM Loan) which represents a true
and correct reproduction of the original Mortgage and which has either been certified (i) on the face thereof by the public
recording office in the appropriate jurisdiction in which the Mortgaged Property is located, or (ii) by the originator, the related
Lender or the escrow or title company which provided closing services in connection with such Mortgage Loan as a true and correct
copy the original of which has been sent for recordation, (y) unless the Mortgage Loan is a MERS Loan, an original Mortgage
assignment thereof duly executed and acknowledged in recordable form (A) in blank or (B) to “LaSalle Bank National
Association, as Trustee,” or to “WaMu Mortgage Pass-Through Certificates Series 2005-AR3 Trust” and (z) unless
the Mortgage Loan is a MOM Loan, true and correct copies, certified by the applicable county recorder or by the originator or
Lender as described above, of all intervening assignments evidencing a complete chain of assignment from the originator to the name
holder or the payee endorsing the related Mortgage Note (or, in the case of a MERS Loan other than a MOM Loan, from the originator
to MERS);



provided, however, that in the event the Company acquired the Mortgage Loan from an
affiliate of the Company, then the Mortgage File need not include a Mortgage assignment executed in blank or to LaSalle Bank
National Association or the Trust as provided in clause (X)(iii)(1)(y) or (X)(iii)(2)(y) above, as applicable (but the Mortgage
File shall, unless the Mortgage Loan was originated by such affiliate of the Company, include an intervening Mortgage assignment to
such affiliate as provided in clause (X)(iii)(1)(z) or (X)(iii)(2)(z) above, as applicable); and


(iv)       For any
Mortgage Loan that has been modified or amended, the original instrument or instruments effecting such modification or
amendment;


and (Y) with respect to each Cooperative Loan:


(i)        
the original Mortgage Note endorsed (A) in blank, without recourse, or (B) to “LaSalle Bank National Association, as Trustee,
without recourse” or to “WaMu Mortgage Pass-Through Certificates Series 2005-AR3 Trust, without recourse” and all
intervening endorsements evidencing a complete chain of endorsements, from the originator to the Trustee or the Trust, as
applicable, or, in the event of any Destroyed Mortgage Note, a copy or a duplicate original of the Mortgage Note (or portion
thereof, as applicable), together with an original lost note affidavit from the originator of the Cooperative Loan or the Company
(or any affiliate of the Company from which the Company acquired the Mortgage Loan), as applicable, stating that the original
Mortgage Note (or portion thereof, as applicable) was lost, misplaced or destroyed, together with a copy of the Mortgage Note (or
portion thereof, as applicable); provided, however, that in the event the Company acquired the Cooperative Loan from an
affiliate of the Company, then the Mortgage Note need not be endorsed in blank or to LaSalle Bank National Association or the Trust
as provided above (but, if not so endorsed, shall be made payable to, or endorsed by the originator or successor lender named
therein to, such affiliate of the Company);


(ii)        A
counterpart of the Cooperative Lease and the Assignment of Proprietary Lease to the originator of the Cooperative
Loan;


(iii)       The related
Cooperative Stock Certificate, representing the related Cooperative Stock pledged with respect to such Cooperative Loan, together
with an undated stock power (or other similar instrument) executed in blank;


(iv)       The
Recognition Agreement;


(v)        The
Security Agreement;


(vi)       Copies of
the original UCC financing statement, and any continuation statements, filed by the originator of such Cooperative Loan as secured
party, each with evidence of recording thereof, evidencing the interest of the originator under the Security Agreement and the
Assignment of Proprietary Lease;


(vii)      Copies of the
filed UCC assignments or amendments of the security interest referenced in clause (vi) above showing an unbroken chain of title
from the originator to the Trust, each with evidence of recording thereof, evidencing the interest of the assignee under the
Security Agreement and the Assignment of Proprietary Lease;


(viii)      An executed
assignment of the interest of the originator in the Security Agreement, the Assignment of Proprietary Lease and the Recognition
Agreement, showing an unbroken chain of title from the originator to the Trust; and


(ix)       For any
Cooperative Loan that has been modified or amended, the original instrument or instruments effecting such modification or
amendment;


provided, however, that in the event the Company
acquired the Cooperative Loan from an affiliate of the Company, then the Mortgage File need not include (1) a UCC assignment or
amendment of the security interest referenced in clause (Y)(vi) above to the Trust as provided in clause (Y)(vii) above (but the
Mortgage File shall, unless the Cooperative Loan was originated by such affiliate of the Company, include a UCC assignment or
amendment of such security interest to such affiliate) or (2) an assignment of the interest of the originator in the Security
Agreement, the Assignment of Proprietary Lease and the Recognition Agreement to the Trust as provided in clause (Y)(viii) above
(but the Mortgage File shall, unless the Cooperative Loan was originated by such affiliate of the Company, include an assignment of
such interest to such affiliate).


Mortgage Interest Rate:  For any
Mortgage Loan, the per annum rate at which interest accrues on such Mortgage Loan pursuant to the terms of the related Mortgage
Note.


Mortgage Loan Schedule:  The schedule,
as amended from time to time, of Mortgage Loans attached hereto as Exhibit D, which shall set forth as to each Mortgage Loan the
following, among other things:


(i)        
its loan number,


(ii)        the
address of the Mortgaged Property,


(iii)       the name of
the Mortgagor,


(iv)       the Original
Value of the property subject to the Mortgage,


(v)        the
Principal Balance as of the Cut-Off Date,


(vi)       the Mortgage
Interest Rate, as of the Cut-Off Date, borne by the Mortgage Note and the Rate Ceiling, Rate Floor, subsequent Periodic Cap, Index
and Margin, as applicable, borne by the Mortgage Note,


(vii)      whether a Primary
Insurance Policy is in effect as of the Cut-Off Date, and, if so, whether such Primary Insurance Policy is a Special Primary
Insurance Policy,


(viii)      the maturity of
the Mortgage Note,


(ix)       the Master
Servicing Fee Rate and the Servicing Fee Rate, and



(x)       
whether it imposes penalties for early prepayments.


Mortgage Loans:  The mortgage loans
and cooperative loans (if any) listed on the Mortgage Loan Schedule and transferred and assigned to the Trust pursuant hereto. With
respect to each Mortgage Loan that is a Cooperative Loan, “Mortgage Loan” shall include, but not be limited to, the
Mortgage Note, Security Agreement, Assignment of Proprietary Lease, Recognition Agreement, Cooperative Stock Certificate and
Cooperative Lease, and, with respect to each Mortgage Loan other than a Cooperative Loan, “Mortgage Loan” shall
include, but not be limited to the Mortgage Note and the related Mortgage.


Mortgage Note:  The note or other
evidence of the indebtedness of a Mortgagor under a Mortgage Loan.


Mortgage Pool:  All of the Mortgage
Loans.


Mortgage Pool Assets:  (i) The
Mortgage Loans (including all Substitute Mortgage Loans) identified on the Mortgage Loan Schedule, and all rights pertaining
thereto, including the related Mortgage Notes, Mortgages, Cooperative Stock Certificates, Cooperative Leases, Security Agreements,
Assignments of Proprietary Lease, and Recognition Agreements, and all payments and distributions with respect to the Mortgage Loans
payable on and after the Cut-Off Date; (ii) the Certificate Account, the Investment Account, and all money, instruments,
investment property, and other property credited thereto, carried therein, or deposited therein (except amounts constituting the
Master Servicing Fee or the Servicing Fee); (iii) the Custodial Accounts for P&I, the Custodial Accounts for Reserves, any
Buydown Fund Account (to the extent of the amounts on deposit or other property therein attributable to the Mortgage Loans), and
all money, instruments, investment property, and other property credited thereto, carried therein, or deposited therein (except
amounts constituting the Master Servicing Fee or the Servicing Fee); (iv) all property that secured a Mortgage Loan and that has
been acquired by foreclosure or deed in lieu of foreclosure or, in the case of a Cooperative Loan, a similar form of conversion,
after the Cut-Off Date; and (v) each FHA insurance policy, Primary Insurance Policy, VA guaranty, and other insurance policy
related to any Mortgage Loan, and all amounts paid or payable thereunder and all proceeds thereof.


Mortgaged Property:  With respect to
any Mortgage Loan, other than a Cooperative Loan, the real property, together with improvements thereto, and, with respect to any
Cooperative Loan, the related Cooperative Stock and Cooperative Lease, securing the indebtedness of the Mortgagor under the related
Mortgage Loan.  “Mortgaged Property” shall also refer to property which once secured the indebtedness of a
Mortgagor under the related Mortgage Loan but which was acquired by the Trust upon foreclosure or other liquidation of such
Mortgage Loan.


Mortgagor:  The obligor on a Mortgage
Note.


Nonrecoverable Advance:  With respect
to any Mortgage Loan, any advance which the Master Servicer shall determine to be a Nonrecoverable Advance pursuant to Section 4.03
and which was, or is proposed to be, made by (i) the Master Servicer or (ii) a Servicer pursuant to its Selling and Servicing
Contract.


Non-U.S. Person:  A Person that is not
a U.S. Person.


Notice Addresses:  (a) In the case of
the Company, 75 North Fairway Drive, Vernon Hills, Illinois 60061, Attention: Master Servicing Department, with a copy to:
Washington Mutual Legal Department, 1201 Third Avenue, WMT 1706, Seattle, Washington 98101, Attention: WMMSC, or such other address
as may hereafter be furnished to the Trustee in writing by the Company, (b) in the case of the Trustee, at its Corporate Trust
Office, or such other address as may hereafter be furnished to the Master Servicer in writing by the Trustee, (c) in the case
of the Delaware Trustee, 1314 King Street, Wilmington, Delaware  19801, or such other address as may hereafter be furnished to
the Master Servicer in writing by the Delaware Trustee, (d) in the case of the Trust, c/o LaSalle Bank National Association,
at the Corporate Trust Office, or such other address as may hereafter be furnished to the Master Servicer in writing by the
Trustee, (e) in the case of the Certificate Registrar, at its Corporate Trust Office, or such other address as may hereafter be
furnished to the Trustee in writing by the Certificate Registrar, (f) in the case of S&P, 55 Water Street, 41st Floor, New
York, New York 10041-0003, Attention:  Frank Raiter, or such other address as may hereafter be furnished to the Trustee and
Master Servicer in writing by S&P and (g) in the case of Moody’s, 99 Church Street, New York, New York 10007,
Attention:  Monitoring, or such other address as may hereafter be furnished to the Trustee and Master Servicer in writing by
Moody’s.


OTS:  The Office of Thrift
Supervision, or any successor thereto.


Officer’s Certificate:  A
certificate signed by the Chairman of the Board, the President, a Vice President, or the Treasurer of the Master Servicer and
delivered to the Trustee or the Delaware Trustee, as applicable.


One-Year CMT:  The weekly average
yield on United States Treasury Securities adjusted to a constant maturity of one year, as made available by the Federal Reserve
Board, published in Federal Reserve Statistical Release H.15(519) most recently available as of 45 days before the applicable
Adjustment Date.


One-Year LIBOR: The average of interbank
offered rates for one-year U.S. dollar-denominated deposits in the London market, as published in The Wall Street Journal
and most recently available as of the date 45 days before the applicable Adjustment Date.


Opinion of Counsel:  A written opinion
of counsel, who shall be reasonably acceptable to the Trustee or the Delaware Trustee, as applicable, and who may be counsel
(including in-house counsel) for the Company or the Master Servicer.


Original Trust Agreement:  The Trust
Agreement, dated as of February 1, 2005, between the Company and the Delaware Trustee, providing for the creation of the Trust.


Original Value:  With respect to any
Mortgage Loan other than a Mortgage Loan originated for the purpose of refinancing an existing mortgage debt, the lesser of (a) the
Appraised Value (if any) of the Mortgaged Property at the time the Mortgage Loan was originated or (b) the purchase price paid for
the Mortgaged Property by the Mortgagor. With respect to a Mortgage Loan originated for the purpose of refinancing existing
mortgage debt, the Original Value shall be equal to the Appraised Value of the Mortgaged Property.


Ownership Interest:  With respect to
any Residual Certificate, any ownership or security interest in such Residual Certificate, including any interest in a Residual
Certificate as the Holder thereof and any other interest therein whether direct or indirect, legal or beneficial, as owner or as
pledgee.


Pass-Through Entity:  Any regulated
investment company, real estate investment trust, common trust fund, partnership, trust or estate, and any organization to which
Section 1381 of the Code applies.


Pass-Through Rate:  For each Mortgage
Loan, the Mortgage Interest Rate for such Mortgage Loan less (i) the Servicing Fee Rate for such Mortgage Loan, (ii) the Master
Servicing Fee Rate for such Mortgage Loan and (iii) if such Mortgage Loan was covered by a Special Primary Insurance Policy on the
Closing Date (even if no longer so covered), the per annum rate at which the applicable Special Primary Insurance Premium for such
Mortgage Loan is calculated. For each Mortgage Loan, any calculation of monthly interest at such rate shall be based upon annual
interest at such rate (computed on the basis of a 360-day year of twelve 30-day months) on the unpaid Principal Balance of such
Mortgage Loan divided by twelve, and any calculation of interest at such rate by reason of a Payoff shall be based upon annual
interest at such rate on the outstanding Principal Balance of such Mortgage Loan multiplied by a fraction, the numerator of which
is the number of days elapsed from the Due Date of the last scheduled payment of principal and interest to, but not including, the
date of such Payoff, and the denominator of which is (a) for Payoffs received on a Due Date, 360, and (b) for all other Payoffs,
365.


Paying Agent:  Any paying agent
appointed by the Trustee pursuant to Section 8.12.


Payoff:  Any Mortgagor payment of
principal on a Mortgage Loan equal to the entire outstanding Principal Balance of such Mortgage Loan, if received in advance of the
last scheduled Due Date for such Mortgage Loan and accompanied by an amount of interest equal to accrued unpaid interest on the
Mortgage Loan to the date of such payment-in-full.  (Prepayment penalties are not payments of principal and hence Payoffs do
not include prepayment penalties.)


Payoff Earnings:  For any Distribution
Date with respect to each Mortgage Loan on which a Payoff was received by the Master Servicer during the Payoff Period, the
aggregate of the interest earned by the Master Servicer from investment of each such Payoff from the date of receipt of such Payoff
until the Business Day immediately preceding the related Distribution Date (net of investment losses).


Payoff Interest:  For any Distribution
Date with respect to a Mortgage Loan for which a Payoff was received on or after the first calendar day of the month of such
Distribution Date and before the 15th calendar day of such month, an amount of interest thereon at the applicable Pass-Through Rate
from the first day of the month of distribution through the day of receipt thereof; to the extent (together with Payoff Earnings
and the aggregate Master Servicing Fee) not required to be distributed as Compensating Interest on such Distribution Date, Payoff
Interest shall be payable to the Master Servicer as additional servicing compensation.


Payoff Period:  For the first
Distribution Date, the period from the Cut-Off Date through March 14, 2005, inclusive; and for any Distribution Date
thereafter, the period from the 15th day of the Prior Period through the 14th day of the month of such Distribution Date,
inclusive.


Percentage Interest:  (a)  With
respect to the right of each Certificate of a particular Class in the distributions allocated to such Class, “Percentage
Interest” shall mean the percentage equal to:


(i)        
with respect to any Certificate (other than the Residual Certificates), its Certificate Principal Balance divided by the applicable
Class Principal Balance; and


(ii)        with
respect to any Residual Certificate, the percentage set forth on the face of such Certificate.


(b)        With respect to the
rights of each Certificate in connection with Sections 5.09, 7.01, 8.01(c), 8.02, 8.07, 10.01 and 10.03, “Percentage
Interest” shall mean the percentage equal to:


(i)        
with respect to any Certificate (other than the Residual Certificates), its Certificate Principal Balance divided by the Aggregate
Certificate Principal Balance of the Certificates; and


(ii)        with
respect to any Residual Certificate, zero.


Periodic Cap: 
For each Mortgage Loan, any applicable limit on adjustment of the Mortgage Interest Rate for each Adjustment Date specified in the
applicable Mortgage Note and designated as such in the Mortgage Loan Schedule.


Permitted Transferee:  With respect to
the holding or ownership of any Residual Certificate, any Person other than (i) the United States, a State or any political
subdivision thereof, or any agency or instrumentality of any of the foregoing, (ii) a foreign government, International
Organization or any agency or instrumentality of either of the foregoing, (iii) an organization (except certain farmers’
cooperatives described in Code Section 521) which is exempt from the taxes imposed by Chapter 1 of the Code (unless such
organization is subject to the tax imposed by Section 511 of the Code on unrelated business taxable income), (iv) rural electric
and telephone cooperatives described in Code Section 1381(a)(2)(C), (v) any “electing large partnership” as defined in
Section 775(a) of the Code, (vi) any Person from whom the Trustee has not received an affidavit to the effect that it is not a
“disqualified organization” within the meaning of Section 860E(e)(5) of the Code, and (vii) any other Person so
designated by the Company based upon an Opinion of Counsel that the transfer of an Ownership Interest in a Residual Certificate to
such Person may cause REMIC I to fail to qualify as a REMIC at any time that the Certificates are outstanding. The terms
“United States,” “State” and “International Organization” shall have the meanings set forth in
Code Section 7701 or successor provisions. A corporation shall not be treated as an instrumentality of the United States or of any
State or political subdivision thereof if all of its activities are subject to tax, and, with the exception of the Freddie Mac, a
majority of its board of directors is not selected by such governmental unit.


Person:  Any individual, corporation,
limited liability company, partnership, joint venture, association, joint-stock company, trust, unincorporated organization or
government or any agency or political subdivision thereof.


Prepaid Monthly Payment:  Any Monthly
Payment received prior to its scheduled Due Date, which is intended to be applied to a Mortgage Loan on its scheduled Due Date and
held in the related Custodial Account for P&I until the Withdrawal Date following its scheduled Due Date.


Primary Insurance Policy:  A policy of
mortgage guaranty insurance, if any, on an individual Mortgage Loan or on pools of mortgage loans that include an individual
Mortgage Loan, providing coverage as required by Section 2.08(xi) (including any Special Primary Insurance Policy).


Principal Balance:  Except as used in
Sections 2.07, 3.09 and 9.01 and for purposes of the definition of Purchase Price, at the time of any determination, the principal
balance of a Mortgage Loan remaining to be paid at the close of business on the Cut‐Off Date, after application of all
scheduled principal payments due on or before the Cut‐Off Date, whether or not received, reduced by all amounts distributed
or (except when such determination occurs earlier in the month than the Distribution Date) to be distributed to Certificateholders
through the Distribution Date in the month of determination that are reported as allocable to principal of such Mortgage Loan.


For purposes of the definition of Purchase Price and as used in
Sections 2.07, 3.09 and 9.01, at the time of any determination, the principal balance of a Mortgage Loan remaining to be paid at
the close of business on the Cut-Off Date, after deduction of all scheduled principal payments due on or before the Cut-Off Date,
whether or not received, reduced by all amounts distributed or to be distributed to Certificateholders through the Distribution
Date in the month of determination that are reported as allocable to principal of such Mortgage Loan.


In the case of a Substitute Mortgage Loan, “Principal
Balance” shall mean, at the time of any determination, the principal balance of such Substitute Mortgage Loan transferred to
the Trust, on the date of substitution, reduced by all amounts distributed or to be distributed to Certificateholders through the
Distribution Date in the month of determination that are reported as allocable to principal of such Substitute Mortgage
Loan.


The Principal Balance of a Mortgage Loan (including a Substitute
Mortgage Loan) shall not be adjusted solely by reason of any bankruptcy or similar proceeding or any moratorium or similar waiver
or grace period. Whenever a Realized Loss has been incurred with respect to a Mortgage Loan during a calendar month, the Principal
Balance of such Mortgage Loan shall be reduced by the amount of such Realized Loss as of the Due Date next following the end of
such calendar month.


Principal Payment:  Any payment of
principal on a Mortgage Loan other than a Principal Prepayment.


Principal Payment Amount:  For any
Distribution Date, the sum of (i) the scheduled principal payments (if any) on the Mortgage Loans due on the related Due Date, (ii)
the principal portion of proceeds received with respect to any Mortgage Loan which was purchased or repurchased pursuant to a
Purchase Obligation or as permitted by this Agreement during the Prior Period and (iii) any other unscheduled payments of principal
which were received with respect to any Mortgage Loan during the Prior Period, other than Payoffs, Curtailments, Liquidation
Principal and Subsequent Recoveries.


Principal Prepayment:  Any payment of
principal on a Mortgage Loan which constitutes a Payoff or a Curtailment.


Principal Prepayment Amount:  For any
Distribution Date, the sum of (i) Curtailments received during the Prior Period from the Mortgage Loans and (ii) Payoffs received
during the Payoff Period from the Mortgage Loans.


Prior Period:  With respect to any
Distribution Date, the calendar month immediately preceding such Distribution Date.


Prospectus:   The Prospectus,
dated February 10, 2004, and the Prospectus Supplement, dated February 18, 2005, of the Company.


Purchase Obligation:  An obligation of
the Company to repurchase Mortgage Loans under the circumstances and in the manner provided in Section 2.07 or Section 2.08.


Purchase Price:  With respect to any
Mortgage Loan to be purchased pursuant to a Purchase Obligation or pursuant to Section 3.01, an amount equal to the sum of (i) the
Principal Balance thereof, (ii) unpaid accrued interest thereon, if any, during the calendar month in which the date of purchase
occurs to the last day of such month at a rate equal to the applicable Pass-Through Rate and (iii) with respect to any Mortgage
Loan to be purchased pursuant to Section 2.08, any costs and damages incurred by the Trust in connection with any violation by such
Mortgage Loan of any predatory and abusive lending laws, to the extent such costs and damages result from a breach of the
representation and warranty made by the Company pursuant to clause (viii) of Section 2.08; provided, however, that to the extent
that such costs and damages constitute a set-off against the principal balance of the Mortgage Loan, such costs and damages will
not be paid pursuant to this clause (iii), and the amount paid pursuant to clause (i) above will be calculated without regard to
such set-off; provided, further, that no Mortgage Loan shall be purchased or required to be purchased pursuant to Section 2.08, or
more than two years after the Closing Date under Section 2.07, unless (a) the Mortgage Loan to be purchased is in default, or
default is in the judgment of the Company reasonably imminent, or (b) the Company, at its expense, delivers to the Trustee an
Opinion of Counsel addressed to the Trust and the Trustee to the effect that the purchase of such Mortgage Loan will not give rise
to a tax on a prohibited transaction, as defined in Section 860F(a) of the Code.


Qualified Insurer:  A mortgage
guaranty insurance company duly qualified as such under the laws of the states in which the Mortgaged Properties are located if
such qualification is necessary to issue the applicable insurance policy or bond, duly authorized and licensed in such states to
transact the applicable insurance business and to write the insurance provided by the Primary Insurance Policies and approved as an
insurer by the Master Servicer. A Qualified Insurer must have the rating required by the Rating Agencies.


Rate Ceiling:  The maximum per annum
Mortgage Interest Rate permitted under the related Mortgage Note.


Rate Floor:  The minimum per annum
Mortgage Interest Rate permitted under the related Mortgage Note.


Rating Agency:  Initially, each of
S&P and Fitch and thereafter, each nationally recognized statistical rating organization that has rated the Certificates at the
request of the Company, or their respective successors in interest.


Ratings:  As of any date of
determination, the ratings, if any, of the Certificates as assigned by the applicable Rating Agencies.


Realized Loss:  For any Distribution
Date, with respect to any Mortgage Loan which became a Liquidated Mortgage Loan during the related Prior Period, the sum of (i) the
principal balance of such Mortgage Loan remaining outstanding and the principal portion of Nonrecoverable Advances actually
reimbursed with respect to such Mortgage Loan (the principal portion of such Realized Loss), and (ii) the accrued interest on such
Mortgage Loan remaining unpaid and the interest portion of Nonrecoverable Advances actually reimbursed with respect to such
Mortgage Loan (the interest portion of such Realized Loss); provided, however, that for purposes of allocating
Realized Losses to the Certificates pursuant to this definition of “Realized Loss,” the aggregate principal portion of
Realized Losses for any Distribution Date shall be reduced by the Cumulative Carry-Forward Subsequent Recoveries Amount for such
Distribution Date. For any Distribution Date, with respect to any Mortgage Loan which is not a Liquidated Mortgage Loan, the amount
of the Bankruptcy Loss incurred with respect to such Mortgage Loan as of the related Due Date.


Realized Losses shall be allocated among the Certificates (i) for
Realized Losses allocable to principal (a) first, to the Class B-6 Certificates, until the Class B-6 Principal Balance has been
reduced to zero, (b) second, to the Class B-5 Certificates, until the Class B-5 Principal Balance has been reduced to zero, (c)
third, to the Class B-4 Certificates, until the Class B-4 Principal Balance has been reduced to zero, (d) fourth, to the Class B-3
Certificates, until the Class B-3 Principal Balance has been reduced to zero, (e) fifth, to the Class B-2 Certificates, until the
Class B-2 Principal Balance has been reduced to zero, (f) sixth, to the Class B-1 Certificates, until the Class B-1 Principal
Balance has been reduced to zero, (g) seventh, to the Class A Certificates, pro rata, in reduction of the Class Principal Balances
of the Class A Certificates; and (ii) for Realized Losses allocable to interest (a) first, to the Class B-6 Certificates, in
reduction of accrued but unpaid interest thereon and then in reduction of the Class B-6 Principal Balance, (b) second, to the Class
B-5 Certificates, in reduction of accrued but unpaid interest thereon and then in reduction of the Class B-5 Principal Balance, (c)
third, to the Class B-4 Certificates, in reduction of accrued but unpaid interest thereon and then in reduction of the Class B-4
Principal Balance, (d) fourth, to the Class B-3 Certificates, in reduction of accrued but unpaid interest thereon and then in
reduction of the Class B-3 Principal Balance, (e) fifth, to the Class B-2 Certificates, in reduction of accrued but unpaid interest
thereon and then in reduction of the Class B-2 Principal Balance, (f) sixth, to the Class B-1 Certificates, in reduction of accrued
but unpaid interest thereon and then in reduction of the Class B-1 Principal Balance, (g) seventh, to the Class A Certificates, pro
rata according to accrued but unpaid interest on such Classes, in reduction thereof, and then to such Classes , pro rata according
to Class Principal Balance thereof, in reduction thereof.; provided, however, until the Class A-3 Principal Balance has been
reduced to zero, all principal losses that would otherwise be allocated to the Class A-2 Certificates pursuant to clause (i)
of this paragraph shall instead be allocated to the Class A-3 Certificates, in reduction of the Class A-3 Principal Balance,
and all interest losses that would otherwise be allocated to the Class A-2 Certificates pursuant to clause (ii) of this
paragraph shall instead be allocated to the Class A-3 Certificates, in reduction of accrued but unpaid interest thereon, and then
in reduction of the Class A-3 Principal Balance.


On each Distribution Date, after giving effect to the principal
distributions and allocations of losses as provided in this Agreement (without regard to this paragraph), if the aggregate Class
Principal Balance of all outstanding Classes of Certificates (plus any Cumulative Carry-Forward Subsequent Recoveries Amount for
such Distribution Date) exceeds the aggregate principal balance of the Mortgage Loans remaining to be paid at the close of business
on the Cut-Off Date, after deduction of (i) all principal payments due on or before the Cut-Off Date in respect of each Mortgage
Loan whether or not paid, and (ii) all amounts of principal in respect of each Mortgage Loan that have been received or advanced
and included in the Available Distribution Amount and all losses in respect of each Mortgage Loan that have been allocated to the
Certificates on such Distribution Date or prior Distribution Dates then such excess will be deemed a principal loss and will be
allocated to the most junior Class of Class B Certificates, in reduction of the Class Principal Balance thereof.


Recognition Agreement:  With respect
to a Cooperative Loan, the recognition agreement between the Cooperative and the originator of such Cooperative Loan.


Record Date:  The last Business Day of
the month immediately preceding the month of the related Distribution Date.


Relief Act Shortfall:  For any
Distribution Date for any Mortgage Loan with respect to which the Servicemembers Civil Relief Act, formerly known as the
Soldiers’ and Sailors’ Civil Relief Act of 1940, or any comparable state legislation (collectively, the
“Relief Act”), limits the amount of interest payable by the related Mortgagor, an amount equal to one
month’s interest on such Mortgage Loan at an annual interest rate equal to the excess, if any, of (i) the annual interest
rate otherwise payable by the Mortgagor on the related Due Date under the terms of the related Mortgage Note over (ii) the annual
interest rate payable by the Mortgagor on the related Due Date by application of the Relief Act.


REMIC:  A real estate mortgage
investment conduit, as such term is defined in the Code.


REMIC Provisions:  Sections 860A
through 860G of the Code, related Code provisions and regulations promulgated thereunder, as the foregoing may be in effect from
time to time.


REMIC I:  The segregated pool of
assets of the Trust consisting of the REMIC I Assets, which shall be a REMIC pursuant to the Code, with respect to which a separate
REMIC election is to be made and the beneficial interests in which shall be the Certificates.


REMIC I Assets:  All of the Mortgage
Pool Assets.


REMIC I Regular Interests: The Certificates
(other than the Class R Certificates).


Residual Certificates:  The Class R
Certificates.


Residual Distribution Amount:  For any
Distribution Date, any portion of the Available Distribution Amount remaining after all distributions of the Available Distribution
Amount pursuant to the definition of “Distribution Amount” (other than the distributions pursuant to the last subclause
thereof).


Upon termination of the obligations created by this Agreement and
liquidation of REMIC I, the amounts which remain on deposit in the Certificate Account after payment to the Holders of the
Certificates of the amounts set forth in Section 9.01 of this Agreement, and subject to the conditions set forth therein, shall be
distributed to the Class R Certificates in accordance with the preceding sentences of this definition as if the date of such
distribution were a Distribution Date.


Responsible Officer:  When used with
respect to the Trustee or the Delaware Trustee, any officer assigned to and working in the Corporate Trust Office (in the case of
the Trustee) or its corporate trust office (in the case of the Delaware Trustee) or, in each case, in a similar group and also,
with respect to a particular matter, any other officer to whom such matter is referred because of such officer’s knowledge of
and familiarity with the particular subject.


ROV Mortgage Loan:  A Mortgage Loan
with respect to which the value set forth on the appraisal has been appealed and, as a result, an internal valuation has been
conducted and included in a residential appraisal review contained in the related credit file.


S&P:  Standard & Poor’s
Ratings Services, a division of The McGraw-Hill Companies, Inc., provided that at any time it be a Rating Agency.


Secretary of State:  The Secretary of
State of the State of Delaware.


Securities Act:  The Securities Act of
1933, as amended.


Security Agreement:  With respect to a
Cooperative Loan, the agreement or mortgage creating a security interest in favor of the originator of the Cooperative Loan in the
related Cooperative Stock.


Selling and Servicing Contract:  (a)
The contract (including the Washington Mutual Mortgage Securities Corp. Selling Guide and Washington Mutual Mortgage Securities
Corp. Servicing Guide to the extent incorporated by reference therein) between the Company and a Person relating to the sale of the
Mortgage Loans to the Company and the servicing of such Mortgage Loans for the benefit of the Certificateholders, which contract is
substantially in the form of Exhibit E hereto, as such contract may be amended or modified from time to time; provided, however,
that any such amendment or modification shall not materially adversely affect the interests and rights of Certificateholders or (b)
any other similar contract, including any mortgage loan purchase and servicing agreement or any assignment, assumption and
recognition agreement related to a mortgage loan purchase and sale agreement, providing substantially similar rights and benefits
as those provided by the forms of contract attached as Exhibit E hereto.


Senior Certificates:  The Class A and
Class R Certificates.


Senior Liquidation Amount:  For any
Distribution Date, the sum of (A) the aggregate, for each Mortgage Loan which became a Liquidated Mortgage Loan during the Prior
Period, of the lesser of: (i) the Senior Percentage of the Principal Balance of such Mortgage Loan and (ii) the Senior Prepayment
Percentage of the Liquidation Principal with respect to such Mortgage Loan and (B) the Senior Prepayment Percentage of any
Subsequent Recoveries for such Distribution Date.


Senior Percentage:  For any
Distribution Date, the aggregate Class Principal Balance of the Class A and Residual Certificates divided by the aggregate Class
Principal Balance of the Class A, Class B and Residual Certificates, in each case immediately before such Distribution Date.


Senior Prepayment Percentage:  Subject
to the immediately succeeding paragraph, (A) for any Distribution Date prior to the seventh anniversary of the first Distribution
Date, the Senior Prepayment Percentage shall equal 100% and (B) for any Distribution Date on or after the seventh anniversary of
the first Distribution Date, the Senior Prepayment Percentage shall be calculated as follows: (1) for any such Distribution Date on
or after the seventh anniversary but before the eighth anniversary of the first Distribution Date, the Senior Percentage for such
Distribution Date plus 70% of the Subordinate Percentage for such Distribution Date; (2) for any such Distribution Date on or after
the eighth anniversary but before the ninth anniversary of the first Distribution Date, the Senior Percentage for such Distribution
Date plus 60% of the Subordinate Percentage for such Distribution Date; (3) for any such Distribution Date on or after the ninth
anniversary but before the tenth anniversary of the first Distribution Date, the Senior Percentage for such Distribution Date plus
40% of the Subordinate Percentage for such Distribution Date; (4) for any such Distribution Date on or after the tenth anniversary
but before the eleventh anniversary of the first Distribution Date, the Senior Percentage for such Distribution Date plus 20% of
the Subordinate Percentage for such Distribution Date; and (5) for any such Distribution Date thereafter, the Senior Percentage for
such Distribution Date; provided, however, that (x) for any Distribution Date on or prior to the Distribution Date in
February 2008, if (i) the Subordinate Percentage for such Distribution Date is greater than or equal to twice the Subordinate
Percentage as of the Closing Date and (ii) cumulative Realized Losses on the Mortgage Loans allocated to the Class B Certificates,
as a percentage of the aggregate Class Principal Balance of the Class B Certificates as of the Closing Date, do not exceed 20%,
then the Senior Prepayment Percentage shall equal the Senior Percentage for such Distribution Date plus 50% of the Subordinate
Percentage for such Distribution Date and (y) for any Distribution Date after the Distribution Date in February 2008, if (i)
the Subordinate Percentage for such Distribution Date is greater than or equal to twice the Subordinate Percentage as of the
Closing Date and (ii) cumulative Realized Losses on the Mortgage Loans allocated to the Class B Certificates, as a percentage of
the aggregate Class Principal Balance of the Class B Certificates as of the Closing Date, do not exceed 30%, then the Senior
Prepayment Percentage shall equal the Senior Percentage for such Distribution Date.


Notwithstanding the immediately preceding paragraph, (A) for any
Distribution Date, if the Senior Percentage for such Distribution Date is greater than the Senior Percentage as of the Closing
Date, then the Senior Prepayment Percentage shall equal 100%, (B) for any Distribution Date on or before the seventh anniversary of
the first Distribution Date, if any of the tests specified in clauses (a) and (b) below is met, then the Senior Prepayment
Percentage shall equal 100% and (C) for any Distribution Date after the seventh anniversary of the first Distribution Date, if any
of the tests specified in clauses (a) and (b) below is met (unless either (x) the Senior Percentage for such Distribution Date is
greater than the Senior Percentage as of the Closing Date or (y) there is no Earlier Distribution Date (as defined below), in each
of which case the Senior Prepayment Percentage shall equal 100%), then the Senior Prepayment Percentage shall be calculated as
follows:  (1) if the most recent preceding Distribution Date on which none of the tests specified in clauses (a) and (b) below
was met (such date referred to as the “Earlier Distribution Date”) is on or after the seventh anniversary but
before the eighth anniversary of the first Distribution Date, then the Senior Prepayment Percentage shall equal the Senior
Percentage for the current Distribution Date plus 70% of the Subordinate Percentage for the current Distribution Date, (2) if the
Earlier Distribution Date is on or after the eighth anniversary but before the ninth anniversary of the first Distribution Date,
then the Senior Prepayment Percentage shall equal the Senior Percentage for the current Distribution Date plus 60% of the
Subordinate Percentage for the current Distribution Date, (3) if the Earlier Distribution Date is on or after the ninth anniversary
but before the tenth anniversary of the first Distribution Date, then the Senior Prepayment Percentage shall equal the Senior
Percentage for the current Distribution Date plus 40% of the Subordinate Percentage for the current Distribution Date, (4) if the
Earlier Distribution Date is on or after the tenth anniversary but before the eleventh anniversary of the first Distribution Date,
then the Senior Prepayment Percentage shall equal the Senior Percentage for the current Distribution Date plus 20% of the
Subordinate Percentage for the current Distribution Date, and (5) if the Earlier Distribution Date is on or after the eleventh
anniversary of the first Distribution Date, then the Senior Prepayment Percentage shall equal the Senior Percentage for the current
Distribution Date:



(a)        the mean aggregate Principal Balance, as of the Distribution Date in each of
the immediately preceding six calendar months, of the Mortgage Loans which were 60 or more days delinquent as of such date
(including Mortgage Loans in bankruptcy or foreclosure and Mortgaged Properties held by REMIC I) is greater than 50% of the
aggregate Class Principal Balance of the Class B Certificates as of the current Distribution Date, or



(b)        cumulative Realized Losses on the Mortgage Loans allocated to the Class B
Certificates, as a percentage of the aggregate Class Principal Balance of the Class B Certificates as of the Closing Date, are
greater than, for any Distribution Date (1) before the eighth anniversary of the first Distribution Date, 30%, (2) on or after the
eighth anniversary but before the ninth anniversary of the first Distribution Date, 35%, (3) on or after the ninth anniversary but
before the tenth anniversary of the first Distribution Date, 40%, (4) on or after the tenth anniversary but before the eleventh
anniversary of the first Distribution Date, 45%, and (5) on or after the eleventh anniversary of the first Distribution Date,
50%.


If on any Distribution Date the allocation to the Class A Certificates
of Principal Prepayments in the percentage required would reduce the aggregate Class Principal Balance of such Certificates below
zero, the Senior Prepayment Percentage for such Distribution Date shall be limited to the percentage necessary to reduce such
aggregate Class Principal Balance to zero.


Senior Principal Distribution Amount: 
For any Distribution Date, an amount equal to the sum of (a) the Senior Percentage of the Principal Payment Amount, (b) the Senior
Prepayment Percentage of the Principal Prepayment Amount and (c) the Senior Liquidation Amount.


Senior Subordinate Certificates:  The
Subordinate Certificates other than the Junior Subordinate Certificates.


Servicer:  A mortgage loan servicing
institution to which the Master Servicer has assigned servicing duties with respect to any Mortgage Loan under a Selling and
Servicing Contract; provided, however, the Master Servicer may designate itself or one or more other mortgage loan servicing
institutions as Servicer upon termination of an initial Servicer’s servicing duties.


Servicing Fee:  For each Mortgage
Loan, the monthly fee paid to the Servicer to perform primary servicing functions for the Master Servicer with respect to such
Mortgage Loan, equal to 1/12 of the product of (i) the Servicing Fee Rate for such Mortgage Loan and (ii) the outstanding Principal
Balance of such Mortgage Loan.  In addition, any prepayment penalty received on a Mortgage Loan will be paid as additional
servicing compensation to the Master Servicer or the related Servicer.


Servicing Fee Rate:  For each Mortgage
Loan, the per annum rate payable to the Servicer, as set forth for such Mortgage Loan in the Mortgage Loan Schedule, equal to
0.375%.


Servicing Officer:  Any officer of the
Master Servicer (or of the Servicer, but only with respect to the Custodial Agreement) involved in, or responsible for, the
administration and servicing of the Mortgage Loans or the Certificates, as applicable, whose name and specimen signature appear on
a list of servicing officers furnished to the Trustee by the Master Servicer, as such list may from time to time be amended.


Special Primary Insurance Policy:  Any
Primary Insurance Policy covering a Mortgage Loan the premium of which is payable by the Trustee pursuant to Section 4.01(a), if so
identified in the Mortgage Loan Schedule. There are no Special Primary Insurance Policies with respect to any of the Mortgage
Loans.


Special Primary Insurance Premium: 
With respect to any Special Primary Insurance Policy, the monthly premium payable thereunder.


Statutory Trust Statute:  Chapter 38
of Title 12 of the Delaware Code, 12 Del.C. §3801 et seq., as the same may be amended from time to time.


Streamlined Mortgage Loan:  A Mortgage
Loan originated in connection with the refinance of a mortgage loan pursuant to the related seller’s, under the related
Selling and Servicing Contract by which the Company acquired the Mortgage Loan, streamlined loan documentation program then in
effect.


Subordinate Certificates:  The Class B
Certificates.


Subordinate Liquidation Amount:  For
any Distribution Date, the excess, if any, of the sum of (A) the aggregate of Liquidation Principal for all Mortgage Loans which
became Liquidated Mortgage Loans during the Prior Period and (B) any Subsequent Recoveries for such Distribution Date, over the
Senior Liquidation Amount for such Distribution Date.


Subordinate Percentage:  For any
Distribution Date, the excess of 100% over the Senior Percentage for such date.


Subordinate Prepayment Percentage: 
For any Distribution Date, the excess of 100% over the Senior Prepayment Percentage for such Distribution Date; provided,
however, that if the aggregate Class Principal Balance of the Class A and Residual Certificates has been reduced to zero, then
the Subordinate Prepayment Percentage shall equal 100%.


Subordinate Principal Distribution
Amount:  For any Distribution Date, the sum of (i) the Subordinate Percentage of the Principal Payment Amount, (ii)
the Subordinate Principal Prepayments Distribution Amount and (iii) the Subordinate Liquidation Amount.


For any Distribution Date, the Subordinate Principal Distribution
Amount shall be allocated pro rata, by Class Principal Balance, among the Classes of Class B Certificates and paid in the order of
distribution to such Classes pursuant to the definition of “Distribution Amount” except as otherwise stated in such
definition. Notwithstanding the foregoing, for any Distribution Date prior to distributions on such date, if the Subordination
Level for any Class or Classes of Class B Certificates is less than such Subordination Level as of the Closing Date, then the pro
rata portion of the Subordinate Principal Prepayments Distribution Amount, if any, otherwise allocable to such Class or Classes of
Class B Certificates shall be allocated to the more senior Classes of Class B Certificates, pro rata according to the Class
Principal Balances of such Classes. For purposes of this definition and the definition of “Subordination Level,” the
relative seniority, from highest to lowest, of the Class B Certificates shall be as follows: Class B-1, Class B-2, Class B-3, Class
B-4, Class B-5 and Class B-6.


Subordinate Principal Prepayments Distribution
Amount:  For any Distribution Date, the Subordinate Prepayment Percentage of the Principal Prepayment Amount.


Subordination Level:  On any specified
date, with respect to any Class of Class B Certificates, the percentage obtained by dividing the aggregate Class Principal Balance
of such Class and the Classes of Class B Certificates which are subordinate in right of payment to such Class by the aggregate
Class Principal Balance of the Certificates as of such date prior to giving effect to distributions of principal and interest and
allocations of Realized Losses on the Mortgage Loans on such date.


Subsequent Recoveries: For any Distribution Date, amounts received by the Master Servicer during the Prior
Period (after deduction of amounts reimbursable under Section 3.05(a)(i) and (ii)) in connection with the liquidation of defaulted
Mortgage Loans after such Mortgage Loans became Liquidated Mortgage Loans, for each such Mortgage Loan up to the amount of Realized
Losses, if any, previously allocated in respect of such Mortgage Loan in reduction of the Class Principal Balance of any Class of
Certificates.


Substitute Mortgage Loan:  A Mortgage
Loan which is substituted for another Mortgage Loan pursuant to and in accordance with the provisions of Section 2.07.


Tax Matters Person:  A Holder of a
Class R Certificate with a Percentage Interest of at least 0.01% or any Permitted Transferee of such Class R Certificateholder
designated as succeeding to the position of Tax Matters Person in a notice to the Trustee signed by authorized representatives of
the transferor and transferee of such Class R Certificate. The Company is hereby appointed to act as the Tax Matters Person for
REMIC I so long as it holds a Class R Certificate with a Percentage Interest of at least 0.01%. The Company is hereby appointed to
act as agent for the Tax Matters Person for REMIC I, to perform the functions of such Tax Matters Person as provided herein, so
long as the Company is the Master Servicer hereunder, in the event that the Company ceases to hold a Class R Certificate with the
required Percentage Interest. In the event that the Company ceases to be the Master Servicer hereunder, the successor Master
Servicer is hereby appointed to act as agent for the Tax Matters Person for REMIC I, to perform the functions of such Tax Matters
Person as provided herein. If the Tax Matters Person for REMIC I becomes a Disqualified Organization, the last preceding Holder,
that is not a Disqualified Organization, of the Class R Certificate held by the Disqualified Organization shall be Tax Matters
Person pursuant to and as permitted by Section 5.01(c). If any Person is appointed as tax matters person by the Internal Revenue
Service pursuant to the Code, such Person shall be Tax Matters Person.


Termination Date:  The date upon which
final payment of the Certificates will be made pursuant to the procedures set forth in Section 9.01(b).


Termination Payment:  The final
payment delivered to the Certificateholders on the Termination Date pursuant to the procedures set forth in Section 9.01(b).


Transfer:  Any direct or indirect
transfer or sale of any Ownership Interest in a Residual Certificate.


Transferee:  Any Person who is
acquiring by Transfer any Ownership Interest in a Residual Certificate.


Transferee Affidavit and Agreement: 
An affidavit and agreement in the form attached hereto as Exhibit J.


Trust:  WaMu Mortgage Pass-Through
Certificates Series 2005-AR3 Trust, a Delaware statutory trust, created pursuant to this Agreement.


Trustee:  LaSalle Bank National
Association, or its successor-in-interest as provided in Section 8.09, or any successor trustee appointed as herein provided.


Uncollected Interest:  With respect to
any Distribution Date for any Mortgage Loan on which a Payoff was made by a Mortgagor during the related Payoff Period, except for
Payoffs received during the period from the first through the 14th day of the month of such Distribution Date, an amount equal to
one month’s interest at the applicable Pass-Through Rate on such Mortgage Loan less the amount of interest actually paid by
the Mortgagor with respect to such Payoff.


Uncompensated Interest Shortfall:  For
any Distribution Date, the sum of (i) the aggregate Relief Act Shortfall for such Distribution Date, (ii) aggregate Curtailment
Shortfall for such Distribution Date and (iii) the excess, if any, of (a) aggregate Uncollected Interest for such Distribution Date
over (b) Compensating Interest for such Distribution Date.


Uncompensated Interest Shortfall shall be allocated to the Class A and
Class B Certificates, pro rata according to the amount of interest accrued on each such Class during the immediately preceding
accrual period, in reduction thereof.


Underwriters:  WaMu Capital Corp. and
Bear, Stearns & Co. Inc.


Underwriting Standards:  The
underwriting standards of the Company or Washington Mutual Bank, FA, as applicable.


Uninsured Cause:  Any cause of damage
to a Mortgaged Property, the cost of the complete restoration of which is not fully reimbursable under the hazard insurance
policies required to be maintained pursuant to Section 3.07.


U.S. Person:  A citizen or resident of
the United States of America, a corporation, partnership or other entity created or organized in or under the laws of the United
States of America, any state thereof or the District of Columbia, or an estate or trust that is subject to U.S. federal income tax
regardless of the source of its income.


VA:  The Department of Veterans
Affairs, formerly known as the Veterans Administration, or any successor thereto.


Weighted Average Pass-Through Rate: 
For any Distribution Date, the weighted average of the Pass-Through Rates on the Mortgage Loans as of the second preceding Due Date
(after giving effect to the payments due on the Mortgage Loans on that Due Date).


Withdrawal Date:  Any day during the
period commencing on the 18th day of the month of the related Distribution Date (or if such day is not a Business Day, the
immediately preceding Business Day) and ending on the last Business Day prior to the 21st day of the month of such Distribution
Date. The “related Due Date” for any Withdrawal Date is the Due Date immediately preceding the related
Distribution Date. 



ARTICLE
II



Creation of the Trust; Conveyance
of the Mortgage Pool Assets;

REMIC Election and Designations;
Original Issuance of Certificates



Section 2.01.        Creation of the Trust.  The Trust is hereby created and shall be known as “WaMu Mortgage
Pass-Through Certificates Series 2005-AR3 Trust”. The purpose of the Trust is, and the Trust shall have the power and
authority, to engage in the following activities, all as provided by and subject to the terms of this Agreement:



(i)         to acquire, hold, lease, manage, administer, control, invest, reinvest,
operate and/or transfer the Mortgage Pool Assets;



(ii)        to issue the Certificates;



(iii)       to make distributions to the Certificates; and



(iv)       to engage in such other activities, including entering into agreements, as are
described in or required by the terms of this Agreement or as are necessary, suitable or convenient to accomplish the foregoing or
incidental thereto.



LaSalle Bank National
Association is hereby appointed as a trustee of the Trust, to have all the rights, duties and obligations of the Trustee with
respect to the Trust expressly set forth hereunder, and LaSalle Bank National Association hereby accepts such appointment and the
Trust created hereby.  Christiana Bank & Trust Company, is hereby appointed as a Delaware trustee of the Trust, to have
all the rights, duties and obligations of the Delaware Trustee with respect to the Trust hereunder, and Christiana Bank & Trust
Company, hereby accepts such appointment and the Trust created hereby.  It is the intention of the Company, the Trustee and
the Delaware Trustee that the Trust constitute a statutory trust under the Statutory Trust Statute, that this Agreement constitute
the governing instrument of the Trust, and that this Agreement amend and restate the Original Trust Agreement.  The parties
hereto acknowledge and agree that, prior to the execution and delivery hereof, the Delaware Trustee has filed the Certificate of
Trust. 


The assets of the Trust shall remain in the custody of the Trustee (or
the Custodian), on behalf of the Trust, and shall be owned by the Trust except as otherwise expressly set forth herein. 
Moneys to the credit of the Trust shall be held by the Trustee and invested as provided herein.  All assets received and held
in the Trust will not be subject to any right, charge, security interest, lien or claim of any kind in favor of either of LaSalle
Bank National Association or Christiana Bank & Trust Company in its own right, or any Person claiming through it.  Neither
the Trustee nor the Delaware Trustee, on behalf of the Trust, shall have the power or authority to transfer, assign, hypothecate,
pledge or otherwise dispose of any of the assets of the Trust to any Person, except as permitted herein.  No creditor of a
beneficiary of the Trust, of the Trustee, of the Delaware Trustee, of the Master Servicer or of the Company shall have any right to
obtain possession of, or otherwise exercise legal or equitable remedies with respect to, the property of the Trust, except in
accordance with the terms of this Agreement.



Section 2.02.        Restrictions on Activities of the Trust. Notwithstanding any other provision of this Agreement and any
provision of law that otherwise so empowers the Trust, so long as any Certificates are outstanding, the Trust shall not, and none
of the Trustee, the Delaware Trustee, the Company or the Master Servicer shall (except by amendment of this Agreement permitted by
Section 10.01) knowingly cause the Trust to, do any of the following:



(i)         engage in any business or activity other than those set forth in Section
2.01;



(ii)        incur or assume any indebtedness except for such indebtedness that may be
incurred by the Trust in connection with the execution or performance of this Agreement or any other agreement contemplated
hereby;



(iii)       guarantee or otherwise assume liability for the debts of any other
party;



(iv)       do any act in contravention of this Agreement or any other agreement contemplated
hereby to which the Trust is a party;



(v)        do any act which would make it impossible to carry on the ordinary business of
the Trust;



(vi)       confess a judgment against the Trust;



(vii)      possess or assign the assets of the Trust for other than a Trust purpose;



(viii)      cause the Trust to lend any funds to any entity, except as contemplated by this
Agreement; or



(ix)       change the purposes and powers of the Trust from those set forth in this
Agreement.



Section 2.03.        Separateness Requirements. Notwithstanding any other provision of this Agreement and any provision of law
that otherwise so empowers the Trust, so long as any Certificates are outstanding, the Trust shall perform the following:



(i)         except as expressly permitted by this Agreement or the Custodial
Agreement, maintain its books, records, bank accounts and files separate from those of any other Person;



(ii)        except as expressly permitted by this Agreement, maintain its assets in its
own separate name and in such a manner that it is not costly or difficult to segregate, identify, or ascertain such
assets;



(iii)       consider the interests of the Trust's creditors in connection with its
actions;



(iv)       hold itself out to creditors and the public as a legal entity separate and distinct
from any other Person and correct any known misunderstanding regarding its separate identity and refrain from engaging in any
activity that compromises the separate legal identity of the Trust;



(v)        prepare and maintain separate records, accounts and financial statements in
accordance with generally accepted accounting principles, consistently applied, and susceptible to audit.  To the extent it is
included in consolidated financial statements or consolidated tax returns, such financial statements and tax returns will reflect
the separateness of the respective entities and indicate that the assets of the Trust will not be available to satisfy the debts of
any other Person;



(vi)       allocate and charge fairly and reasonably any overhead shared with any other
Person;



(vii)      transact all business with affiliates on an arm’s-length basis and pursuant to
written, enforceable agreements;



(viii)      conduct business solely in the name of the Trust.  In that regard all written and
oral communications of the Trust, including, without limitation, letters, invoices, purchase orders and contracts, shall be made
solely in the name of the Trust (or the Trustee on behalf of the Trust);



(ix)       maintain a separate office through which its business shall be conducted, provided
that such office may be an office of the Trustee, which office shall not be shared with the Company or any affiliates of the
Company;



(x)        in the event that services have been or are in the future performed or paid by
any Person on behalf of the Trust (other than the Trustee, the Delaware Trustee, the Master Servicer or the Tax Matters Person as
permitted herein), reimburse such Person, as applicable, for the commercially reasonable value of such services or expenses
provided or incurred by such Person.  Accordingly, (i) the Trust shall reimburse such Person, as applicable, for the
commercially reasonable value of such services or expenses provided or incurred by such Person; (ii) to the extent invoices for
such services are not allocated and separately billed to the Trust, the amount thereof that was or is to be allocated and
separately billed to the Trust was or will be reasonably related to the services provided to the Trust; and (iii) any other
allocation of direct, indirect or overhead expenses for items shared between the Trust and any other Person, was or will be, to the
extent practicable, allocated on the basis of actual use or value of services rendered or otherwise on a basis reasonably related
to actual use or the value of services rendered;



(xi)       except as expressly permitted by this Agreement, not commingle its assets or funds
with those of any other Person;



(xii)      except as expressly permitted by this Agreement, not assume, guarantee, or pay the debts
or obligations of any other Person;



(xiii)      except as expressly permitted by this Agreement, not pledge its assets for the benefit
of any other Person;



(xiv)     not hold out its credit or assets as being available to satisfy the obligations of
others;



(xv)      pay its liabilities only out of its funds;



(xvi)     pay the salaries of its own employees, if any; and



(xvii)     cause the agents and other representatives of the Trust, if any, to act at all times with
respect to the Trust consistently and in furtherance of the foregoing.


None of the Trustee, the Delaware Trustee, the Company or the Master
Servicer shall (except by amendment of this Agreement permitted by Section 10.01) take any action that is inconsistent with the
purposes of the Trust or Section 2.02 or Section 2.03.  Neither the Company nor the Master Servicer shall (except by amendment
of this Agreement permitted by Section 10.01) direct the Trustee or the Delaware Trustee to take any action that is inconsistent
with the purposes of the Trust or Section 2.02 or Section 2.03.



Section 2.04.        Conveyance of Mortgage Pool Assets; Security Interest.


Concurrently with the execution and delivery hereof, the Company does
hereby irrevocably sell, transfer, assign, set over and otherwise convey to the Trust, without recourse, all the Company’s
right, title and interest in and to the Mortgage Pool Assets (such transfer and assignment by the Company to be referred to herein
as the “Conveyance”).


It is the express intent of the parties hereto that the Conveyance of
the Mortgage Pool Assets to the Trust by the Company as provided in this Section 2.04 be, and be construed as, an absolute sale of
the Mortgage Pool Assets. It is, further, not the intention of the parties that such Conveyance be deemed the grant of a security
interest in the Mortgage Pool Assets by the Company to the Trust to secure a debt or other obligation of the Company. However, in
the event that, notwithstanding the intent of the parties, the Mortgage Pool Assets are held to be the property of the Company, or
if for any other reason this Agreement is held or deemed to create a security interest in the Mortgage Pool Assets,
then:


(a)        this Agreement shall
constitute a security agreement;


(b)        the conveyance provided
for in this Section 2.04 shall be deemed to be a grant by the Company to the Trust of, and the Company hereby grants to the Trust,
to secure all of the Company’s obligations hereunder, a security interest in all of the Company’s right, title, and
interest, whether now owned or hereafter acquired, in and to:



(I)       
The Mortgage Pool Assets;



(II)       All
accounts, chattel paper, deposit accounts, documents, general intangibles, goods, instruments, investment property,
letter-of-credit rights, letters of credit, money, and oil, gas, and other minerals, consisting of, arising from, or relating to,
any of the foregoing; and



(III)      All
proceeds of the foregoing.


The Company shall file such financing statements, and the Company and
the Trustee acting on behalf of the Trust at the direction of the Company shall, to the extent consistent with this Agreement, take
such other actions as may be necessary to ensure that, if this Agreement were found to create a security interest in the Mortgage
Pool Assets, such security interest would be a perfected security interest of first priority under applicable law and will be
maintained as such throughout the term of the Agreement. In connection herewith, the Trust shall have all of the rights and
remedies of a secured party and creditor under the Uniform Commercial Code as in force in the relevant jurisdiction.


In the event that a pleading is filed in a court of competent
jurisdiction asserting that this Agreement creates a security interest in the Mortgage Pool Assets, the Trustee on behalf of the
Trust shall take actual possession of the Mortgage Pool Assets or, at the Company's option, the Trustee on behalf of the Trust
shall be provided an Opinion of Counsel addressed to the Trust and the Trustee reasonably satisfactory to the Trustee to the effect
that such security interest is a perfected security interest of first priority while the Mortgage Pool Assets are in the possession
of the Company or its affiliates.



Section 2.05.        Delivery of Mortgage Files.


In connection with the sale, transfer and assignment referred to in
Section 2.04, the Company, concurrently with the execution and delivery hereof, does deliver to, and deposit with, or cause to be
delivered to and deposited with, the Trustee or Custodian the Mortgage Files, which shall at all times be identified in the records
of the Trustee or the Custodian, as applicable, as being held by or on behalf of the Trust.


Concurrently with the execution and delivery hereof, the Company shall
cause to be filed the UCC assignment or amendment referred to in clause (Y)(vii) of the definition of “Mortgage
File.”  In connection with its servicing of Cooperative Loans, the Master Servicer will use its best efforts to file
timely continuation statements, if necessary, with regard to each financing statement and assignment relating to Cooperative
Loans.


In instances where the original recorded Mortgage or any intervening
assignment thereof (recorded or in recordable form) required to be included in the Mortgage File pursuant to the definition of
“Mortgage File” relating to a Mortgage Loan is not included in the Mortgage File delivered to the Trustee (or the
Custodian) prior to or concurrently with the execution and delivery hereof (due to a delay on the part of the recording office),
the Company shall deliver to the Trustee (or the Custodian) a fully legible reproduction (which may be in electronic form) of the
original Mortgage or intervening assignment provided that the originator, the related Lender or the escrow or title company which
provided closing services in connection with such Mortgage Loan certifies on the face of such reproduction(s) or copy as follows:
“Certified true and correct copy of original which has been transmitted for recordation.” For purposes hereof,
transmitted for recordation means having been mailed or otherwise delivered for recordation to the appropriate authority. In all
such instances, the Company shall transmit the original recorded Mortgage and any intervening assignments with evidence of
recording thereon (or a copy of such original Mortgage or intervening assignment certified by the applicable recording office)
(which may be in electronic form) (collectively, “Recording Documents”) to the Trustee (or the Custodian) within
270 days after the execution and delivery hereof. In instances where, due to a delay on the part of the recording office where any
such Recording Documents have been delivered for recordation, the Recording Documents cannot be delivered to the Trustee within 270
days after execution and delivery hereof, the Company shall deliver to the Trustee within such time period a certificate (a
“Company Officer’s Certificate”) signed by the Chairman of the Board, President, any Vice President or
Treasurer of the Company stating the date by which the Company expects to receive such Recording Documents from the applicable
recording office. In the event that Recording Documents have still not been received by the Company and delivered to the Trustee
(or the Custodian) by the date specified in its previous Company Officer’s Certificate delivered to the Trustee, the Company
shall deliver to the Trustee by such date an additional Company Officer’s Certificate stating a revised date by which the
Company expects to receive the applicable Recording Documents. This procedure shall be repeated until the Recording Documents have
been received by the Company and delivered to the Trustee (or the Custodian).


For Mortgage Loans for which the Company has received a Payoff after
the Cut-Off Date and prior to the date of execution and delivery hereof, the Company, in lieu of delivering the above documents,
herewith delivers to the Trustee a certification of a Servicing Officer of the nature set forth in Section 3.10.


The Trustee is authorized, with the Master Servicer’s consent,
to appoint any bank or trust company approved by each of the Company and the Master Servicer as Custodian of the documents or
instruments referred to in this Section 2.05 or in Section 2.10, and to enter into a Custodial Agreement for such purpose;
provided, however, that the Trustee shall be and remain liable for the acts of any such Custodian only to the extent that it is
responsible for its own acts hereunder.  Any documents delivered by the Company or the Master Servicer to the Custodian shall
be deemed to have been delivered to the Trustee for all purposes hereunder; and any documents held by the Custodian shall be deemed
to be held by the Trustee for all purposes hereunder. There shall be a written Custodial Agreement between the Trustee and each
Custodian. Each Custodial Agreement shall contain an acknowledgment by the Custodian that all Mortgage Pool Assets, Mortgage Files,
and other documents and property held by it at any time are held by it for the benefit of the Trust.  Pursuant to the Initial
Custodial Agreement, the Initial Custodian shall perform responsibilities of the Trustee on the Trustee’s behalf with respect
to the delivery, receipt, examination, custody and release of the Mortgage Files related to the Mortgage Loans identified in the
Initial Custodial Agreement, as provided therein.  The Trustee shall not have any responsibility for the acts or omissions of
the Initial Custodian provided however that nothing herein shall relieve the Trustee from liability for its own negligent action,
its own negligent failure to act or its willful misconduct.


On or promptly after the Closing Date, the Master Servicer shall cause
the MERS® System to indicate that each MERS Loan, if any, has been assigned to “LaSalle Bank National Association, as
Trustee, without recourse” or to “WaMu Mortgage Pass-Through Certificates Series 2005-AR3 Trust, without
recourse” by including in the MERS® System computer files (a) the code necessary to identify the Trustee and (b) the code
necessary to identify the series of the Certificates issued in connection with such Mortgage Loans; provided, however, that
in the event the Company acquired such Mortgage Loans from an affiliate of the Company, then the Master Servicer need not cause the
MERS® System to indicate such assignment.  The Master Servicer shall not alter the codes referenced in this paragraph with
respect to any MERS Loan during the term of this Agreement except in connection with an assignment of such MERS Loan or
de-registration thereof from the MERS® System in accordance with the terms of this Agreement.



Section 2.06.        REMIC Election for REMIC I.


The Tax Matters Person, shall, on behalf of REMIC I, elect to treat
REMIC I as a REMIC within the meaning of Section 860D of the Code and, if necessary, under applicable state laws. Such election
shall be included in the Form 1066 and any appropriate state return to be filed on behalf of REMIC I for its first taxable
year.


The Closing Date is hereby designated as the “startup day”
of REMIC I within the meaning of Section 860G(a)(9) of the Code.


The regular interests (as set forth in the table contained in the
Preliminary Statement hereto) relating to REMIC I are hereby designated as “regular interests” in REMIC I for purposes
of Section 860G(a)(1) of the Code. The Class R Certificates are hereby designated as the sole class of “residual
interest” in REMIC I for purposes of Section 860G(a)(2) of the Code.


The parties intend that the affairs of REMIC I shall constitute, and
that the affairs of  REMIC I shall be conducted so as to qualify REMIC I as a REMIC. In furtherance of such intention, the Tax
Matters Person shall, on behalf of REMIC I: (a) prepare and file, or cause to be prepared and filed, a federal tax return using a
calendar year as the taxable year and using an accrual method of accounting for REMIC I when and as required by the REMIC
Provisions and other applicable federal income tax laws; (b) make an election, on behalf of the trust, for REMIC I to be treated as
a REMIC on the federal tax return of  REMIC I for its first taxable year, in accordance with the REMIC Provisions; (c) prepare
and forward, or cause to be prepared and forwarded, to the Certificateholders and the Trustee, all information reports as and when
required to be provided to them in accordance with the REMIC Provisions, and make available the information necessary for the
application of Section 860E(e) of the Code; (d) conduct the affairs of REMIC I at all times that any REMIC I Regular Interests are
outstanding so as to maintain the status of REMIC I as a REMIC under the REMIC Provisions; (e) not knowingly or intentionally take
any action or omit to take any action that would cause the termination of the REMIC status of REMIC I; and (f) pay the amount of
any federal prohibited transaction penalty taxes imposed on REMIC I when and as the same shall be due and payable (but such
obligation shall not prevent the Company or any other appropriate person from contesting any such tax in appropriate proceedings
and shall not prevent the Company from withholding payment of such tax, if permitted by law, pending the outcome of such
proceedings); provided, that the Company shall be entitled to be indemnified by REMIC I for any such prohibited transaction penalty
taxes if the Company’s failure to exercise reasonable care was not the primary cause of the imposition of such prohibited
transaction penalty taxes.


The Trustee and the Master Servicer shall promptly provide the Company
with such information in the possession of the Trustee or the Master Servicer, respectively, as the Company may from time to time
request for the purpose of enabling the Company to prepare tax returns. If so requested by the Tax Matters Person, the Trustee
shall sign tax returns on behalf of REMIC I.


In the event that a Mortgage Loan is discovered to have a defect
which, had such defect been discovered before the startup day, would have prevented such Mortgage Loan from being a
“qualified mortgage” within the meaning of Section 860G(a)(3) of the Code, and the Company does not repurchase such
Mortgage Loan within 90 days of such date, the Master Servicer, on behalf of the Trustee, shall within 90 days of the date such
defect is discovered sell such Mortgage Loan at such price as the Master Servicer in its sole discretion, determines to be the
greatest price that will result in the purchase thereof within 90 days of such date, unless the Master Servicer delivers to the
Trustee an Opinion of Counsel to the effect that continuing to hold such Mortgage Loan will not adversely affect the status of the
electing portion of REMIC I as a REMIC for federal income tax purposes.


In the event that any tax is imposed on “prohibited
transactions” of REMIC I as defined in Section 860F of the Code and not paid by the Company pursuant to clause (f) of the
third preceding paragraph, such tax shall be charged against amounts otherwise distributable to the Class R Certificates.
Notwithstanding anything to the contrary contained herein, the Trustee is hereby authorized to retain from amounts otherwise
distributable to the Class R Certificates on any Distribution Date sufficient funds to reimburse the Tax Matters Person (or any
agent therefor appointed in accordance with the definition of “Tax Matters Person” herein, if applicable), for the
payment of such tax (upon the written request of the Tax Matters Person or its agent, to the extent reimbursable, and to the extent
that the Tax Matters Person or its agent has not been previously reimbursed therefor).



Section 2.07.        Acceptance by
Trustee. The Trustee acknowledges receipt (or with respect to any Mortgage Loan subject to a Custodial Agreement,
receipt by the Custodian thereunder) on behalf of the Trust of the documents (or certified copies thereof as specified in Section
2.05) referred to in Section 2.05 above, but without having made the review required to be made within 45 days pursuant to this
Section 2.07.  The Trustee acknowledges that all Mortgage Pool Assets, Mortgage Files, and related documents and property held
by it at any time are held by it as Trustee of the Trust for the benefit of the holders of the Certificates. The Trustee agrees,
for the benefit of the Trust, to review (or, with respect to the Mortgage Loans identified in the Initial Custodial Agreement,
cause the Initial Custodian to review) each Mortgage File within 45 days after the Closing Date and deliver to the Company a
certification (or, with respect to the Mortgage Loans identified in the Initial Custodial Agreement, cause the Initial Custodian to
deliver to the Company a certification, which satisfies the applicable requirements of this Agreement in the form attached as
Exhibit M hereto, to the effect that, except as noted, all documents required (in the case of instruments described in clauses
(X)(ii), (X)(iv) and (Y)(ix) of the definition of “Mortgage File,” known by the Trustee to be required) pursuant to the
definition of “Mortgage File” and Section 2.05 have been executed and received, and that such documents relate to the
Mortgage Loans identified in the Mortgage Loan Schedule. In performing such review, the Trustee may rely upon the purported
genuineness and due execution of any such document, and on the purported genuineness of any signature thereon. The Trustee shall
not be required to make any independent examination of any documents contained in each Mortgage File beyond the review specifically
required herein. The Trustee makes no representations as to: (i) the validity, legality, enforceability or genuineness of any of
the Mortgage Loans identified on the Mortgage Loan Schedule, or (ii) the collectability, insurability, effectiveness or suitability
of any Mortgage Loan. If the Trustee finds any document or documents constituting a part of a Mortgage File not to have been
executed or received, or to be unrelated to the Mortgage Loans identified in the Mortgage Loan Schedule, the Trustee shall promptly
so notify the Company. The Company hereby covenants and agrees that, if any such defect cannot be corrected or cured, the Company
shall, not later than 60 days after the Trustee’s notice to it respecting such defect, within the three-month period
commencing on the Closing Date (or within the two-year period commencing on the Closing Date if the related Mortgage Loan is a
“defective obligation” within the meaning of Section 860G(a)(4)(B)(ii) of the Code and Treasury Regulation Section
1.860G-2(f)), either (i) repurchase the related Mortgage Loan from the Trust at the Purchase Price, or (ii) substitute for any
Mortgage Loan to which such defect relates a different mortgage loan (a “Substitute Mortgage Loan”) which is a
“qualified replacement mortgage” (as defined in the Code) and, (iii) after such three-month or two-year period, as
applicable, the Company shall repurchase the Mortgage Loan from the Trust at the Purchase Price but only if the Mortgage Loan is in
default or default is, in the judgment of the Company, reasonably imminent. If such defect would cause the Mortgage Loan to be
other than a “qualified mortgage” (as defined in the Code), then notwithstanding the previous sentence or any provision
in the definition of “Purchase Price,” the repurchase or substitution must occur within the sooner of (i) 90 days from
the date the defect was discovered or (ii) in the case of substitution, two years from the Closing Date.


Such Substitute Mortgage Loan shall be an adjustable rate mortgage
loan with a first  Adjustment Date occurring on approximately the same date as, but not earlier than, the first Adjustment
Date for the Mortgage Loan being substituted for and adjustments annually thereafter, based on the Index, mature no later than, and
not more than two years earlier than, have a principal balance and Loan-to-Value Ratio equal to or less than, and have a
Pass-Through Rate on the date of substitution equal to or no more than 1 percentage point greater than, and a Margin, Rate Ceiling
and Rate Floor equal to or greater than, and a Periodic Cap no more than 0.5 percentage point greater or smaller than, the Mortgage
Loan being substituted for. In addition, if the Mortgage Loan being substituted for does not provide for any payments of principal
prior to its first Adjustment Date, such substitute Mortgage Loan also shall not provide for such payments of principal. If the
aggregate of the principal balances of the Substitute Mortgage Loans substituted for a Mortgage Loan is less than the Principal
Balance of such Mortgage Loan, the Company shall pay the difference in cash, together with unpaid accrued interest, if any, on the
difference between the aggregate of the principal balances of the Substitute Mortgage Loans and the Principal Balance of such
Mortgage Loan during the calendar month in which the substitution occurs to the last day of such month at a rate equal to the
applicable Pass-Through Rate, to the Trustee for deposit into the Certificate Account, and such payment by the Company shall be
treated in the same manner as proceeds of the repurchase by the Company of a Mortgage Loan pursuant to this Section 2.07.
Furthermore, such Substitute Mortgage Loan shall otherwise have such characteristics so that the representations and warranties of
the Company set forth in Section 2.08 hereof would not have been incorrect had such Substitute Mortgage Loan originally been a
Mortgage Loan, and the Company shall be deemed to have made such representations and warranties as to such Substitute Mortgage
Loan. A Substitute Mortgage Loan may be substituted for a defective Mortgage Loan whether or not such defective Mortgage Loan is
itself a Substitute Mortgage Loan.  Notwithstanding anything herein to the contrary, each Substitute Mortgage Loan shall be
deemed to have the same Pass-Through Rate as the Mortgage Loan for which it was substituted.


The Purchase Price for each purchased or repurchased Mortgage Loan
shall be deposited by the Company in the Certificate Account and, upon receipt by the Trustee of written notification of such
deposit signed by a Servicing Officer, the Trustee shall (or, if applicable, shall cause the Custodian to) release to the Company
the related Mortgage File and shall execute and deliver (or, in the event that the Mortgage Files are held in the name of the
Custodian, shall cause the Custodian to execute and deliver) on behalf of the Trust such instruments of transfer or assignment, in
each case without recourse, as shall be necessary to vest in the Company or its designee or assignee title to any Mortgage Loan
released pursuant hereto. In furtherance of the foregoing, if such Mortgage Loan is a MERS Loan and as a result of the repurchase
thereof such Mortgage Loan shall cease to be serviced by a servicer that is a member of MERS or if the Company or its assignee
shall so request, the Master Servicer shall cause MERS to execute and deliver an assignment of the Mortgage in recordable form from
MERS to the Company or its assignee and shall cause the Mortgage Loan to be removed from registration on the MERS® System in
accordance with MERS’ rules and procedures. The obligation of the Company to repurchase or substitute any Mortgage Loan as to
which such a defect in a constituent document exists shall constitute the sole remedy respecting such defect available to the Trust
or the Holders of the Certificates.



Section 2.08.        Representations and
Warranties of the Company Concerning the Mortgage Loans. With respect to the conveyance of the Mortgage Loans
provided for in Section 2.04 herein, the Company hereby represents and warrants to the Trust that as of the Cut-Off Date unless
otherwise indicated:


(i)                  The
information set forth in the Mortgage Loan Schedule was true and correct in all material respects at the date or dates respecting
which such information is furnished;


(ii)        As of
the Closing Date, each Mortgage relating to a Mortgage Loan that is not a Cooperative Loan is a valid and enforceable (subject to
Section 2.08(xvi)) first lien on an unencumbered estate in fee simple or (if the related Mortgage Loan is secured by the interest
of the Mortgagor as a lessee under a ground lease) leasehold estate in the related Mortgaged Property subject only to (a) liens for
current real property taxes and special assessments; (b) covenants, conditions and restrictions, rights of way, easements and other
matters of public record as of the date of recording such Mortgage, such exceptions appearing of record being acceptable to
mortgage lending institutions generally or specifically reflected in the appraisal obtained in connection with the origination of
the Mortgage Loan; (c) exceptions set forth in the title insurance policy relating to such Mortgage, such exceptions being
acceptable to mortgage lending institutions generally; and (d) other matters to which like properties are commonly subject which do
not materially interfere with the benefits of the security intended to be provided by the Mortgage;


(iii)       Immediately
upon the transfer and assignment contemplated herein, the Trust shall have good title to, and will be the sole legal owner of, each
Mortgage Loan, free and clear of any encumbrance or lien (other than any lien under this Agreement);


(iv)       As of the
day prior to the Cut-Off Date, all payments due on each Mortgage Loan had been made and no Mortgage Loan had been delinquent (i.e.,
was more than 30 days past due) more than once in the preceding 12 months and any such delinquency lasted for no more than 30
days;


(v)        As of
the Closing Date, there is no late assessment for delinquent taxes outstanding against any Mortgaged Property;


(vi)       As of the
Closing Date, there is no offset, defense or counterclaim to any Mortgage Note, including the obligation of the Mortgagor to pay
the unpaid principal or interest on such Mortgage Note except to the extent that the Buydown Agreement for a Buydown Loan forgives
certain indebtedness of a Mortgagor;


(vii)      As of the Closing
Date, each Mortgaged Property is free of damage and in good repair, ordinary wear and tear excepted;


(viii)      Each Mortgage
Loan at the time it was made complied with all applicable local, state and federal laws, including, without limitation, usury,
equal credit opportunity, disclosure and recording laws, and predatory and abusive lending laws applicable to the originating
lender;


(ix)       Each
Mortgage Loan was originated by a savings association, savings bank, credit union, insurance company, or similar institution which
is supervised and examined by a federal or state authority or by a mortgagee approved by the FHA and will be serviced by an
institution which meets the servicer eligibility requirements established by the Company;


(x)        As of
the Closing Date, each Mortgage Loan that is not a Cooperative Loan is covered by an ALTA form or CLTA form of mortgagee title
insurance policy or other form of policy of insurance which has been issued by, and is the valid and binding obligation of, a title
insurer which, as of the origination date of such Mortgage Loan, was qualified to do business in the state in which the related
Mortgaged Property is located. Such policy insures the originator of the Mortgage Loan, its successors and assigns as to the first
priority lien of the Mortgage in the original principal amount of the Mortgage Loan subject to the exceptions set forth in such
policy. Such policy is in full force and effect and inures to the benefit of the Trust upon the consummation of the transactions
contemplated by this Agreement and no claims have been made under such policy, and no prior holder of the related Mortgage,
including the Company, has done, by act or omission, anything which would impair the coverage of such policy;


(xi)       Each
Mortgage Loan with a Loan-to-Value Ratio as of the Cut-Off Date in excess of 80% was covered by a Primary Insurance Policy or an
FHA insurance policy or a VA guaranty, and such policy or guaranty is valid and remains in full force and effect;


(xii)      As of the Closing
Date, all policies of insurance required by this Agreement or by a Selling and Servicing Contract  have been validly issued
and remain in full force and effect, including such policies covering the Company, the Master Servicer or any
Servicer;


(xiii)      As of the
Closing Date, each insurer issuing a Primary Insurance Policy holds a rating acceptable to the Rating Agencies;


(xiv)     Each Mortgage
(exclusive of any riders thereto) was documented by appropriate Fannie Mae/Freddie Mac mortgage instruments in effect at the time
of origination, or other instruments approved by the Company;


(xv)      As of the Closing
Date, the Mortgaged Property securing each Mortgage relating to a Mortgage Loan that is not a Cooperative Loan is improved with a
one- to four-family dwelling unit, including units in a duplex, triplex, fourplex, condominium project, townhouse, a planned unit
development or a de minimis planned unit development;


(xvi)     As of the Closing Date,
each Mortgage and Mortgage Note is the legal, valid and binding obligation of the maker thereof and is enforceable in accordance
with its terms, except only as such enforcement may be limited by laws affecting the enforcement of creditors’ rights
generally and principles of equity;


(xvii)     As of the date of
origination, as to Mortgaged Properties which are units in condominiums or planned unit developments, all of such units met the
applicable Underwriting Standards, are located in a condominium or planned unit development projects which have received Fannie Mae
or Freddie Mac approval, or are approvable by Fannie Mae or Freddie Mac or have otherwise been approved by the
Company;


(xviii)    None of the Mortgage Loans
are Buydown Loans;


(xix)     Based solely on
representations of the Mortgagors obtained at the origination of the related Mortgage Loans, approximately 94.07% (by Principal
Balance) of the Mortgage Loans will be secured by owner occupied Mortgaged Properties which are the primary residences of the
related Mortgagors and approximately 5.93% (by Principal Balance) of the Mortgage Loans will be secured by owner occupied Mortgaged
Properties which were second or vacation homes of the Mortgagors;



(xx)      Prior to origination or refinancing, an appraisal of each Mortgaged Property was made by
an appraiser on a form satisfactory to Fannie Mae or Freddie Mac;


(xxi)     The Mortgage Loans have
been underwritten substantially in accordance with the applicable Underwriting Standards;


(xxii)     All of the Mortgage
Loans have due-on-sale clauses; however, the due on sale provisions may not be exercised at the time of a transfer if prohibited by
law or the terms of the related Mortgage Note;


(xxiii)    The Company used no adverse
selection procedures in selecting the Mortgage Loans from among the outstanding adjustable rate conventional mortgage loans
purchased by it which were available for inclusion in the Mortgage Pool and as to which the representations and warranties in this
Section 2.08 could be made;


(xxiv)    With respect to each
Cooperative Loan, the Cooperative Stock that is pledged as security for the Cooperative Loan is held by a person as a
tenant-stockholder (as defined in Section 216 of the Code) in a cooperative housing corporation (as defined in Section 216 of the
Code);


(xxv)    Each Cooperative Loan is
secured by a valid, subsisting and enforceable (except as such enforcement may be limited by laws affecting the enforcement of
creditors’ rights generally and principles of equity) perfected first lien and security interest in the related Cooperative
Stock securing the related Mortgage Note, subject only to (a) liens of the Cooperative for unpaid assessments representing the
Mortgagor’s pro rata share of the Cooperative’s payments for its blanket mortgage, current and future real property
taxes, insurance premiums, maintenance fees and other assessments to which like collateral is commonly subject, and (b) other
matters to which like collateral is commonly subject which do not materially interfere with the benefits of the security intended
to be provided by the Security Agreement;


(xxvi)    With respect to any Mortgage
Loan as to which an affidavit has been delivered to the Trustee certifying that the original Mortgage Note is a Destroyed Mortgage
Note, if such Mortgage Loan is subsequently in default, the enforcement of such Mortgage Loan or of the related Mortgage by or on
behalf of the Trust will not be materially adversely affected by the absence of the original Mortgage Note (or portion thereof, as
applicable);


(xxvii)   Based upon an appraisal of the
Mortgaged Property securing each Mortgage Loan, approximately 99.72% (by Principal Balance) of the Mortgage Loans had a current
Loan-to-Value Ratio less than or equal to 80%, approximately 0.28% (by Principal Balance) of the Mortgage Loans had a current
Loan-to-Value Ratio greater than 80% but less than or equal to 90% and no Mortgage Loan had a current Loan-to-Value Ratio greater
than 90%;


(xxviii)  Approximately 63.44% (by Principal
Balance) of the Mortgage Loans were originated for the purpose of refinancing existing mortgage debt, including cash-out
refinancings; and approximately 36.55% (by Principal Balance) of the Mortgage Loans were originated for the purpose of purchasing
the Mortgaged Property;


(xxix)    Not less than approximately
30.15% (by Principal Balance) of the Mortgage Loans were originated under full documentation programs;


(xxx)    Each Mortgage Loan
constitutes a qualified mortgage under Section 860G(a)(3)(A) of the Code and Treasury Regulations Section
1.860G-2(a)(1);



(xxxi)    No Mortgage Loan is
subject to the Home Ownership and Equity Protection Act of 1994 or Section 226.32 of Regulation Z, is a “high-cost”
loan or a “predatory” loan as defined under any state or local law or regulation applicable to the originator of such
Mortgage Loan or which would result in liability to the purchaser or assignee of such Mortgage Loan under any predatory or abusive
lending law, or, without limiting the generality of the foregoing, is a “covered” loan under the laws of the states of
California, Colorado or Ohio;



(xxxii)   No Mortgage Loan is a
High Cost Loan or Covered Loan (as such terms are defined in the Standard & Poor's LEVELS® Glossary in effect on the
Closing Date, which is now Version 5.6b Revised, Appendix E, applicable portions of which are attached hereto as Exhibit C) and no
Mortgage Loan originated on or after October 1, 2002 through March 6, 2003 is governed by the Georgia Fair Lending Act;
and


(xxxiii)  With respect to each Mortgage Loan,
the Periodic Cap shall equal five percentage points on the first Adjustment Date and shall equal two percentage points on each
Adjustment Date thereafter.


It is understood and agreed that the representations and warranties
set forth in this Section 2.08 shall survive delivery of the respective Mortgage Files to the Trustee or the Custodian, as the case
may be, and shall continue throughout the term of this Agreement. Upon discovery by any of the Company, the Master Servicer, the
Trustee or the Custodian of a breach of any of the foregoing representations and warranties which materially and adversely affects
the value of the related Mortgage Loans or the interests of the Trust in the related Mortgage Loans, the Company, the Master
Servicer, the Trustee or the Custodian, as the case may be, discovering such breach shall give prompt written notice to the others.
Any breach of the representation set forth in clause (xxxi) or (xxxii) of this Section 2.08 shall be deemed to materially and
adversely affect the value of the related Mortgage Loans or the interests of the Trust in the related Mortgage Loans. Within 90
days of its discovery or its receipt of notice of breach, the Company shall repurchase, subject to the limitations set forth in the
definition of “Purchase Price,” or substitute for the affected Mortgage Loan or Mortgage Loans or any property acquired
in respect thereof from the Trust, unless it has cured such breach in all material respects. After the end of the three-month
period beginning on the “start-up day,” any such substitution shall be made only if the Company provides to the Trustee
an Opinion of Counsel addressed to the Trust and the Trustee reasonably satisfactory to the Trustee that each Substitute Mortgage
Loan will be a “qualified replacement mortgage” within the meaning of Section 860G(a)(4) of the Code. Such substitution
shall be made in the manner and within the time limits set forth in Section 2.07. Any such repurchase by the Company shall be
accomplished in the manner and at the Purchase Price, if applicable, but shall not be subject to the time limits, set forth in
Section 2.07. It is understood and agreed that the obligation of the Company to provide such substitution or to make such
repurchase of any affected Mortgage Loan or Mortgage Loans or any property acquired in respect thereof as to which a breach has
occurred and is continuing shall constitute the sole remedy respecting such breach available to the Holders of the Certificates or
the Trustee on behalf of the Holders of the Certificates.



Section 2.09.        Acknowledgment of Transfer of
Mortgage Pool Assets. The Trustee hereby acknowledges and accepts on behalf of the Trust the transfer and assignment
to the Trust of the Mortgage Pool Assets, but without having made the review required to be made within 45 days pursuant to Section
2.07, and declares that as of the Closing Date it (or, with respect to the Mortgage Loans identified in the Initial Custodial
Agreement, the Custodian on behalf of the Trustee) holds and shall hold any documents constituting a part of the Mortgage Pool
Assets, and the Mortgage Pool Assets, as Trustee in trust, upon the trust herein set forth, for the use and benefit of all present
and future Holders of the Certificates.  In connection therewith, as of the Closing Date, in exchange for the Mortgage Pool
Assets, the Trustee on behalf of the Trust does hereby issue to the Company the Certificates.



Section 2.10.        Acknowledgement of Transfer of REMIC I Assets; Authentication of Certificates. The Trustee hereby
acknowledges and accepts on behalf of the Trust the assignment to the Trust of the REMIC I Assets and declares that as of the
Closing Date it holds and shall hold any documents constituting a part of the REMIC I Assets, and the REMIC I Assets, as Trustee in
trust, upon the trust herein set forth, for the use and benefit of all present and future Holders of the Certificates (other than
the Class R Certificates).  In connection therewith, as of the Closing Date, in exchange for the REMIC I Assets, the Trustee
on behalf of the Trust shall cause to be authenticated and delivered, upon and pursuant to the order of the Company, the
Certificates in Authorized Denominations.



Section 2.11.        Legal Title. Legal title to all assets of the Trust shall be vested at all times in the Trust as a separate
legal entity.



Section 2.12.        Compliance with ERISA Requirements. For purposes of ensuring compliance with the requirements of the
“underwriter’s exemption” (U.S. Department of Labor Prohibited Transaction Exemption 2002-41, 67 Fed. Reg. 54487
(Aug. 22, 2002)), issued under ERISA, and for the avoidance of any doubt as to the applicability of other provisions of this
Agreement, to the fullest extent permitted by applicable law and except as contemplated by this Agreement, (1) the Trust shall not
be a party to any merger, consolidation or reorganization, or liquidate or sell its assets and (2) so long as any Certificates are
outstanding, none of the Company, the Trustee or the Delaware Trustee shall institute against the Trust, or join in any institution
against the Trust of, any bankruptcy or insolvency proceedings under any federal or state bankruptcy, insolvency or similar
law.



Section 2.13.        Additional Representation of
the Company Concerning the Mortgage Loans. The Company hereby represents and warrants to the Trust that it does not
intend for the Mortgage Pool to include any Mortgage Loan that is a high-cost home loan as defined under the New Jersey Home
Ownership Security Act of 2002, the New Mexico Home Loan Protection Act or the Massachusetts Predatory Home Loan Practices
Act.  Based on the foregoing representation and warranty and on the Company’s obligation, pursuant to Section 2.08, to
repurchase or substitute for the affected Mortgage Loan in the event of a breach of the representation set forth in clause (xxxi)
of Section 2.08, the other parties hereto agree and understand that it is not intended for the Mortgage Pool to include any
Mortgage Loan that is a high-cost home loan as defined under the New Jersey Home Ownership Security Act of 2002, the New Mexico
Home Loan Protection Act or the Massachusetts Predatory Home Loan Practices Act.



ARTICLE
III



Administration and Servicing of Mortgage Loans



Section 3.01.        The Company to Act as Master
Servicer.  The Company shall act as Master Servicer to service and administer the Mortgage Loans on behalf of
the Trust in accordance with the terms hereof, consistent with prudent mortgage loan servicing practices and (unless inconsistent
with prudent mortgage loan servicing practices) in the same manner in which, and with the same care, skill, prudence and diligence
with which, it services and administers similar mortgage loans for other portfolios, and shall have full power and authority to do
or cause to be done any and all things in connection with such servicing and administration which a prudent servicer of mortgage
loans would do under similar circumstances, including, without limitation, the power and authority to bring actions and defend the
Mortgage Pool Assets on behalf of the Trust in order to enforce the terms of the Mortgage Notes.  The Master Servicer may
perform its master servicing responsibilities through agents or independent contractors, but shall not thereby be released from any
of its responsibilities hereunder and the Master Servicer shall diligently pursue all of its rights against such agents or
independent contractors.


The Master Servicer shall make reasonable efforts to collect or cause
to be collected all payments called for under the terms and provisions of the Mortgage Loans and shall, to the extent such
procedures shall be consistent with this Agreement and the terms and provisions of any Primary Insurance Policy, any FHA insurance
policy or VA guaranty, any hazard insurance policy, and federal flood insurance, cause to be followed such collection procedures as
are followed with respect to mortgage loans comparable to the Mortgage Loans and held in portfolios of responsible mortgage lenders
in the local areas where each Mortgaged Property is located. The Master Servicer shall enforce “due-on-sale” clauses
with respect to the related Mortgage Loans, to the extent permitted by law, subject to the provisions set forth in Section
3.08.


Consistent with the foregoing, the Master Servicer may, in accordance
with prudent mortgage loan servicing practices, (i) waive or cause to be waived any assumption fee or late payment charge in
connection with the prepayment of any Mortgage Loan and (ii) only upon determining that the coverage of any applicable insurance
policy or guaranty related to a Mortgage Loan will not be materially adversely affected, arrange a schedule, running for no more
than 180 days after the first delinquent Due Date, for payment of any delinquent installment on any Mortgage Note or for the
liquidation of delinquent items. Subject to the fourth sentence of this paragraph, the Master Servicer shall have the right, but
not the obligation, to purchase any Mortgage Loan delinquent 90 consecutive days or more for an amount equal to its Purchase Price;
provided, however, that the aggregate Purchase Price of Mortgage Loans so purchased pursuant to this sentence shall not
exceed one-half of one percent (0.50%) of the aggregate Principal Balance, as of the Cut-Off Date, of all Mortgage Loans. 
Subject to the fourth sentence of this paragraph, the Master Servicer shall also have the right, but not the obligation, to
purchase, for an amount equal to its Purchase Price, any Mortgage Loan delinquent 90 consecutive days or more, for the purpose of
requiring the Person who sold such Mortgage Loan to the Company to repurchase such Mortgage Loan based on a breach of a
representation or warranty made by such Person in connection with the Company’s purchase or acquisition of such Mortgage
Loan.  Notwithstanding the immediately preceding two sentences, the Master Servicer’s right to purchase any Mortgage
Loan pursuant to either of such preceding sentences shall be subject to the following additional conditions: (x) if the date on
which the Mortgage Loan first became 90-day delinquent (the “Initial Delinquency Date”) occurred during the
first two calendar months of a calendar quarter, the Master Servicer may exercise the purchase right during the period commencing
on the Initial Delinquency Date and ending on the last Master Servicer Business Day of such calendar quarter, (y) if the Initial
Delinquency Date occurred during the third calendar month of a calendar quarter, the Master Servicer may exercise the purchase
right during the period commencing on the first day of the immediately succeeding calendar quarter and ending on the last Master
Servicer Business Day of such succeeding calendar quarter and (z) if the Master Servicer does not exercise the purchase right with
respect to a Mortgage Loan during the period specified in clause (x) or (y), as applicable, such Mortgage Loan shall thereafter
again become eligible for purchase pursuant to the preceding two sentences only after the Mortgage Loan ceases to be 90-day
delinquent and thereafter becomes 90-day delinquent again.  For purposes of this paragraph, a Mortgage Loan is considered
delinquent for 90 consecutive days if a Monthly Payment is not received by the first day of the third month following the month
during which such payment was due.


Consistent with the terms of this Section 3.01, the Master Servicer
may waive, modify or vary any term of any Mortgage Loan or consent to the postponement of strict compliance with any such term or
in any manner grant indulgence to any Mortgagor if it has determined, exercising its good faith business judgment in the same
manner as it would if it were the owner of the related Mortgage Loan, that the security for, and the timely and full collectability
of, such Mortgage Loan would not be adversely affected by such waiver, modification, postponement or indulgence; provided, however,
that (unless the Mortgagor is in default with respect to the Mortgage Loan or in the reasonable judgment of the Master Servicer
such default is imminent) the Master Servicer shall not permit any modification with respect to any Mortgage Loan that would (i)
change the applicable Mortgage Interest Rate, defer or forgive the payment of any principal or interest, reduce the outstanding
principal balance (except for actual payments of principal) or extend the final maturity date with respect to such Mortgage Loan,
or (ii) be inconsistent with the terms of any applicable Primary Insurance Policy, FHA insurance policy, VA guaranty, hazard
insurance policy or federal flood insurance policy. Notwithstanding the foregoing, the Master Servicer shall not permit any
modification with respect to any Mortgage Loan that would both constitute a sale or exchange of such Mortgage Loan within the
meaning of Section 1001 of the Code (including any proposed, temporary or final regulations promulgated thereunder) (other than in
connection with a proposed conveyance or assumption of such Mortgage Loan that is treated as a Principal Prepayment or in a default
situation) and cause REMIC I to fail to qualify as such under the Code. The Master Servicer shall be entitled to approve a request
from a Mortgagor for a partial release of the related Mortgaged Property, the granting of an easement thereon in favor of another
Person, any alteration or demolition of the related Mortgaged Property or other similar matters if it has determined, exercising
its good faith business judgment in the same manner as it would if it were the owner of the related Mortgage Loan, that the
security for, and the timely and full collectability of, such Mortgage Loan would not be adversely affected thereby and that REMIC
I would not fail to continue to qualify as a REMIC under the Code as a result thereof and that no tax on “prohibited
transactions” or “contributions” after the startup day would be imposed on REMIC I as a result
thereof.


The Master Servicer is hereby authorized and empowered by the Trust
to, and shall, execute and deliver or cause to be executed and delivered on behalf of the Holders of the Certificates, and the
Trust or any of them, any and all instruments of satisfaction or cancellation, or of partial or full release, discharge or
modification, assignments of Mortgages and endorsements of Mortgage Notes in connection with refinancings (in jurisdictions where
such assignments are the customary and usual standard of practice of mortgage lenders) and all other comparable instruments, with
respect to the Mortgage Loans and with respect to the Mortgaged Properties. The Master Servicer is hereby further authorized and
empowered by the Trust to execute and deliver or cause to be executed and delivered on behalf of the Holders of the Certificates
and the Trust, or any of them, such instruments of assignment or other comparable instruments as the Master Servicer shall, in its
sole judgment, deem appropriate in order to register any Mortgage Loan on the MERS® System or to cause the removal of any
Mortgage Loan from registration thereon. Any expenses incurred in connection with the actions described in the preceding sentence
shall be borne by the Master Servicer with no right of reimbursement; provided, however, that any such expenses incurred as
a result of any termination by MERS of the MERS® System shall be reimbursable to the Master Servicer.  The Trustee on
behalf of the Trust shall execute and furnish to the Master Servicer, at the Master Servicer’s direction, any powers of
attorney and other documents prepared by the Master Servicer and determined by the Master Servicer to be necessary or appropriate
to enable the Master Servicer to carry out its supervisory, servicing and administrative duties under this Agreement.


The Master Servicer and each Servicer shall obtain (to the extent
generally commercially available) and maintain fidelity bond and errors and omissions coverage acceptable to Fannie Mae or Freddie
Mac with respect to their respective obligations under this Agreement and the applicable Selling and Servicing Contract,
respectively. The Master Servicer or each Servicer, as applicable, shall establish escrow accounts for, or pay when due (by means
of an advance), any tax liens in connection with the Mortgaged Properties that are not paid by the Mortgagors when due to the
extent that any such payment would not constitute a Nonrecoverable Advance when made.


In connection with the servicing and administering of each Mortgage
Loan, the Master Servicer and any affiliate of the Master Servicer (i) may perform services such as appraisals, default management
and (in the case of affiliates only) brokerage services that are not customarily provided by servicers of mortgage loans, and shall
be entitled to reasonable compensation therefor and (ii) may, at its own discretion and on behalf of the Trust, obtain credit
information in the form of a “credit score” from a credit repository.



Section 3.02.        Custodial Accounts and
Buydown Fund Accounts. The Master Servicer shall cause to be established and maintained by each Servicer under the
Master Servicer’s supervision the Custodial Account for P&I, Buydown Fund Accounts (if any) and special Custodial Account
for Reserves and shall deposit or cause to be deposited therein daily the following amounts received or advanced by the Servicer
with respect to the Mortgage Loans:


(i)        
all scheduled payments of principal;


(ii)        all
scheduled payments of interest, net of the Servicing Fees due the applicable Servicers;


(iii)       all
Curtailments and Payoffs; and


(iv)       all
Insurance Proceeds, Liquidation Proceeds, Excess Liquidation Proceeds and Subsequent Recoveries;



provided, however, that (x)
proceeds received with respect to individual Mortgage Loans from any title, hazard, or FHA insurance policy, VA guaranty, Primary
Insurance Policy or other insurance policy (other than any Special Primary Insurance Policy) covering such Mortgage Loans, if
required for the restoration or repair of the related Mortgaged Property, may be deposited either in the Custodial Account for
Reserves or the Custodial Account for P&I and (y) such proceeds (other than proceeds from any Special Primary Insurance
Policy), if not required for the restoration or repair of the related Mortgaged Property, and if not released to the Mortgagor in
accordance with prudent mortgage loan servicing practices, shall be deposited in the Custodial Account for P&I, and shall be
applied to the balances of the related Mortgage Loans as payments of interest and principal.


The Master Servicer is hereby authorized to make withdrawals from and
to issue drafts against the Custodial Accounts for P&I and the Custodial Accounts for Reserves for the purposes required or
permitted by this Agreement. Each Custodial Account for P&I and each Custodial Account for Reserves shall bear a designation
clearly showing the respective interests of the applicable Servicer, as trustee, and of the Master Servicer, in substantially one
of the following forms:



(a)       
With respect to the Custodial Account for P&I: (i) [Servicer’s Name], as agent, trustee and/or bailee of principal and
interest custodial account for Washington Mutual Mortgage Securities Corp., its successors and assigns, for various owners of
interests in Washington Mutual Mortgage Securities Corp. mortgage-backed pools or (ii) [Servicer’s Name] in trust for
Washington Mutual Mortgage Securities Corp.;



(b)       
With respect to the Custodial Account for Reserves: (i) [Servicer’s Name], as agent, trustee and/or bailee of taxes and
insurance custodial account for Washington Mutual Mortgage Securities Corp., its successors and assigns for various mortgagors
and/or various owners of interests in Washington Mutual Mortgage Securities Corp. mortgage-backed pools or (ii) [Servicer’s
Name] in trust for Washington Mutual Mortgage Securities Corp. and various Mortgagors.


The Master Servicer hereby undertakes to assure remittance to the
Certificate Account of all amounts relating to the Mortgage Loans that have been collected by any Servicer and are due to the
Certificate Account pursuant to Section 4.01 of this Agreement.


Funds held in the Custodial Account for P&I and the Custodial
Account for Reserves may, at the Master Servicer’s option, be invested in (i) one or more Eligible Investments which shall in
no event mature later than the Business Day prior to the related Withdrawal Date (except if such Eligible Investments are
obligations of the Trustee, such Eligible Investments may mature on the Withdrawal Date), or (ii) such other instruments as shall
be required to maintain the Ratings.



Section 3.03.        The Investment Account;
Eligible Investments. (a)    Not later than the Withdrawal Date, the Master Servicer shall withdraw
or direct the withdrawal of funds in the Custodial Accounts for P&I, for deposit in the Investment Account, in an amount
representing:


(i)                 
Scheduled installments of principal and interest on the Mortgage Loans received or advanced by the applicable Servicers which were
due on the related Due Date, net of the Servicing Fees due the applicable Servicers and less any amounts to be withdrawn later by
the applicable Servicers from the applicable Buydown Fund Accounts;


(ii)                Payoffs and the
proceeds of other types of liquidations of the Mortgage Loans received by the applicable Servicer for such Mortgage Loans during
the applicable Payoff Period, with interest to the date of Payoff or liquidation less any amounts to be withdrawn later by the
applicable Servicers from the applicable Buydown Fund Accounts; and


(iii)               Curtailments received by
the applicable Servicers in the Prior Period.


At its option, the Master Servicer may invest funds withdrawn from the
Custodial Accounts for P&I, as well as any Buydown Funds, Insurance Proceeds and Liquidation Proceeds previously received by
the Master Servicer (including amounts paid by the Company in respect of any Purchase Obligation or its substitution obligations
set forth in Section 2.07 or Section 2.08 or in connection with the exercise of the option to terminate this Agreement pursuant to
Section 9.01) for its own account and at its own risk, during any period prior to their deposit in the Certificate Account. Such
funds, as well as any funds which were withdrawn from the Custodial Accounts for P&I on or before the Withdrawal Date, but not
yet deposited into the Certificate Account, shall immediately be deposited by the Master Servicer with the Investment Depository in
an Investment Account in the name of the Master Servicer and the Trust for investment only as set forth in this Section 3.03. The
Master Servicer shall bear any and all losses incurred on any investments made with such funds and shall be entitled to retain all
gains realized on such investments as additional servicing compensation. Not later than the Business Day prior to the Distribution
Date, the Master Servicer shall deposit such funds, net of any gains (except Payoff Earnings) earned thereon, in the Certificate
Account.


(b)        Funds held in the
Investment Account shall be invested in (i) one or more Eligible Investments which shall in no event mature later than the Business
Day prior to the related Distribution Date (except if such Eligible Investments are obligations of the Trustee, such Eligible
Investments may mature on the Distribution Date), or (ii) such other instruments as shall be required to maintain the
Ratings.



Section 3.04.        The Certificate Account.


(a)        On or prior to the
Closing Date, the Trustee shall establish the Certificate Account, which shall be entitled “Washington Mutual Mortgage
Securities Corp. Certificate Account under the Pooling and Servicing Agreement, dated as of February 1, 2005, among Washington
Mutual Mortgage Securities Corp., as Depositor and Master Servicer, LaSalle Bank National Association, as the Trustee, and
Christiana Bank & Trust Company, as the Delaware Trustee, for the benefit of the WaMu Mortgage Pass-Through Certificates Series
2005-AR3 Trust created pursuant thereto”.  Promptly after the Closing Date, the Trustee shall communicate to the Master
Servicer the account number and wiring instructions for the Certificate Account.


Not later than the Business Day prior to the related Distribution
Date, the Master Servicer shall direct the Investment Depository to deposit into the Certificate Account the amounts previously
deposited into the Investment Account (which may include a deposit of Eligible Investments) to which the Holders of the
Certificates are entitled or which are necessary for payment of any Special Primary Insurance Premiums. In addition, not later than
the Business Day prior to the Distribution Date, the Master Servicer shall deposit into the Certificate Account any Monthly P&I
Advances or other payments required to be made by the Master Servicer pursuant to Section 4.02 of this Agreement and any Insurance
Proceeds or Liquidation Proceeds (including amounts paid by the Company in respect of any Purchase Obligation) not previously
deposited in the Custodial Accounts for P&I or the Investment Account, and any amounts paid by the Master Servicer in
connection with the exercise of its option to terminate this Agreement pursuant to Section 9.01 or any other purchase of Mortgage
Loans permitted by this Agreement.


(b)        Funds held in the
Certificate Account shall be invested at the written direction of the Master Servicer in (i) one or more Eligible Investments which
shall in no event mature later than the Business Day prior to the related Distribution Date (except if such Eligible Investments
are obligations of the Trustee, such Eligible Investments may mature on the Distribution Date), or (ii) such other instruments as
shall be required to maintain the Ratings.  The Master Servicer shall be entitled to receive any gains earned on such Eligible
Investments and shall bear any losses suffered in connection therewith.  If the Trustee has not received such written
investment directions from the Master Servicer, the Trustee shall not invest funds held in the Certificate Account.  The
Trustee shall have no liability for any losses on investments of funds held in the Certificate Account.



Section 3.05.       
 Permitted Withdrawals from the Certificate Account, the Investment Account, Custodial Accounts for P&I
 and Custodial Accounts for Reserves and of Buydown Funds from the
Buydown Fund Accounts.


(a)        The
Master Servicer is authorized to make withdrawals (or, in the case of the Certificate Account, to direct the Trustee to make
withdrawals), from time to time, from the Investment Account, the Certificate Account, the Custodial Accounts for P&I
or the Custodial Accounts for Reserves established by the
Servicers of amounts deposited therein in respect of the Certificates (and, to the extent applicable, to make deposits of the
amounts withdrawn), as follows:


(i)                  To
reimburse itself or the applicable Servicer for Monthly P&I Advances made pursuant to Section 4.02 or a Selling and Servicing
Contract, such right to reimbursement pursuant to this paragraph (i) being limited to amounts received on particular Mortgage Loans
(including, for this purpose, Insurance Proceeds and Liquidation Proceeds) which represent late recoveries of principal and/or
interest respecting which any such Monthly P&I Advance was made;


(ii)                To reimburse itself
or the applicable Servicer for amounts expended by or for the account of the Master Servicer pursuant to Section 3.09 or amounts
expended by such Servicer pursuant to the Selling and Servicing Contracts in connection with the restoration of property damaged by
an Uninsured Cause or in connection with the liquidation of a Mortgage Loan;


(iii)               To pay to itself, with
respect to the related Mortgage Loans, the Master Servicing Fee (net of Compensating Interest reduced by Payoff Earnings and Payoff
Interest) as to which no prior withdrawals from funds deposited by the Master Servicer have been made;


(iv)              
To
reimburse itself or the applicable Servicer for advances made with respect to related Mortgage Loans (except for Mortgage Loans
purchased pursuant to a Purchase Obligation or pursuant to the second or third sentence of the third paragraph of Section 3.01)

for (A) amounts advanced with respect to payments of taxes referred to in the last sentence
of the sixth paragraph of Section 3.01 (to the extent that such amounts have not otherwise been recovered by the Master
Servicer or the Servicer, as applicable), (B) amounts incurred in maintaining any insurance described in Section 3.07 and (C) for
amounts which the Master Servicer has determined to be Nonrecoverable Advances;


(v)                To pay to itself
reinvestment earnings deposited or earned in the Investment Account and the Certificate Account to which it is entitled and to
reimburse itself for expenses incurred by and reimbursable to it pursuant to Section 6.03;


(vi)              To deposit to the Investment
Account amounts in the Certificate Account not required to be on deposit therein at the time of such withdrawal;


(vii)             To deposit in the Certificate
Account, not later than the Business Day prior to the related Distribution Date, the amounts in the Investment Account specified in
Section 3.04(a);


(viii)           To pay on behalf of the Trustee any Special
Primary Insurance Premium payable by the Trustee pursuant to Section 4.01(a); provided, the Master Servicer shall give
written notice thereof to the Trustee prior to noon New York City time two Business Days prior to the applicable Distribution Date;
and



after making or providing for
the above withdrawals


(ix)              To clear and terminate the
Investment Account and the Certificate Account following termination of this Agreement pursuant to Section 9.01.


Since, in connection with withdrawals pursuant to paragraphs (i) and
(ii), the Master Servicer’s entitlement thereto is limited to collections or other recoveries on the related Mortgage Loan,
the Master Servicer or the applicable Servicer shall keep and maintain separate accounting for each Mortgage Loan, for the purpose
of justifying any such withdrawals.


(b)        The Master Servicer or
the applicable Servicer, if such Servicer holds and maintains a Buydown Fund Account, is authorized to make withdrawals, from time
to time, of Buydown Funds from the Buydown Fund Account or Custodial Account for P&I established by any Servicer under its
supervision (and, to the extent applicable, to make deposits of the amounts withdrawn), as follows:


(i)        
To deposit each month in the Investment Account the amount necessary to supplement payments received on Buydown
Loans;


(ii)        In the
event of a Payoff of any Mortgage Loan having a related Buydown Fund, to apply amounts remaining in Buydown Fund Accounts to reduce
the required amount of such principal Payoff (or, if the Mortgagor has made a Payoff, to refund such remaining Buydown Fund amounts
to the Person entitled thereto);


(iii)       In the
event of foreclosure or liquidation of any Mortgage Loan having a Buydown Fund, to deposit remaining Buydown Fund amounts in the
Investment Account as Liquidation Proceeds; and


(iv)       To clear and
terminate the portion of any account representing Buydown Funds following termination of this Agreement pursuant to Section
9.01;


(c)        The Trustee is
authorized to make withdrawals from time to time from the Certificate Account to reimburse itself for advances it has made as
successor Master Servicer pursuant to Section 7.01(a) hereof that it has determined to be Nonrecoverable Advances.


(d)        Each Servicer is
authorized to make withdrawals, from time to time, from the related Custodial Account for P&I, (i) to pay to itself, with
respect to the related Mortgage Loans, the Servicing Fee and (ii) to reimburse itself for expenses to the same extent that the
Master Servicer is authorized to make withdrawals to reimburse the Servicer for expenses pursuant to clauses (i), (ii) and (iv) of
Section 3.05(a), in the case of each of clause (d)(i) and (d)(ii), to the extent no prior withdrawals of such amounts have been
made by the Servicer or the Master Servicer.



Section 3.06.        Maintenance of Primary
Insurance Policies; Collections Thereunder. The Master Servicer shall use commercially reasonable efforts to keep,
or to cause the Servicers to keep, in full force and effect each Primary Insurance Policy (except any Special Primary Insurance
Policy) required with respect to a Mortgage Loan until no longer required, and the Master Servicer shall use commercially
reasonable efforts to keep in full force and effect each Special Primary Insurance Policy, if any. Notwithstanding the foregoing,
the Master Servicer shall have no obligation to maintain any Primary Insurance Policy for a Mortgage Loan for which the outstanding
Principal Balance thereof at any time subsequent to origination was 80% or less of the Appraised Value of the related Mortgaged
Property, unless required by applicable law.


Unless required by applicable law, the Master Servicer shall not
cancel or refuse to renew, or allow any Servicer under its supervision to cancel or refuse to renew, any Primary Insurance Policy
in effect at the date of the initial issuance of the Certificates that is required to be kept in force hereunder; provided,
however, that neither the Master Servicer nor any Servicer shall advance funds for the payment of any premium due under (i) any
Primary Insurance Policy (other than a Special Primary Insurance Policy) if it shall determine that such an advance would be a
Nonrecoverable Advance or (ii) any Special Primary Insurance Policy.



Section 3.07.        Maintenance of Hazard
Insurance. The Master Servicer shall cause to be maintained for each Mortgage Loan (other than a Cooperative Loan)
fire insurance with extended coverage in an amount which is not less than the original principal balance of such Mortgage Loan,
except in cases approved by the Master Servicer in which such amount exceeds the value of the improvements to the Mortgaged
Property. The Master Servicer shall also require fire insurance with extended coverage in a comparable amount on property acquired
upon foreclosure, or deed in lieu of foreclosure, of any Mortgage Loan (other than a Cooperative Loan). Any amounts collected under
any such policies (other than amounts to be applied to the restoration or repair of the related Mortgaged Property) shall be
deposited into the Custodial Account for P&I, subject to withdrawal pursuant to the applicable Selling and Servicing Contract
and pursuant to Section 3.03 and Section 3.05. Any unreimbursed costs incurred in maintaining any insurance described in this
Section 3.07 shall be recoverable as an advance by the Master Servicer or the applicable Servicer from the related Custodial
Account for P&I, the Investment Account or the Certificate Account. Such insurance shall be with insurers approved by the
Master Servicer and Fannie Mae or Freddie Mac. Other additional insurance may be required of a Mortgagor, in addition to that
required pursuant to such applicable laws and regulations as shall at any time be in force and as shall require such additional
insurance. Where any part of any improvement to the Mortgaged Property (other than a Mortgaged Property secured by a Cooperative
Loan) is located in a federally designated special flood hazard area and in a community which participates in the National Flood
Insurance Program at the time of origination of the related Mortgage Loan, the Master Servicer shall cause flood insurance to be
provided. The hazard insurance coverage required by this Section 3.07 may be met with blanket policies providing protection
equivalent to individual policies otherwise required. The Master Servicer or the applicable Servicer shall be responsible for
paying any deductible amount on any such blanket policy. The Master Servicer agrees to present, or cause to be presented, on behalf
of and for the benefit of the Trust, claims under the hazard insurance policy respecting any Mortgage Loan, and in this regard to
take such reasonable actions as shall be necessary to permit recovery under such policy.



Section 3.08.        Enforcement of Due-on-Sale
Clauses; Assumption Agreements. When any Mortgaged Property is about to be conveyed by the Mortgagor, the Master
Servicer shall, to the extent it has knowledge of such prospective conveyance and prior to the time of the consummation of such
conveyance, exercise on behalf of the Trust the Trust’s rights to accelerate the maturity of such Mortgage Loan, to the
extent that such acceleration is permitted by the terms of the related Mortgage Note, under any “due-on-sale” clause
applicable thereto; provided, however, that the Master Servicer shall not exercise any such right if the due-on-sale clause, in the
reasonable belief of the Master Servicer, is not enforceable under applicable law or if such exercise would result in non-coverage
of any resulting loss that would otherwise be covered under any insurance policy. In the event the Master Servicer is prohibited
from exercising such right, the Master Servicer is authorized to take or enter into an assumption and modification agreement from
or with the Person to whom a Mortgaged Property has been or is about to be conveyed, pursuant to which such Person becomes liable
under the Mortgage Note and, unless prohibited by applicable state law or unless the Mortgage Note contains a provision allowing a
qualified borrower to assume the Mortgage Note, the Mortgagor remains liable thereon; provided that the Mortgage Loan shall
continue to be covered (if so covered before the Master Servicer enters such agreement) by any related Primary Insurance Policy.
The Master Servicer is also authorized to enter into a substitution of liability agreement with such Person, pursuant to which the
original Mortgagor is released from liability and such Person is substituted as Mortgagor and becomes liable under the Mortgage
Note.  The Master Servicer shall not enter into any substitution or assumption with respect to a Mortgage Loan if such
substitution or assumption shall (i) both constitute a “significant modification” effecting an exchange or reissuance
of such Mortgage Loan under the Code (or Treasury regulations promulgated thereunder) and cause REMIC I to fail to qualify as a
REMIC under the REMIC Provisions or (ii) cause the imposition of any tax on “prohibited transactions” or
“contributions” after the startup day under the REMIC Provisions.  The Master Servicer shall notify the Trustee
that any such substitution or assumption agreement has been completed by forwarding to the Trustee the original copy of such
substitution or assumption agreement and other documents and instruments constituting a part thereof. In connection with any such
assumption or substitution agreement, the terms of the related Mortgage Note shall not be changed. Any fee collected by the
applicable Servicer for entering into an assumption or substitution of liability agreement shall be retained by such Servicer as
additional servicing compensation.


Notwithstanding the foregoing paragraph or any other provision of this
Agreement, the Master Servicer shall not be deemed to be in default, breach or any other violation of its obligations hereunder by
reason of any assumption of a Mortgage Loan by operation of law or any assumption which the Master Servicer may be restricted by
law from preventing, for any reason whatsoever.



Section 3.09.        Realization Upon Defaulted
Mortgage Loans. The Master Servicer shall foreclose upon or otherwise comparably convert, or cause to be foreclosed
upon or comparably converted, the ownership of any Mortgaged Property securing a Mortgage Loan which comes into and continues in
default and as to which no satisfactory arrangements can be made for collection of delinquent payments pursuant to Section 3.01. In
lieu of such foreclosure or other conversion, and taking into consideration the desirability of maximizing net Liquidation Proceeds
after taking into account the effect of Insurance Proceeds upon Liquidation Proceeds, the Master Servicer may, to the extent
consistent with prudent mortgage loan servicing practices, accept a payment of less than the outstanding Principal Balance of a
delinquent Mortgage Loan in full satisfaction of the indebtedness evidenced by the related Mortgage Note and release the lien of
the related Mortgage upon receipt of such payment. The Master Servicer shall not foreclose upon or otherwise comparably convert a
Mortgaged Property if the Master Servicer is aware of evidence of toxic waste, other hazardous substances or other evidence of
environmental contamination thereon and the Master Servicer determines that it would be imprudent to do so. In connection with such
foreclosure or other conversion, the Master Servicer shall cause to be followed such practices and procedures as it shall deem
necessary or advisable and as shall be normal and usual in general mortgage servicing activities. The foregoing is subject to the
provision that, in the case of damage to a Mortgaged Property from an Uninsured Cause, the Master Servicer shall not be required to
advance its own funds towards the restoration of the property unless it shall be determined in the sole judgment of the Master
Servicer, (i) that such restoration will increase the proceeds of liquidation of the Mortgage Loan to Certificateholders after
reimbursement to itself for such expenses, and (ii) that such expenses will be recoverable to it through Liquidation Proceeds. The
Master Servicer shall be responsible for all other costs and expenses incurred by it in any such proceedings; provided, however,
that it shall be entitled to reimbursement thereof (as well as its normal servicing compensation) as an advance. The Master
Servicer shall maintain information required for tax reporting purposes regarding any Mortgaged Property which is abandoned or
which has been foreclosed or otherwise comparably converted. The Master Servicer shall report such information to the Internal
Revenue Service and the Mortgagor in the manner required by applicable law.


The Master Servicer may enter into one or more special servicing
agreements with a Lowest Class B Owner, subject to each Rating Agency's acknowledgment that the Ratings of the Certificates in
effect immediately prior to the entering into of such agreement would not be qualified, downgraded or withdrawn and the
Certificates would not be placed on credit review status (except for possible upgrading) as a result of such agreement.  Any
such agreement may contain provisions whereby such Lowest Class B Owner may (a) instruct the Master Servicer to instruct a Servicer
to the extent permitted under the applicable Selling and Servicing Contract to commence or delay foreclosure proceedings with
respect to related delinquent Mortgage Loans, provided that the Lowest Class B Owner deposits a specified amount of cash with the
Master Servicer that will be available for distribution to Certificateholders if Liquidation Proceeds are less than they otherwise
may have been had the Servicer acted pursuant to its normal servicing procedures, (b) purchase such delinquent Mortgage Loans from
the Trust immediately prior to the commencement of foreclosure proceedings at a price equal to the aggregate outstanding Principal
Balance of such Mortgage Loans plus accrued interest thereon at the applicable Mortgage Interest Rate through the last day of the
month in which such Mortgage Loans are purchased and/or (c) assume all of the servicing rights and obligations with respect to such
delinquent Mortgage Loans so long as (i) the Master Servicer has the right to transfer the servicing rights and obligations of such
Mortgage Loans to another servicer and (ii) such Lowest Class B Owner will service such Mortgage Loans in accordance with the
applicable Selling and Servicing Contract.


REMIC I shall not acquire any real property (or personal property
incident to such real property) except in connection with a default or imminent default of a Mortgage Loan. In the event that REMIC
I acquires any real property (or personal property incident to such real property) in connection with a default or imminent default
of a Mortgage Loan, such property shall be disposed of by the Master Servicer as soon as practicable in a manner that, consistent
with prudent mortgage loan servicing practices, maximizes the net present value of the recovery to the Trust, but in any event
within three years after its acquisition by the Master Servicer for REMIC I unless the Master Servicer provides to the Trustee an
Opinion of Counsel to the effect that the holding by REMIC I of such Mortgaged Property subsequent to three years after its
acquisition will not result in the imposition of taxes on “prohibited transactions” of REMIC I as defined in Section
860F of the Code or under the law of any state in which real property securing a Mortgage Loan owned by REMIC I is located or cause
REMIC I to fail to qualify as a REMIC for federal income tax purposes or for state tax purposes under the laws of any state in
which real property securing a Mortgage Loan owned by REMIC I is located at any time that any Certificates are outstanding. The
Master Servicer shall conserve, protect and operate each such property for the Certificateholders solely for the purpose of its
prompt disposition and sale in a manner which does not cause such property to fail to qualify as “foreclosure property”
within the meaning of Section 860G(a)(8) or result in the receipt by the REMIC of any “income from non-permitted
assets” within the meaning of Section 860F(a)(2)(B) of the Code or any “net income from foreclosure property”
which is subject to taxation under the REMIC Provisions. Pursuant to its efforts to sell such property, the Master Servicer shall
either itself or through an agent selected by the Master Servicer protect and conserve such property in the same manner and to such
extent as is customary in the locality where such property is located and may, incident to its conservation and protection of the
assets of the Trust, rent the same, or any part thereof, as the Master Servicer deems to be in the best interest of the Master
Servicer and the Trust for the period prior to the sale of such property. Additionally, the Master Servicer shall perform the tax
withholding and shall file information returns with respect to the receipt of mortgage interests received in a trade or business,
the reports of foreclosures and abandonments of any Mortgaged Property and the information returns relating to cancellation of
indebtedness income with respect to any Mortgaged Property required by Sections 6050H, 6050J and 6050P, respectively, of the Code,
and deliver to the Trustee an Officers’ Certificate on or before March 31 of each year stating that such reports have been
filed.  Such reports shall be in form and substance sufficient to meet the reporting requirements imposed by Sections 6050H,
6050J and 6050P of the Code.


Notwithstanding any other provision of this Agreement, the Master
Servicer and the Trustee, as applicable, shall comply with all federal withholding requirements with respect to payments to
Certificateholders of interest or original issue discount that the Master Servicer or the Trustee reasonably believes are
applicable under the Code.  The consent of Certificateholders shall not be required for any such withholding.  Without
limiting the foregoing, the Master Servicer agrees that it will not withhold with respect to payments of interest or original issue
discount in the case of a Certificateholder that has furnished or caused to be furnished an effective Form W-8 or an acceptable
substitute form or a successor form and who is not a “10 percent shareholder” within the meaning of Code Section
871(h)(3)(B) or a “controlled foreign corporation” described in Code Section 881(c)(3)(C) with respect to REMIC I or
the depositor.  In the event the Trustee withholds any amount from interest or original issue discount payments or advances
thereof to any Certificateholder pursuant to federal withholding requirements, the Trustee shall indicate the amount withheld to
such Certificateholder.



Section 3.10.        Trustee to Cooperate; Release
of Mortgage Files. Upon the Payoff or scheduled maturity of any Mortgage Loan, the Master Servicer shall cause such
final payment to be immediately deposited in the related Custodial Account for P&I or the Investment Account.  The Master
Servicer shall promptly notify the Trustee thereof by a certification (which certification shall include a statement to the effect
that all amounts received in connection with such payment which are required to be deposited in either such account have been so
deposited) of a Servicing Officer and shall request delivery to it of the Mortgage File; provided, however, that such
certification shall not be required if the Mortgage File is held by a Custodian which is also the Servicer of the Mortgage Loan.
Upon receipt of such certification and request, the Trustee (or Custodian) shall, not later than the fifth succeeding Business Day,
release, or cause to be released, the related Mortgage File to the Master Servicer or the applicable Servicer indicated in such
request. With any such Payoff or other final payment, the Master Servicer is authorized (i) to prepare for and procure from the
trustee or mortgagee under the Mortgage which secured the Mortgage Note a deed of full reconveyance or other form of satisfaction
or assignment of Mortgage and endorsement of Mortgage Note in connection with a refinancing covering the Mortgaged Property, which
satisfaction, endorsed Mortgage Note or assigning document shall be delivered by the Master Servicer to the person or persons
entitled thereto, and (ii) with respect to any MERS Loan, to cause the removal of such Mortgage Loan from registration on the
MERS® System. No expenses incurred in connection with such satisfaction or assignment shall be payable to the Master Servicer
by the Trustee or from the Certificate Account, the related Investment Account or the related Custodial Account for P&I. From
time to time as appropriate for the servicing or foreclosure of any Mortgage Loan, including, for this purpose, collection under
any Primary Insurance Policy, the Trustee shall, upon request of the Master Servicer and delivery to it of a trust receipt signed
by a Servicing Officer, release not later than the fifth Business Day following the date of receipt of such request and trust
receipt the related Mortgage File to the Master Servicer or the related Servicer as indicated by the Master Servicer and shall
execute such documents as shall be necessary to the prosecution of any such proceedings. Such trust receipt shall obligate the
Master Servicer to return the Mortgage File to the Trustee when the need therefor by the Master Servicer no longer exists, unless
the Mortgage Loan shall be liquidated, in which case, upon receipt of a certificate of a Servicing Officer similar to that herein
above specified, the trust receipt shall be released by the Trustee to the Master Servicer.



Section 3.11.        Compensation to the Master
Servicer and the Servicers. As compensation for its activities hereunder, the Master Servicer shall be entitled to
receive from the Investment Account and the Certificate Account the amounts provided for by Section 3.05(a)(iii). The Master
Servicer shall be required to pay all expenses incurred by it in connection with its activities hereunder and shall not be entitled
to reimbursement therefor, except as specifically provided herein.


As compensation for its activities under the applicable Selling and
Servicing Contract, the applicable Servicer shall be entitled to withhold or withdraw from the related Custodial Account for
P&I the amounts provided for in such Selling and Servicing Contract to the extent not inconsistent with this Agreement
(including Section 3.05(d)). Each Servicer is required to pay all expenses incurred by it in connection with its servicing
activities under its Selling and Servicing Contract (including payment of premiums for Primary Insurance Policies, other than
Special Primary Insurance Policies, if required) and shall not be entitled to reimbursement therefor except as specifically
provided in such Selling and Servicing Contract and not inconsistent with this Agreement.



Section 3.12.        Reports to the Trustee;
Certificate Account Statement. Not later than 15 days after each Distribution Date, the Master Servicer shall
forward a statement, certified by a Servicing Officer, to the Trustee setting forth the status of the Certificate Account as of the
close of business on such Distribution Date and showing, for the period covered by such statement, the aggregate of deposits into
and withdrawals from the Certificate Account for each category of deposit specified in Section 3.04 and each category of withdrawal
specified in Section 3.05, and stating that all distributions required by this Agreement have been made (or if any required
distribution has not been made, specifying the nature and amount thereof).  The Trustee shall make available such statements
to any Certificateholder upon request at the expense of the Master Servicer.  Such statement shall also, to the extent
available, include information regarding delinquencies on the Mortgage Loans, indicating the number and aggregate Principal Balance
of Mortgage Loans which are one, two, three or more months delinquent, the number and aggregate Principal Balance of Mortgage Loans
with respect to which foreclosure proceedings have been initiated and the book value of any Mortgaged Property acquired by the
Trust through foreclosure, deed in lieu of foreclosure or other exercise of the Trust’s security interest in the Mortgaged
Property.  The filing of such statement and reports with the Trustee is for informational purposes only, and, except for
making available such statements and reports to any Certificateholder, upon request, the Trustee shall have no responsibility with
respect thereto.



Section 3.13.        Annual Statement as to
Compliance. The Master Servicer shall deliver to the Trustee, on or before April 30 of each year, beginning with the
first April 30 succeeding the Cut-Off Date by at least six months, an Officer’s Certificate stating as to the signer thereof,
that (i) a review of the activities of the Master Servicer during the preceding calendar year and performance under this Agreement
has been made under such officer’s supervision, and (ii) to the best of such officer’s knowledge, based on such review,
the Master Servicer has fulfilled all its obligations under this Agreement throughout such year, or, if there has been a default in
the fulfillment of any such obligation, specifying each such default known to such officer and the nature and status thereof.
Copies of such statement shall be provided by the Master Servicer to Certificateholders upon request or by the Trustee (solely to
the extent that such copies are available to the Trustee) at the expense of the Master Servicer, should the Master Servicer fail to
so provide such copies. 



Section 3.14.        Access to Certain
Documentation and Information Regarding the Mortgage Loans. In the event that the Certificates are legal for
investment by federally-insured savings associations, the Master Servicer shall provide to the OTS, the FDIC and the supervisory
agents and examiners of the OTS and the FDIC access to the documentation regarding the related Mortgage Loans required by
applicable regulations of the OTS or the FDIC, as applicable, and shall in any event provide such access to the documentation
regarding such Mortgage Loans to the Trustee and its representatives, such access being afforded without charge, but only upon
reasonable request and during normal business hours at the offices of the Master Servicer designated by it.



Section 3.15.        Annual Independent Public
Accountants’ Servicing Report. On or before April 30 of each year, beginning with the first April 30
succeeding the Cut-Off Date by at least six months, the Master Servicer, at its expense, shall furnish to the Trustee a copy of a
report delivered to the Master Servicer by a firm of independent public accountants (who may also render other services to the
Master Servicer or any affiliate thereof) to the effect that, on the basis of an examination conducted by such firm in accordance
with standards established by the American Institute of Certified Public Accountants, the Master Servicer has complied with certain
minimum residential mortgage loan servicing standards in its role as Master Servicer with respect to the servicing of residential
mortgage loans (including the Mortgage Loans) during the most recently completed fiscal year.  In rendering its report such
firm may rely, (a) as to matters relating to the Certificates, upon a statistical sampling of series of mortgage-backed
certificates which may include the Certificates and (b) as to matters relating to the direct servicing of residential mortgage
loans by subservicers, upon comparable reports of firms of independent certified public accountants rendered on the basis of
examinations conducted in accordance with the same standards (rendered within one year of such report) with respect to those
subservicers.



Section 3.16.        [Reserved.]



Section 3.17.        [Reserved.]



Section 3.18.        [Reserved.]



Section 3.19.        [Reserved.]



Section 3.20.        Assumption or Termination of
Selling and Servicing Contracts by Trustee. In the event the Master Servicer, or any successor Master Servicer,
shall for any reason no longer be the Master Servicer (including by reason of an Event of Default), the Trustee as trustee
hereunder or its designee shall thereupon assume all of the rights and obligations of the Master Servicer under the Selling and
Servicing Contracts with respect to the related Mortgage Loans unless the Trustee elects to terminate the Selling and Servicing
Contracts with respect to such Mortgage Loans in accordance with the terms thereof. The Trustee, its designee or the successor
servicer for the Trustee shall be deemed to have assumed all of the Master Servicer’s interest therein with respect to the
related Mortgage Loans and to have replaced the Master Servicer as a party to the Selling and Servicing Contracts to the same
extent as if the rights and duties under the Selling and Servicing Contracts relating to such Mortgage Loans had been assigned to
the assuming party, except that the Master Servicer shall not thereby be relieved of any liability or obligations under the Selling
and Servicing Contracts with respect to the Master Servicer’s duties to be performed prior to its termination hereunder.


The Master Servicer at its expense shall, upon request of the Trustee,
deliver to the assuming party all documents and records relating to the Selling and Servicing Contracts and the Mortgage Loans then
being master serviced by the Master Servicer and an accounting of amounts collected and held by the Master Servicer and otherwise
use its best efforts to effect the orderly and efficient transfer of the rights and duties under the related Selling and Servicing
Contracts relating to such Mortgage Loans to the assuming party.



ARTICLE
IV



Payments to Certificateholders; Payment of Expenses



Section 4.01.        Distributions to
Certificateholders; Payment of Special Primary Insurance Premiums .  On each Distribution Date, the Trustee (or
any duly appointed paying agent) shall (i) subject to Section 3.05(a)(viii), withdraw from the Certificate Account any Special
Primary Insurance Premium payable on such Distribution Date and pay such amount to the insurer under the applicable Special Primary
Insurance Policy and (ii) withdraw from the Certificate Account the Available Distribution Amount for such Distribution Date and
distribute, from the amount so withdrawn, to the extent of the Available Distribution Amount, the Distribution Amount to the
Certificateholders, all in accordance with the written statement received from the Master Servicer pursuant to Section 4.02(b) and
without any responsibility to recalculate, verify or confirm the information in such statement.  Any Special Primary Insurance
Premiums distributed pursuant to clause (i) above shall be distributed by means of payment acceptable to the insurer under the
respective Special Primary Insurance Policy as directed by the related insurer to the Master Servicer.  Amounts distributed to
the Certificateholders pursuant to clause (ii) above shall be distributed by wire transfer in immediately available funds for the
account of, or by check mailed to, each such Certificateholder of record on the immediately preceding Record Date (other than as
provided in Section 9.01 respecting the final distribution), as specified by each such Certificateholder and at the address of such
Holder appearing in the Certificate Register.


(b)        All reductions in the
Certificate Principal Balance of a Certificate effected by distributions of principal and all allocations of Realized Losses made
on any Distribution Date shall be binding upon all Holders of such Certificate and of any Certificate issued upon the registration
of transfer or exchange therefor or in lieu thereof, whether or not such distribution is noted on such Certificate. The final
distribution of principal of each Certificate (and the final distribution upon the Class R Certificates upon (i) the termination of
REMIC I and (ii) the payment, or making provision for payment, of all liabilities of the Trust) shall be payable in the manner
provided above only upon presentation and surrender thereof on or after the Distribution Date therefor at the office or agency of
the Certificate Registrar specified in the notice delivered pursuant to Section 4.01(c)(ii) and Section 9.01(b).


(c)        Whenever, on the basis
of Curtailments, Payoffs and Monthly Payments on the Mortgage Loans and Insurance Proceeds and Liquidation Proceeds received and
expected to be received during the Payoff Period, the Master Servicer has notified the Trustee in writing by the 15th day of the
month that it believes that the entire remaining unpaid Class Principal Balance of any Class of Certificates will become
distributable on the next Distribution Date, the Trustee shall, no later than the 18th day of the month of such Distribution Date,
mail or cause to be mailed to each Person in whose name a Certificate to be so retired is registered at the close of business on
the Record Date and to the Rating Agencies a notice to the effect that:


(i)                  it is
expected that funds sufficient to make such final distribution will be available in the Certificate Account on such Distribution
Date, and


(ii)                if such funds are
available, (A) such final distribution will be payable on such Distribution Date, but only upon presentation and surrender of such
Certificate at the office or agency of the Certificate Registrar maintained for such purpose (the address of which shall be set
forth in such notice), and (B) no interest shall accrue on such Certificate after such Distribution Date.



Section 4.02.        Advances by the Master
Servicer; Distribution Reports to the Trustee.


(a)        To the extent described
below, the Master Servicer is obligated to advance its own funds to the Certificate Account to cover any shortfall between (i)
payments scheduled to be received in respect of Mortgage Loans, and (ii) the amounts actually deposited in the Certificate Account
on account of such payments (including amounts advanced by a Servicer pursuant to a Selling and Servicing Contract). The Master
Servicer’s obligation to make any advance or advances described in this Section 4.02 is effective only to the extent that
such advance is, in the good faith judgment of the Master Servicer made on or before the second Business Day prior to each
Distribution Date, reimbursable from Insurance Proceeds or Liquidation Proceeds of the related Mortgage Loans or recoverable as
late Monthly Payments with respect to the related Mortgage Loans or otherwise.


Prior to the close of business on the second Business Day prior to
each Distribution Date, the Master Servicer shall determine whether or not it will make a Monthly P&I Advance on the Business
Day prior to such Distribution Date (in the event that the applicable Servicer fails to make such advances) and shall furnish a
written statement to the Trustee, the Paying Agent, if any, and to any Certificateholder requesting the same, setting forth the
aggregate amount to be advanced on account of principal and interest in respect of the Mortgage Loans, stated
separately.


In the event that the Master Servicer shall be required to make a
Monthly P&I Advance, it shall on the Business Day prior to the related Distribution Date either (i) deposit in the Certificate
Account an amount equal to such Monthly P&I Advance, (ii) make an appropriate entry in the records of the Certificate Account
that funds in such account being held for future distribution or withdrawal have been, as permitted by this Section 4.02, used by
the Master Servicer to make such Monthly P&I Advance, or (iii) make advances in the form of any combination of (i) and (ii)
aggregating the amount of such Monthly P&I Advance. Any funds being held for future distribution to Certificateholders and so
used shall be replaced by the Master Servicer by deposit in the Certificate Account on the Business Day immediately preceding any
future Distribution Date to the extent that funds in the Certificate Account on such Distribution Date with respect to the Mortgage
Loans shall be less than payments to Certificateholders required to be made on such date with respect to the Mortgage Loans. Under
each Selling and Servicing Contract, the Master Servicer is entitled to receive from the Custodial Accounts for P&I established
by the Servicers amounts received by the applicable Servicers on particular Mortgage Loans as late payments of principal and
interest or as Liquidation or Insurance Proceeds and respecting which the Master Servicer has made an unreimbursed advance of
principal and interest. The Master Servicer is also entitled to receive other amounts from the related Custodial Accounts for
P&I established by the Servicers to reimburse itself for prior Nonrecoverable Advances respecting Mortgage Loans serviced by
such Servicers. The Master Servicer shall deposit these amounts in the Investment Account prior to withdrawal pursuant to Section
3.05.


In accordance with Section 3.05, Monthly P&I Advances are
reimbursable to the Master Servicer from cash in the Investment Account or the Certificate Account to the extent that the Master
Servicer shall determine that any such advances previously made are Nonrecoverable Advances pursuant to Section 4.03.


(b)        Prior to noon New York
City time two Business Days prior to each Distribution Date, the Master Servicer shall provide (x) the Trustee and (y) the Company
(if the Company is no longer acting as Master Servicer) with a statement in writing of (1) the amount, as applicable, of (i)
interest, (ii) the interest portion, if any, of Realized Losses, (iii) Uncompensated Interest Shortfall, (iv) scheduled principal,
(v) Principal Prepayments, (vi) Liquidation Principal, (vii) Subsequent Recoveries, (viii) the principal portion of Realized Losses
(after giving effect to any reduction thereof by application of any Cumulative Carry-Forward Subsequent Recoveries Amount), (ix)
the Residual Distribution Amount and (x) the Excess Liquidation Proceeds to be distributed or allocated, as applicable, to each
Class of Certificates on such Distribution Date (such amounts to be determined in accordance with the definition of
“Distribution Amount” and Section 4.01 hereof and other related definitions set forth in Article I hereof); (2) the
applicable Class Principal Balance after giving effect to such distributions and allocations; (3) the Cumulative Carry-Forward
Subsequent Recoveries Amount for such Distribution Date; and (4) the amount of any Special Primary Insurance Premium payable on
such Distribution Date.



Section 4.03.        Nonrecoverable
Advances. Any advance previously made by a Servicer pursuant to its Selling and Servicing Contract with respect to a
Mortgage Loan or by the Master Servicer that the Master Servicer shall determine in its good faith judgment not to be ultimately
recoverable from Insurance Proceeds or Liquidation Proceeds or otherwise with respect to such Mortgage Loan or recoverable as late
Monthly Payments with respect to such Mortgage Loan shall be a Nonrecoverable Advance. The determination by the Master Servicer
that it or the applicable Servicer has made a Nonrecoverable Advance or that any advance would constitute a Nonrecoverable Advance,
shall be evidenced by an Officer’s Certificate of the Master Servicer delivered to the Trustee on the Determination Date and
detailing the reasons for such determination.  Notwithstanding any other provision of this Agreement, any insurance policy
relating to the Mortgage Loans, or any other agreement relating to the Mortgage Loans to which the Company or the Master Servicer
is a party, (a) the Master Servicer and each Servicer shall not be obligated to, and shall not, make any advance that, after
reasonable inquiry and in its sole discretion, the Master Servicer or such Servicer shall determine would be a Nonrecoverable
Advance, and (b) the Master Servicer and each Servicer shall be entitled to reimbursement for any advance as provided in Section
3.05(a)(i), (ii) and (iv) and Section 3.05(d) of this Agreement.



Section 4.04.        Statements to
Certificateholders. With each distribution from the Certificate Account on a Distribution Date, the Trustee shall
send to each Rating Agency and shall make available to each Certificateholder the statement required by Section 4.02(b). The
Trustee may make available such statement and certain other information, including, without limitation, information required to be
provided by the Trustee pursuant to Sections 3.12 and 3.13, to Certificateholders through the Trustee’s Corporate Trust home
page on the world wide web. Such web page is currently located at “www.etrustee.net”.  The location of such web
page and the procedures used therein are subject to change from time to time at the Trustee’s discretion.


Upon request by any Certificateholder or Rating Agency or the Trustee,
the Master Servicer shall forward to such Certificateholder or Rating Agency and the Trustee and the Company (if the Company is no
longer acting as Master Servicer) an additional report which sets forth with respect to the Mortgage Loans:



(a)       
The number and aggregate Principal Balance of the Mortgage Loans delinquent one, two and three months or more;



(b)       
The (i) number and aggregate Principal Balance of Mortgage Loans with respect to which foreclosure proceedings have been initiated,
and (ii) the number and aggregate book value of Mortgaged Properties acquired through foreclosure, deed in lieu of foreclosure or
other exercise of rights respecting the Trust’s security interest in the Mortgage Loans; and



(c)       
The cumulative amount of Realized Losses allocated to the related Certificates since the Cut-Off Date.


Upon request by any Certificateholder, the Master Servicer, as soon as
reasonably practicable, shall provide the requesting Certificateholder with such information as is necessary and appropriate, in
the Master Servicer’s sole discretion, for purposes of satisfying applicable reporting requirements under Rule 144A of the
Securities Act.


The Company may make available any reports, statements or other
information to Certificateholders through the Company’s home page on the world wide web. As of the Closing Date, such web
page is located at “www.wamumsc.com” and information is available by clicking on “Investor
Information.”



ARTICLE
V



The Certificates



Section 5.01.        The
Certificates.


(a)        The Certificates shall
be substantially in the forms set forth in Exhibits A and B with the additional insertion from Exhibit H attached hereto, and shall
be executed by the Trustee on behalf of the Trust, authenticated by the Trustee (or any duly appointed Authenticating Agent) and
delivered (i) upon and pursuant to the order of the Company and (ii) upon receipt by the Trustee of the documents specified in
Section 2.01. The Certificates shall be issuable in Authorized Denominations. Certificates shall be executed by manual or facsimile
signature on behalf of the Trust by authorized officers of the Trustee. Certificates bearing the manual or facsimile signatures of
individuals who were at the time of execution the proper officers of the Trustee shall bind the Trust, notwithstanding that such
individuals or any of them have ceased to hold such offices prior to the authentication and delivery of such Certificates or did
not hold such offices at the date of such Certificates. No Certificate shall be entitled to any benefit under this Agreement, or be
valid for any purpose, unless there appears on such Certificate a certificate of authentication substantially in the form provided
for herein executed by the Trustee or any Authenticating Agent by manual signature, and such certificate upon any Certificate shall
be conclusive evidence, and the only evidence, that such Certificate has been duly authenticated and delivered hereunder. All
Certificates shall be dated the date of their authentication.


(b)        The following
definitions apply for purposes of this Section 5.01: “Disqualified Organization” means any Person which is not a
Permitted Transferee, but does not include any “Pass-Through Entity” which owns or holds a Residual Certificate and of
which a Disqualified Organization, directly or indirectly, may be a stockholder, partner or beneficiary; “Pass-Through
Entity” means any regulated investment company, real estate investment trust, common trust fund, partnership, trust or
estate, and any organization to which Section 1381 of the Code applies; “Ownership Interest” means, with respect
to any Residual Certificate, any ownership or security interest in such Residual Certificate, including any interest in a Residual
Certificate as the Holder thereof and any other interest therein whether direct or indirect, legal or beneficial, as owner or as
pledgee; “Transfer” means any direct or indirect transfer or sale of, or directly or indirectly transferring or
selling any Ownership Interest in a Residual Certificate; and “Transferee” means any Person who is acquiring by
Transfer any Ownership Interest in a Residual Certificate.


(c)        Restrictions on
Transfers of the Residual Certificates to Disqualified Organizations are set forth in this Section 5.01(c).


(i)                  Each
Person who has or who acquires any Ownership Interest in a Residual Certificate shall be deemed by the acceptance or acquisition of
such Ownership Interest to have agreed to be bound by the following provisions and to have irrevocably authorized the Trustee or
its designee under clause (iii)(A) below to deliver payments to a Person other than such Person and to negotiate the terms of any
mandatory sale under clause (iii)(B) below and to execute all instruments of transfer and to do all other things necessary in
connection with any such sale. The rights of each Person acquiring any Ownership Interest in a Residual Certificate are expressly
subject to the following provisions:



(A)       Each
Person holding or acquiring any Ownership Interest in a Residual Certificate shall be a Permitted Transferee and shall promptly
notify the Trustee of any change or impending change in its status as a Permitted Transferee.



(B)       In
connection with any proposed Transfer of any Ownership Interest in a Residual Certificate to a U.S. Person, the Trustee shall
require delivery to it, and shall not register the Transfer of any Residual Certificate until its receipt of (1) an affidavit and
agreement (a “Transferee Affidavit and Agreement”) attached hereto as Exhibit J from the proposed Transferee, in
form and substance satisfactory to the Company, representing and warranting, among other things, that it is not a Non-U.S. Person,
that such transferee is a Permitted Transferee, that it is not acquiring its Ownership Interest in the Residual Certificate that is
the subject of the proposed Transfer as a nominee, trustee or agent for any Person who is not a Permitted Transferee, that for so
long as it retains its Ownership Interest in a Residual Certificate, it will endeavor to remain a Permitted Transferee, and that it
has reviewed the provisions of this Section 5.01(c) and agrees to be bound by them, and (2) a certificate, attached hereto as
Exhibit I, from the Holder wishing to transfer the Residual Certificate, in form and substance satisfactory to the Company,
representing and warranting, among other things, that no purpose of the proposed Transfer is to allow such Holder to impede the
assessment or collection of tax.



(C)      
Notwithstanding the delivery of a Transferee Affidavit and Agreement by a proposed Transferee under clause (B) above, if the
Trustee has actual knowledge that the proposed Transferee is not a Permitted Transferee, no Transfer of an Ownership Interest in a
Residual Certificate to such proposed Transferee shall be effected.



(D)       Each
Person holding or acquiring any Ownership Interest in a Residual Certificate agrees by holding or acquiring such Ownership Interest
(i) to require a Transferee Affidavit and Agreement from any other Person to whom such Person attempts to transfer its Ownership
Interest and to provide a certificate to the Trustee in the form attached hereto as Exhibit J; (ii) to obtain the express written
consent of the Company prior to any transfer of such Ownership Interest, which consent may be withheld in the Company’s sole
discretion; and (iii) to provide a certificate to the Trustee in the form attached hereto as Exhibit I.


(ii)                The Trustee shall
register the Transfer of any Residual Certificate only if it shall have received the Transferee Affidavit and Agreement, a
certificate of the Holder requesting such transfer in the form attached hereto as Exhibit J and all of such other documents as
shall have been reasonably required by the Trustee as a condition to such registration.


(iii)      
(A)       If any “disqualified organization” (as defined in Section 860E(e)(5) of the
Code) shall become a holder of a Residual Certificate, then the last preceding Permitted Transferee shall be restored, to the
extent permitted by law, to all rights and obligations as Holder thereof retroactive to the date of registration of such Transfer
of such Residual Certificate. If any Non-U.S. Person shall become a holder of a Residual Certificate, then the last preceding
holder which is a U.S. Person shall be restored, to the extent permitted by law, to all rights and obligations as Holder thereof
retroactive to the date of registration of the Transfer to such Non-U.S. Person of such Residual Certificate. If a transfer of a
Residual Certificate is disregarded pursuant to the provisions of Treasury Regulations Section 1.860E-1 or Section 1.860G-3, then
the last preceding Permitted Transferee shall be restored, to the extent permitted by law, to all rights and obligations as Holder
thereof retroactive to the date of registration of such Transfer of such Residual Certificate. Neither the Trust nor the Trustee
shall be under any liability to any Person for any registration of Transfer of a Residual Certificate that is in fact not permitted
by this Section 5.01(c) or for making any payments due on such Certificate to the holder thereof or for taking any other action
with respect to such holder under the provisions of this Agreement.



(B)       If any purported Transferee shall become a Holder of a Residual Certificate in
violation of the restrictions in this Section 5.01(c) and to the extent that the retroactive restoration of the rights of the
Holder of such Residual Certificate as described in clause (iii)(A) above shall be invalid, illegal or unenforceable, then the
Company shall have the right, without notice to the Holder or any prior Holder of such Residual Certificate, to sell such Residual
Certificate to a purchaser selected by the Company on such terms as the Company may choose. Such purported Transferee shall
promptly endorse and deliver each Residual Certificate in accordance with the instructions of the Company. Such purchaser may be
the Company itself or any affiliate of the Company. The proceeds of such sale, net of the commissions (which may include
commissions payable to the Company or its affiliates), expenses and taxes due, if any, shall be remitted by the Company to such
purported Transferee. The terms and conditions of any sale under this clause (iii)(B) shall be determined in the sole discretion of
the Company, and the Company shall not be liable to any Person having an Ownership Interest in a Residual Certificate as a result
of its exercise of such discretion.


(iv)       The Company,
on behalf of the Trustee, shall make available, upon written request from the Trustee, all information necessary to compute any tax
imposed (A) as a result of the Transfer of an Ownership Interest in a Residual Certificate to any Person who is not a Permitted
Transferee, including the information regarding “excess inclusions” of such Residual Certificates required to be
provided to the Internal Revenue Service and certain Persons as described in Treasury Regulation Section 1.860D-1(b)(5), and (B) as
a result of any regulated investment company, real estate investment trust, common trust fund, partnership, trust, estate or
organizations described in Section 1381 of the Code having as among its record holders at any time any Person who is not a
Permitted Transferee. Reasonable compensation for providing such information may be required by the Company from such
Person.


(v)        The
provisions of this Section 5.01 set forth prior to this Section (v) may be modified, added to or eliminated by the Company and the
Trustee, provided that there shall have been delivered to the Trustee the following:



(A)       written notification from each of the Rating Agencies to the effect that the
modification, addition to or elimination of such provisions will not cause such Rating Agency to downgrade its then-current Ratings
of the Certificates; and



(B)       an Opinion of Counsel, in form and substance satisfactory to the Company (as
evidenced by a certificate of the Company), to the effect that such modification, addition to or absence of such provisions will
not cause REMIC I to cease to qualify as a REMIC and will not create a risk that (1) REMIC I may be subject to an entity-level tax
caused by the Transfer of any Residual Certificate to a Person which is not a Permitted Transferee or (2) a Certificateholder or
another Person will be subject to a REMIC-related tax caused by the Transfer of a Residual Certificate to a Person which is not a
Permitted Transferee.


(vi)       The
following legend shall appear on all Residual Certificates:



ANY RESALE, TRANSFER OR OTHER
DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE
TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN
GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER
THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH
ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF
THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A
“DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO
ENABLE THE TRANSFEROR TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE
FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE
OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH
REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A
CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH
HOLDER OF THE CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS
PARAGRAPH.


(vii)      The Tax Matters
Person for REMIC I, while not a Disqualified Organization, shall be the tax matters person for REMIC I within the meaning of
Section 6231(a)(7) of the Code and Treasury Regulation Section 1.860F-4(d).


(d)        In the case of any
Junior Subordinate Certificate presented for registration in the name of any Person, the Trustee shall require (i) an
officer’s certificate substantially in the form of Exhibit N attached hereto acceptable to and in form and substance
satisfactory to the Trustee and the Company, which officer’s certificate shall not be an expense of the Trust, the Trustee,
the Delaware Trustee, the Master Servicer or the Company, and (ii) only if such officer’s certificate indicates that a
Benefit Plan Opinion is delivered in connection therewith, a Benefit Plan Opinion.


In the case of any Residual Certificate presented for registration in
the name of any Person, the Trustee shall require (i) a Transferee Affidavit and Agreement which includes the representation set
forth in paragraph 19 of the form attached hereto as Exhibit J and (ii) only if the representation set forth in such paragraph 19
indicates that a Benefit Plan Opinion is delivered in connection therewith, a Benefit Plan Opinion.


(e)        No transfer, sale,
pledge or other disposition of a Junior Subordinate Certificate shall be made unless such transfer, sale, pledge or other
disposition is made in accordance with this Section 5.01(e) or Section 5.01(f).  Each Person who, at any time, acquires any
ownership interest in any Junior Subordinate Certificate shall be deemed by the acceptance or acquisition of such ownership
interest to have agreed to be bound by the following provisions of this Section 5.01(e) and Section 5.01(f), as applicable. No
transfer of a Junior Subordinate Certificate shall be deemed to be made in accordance with this Section 5.01(e) unless such
transfer is made pursuant to an effective registration statement under the Securities Act or unless the Trustee is provided with
the certificates and an Opinion of Counsel, if required, on which the Trustee may conclusively rely, to the effect that such
transfer is exempt from the registration requirements under the Securities Act, as follows:  In the event that a transfer is
to be made in reliance upon an exemption from the Securities Act, the Trustee shall require, in order to assure compliance with the
Securities Act, that the Certificateholder desiring to effect such transfer certify to the Trustee in writing, in substantially the
form attached hereto as Exhibit F, the facts surrounding the transfer, with such modifications to such Exhibit F as may be
appropriate to reflect the actual facts of the proposed transfer, and that the Certificateholder’s proposed transferee
certify to the Trustee in writing, in substantially the form attached hereto as Exhibit G, the facts surrounding the transfer, with
such modifications to such Exhibit G as may be appropriate to reflect the actual facts of the proposed transfer. If such
certificate of the proposed transferee does not contain substantially the substance of Exhibit G, the Trustee shall require an
Opinion of Counsel that such transfer may be made without registration, which Opinion of Counsel shall not be obtained at the
expense of the Trustee, the Delaware Trustee, the Trust or the Company. Such Opinion of Counsel shall allow for the forwarding, and
the Trustee shall forward, a copy thereof to the Rating Agencies. Notwithstanding the foregoing, any Junior Subordinate Certificate
may be transferred, sold, pledged or otherwise disposed of in accordance with the requirements set forth in Section
5.01(f).


(f)         To effectuate a
Certificate transfer of a Junior Subordinate Certificate in accordance with this Section 5.01(f), the proposed transferee of such
Certificate must provide the Trustee and the Company with an investment letter substantially in the form of Exhibit L attached
hereto, which investment letter shall not be an expense of the Trust, the Trustee, the Delaware Trustee or the Company, and which
investment letter states that, among other things, such transferee (i) is a “qualified institutional buyer” as defined
under Rule 144A, acting for its own account or the accounts of other “qualified institutional buyers” as defined under
Rule 144A, and (ii) is aware that the proposed transferor intends to rely on the exemption from registration requirements under the
Securities Act provided by Rule 144A. Notwithstanding the foregoing, the proposed transferee of such Certificate shall not be
required to provide the Trustee or the Company with Annex 1 or Annex 2 to the form of Exhibit L attached hereto if the Company so
consents prior to each such transfer. Such transfers shall be deemed to have complied with the requirements of this Section
5.01(f). The Holder of a Certificate desiring to effect such transfer does hereby agree to indemnify the Trust, the Trustee, the
Delaware Trustee, the Company, and the Certificate Registrar against any liability that may result if transfer is not made in
accordance with this Agreement.


(g)       
(1)        In the case of any ERISA Restricted Certificate presented for registration in the
name of any Person, the prospective transferee shall be required to provide the Trustee and the Company (A) an officer’s
certificate substantially in the form of Exhibit O attached hereto acceptable to and in form and substance satisfactory to the
Trustee and the Company, which officer’s certificate shall not be an expense of the Trust, the Trustee, the Delaware Trustee,
the Master Servicer or the Company, and (B) only if such officer’s certificate indicates that a Benefit Plan Opinion is
delivered in connection therewith, a Benefit Plan Opinion.



(2)       
Notwithstanding the foregoing, a certification (and, if applicable, a Benefit Plan Opinion) as described in Section 5.01(g)(1)
above will not be required with respect to the transfer of any ERISA Restricted Certificate to a Clearing Agency, or for any
subsequent transfer of any interest in a ERISA Restricted Certificate for so long as such Certificate is a Book-Entry Certificate
(each such ERISA Restricted Certificate, a “Book-Entry ERISA Restricted Certificate”).  Any transferee of a
Book-Entry ERISA Restricted Certificate will be deemed to have represented, by virtue of its acquisition or holding of such
Certificate (or interest therein), that either (i) such transferee is not an employee benefit or other plan subject to the
prohibited transaction provisions of ERISA or Section 4975 of the Code, or any person (including an investment manager, a named
fiduciary or a trustee of any such plan) acting, directly or indirectly, on behalf of or purchasing such Certificate with
“plan assets” of any such plan (a “Plan Investor”), (ii) such transferee is an insurance company,
the source of funds to be used by it to acquire or hold such Certificate is an “insurance company general account”
(within the meaning of Department of Labor Prohibited Transaction Class Exemption (“PTCE”) 95-60), and the
conditions in Sections I and III of PTCE 95-60 have been satisfied (each entity that satisfies this clause (ii), a
“Complying Insurance Company”) or (iii) such Certificate was rated “BBB-” or better (or its
equivalent) by at least one of the Rating Agencies at the time of such transferee’s acquisition of such Certificate (or
interest therein).



(3)       
If any Book-Entry ERISA Restricted Certificate (or any interest therein) is acquired or held in violation of the provisions of
Section 5.01(g)(2) above, then the last preceding transferee that either (i) is not a Plan Investor, (ii) is a Complying Insurance
Company or (iii) acquired such Certificate at a time when such Certificate was rated “BBB-” or better (or its
equivalent) by at least one of the Rating Agencies shall be restored, to the extent permitted by law, to all rights and obligations
as Beneficial Holder thereof retroactive to the date of transfer of such Certificate by such preceding transferee.  Neither
the Trust nor the Trustee shall be under any liability to any Person for making any payments due on such Certificate to such
preceding transferee.



(4)       
Any purported Beneficial Holder whose acquisition or holding of any Book-Entry ERISA Restricted Certificate (or interest therein)
was effected in violation of the restrictions in this Section 5.01(g) shall indemnify and hold harmless the Company, the Trustee,
the Delaware Trustee, the Master Servicer, the Trust and each Underwriter from and against any and all liabilities, claims, costs
or expenses incurred by such parties as a result of such acquisition or holding.



Section 5.02.        Certificates Issuable in
Classes; Distributions of Principal and Interest; Authorized Denominations. The aggregate principal amount of the
Certificates that may be authenticated and delivered under this Agreement is limited to the aggregate Principal Balance of the
Mortgage Loans as of the Cut-Off Date, as specified in the Preliminary Statement to this Agreement, except for Certificates
authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Certificates pursuant to
Section 5.03. Such aggregate principal amount shall be allocated among one or more Classes having designations, types of interests,
initial per annum Certificate Interest Rates, initial Class Principal Balances and Final Maturity Dates as specified in the
Preliminary Statement to this Agreement. The aggregate Percentage Interest of each Class of Certificates of which the Class
Principal Balance equals zero as of the Cut-Off Date that may be authenticated and delivered under this Agreement is limited to
100%. Certificates shall be issued in Authorized Denominations.



Section 5.03.        Registration of Transfer and
Exchange of Certificates. The Trustee shall cause to be maintained at one of its offices or at its designated agent,
a Certificate Register in which there shall be recorded the name and address of each Certificateholder. Subject to such reasonable
rules and regulations as the Trustee may prescribe, the Certificate Register shall be amended from time to time by the Trustee or
its agent to reflect notice of any changes received by the Trustee or its agent pursuant to Section 10.06. The Trustee hereby
appoints itself as the initial Certificate Registrar.


Upon surrender for registration of transfer of any Certificate to the
Trustee at the Corporate Trust Office of the Trustee, or such other address or agency as may hereafter be provided to the Master
Servicer in writing by the Trustee, the Trustee shall execute, and the Trustee or any Authenticating Agent shall authenticate and
deliver, in the name of the designated transferee or transferees, one or more new Certificates of Authorized Denominations. At the
option of the Certificateholders, Certificates may be exchanged for other Certificates in Authorized Denominations of like
Certificate Principal Balance or Percentage Interest, as applicable, upon surrender of the Certificates to be exchanged at any such
office or agency. Whenever any Certificates are so surrendered for exchange, the Trustee on behalf of the Trust shall execute, and
the Trustee, or any Authenticating Agent, shall authenticate and deliver, the Certificates which the Certificateholder making the
exchange is entitled to receive. Every Certificate presented or surrendered for transfer shall (if so required by the Trustee or
any Authenticating Agent) be duly endorsed by, or be accompanied by a written instrument of transfer in form satisfactory to the
Trustee or any Authenticating Agent and duly executed by, the Holder thereof or such Holder’s attorney duly authorized in
writing.


A reasonable service charge may be made for any such exchange or
transfer of Certificates, and the Trustee may require payment of a sum sufficient to cover any tax or governmental charge that may
be imposed in connection with any exchange or transfer of Certificates.


All Certificates surrendered for exchange or transfer shall be
cancelled by the Trustee or any Authenticating Agent.



Section 5.04.        Mutilated, Destroyed, Lost or
Stolen Certificates. If (i) any mutilated Certificate is surrendered to the Trustee or any Authenticating Agent, or
(ii) the Trustee or any Authenticating Agent receives evidence to their satisfaction of the destruction, loss or theft of any
Certificate, and there is delivered to the Trustee or any Authenticating Agent such security or indemnity as may be required by
them to save each of them and the Trust harmless, then, in the absence of notice to the Trustee or any Authenticating Agent that
such Certificate has been acquired by a protected purchaser, the Trustee shall execute and the Trustee or any Authenticating Agent
shall authenticate and deliver, in exchange for or in lieu of any such mutilated, destroyed, lost or stolen Certificate, a new
Certificate of like Certificate Principal Balance or Percentage Interest as applicable. Upon the issuance of any new Certificate
under this Section 5.04, the Trustee or any Authenticating Agent may require the payment of a sum sufficient to cover any tax or
other governmental charge that may be imposed in relation thereto and any other expenses (including the fees and expenses of the
Trustee or any Authenticating Agent) connected therewith. Any replacement Certificate issued pursuant to this Section 5.04 shall
constitute complete and indefeasible evidence of ownership in REMIC I (or with respect to the Class R Certificates, the residual
ownership interests in REMIC I) as if originally issued, whether or not the lost or stolen Certificate shall be found at any
time.



Section 5.05.        Persons Deemed
Owners. The Company, the Master Servicer, the Trust, the Trustee, the Delaware Trustee and any agent of any of them
may treat the Person in whose name any Certificate is registered as the owner of such Certificate for the purpose of receiving
distributions pursuant to Section 4.01 and for all other purposes whatsoever, and neither the Company, the Master Servicer, the
Trust, the Trustee, the Delaware Trustee, the Certificate Registrar nor any agent of the Company, the Master Servicer, the Trust,
the Trustee or the Delaware Trustee shall be affected by notice to the contrary.



Section 5.06.        Temporary
Certificates. Upon the initial issuance of the Certificates, the Trustee on behalf of the Trust may execute, and the
Trustee or any Authenticating Agent shall authenticate and deliver, temporary Certificates which are printed, lithographed,
typewritten or otherwise produced, in any Authorized Denomination, of the tenor of the definitive Certificates in lieu of which
they are issued and with such variations in form from the forms of the Certificates set forth as Exhibits A, B and H hereto as the
Trustee’s officers executing such Certificates may determine, as evidenced by their execution of the Certificates. 
Notwithstanding the foregoing, the Certificates may remain in the form of temporary Certificates.


If temporary Certificates are issued, the Trustee shall cause
definitive Certificates to be prepared within ten Business Days after the Closing Date or as soon as practicable thereafter. After
preparation of definitive Certificates, the temporary Certificates shall be exchangeable for definitive Certificates upon surrender
of the temporary Certificates at the office or agency of the Trustee to be maintained as provided in Section 5.10 hereof, without
charge to the holder. Any tax or governmental charge that may be imposed in connection with any such exchange shall be borne by the
Master Servicer. Upon surrender for cancellation of any one or more temporary Certificates, the Trustee on behalf of the Trust
shall execute and the Trustee or any Authenticating Agent shall authenticate and deliver in exchange therefor a like principal
amount of definitive Certificates of Authorized Denominations. Until so exchanged, the temporary Certificates shall in all respects
be entitled to the same benefits under this Agreement as definitive Certificates.



Section 5.07.        Book-Entry for Book-Entry
Certificates. Notwithstanding the foregoing, the Book-Entry Certificates, upon original issuance, shall be issued in
the form of one or more typewritten Certificates of Authorized Denomination representing the Book-Entry Certificates, to be
delivered to DTC, the initial Clearing Agency, by, or on behalf of, the Company. The Book-Entry Certificates shall initially be
registered on the Certificate Register in the name of Cede & Co., the nominee of DTC, as the initial Clearing Agency, and no
Beneficial Holder shall receive a definitive certificate representing such Beneficial Holder’s interest in any Class of
Book-Entry Certificate, except as provided above and in Section 5.09. Each Book-Entry Certificate shall bear the following
legend:



Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a
New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment,
and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized
representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as
the registered owner hereof, Cede & Co., has an interest herein.


Unless and until definitive, fully registered Book-Entry
Certificates (the “Definitive Certificates”) have been issued to the Beneficial Holders pursuant to Section
5.09:



(a)       
the provisions of this Section 5.07 shall be in full force and effect with respect to the Book-Entry Certificates;



(b)       
the Master Servicer and the Trustee may deal with the Clearing Agency for all purposes with respect to the Book-Entry Certificates
(including the making of distributions on the Book-Entry Certificates) as the sole Certificateholder;



(c)       
to the extent that the provisions of this Section 5.07 conflict with any other provisions of this Agreement, the provisions of this
Section 5.07 shall control; and



(d)       
the rights of the Beneficial Holders shall be exercised only through the Clearing Agency and the DTC Participants and shall be
limited to those established by law and agreements between such Beneficial Holders and the Clearing Agency and/or the DTC
Participants. Pursuant to the Depositary Agreement, unless and until Definitive Certificates are issued pursuant to Section 5.09,
the initial Clearing Agency will make book-entry transfers among the DTC Participants and receive and transmit distributions of
principal and interest on the related Class of Book-Entry Certificates to such DTC Participants.


For purposes of any provision of this Agreement requiring or
permitting actions with the consent of, or at the direction of, Holders of Book-Entry Certificates evidencing a specified
Percentage Interest, such direction or consent may be given by the Clearing Agency at the direction of Beneficial Holders owning
Book-Entry Certificates evidencing the requisite Percentage Interest represented by the Book-Entry Certificates. The Clearing
Agency may take conflicting actions with respect to the Book-Entry Certificates to the extent that such actions are taken on behalf
of the Beneficial Holders.



Section 5.08.        Notices to Clearing
Agency. Whenever notice or other communication to the Certificateholders is required under this Agreement, unless
and until Definitive Certificates shall have been issued to the related Certificateholders pursuant to Section 5.09, the Trustee
shall give all such notices and communications specified herein to be given to Holders of the Book-Entry Certificates to the
Clearing Agency which shall give such notices and communications to the related DTC Participants in accordance with its applicable
rules, regulations and procedures.



Section 5.09.        Definitive
Certificates. If (a) the Clearing Agency or the Master Servicer notifies the Trustee in writing that the Clearing
Agency is no longer willing or able to discharge properly its responsibilities under the Depositary Agreement with respect to the
Book-Entry Certificates and the Trustee or the Master Servicer is unable to locate a qualified successor, (b) the Master Servicer,
with the consent of the related DTC Participants, advises the Trustee in writing that it elects to terminate the book-entry system
with respect to the Book-Entry Certificates through the Clearing Agency or (c) after the occurrence of an Event of Default,
Certificateholders holding Book-Entry Certificates evidencing Percentage Interests aggregating not less than 662⁄3% of the
aggregate Class Principal Balance of such Certificates advise the Trustee and the Clearing Agency through DTC Participants in
writing that the continuation of a book-entry system with respect to the Book-Entry Certificates through the Clearing Agency is no
longer in the best interests of the Certificateholders with respect to such Certificates, the Trustee shall notify all
Certificateholders of Book-Entry Certificates of the occurrence of any such event and of the availability of Definitive
Certificates. Upon surrender to the Trustee of the Book-Entry Certificates by the Clearing Agency, accompanied by registration
instructions from the Clearing Agency for registration, the Trustee on behalf of the Trust shall execute and the Trustee or any
Authenticating Agent shall authenticate and deliver the Definitive Certificates. Neither the Company, the Master Servicer, the
Trust nor the Trustee shall be liable for any delay in delivery of such instructions and may conclusively rely on, and shall be
protected in relying on, such instructions. Upon the issuance of Definitive Certificates for all of the Certificates all references
herein to obligations imposed upon or to be performed by the Clearing Agency shall be deemed to be imposed upon and performed by
the Trustee, to the extent applicable with respect to such Definitive Certificates, and the Trustee shall recognize the Holders of
Definitive Certificates as Certificateholders hereunder.



Section 5.10.        Office for Transfer of
Certificates. The Trustee shall maintain an office or agency where Certificates may be surrendered for registration
of transfer or exchange. The Corporate Trust Office is initially designated for said purposes.



Section 5.11.        Nature of
Certificates. The Certificates shall be personal property giving only the rights specifically set forth therein and
in this Agreement.  The Certificates shall have no preemptive or similar rights and when issued and delivered to the Holders
against payment of the purchase price therefor will be fully paid and nonassessable by the Trust.  The Holders of the
Certificates, in their capacities as such, shall be entitled to the same limitation of personal liability extended to stockholders
of private corporations for profit organized under the General Corporation Law of the State of Delaware. THE RECEIPT AND ACCEPTANCE
OF A CERTIFICATE OR ANY INTEREST THEREIN BY OR ON BEHALF OF A HOLDER OR ANY BENEFICIAL OWNER, WITHOUT ANY SIGNATURE OR FURTHER
MANIFESTATION OF ASSENT, SHALL CONSTITUTE THE UNCONDITIONAL ACCEPTANCE BY THE HOLDER AND ALL OTHERS HAVING A BENEFICIAL INTEREST IN
SUCH CERTIFICATE OF ALL THE TERMS AND PROVISIONS OF THIS AGREEMENT, AND SHALL CONSTITUTE THE AGREEMENT OF THE TRUST, SUCH HOLDER
AND SUCH OTHERS THAT THE TERMS AND PROVISIONS OF THIS AGREEMENT SHALL BE BINDING, OPERATIVE AND EFFECTIVE AS BETWEEN THE TRUST AND
SUCH HOLDER AND SUCH OTHERS.



ARTICLE
VI



The Company and the Master Servicer



Section 6.01.        Liability of the Company and
the Master Servicer. The Company and the Master Servicer shall be liable in accordance herewith only to the extent
of the obligations specifically imposed upon and undertaken by the Company or the Master Servicer, as applicable, herein.



Section 6.02.        Merger or Consolidation of
the Company, or the Master Servicer. Any Corporation into which the Company or the Master Servicer may be merged or
consolidated, or any Corporation resulting from any merger, conversion or consolidation to which the Company or the Master Servicer
shall be a party, or any Corporation succeeding to the business of the Company or the Master Servicer, shall be the successor of
the Company or the Master Servicer hereunder, without the execution or filing of any paper or any further act on the part of any of
the parties hereto, anything herein to the contrary notwithstanding.



Section 6.03.        Limitation on Liability of
the Company, the Master Servicer and Others. Neither the Company nor the Master Servicer nor any of the directors,
officers, employees or agents of the Company or the Master Servicer shall be under any liability to the Trust or the
Certificateholders for any action taken by such Person or by a Servicer or for such Person's or Servicer's refraining from the
taking of any action in good faith pursuant to this Agreement, or for errors in judgment; provided, however, that this provision
shall not protect the Company, the Master Servicer or any such Person against any liability which would otherwise be imposed by
reason of willful misfeasance, bad faith or gross negligence in the performance of duties or by reason of reckless disregard of
duties and obligations hereunder. The Company, the Master Servicer and any director, officer, employee or agent of the Company or
the Master Servicer may rely in good faith on any document of any kind properly executed and submitted by any Person respecting any
matters arising hereunder. The Company, the Master Servicer and any director, officer, employee or agent of the Company or the
Master Servicer shall be indemnified by the Trust and held harmless against any loss, liability or expense incurred in connection
with any legal action relating to this Agreement or the Certificates, other than any loss, liability or expense relating to any
Mortgage Loan (other than as otherwise permitted in this Agreement) or incurred by reason of willful misfeasance, bad faith or
gross negligence in the performance of duties hereunder or by reason of reckless disregard of obligations and duties hereunder. The
Company and the Master Servicer shall not be under any obligation to appear in, prosecute or defend any legal action which is not
incidental to its duties to service the Mortgage Loans in accordance with this Agreement and which in its opinion may involve it in
any expense or liability; provided, however, that the Company or the Master Servicer may in its discretion undertake any such
action which it may deem necessary or desirable with respect to the Mortgage Loans, this Agreement, the Certificates or the rights
and duties of the parties hereto and the interests of the Certificateholders hereunder. In such event, the legal expenses and costs
of such action and any liability resulting therefrom shall be expenses, costs and liabilities of the Trust and the Company and the
Master Servicer shall be entitled to be reimbursed therefor out of the Certificate Account, as provided by Section 3.05.



Section 6.04.        The Company and the Master
Servicer not to Resign. The Company shall not resign from the obligations and duties (including, without limitation,
its obligations and duties as initial Master Servicer) hereby imposed on it except upon determination that its duties hereunder are
no longer permissible under applicable law. Any successor Master Servicer shall not resign from the obligations and duties hereby
imposed on it except upon determination that its duties hereunder are no longer permissible under applicable law. Any such
determination permitting the resignation of the Company or any successor Master Servicer shall be evidenced by an Opinion of
Counsel to such effect delivered to the Trustee. No such resignation shall become effective until the Trustee or a successor Master
Servicer shall have assumed the Master Servicer's responsibilities and obligations in accordance with Section 7.02 hereof.


If the Company is no longer acting as Master Servicer, then the
successor Master Servicer shall give prompt written notice to the Company of any information received by such successor Master
Servicer which affects or relates to an ongoing obligation or right of the Company under this Agreement.



Section 6.05.        Trustee
Access. The Master Servicer shall afford the Company and the Trustee, upon reasonable
notice, during normal business hours access to all records maintained by the Master Servicer, in respect of the Mortgage Loans and
in respect of its rights and obligations hereunder and access to such of its officers as are responsible for such
obligations.  Upon reasonable request, the Master Servicer, shall furnish the Company and the Trustee with its most recent
financial statements (or, for so long as the Company is the Master Servicer, the most recent consolidated financial statements for
the Company appearing in the audited financial statements of Washington Mutual, Inc., or the entity with whose financial statements
the financial statements of the Company are consolidated) and such other information as it possesses, and which it is not
prohibited by law or, to the extent applicable, binding obligations to third parties with respect to confidentiality from
disclosing, regarding its business, affairs, property and condition, financial or otherwise.



ARTICLE
VII



Default 



Section 7.01.        Events of
Default. (a) In case one or more of the following Events of Default by the Master Servicer or by a successor Master
Servicer shall occur and be continuing, that is to say:


(i)                  Any
failure by the Master Servicer to deposit into the Certificate Account any payment required to be deposited therein by the Master
Servicer under the terms of this Agreement which continues unremedied for a period of five Business Days after the date upon which
written notice of such failure, requiring the same to be remedied, shall have been given to the Master Servicer by the Trustee or
to the Master Servicer and the Trustee by the Holders of Certificates evidencing Percentage Interests aggregating not less than 25%
of REMIC I; or


(ii)                Failure on the part
of the Master Servicer duly to observe or perform in any material respect any other of the covenants or agreements on the part of
the Master Servicer contained in the Certificates or in this Agreement which continues unremedied for a period of 60 days after the
date on which written notice of such failure, requiring the same to be remedied, shall have been given to the Master Servicer by
the Trustee, or to the Master Servicer and the Trustee by the Holders of Certificates evidencing Percentage Interests aggregating
not less than 25% of REMIC I; or


(iii)               A decree or order of a
court or agency or supervisory authority having jurisdiction in the premises for the appointment of a trustee in bankruptcy,
conservator or receiver or liquidator in any bankruptcy, insolvency, readjustment of debt, marshalling of assets and liabilities or
similar proceedings, or for the winding‐up or liquidation of its affairs, shall have been entered against the Master Servicer
and such decree or order shall have remained in force undischarged or unstayed for a period of 60 days; or


(iv)              The Master Servicer shall
consent to the appointment of a trustee in bankruptcy, conservator or receiver or liquidator in any bankruptcy, insolvency,
readjustment of debt, marshalling of assets and liabilities or similar proceedings of or relating to the Master Servicer or of or
relating to all or substantially all of its property; or


(v)                The Master Servicer
shall admit in writing its inability to pay its debts generally as they become due, file a petition to take advantage of any
applicable bankruptcy, insolvency or reorganization statute, make an assignment for the benefit of its creditors, or voluntarily
suspend payment of its obligations; or


(vi)              Any failure of the Master
Servicer to make any Monthly P&I Advance (other than a Nonrecoverable Advance) which continues unremedied at the opening of
business on the Distribution Date in respect of which such Monthly P&I Advance was to have been made;


then, and in each and every such case, so long as an Event of
Default shall not have been remedied, either the Trustee or the Holders of Certificates evidencing Percentage Interests aggregating
not less than 25% of REMIC I, by notice in writing to the Company and the Master Servicer (and to the Trustee if given by the
Certificateholders, in which case such notice shall set forth evidence reasonably satisfactory to the Trustee that such Event of
Default has occurred and shall not have been remedied) may terminate all of the rights (other than its right to reimbursement for
advances) and obligations of the Master Servicer, including its right to the Master Servicing Fee, under this Agreement and in and
to the Mortgage Loans and the proceeds thereof, if any. Such determination shall be final and binding. On or after the receipt by
the Master Servicer of such written notice, all authority and power of the Master Servicer under this Agreement, whether with
respect to the Certificates or the Mortgage Loans or otherwise, shall pass to and be vested in the Trustee pursuant to and under
this Section 7.01; and, without limitation, the Trustee is hereby authorized and empowered to execute and deliver, on behalf of the
Master Servicer, as attorney‐in‐fact or otherwise, any and all documents and other instruments, and to do or accomplish
all other acts or things necessary or appropriate to effect the purposes of such notice of termination, whether to complete the
transfer and endorsement or assignment of the Mortgage Loans and related documents, or otherwise. The Master Servicer agrees to
cooperate with the Trustee in effecting the termination of the Master Servicer's responsibilities and rights hereunder, including,
without limitation, the transfer to the Trustee for administration by it of all cash amounts which shall at the time be credited by
the Master Servicer to the Certificate Account or thereafter be received with respect to the Mortgage Loans.


Notwithstanding the foregoing, if an Event of Default described in
clause (vi) of this Section 7.01(a) shall occur, the Trustee shall, by notice in writing to the Master Servicer, which may be
delivered by telecopy, immediately suspend all of the rights and obligations of the Master Servicer thereafter arising under this
Agreement, but without prejudice to any rights it may have as a Certificateholder or to reimbursement of Monthly P&I Advances
and other advances of its own funds, and the Trustee shall act as provided in Section 7.02 to carry out the duties of the Master
Servicer, including the obligation to make any Monthly P&I Advance the nonpayment of which was an Event of Default described in
clause (vi) of this Section 7.01(a). Any such action taken by the Trustee must be prior to the distribution on the relevant
Distribution Date. If the Master Servicer shall within two Business Days following such suspension remit to the Trustee the amount
of any Monthly P&I Advance (plus interest accrued thereon at a per annum rate equal to the prime rate for United States money
center commercial banks as published in The Wall Street Journal) the nonpayment of which by the Master Servicer was an Event
of Default described in clause (vi) of this Section 7.01(a), the Trustee, subject to the last sentence of this paragraph,
shall permit the Master Servicer to resume its rights and obligations as Master Servicer hereunder. The Master Servicer agrees that
it will reimburse the Trustee for actual, necessary and reasonable costs incurred by the Trustee because of action taken pursuant
to clause (vi) of this Section 7.01(a). The Master Servicer agrees that if an Event of Default as described in clause (vi) of this
Section 7.01(a) shall occur more than two times in any twelve month period, the Trustee shall be under no obligation to permit the
Master Servicer to resume its rights and obligations as Master Servicer hereunder.


(b)        In case one or more of
the following Events of Default by the Company shall occur and be continuing, that is to say:


(i)        
Failure on the part of the Company duly to observe or perform in any material respect any of the covenants or agreements on the
part of the Company contained in the Certificates or in this Agreement which continues unremedied for a period of 60 days after the
date on which written notice of such failure, requiring the same to be remedied, shall have been given to the Company by the
Trustee, or to the Company and the Trustee by the Holders of Certificates evidencing Percentage Interests aggregating not less than
25% of REMIC I; or


(ii)        A
decree or order of a court or agency or supervisory authority having jurisdiction in the premises for the appointment of a trustee
in bankruptcy, conservator or receiver or liquidator in any bankruptcy, insolvency, readjustment of debt, marshalling of assets and
liabilities or similar proceedings, or for the winding‐up or liquidation of its affairs, shall have been entered against the
Company and such decree or order shall have remained in force undischarged or unstayed for a period of 60 days; or


(iii)       The Company
shall consent to the appointment of a trustee in bankruptcy, conservator or receiver or liquidator in any bankruptcy, insolvency,
readjustment of debt, marshalling of assets and liabilities or similar proceedings of or relating to the Company or of or relating
to all or substantially all of its property; or


(iv)       The Company
shall admit in writing its inability to pay its debts generally as they become due, file a petition to take advantage of any
applicable bankruptcy, insolvency or reorganization statute, make an assignment for the benefit of creditors, or voluntarily
suspend payment of its obligations;


then, and in each and every such case, so long as such Event of
Default shall not have been remedied, the Holders of Certificates evidencing Percentage Interests aggregating not less than 25% of
REMIC I, by notice in writing to the Company and the Trustee, may direct the Trustee in accordance with Section 10.03 to institute
an action, suit or proceeding in its own name as Trustee hereunder to enforce the Company's obligations hereunder.


(c)        In any circumstances in
which this Agreement states that Certificateholders owning Certificates evidencing a certain Percentage Interest in REMIC I may
take certain action, such action shall be taken by the Trustee, but only if the requisite percentage of Certificateholders required
under this Agreement for taking like action or giving like instruction to the Trustee under this Agreement shall have so directed
the Trustee in writing.



Section 7.02.        Trustee to Act; Appointment
of Successor.


(a)        On and after the date on
which the Master Servicer receives a notice of termination pursuant to Section 7.01 or the Master Servicer resigns pursuant to
Section 6.04, the Trustee shall be the successor in all respects to the Master Servicer under this Agreement and under the Selling
and Servicing Contracts with respect to the Mortgage Loans in the Mortgage Pool and with respect to the transactions set forth or
provided for herein and shall have all the rights and powers and be subject to all the responsibilities, duties and liabilities
relating thereto arising on or after such date of termination or resignation placed on the Master Servicer by the terms and
provisions hereof and thereof, and shall have the same limitations on liability herein granted to the Master Servicer;
provided, that the Trustee shall not under any circumstances be responsible for any representations and warranties or any
Purchase Obligation of the Company or any liability incurred by the Master Servicer prior to such date of termination or
resignation and the Trustee shall not be obligated to make a Monthly P&I Advance if it is prohibited by law from so doing. As
compensation therefor, the Trustee shall be entitled to all funds relating to the Mortgage Loans which the Master Servicer would
have been entitled to retain or to withdraw from the Certificate Account if the Master Servicer had continued to act hereunder,
except for those amounts due to the Master Servicer as reimbursement for advances previously made or amounts previously expended
and are otherwise reimbursable hereunder. Notwithstanding the above, the Trustee may, if it shall be unwilling to so act, or shall
if it is unable to so act, appoint, or petition a court of competent jurisdiction to appoint, any established housing and home
finance institution having a net worth of not less than $10,000,000 as the successor to the Master Servicer hereunder in the
assumption of all or any part of the responsibilities, duties or liabilities of the Master Servicer hereunder. Pending any such
appointment, the Trustee is obligated to act in such capacity. In connection with such appointment and assumption, the Trustee may
make such arrangements for the compensation of such successor out of payments on Mortgage Loans as it and such successor shall
agree; provided, however, that no such compensation shall, together with the compensation to the Trustee, be in excess of
that permitted the Master Servicer hereunder. The Trustee and such successor shall take such actions, consistent with this
Agreement, as shall be necessary to effectuate any such succession.


(b)        In connection with any
termination or resignation of the Master Servicer hereunder, in the event that any of the Mortgage Loans are MERS Loans, either (i)
the successor Master Servicer (including the Trustee if the Trustee is acting as successor Master Servicer) shall represent and
warrant that it is a member of MERS in good standing and shall agree to comply in all material respects with the rules and
procedures of MERS in connection with the servicing of the MERS Loans, in which case the predecessor Master Servicer shall
cooperate with the successor Master Servicer in registering the transfer of servicing of the MERS Loans to the successor Master
Servicer on the MERS® System in accordance with MERS’ rules and procedures, or (ii) if the successor Master Servicer is
not a member of MERS, the predecessor Master Servicer shall cooperate with the successor Master Servicer in (A) de-registering the
MERS Loans from the MERS® System and (B) causing MERS to execute and deliver an assignment from MERS to the Trust of the
Mortgage securing each MERS Loan in recordable form and in the form otherwise provided under clause (X)(iii) of the definition of
“Mortgage File” herein and to execute and deliver such other notices, documents and other instruments as may be
necessary or desirable to effect such de-registration and assignment. The predecessor Master Servicer shall bear any and all fees
of MERS and all fees and costs of preparing and recording any assignments of Mortgages as required under this Section
7.02(b).



Section 7.03.        Notification to
Certificateholders. Upon any such termination or appointment of a successor to the Master Servicer, the Trustee
shall give prompt written notice thereof to the Certificateholders at their respective addresses appearing in the Certificate
Register.



ARTICLE
VIII



Concerning the Trustees 



Section 8.01.        Duties of
Trustees.


(a)        The Trustee, prior to
the occurrence of an Event of Default and after the curing of all Events of Default which may have occurred, undertakes to perform
such duties and only such duties as are specifically set forth in this Agreement. In case an Event of Default has occurred (which
has not been cured or waived) the Trustee shall exercise such of the rights and powers vested in it by this Agreement, and use the
same degree of care and skill in its exercise as a prudent person would exercise or use under the circumstances in the conduct of
such person’s own affairs.


(b)        The Trustee, upon
receipt of all resolutions, certificates, statements, opinions, reports, documents, orders or other instruments furnished to it
which are specifically required to be furnished to it pursuant to any provision of this Agreement, shall examine them to determine
whether they are in the form required by this Agreement; provided, however, that the Trustee shall not be responsible for the
accuracy or content of any such certificate, statement, opinion, report, or other order or instrument furnished by the Company or
Master Servicer to the Trustee pursuant to this Agreement.


(c)        No provision of this
Agreement shall be construed to relieve the Trustee or the Delaware Trustee from liability for its own negligent action, its own
negligent failure to act or its own willful misconduct; provided, however, that:


(i)                  Prior
to the occurrence of an Event of Default and after the curing of all such Events of Default which may have occurred, the duties and
obligations of the Trustee shall be determined solely by the express provisions of this Agreement,


(ii)                Neither the Trustee
nor the Delaware Trustee shall be liable except for the performance of such duties and obligations as are specifically set forth in
this Agreement, no implied covenants or obligations shall be read into this Agreement against the Trustee or the Delaware Trustee,
and, in the absence of bad faith on the part of the Trustee or the Delaware Trustee, such trustee may conclusively rely, as to the
truth of the statements and the correctness of the opinions expressed therein, upon any certificates or opinions furnished to such
trustee and conforming to the requirements of this Agreement; and


(iii)               Neither the Trustee nor
the Delaware Trustee shall be personally liable with respect to any action taken or omitted to be taken by it in good faith in
accordance with the direction of the Certificateholders holding Certificates which evidence Percentage Interests aggregating not
less than 25% of REMIC I relating to the time, method and place of conducting any proceeding for any remedy available to such
trustee, or relating to the exercise of any trust or power conferred upon such trustee under this Agreement.


(d)        Within ten Business Days
after the occurrence of any Event of Default known to the Trustee, the Trustee shall transmit by mail to the Rating Agencies notice
of each Event of Default. Within 90 days after the occurrence of any Event of Default known to the Trustee, the Trustee shall
transmit by mail to all Certificateholders (with a copy to the Rating Agencies) notice of each Event of Default, unless such Event
of Default shall have been cured or waived; provided, however, the Trustee shall be protected in withholding such notice if and so
long as a Responsible Officer of the Trustee in good faith determines that the withholding of such notice is in the best interests
of the Certificateholders; and provided, further, that in the case of any Event of Default of the character specified in Section
7.01(i) and Section 7.01(ii) no such notice to Certificateholders or to the Rating Agencies shall be given until at least 30 days
after the occurrence thereof.


(e)        The immediately
following sentence shall constitute the Trustee's notice required by the U.S. Patriot Act.  In order to comply with its duties
under the U.S. Patriot Act, the Trustee shall obtain and verify certain information and documentation from the other parties to
this Agreement including, but not limited to, each such party’s name, address, and other identifying information.



Section 8.02.        Certain Matters Affecting the
Trustees. Except as otherwise provided in Section 8.01:


(i)        
Each of the Trustee and the Delaware Trustee may request and rely upon and shall be protected in acting or refraining from acting
upon any resolution, Officer’s Certificate, certificate of auditors or any other certificate, statement, instrument, opinion,
report, notice, request, consent, order, approval, bond or other paper or document believed by it to be genuine and to have been
signed or presented by the proper party or parties;


(ii)        Each
of the Trustee and the Delaware Trustee may consult with counsel and any Opinion of Counsel shall be full and complete
authorization and protection in respect of any action taken or suffered or omitted by it hereunder in good faith and in accordance
with such Opinion of Counsel;


(iii)       Neither the
Trustee nor the Delaware Trustee shall be personally liable for any action taken or omitted by it in good faith and reasonably
believed by it to be authorized or within the discretion or rights or powers conferred upon it by this Agreement;


(iv)       Prior to the
occurrence of an Event of Default hereunder and after the curing of all Events of Default which may have occurred, neither the
Trustee nor the Delaware Trustee shall be bound to make any investigation into the facts or matters stated in any resolution,
certificate, statement, instrument, opinion, report, notice, request, consent, order, approval, bond or other paper or document,
unless requested in writing to do so by the Holders of Certificates evidencing Percentage Interests aggregating not less than 25%
of REMIC I; provided, however, that if the payment within a reasonable time to the Trustee or the Delaware Trustee of the costs,
expenses or liabilities likely to be incurred by it in the making of such investigation is, in the opinion of such trustee, not
reasonably assured to such trustee by the security, if any, afforded to it by the terms of this Agreement, such trustee may require
reasonable indemnity against such expense or liability as a condition to proceeding;


(v)        Each of
the Trustee and the Delaware Trustee may execute the trust or any of the powers hereunder or perform any duties hereunder either
directly or by or through agents or attorneys selected by it with reasonable care or (as in the case of the Initial Custodian)
designated by the Company;


(vi)       Neither the
Trustee nor the Delaware Trustee shall be deemed to have knowledge or notice of any matter, including without limitation an Event
of Default, unless actually known by a Responsible Officer, or unless written notice thereof referencing this Agreement or the
Certificates is received at the Notice Address of such trustee;


(vii)      In no event shall
the Trustee or the Delaware Trustee be held liable for acts or omissions of the Master Servicer or the other trustee (excepting the
Trustee’s own actions as Master Servicer).   No provision of this Agreement shall require the Trustee or the
Delaware Trustee to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties
hereunder (except for the giving of required notices), or in the exercise of any of its rights or powers, if it shall have
reasonable grounds for believing the repayment of such funds or adequate indemnity against such risk or liability is not reasonably
assured to it;


(viii)      When the Trustee
is acting as Master Servicer pursuant to Section 7.02, and to the extent permitted under applicable law, the Trustee is hereby
authorized, in making or disposing of any investment permitted hereunder, to deal with itself (in its individual capacity) or with
any one or more of its affiliates, whether it or its affiliate is acting as an agent of the Trustee or of any third person or
dealing as principal for its own account;


(ix)       Except as
expressly provided in this Agreement, in no event shall the Trustee be under any duty or obligation to monitor, determine,
investigate or compel compliance by the Trust with the requirements of the Statutory Trust Statute; and



(x)       
In no event shall the Trustee be obligated or responsible for preparing, executing, filing or delivering in respect of the Trust or
another party either (A) any report or filing required by the Securities and Exchange Commission to be prepared, executed, filed or
delivered in respect of the Trust or another party or (B) any certification in respect of a report or filing required by the
Securities and Exchange Commission.



Section 8.03.        Trustees Not Liable for
Certificates or Mortgage Loans.  The recitals contained herein (other than those relating to the due
organization, power and authority of the Trustee and the Delaware Trustee) and in the Certificates (other than the execution of,
and certificate of authentication on, the Certificates) shall be taken as the statements of the Company or the Trust, as
applicable, and neither the Trustee nor the Delaware Trustee assumes any responsibility for their correctness. Neither the Trustee
nor the Delaware Trustee makes any representations as to the validity or sufficiency of this Agreement or of the Certificates or
any Mortgage Loan. Neither the Trustee nor the Delaware Trustee shall be accountable for the use or application by the Company or
the Trust, as applicable, of any of the Certificates or of the proceeds of such Certificates, or for the use or application of any
funds paid to the Master Servicer, the Servicers or the Company in respect of the Mortgage Loans or deposited into the Custodial
Accounts for P&I, any Buydown Fund Account, or the Custodial Accounts for P&I by any Servicer or into the Investment
Account, or the Certificate Account by the Master Servicer or the Company.



Section 8.04.        Trustees May Own
Certificates.  The Trustee, the Delaware Trustee or any agent or affiliate of such trustee, in its individual
or any other capacity, may become the owner or pledgee of Certificates with the same rights it would have if it were not
trustee.



Section 8.05.        The Master Servicer to Pay
Trustees’ Fees and Expenses.  Subject to separate written agreements with the Trustee and the Delaware
Trustee, the Master Servicer covenants and agrees to, and the Master Servicer shall, pay each of the Trustee and the Delaware
Trustee from time to time, and such trustee shall be entitled to payment, for all services rendered by it in the execution of the
trust hereby created and in the exercise and performance of any of the powers and duties hereunder of such trustee. Except as
otherwise expressly provided herein, the Master Servicer shall pay or reimburse each of the Trustee and the Delaware Trustee upon
such trustee’s request for all reasonable expenses and disbursements incurred or made by such trustee in accordance with any
of the provisions of this Agreement, including any such expenses incurred or made in connection with a transfer of servicing, and
shall indemnify such trustee from any loss, liability or expense incurred by it hereunder (including the reasonable compensation
and the expenses and disbursements of its counsel and of all persons not regularly in its employ and any expenses which arise out
of or are imposed upon the Trustee or the Delaware Trustee in connection with the creation, operation or termination of the Trust)
except any such expense or disbursement as may arise from its own negligence or bad faith. Such obligation shall survive the
termination of this Agreement or resignation or removal of the Trustee or the Delaware Trustee. The Tax Matters Person shall, at
its expense, prepare or cause to be prepared all federal and state income tax and franchise tax and information returns relating to
REMIC I required to be prepared or filed by the Trustee or the Delaware Trustee and shall indemnify the Trustee and the Delaware
Trustee for any liability of such trustees arising from any error in such returns.



Section 8.06.        Eligibility Requirements for
Trustees. The Trustee hereunder shall at all times be (i) an institution insured by the FDIC, (ii) a Corporation
organized and doing business under the laws of the United States of America or of any state, authorized under such laws to exercise
corporate trust powers, having a combined capital and surplus of not less than $50,000,000 and subject to supervision or
examination by federal or state authority and (iii) acceptable to the Rating Agencies. If such Corporation publishes reports of
condition at least annually, pursuant to law or to the requirements of any aforementioned supervising or examining authority, then
for the purposes of this Section 8.06, the combined capital and surplus of such Corporation shall be deemed to be its combined
capital and surplus as set forth in its most recent report of condition so published.  The Delaware Trustee hereunder shall at
all times have its principal place of business in the State of Delaware and shall satisfy the applicable requirements under the
laws of the State of Delaware authorizing it to act as the Delaware trustee of the Trust.  In case at any time the Trustee or
the Delaware Trustee shall cease to be eligible in accordance with the provisions of this Section 8.06, such trustee shall resign
immediately in the manner and with the effect specified in Section 8.07.



Section 8.07.        Resignation and Removal of
Trustees. Each of the Trustee and the Delaware Trustee may at any time resign and be discharged from the trust
hereby created by giving written notice thereof to the Master Servicer. Upon receiving such notice of resignation, the Master
Servicer shall promptly appoint a successor trustee by written instrument, in duplicate, one copy of which instrument shall be
delivered to the resigning trustee and one copy to the successor trustee. If no successor trustee shall have been so appointed and
shall have accepted appointment within 30 days after the giving of such notice of resignation, the resigning trustee may petition
any court of competent jurisdiction for the appointment of a successor trustee.


If at any time the Trustee or the Delaware Trustee shall cease to be
eligible in accordance with the provisions of Section 8.06 and shall fail to resign after written request therefor by the Master
Servicer, or if at any time the Trustee or the Delaware Trustee shall become incapable of acting, or shall be adjudged bankrupt or
insolvent, or a receiver of such trustee or of its property shall be appointed, or any public officer shall take charge or control
of such trustee or of its property or affairs for the purpose of rehabilitation, conservation or liquidation, then the Master
Servicer may remove such trustee and appoint a successor trustee by written instrument, in duplicate, copies of which instrument
shall be delivered to the trustee so removed, the trustee continuing in its capacity and the successor trustee.


The Holders of Certificates evidencing Percentage Interests
aggregating more than 50% of REMIC I may at any time remove the Trustee or the Delaware Trustee and appoint a successor trustee by
written instrument or instruments, in triplicate, signed by such Holders or their attorneys in-fact duly authorized, one complete
set of which instruments shall be delivered to the Master Servicer, one complete set to the Trustee so removed and one complete set
to the successor so appointed.


Any resignation or removal of the Trustee or the Delaware Trustee and
appointment of a successor trustee pursuant to any of the provisions of this Section 8.07 shall become effective upon acceptance of
appointment by the successor trustee as provided in Section 8.08. Any expenses associated with the resignation of the Trustee or
the Delaware Trustee shall be borne by such trustee, and any expenses associated with the removal of the Trustee or the Delaware
Trustee shall be borne by the Master Servicer.



Section 8.08.        Successor
Trustee. Any successor trustee appointed as provided in Section 8.07 shall execute, acknowledge and deliver to the
Master Servicer and to its predecessor trustee an instrument accepting such appointment hereunder, and thereupon the resignation or
removal of the predecessor trustee shall become effective and such successor trustee, without any further act, deed or conveyance,
shall become fully vested with all the rights, powers, duties and obligations of its predecessor hereunder, with like effect as if
originally named as Trustee or Delaware Trustee herein. The predecessor shall deliver to the successor trustee all Mortgage Files,
related documents, statements and all other property held by it hereunder, and the Master Servicer and the predecessor trustee
shall execute and deliver such instruments and do such other things as may reasonably be required for more fully and certainly
vesting and confirming in the successor trustee all such rights, powers, duties and obligations.


No successor trustee shall accept appointment as provided in this
Section 8.08 unless at the time of such appointment such successor trustee shall be eligible under the provisions of Section
8.06.


Upon acceptance of appointment by a successor trustee as provided in
this Section 8.08, the Master Servicer shall mail notice of the succession of such trustee hereunder to (i) all Certificateholders
at their addresses as shown in the Certificate Register and (ii) the Rating Agencies. If the Master Servicer fails to mail such
notice within ten days after acceptance of appointment by the successor trustee, the successor trustee shall cause such notice to
be mailed.



Section 8.09.        Merger or Consolidation of
Trustee. Any Corporation into which the Trustee or the Delaware Trustee may be merged or converted or with which it
may be consolidated, or any Corporation resulting from any merger, conversion or consolidation to which the Trustee or the Delaware
Trustee shall be a party, or any Corporation succeeding to the corporate trust business of such trustee, shall be the successor of
such trustee hereunder, provided such resulting or successor Corporation shall be eligible under the provisions of Section 8.06,
without the execution or filing of any paper or any further act on the part of any of the parties hereto, anything herein to the
contrary notwithstanding.



Section 8.10.        Appointment of Co-Trustee or
Separate Trustee. Notwithstanding any other provisions hereof, at any time, for the purpose of meeting any legal
requirements of any jurisdiction in which any part of the assets of the Trust may at the time be located, the Master Servicer and
the Trustee or the Delaware Trustee, as applicable, acting jointly shall have the power and shall execute and deliver all
instruments to appoint one or more Persons approved by such trustee to act as co-trustee or co-trustees, jointly with such trustee,
or separate trustee or separate trustees, of all or any part of the assets of the Trust and to vest in such Person or Persons, in
such capacity, such title to the assets of the Trust, or any part thereof, and, subject to the other provisions of this Section
8.10, such powers, duties, obligations, rights and trusts as the Master Servicer and the Trustee or the Delaware Trustee, as
applicable, may consider necessary or desirable; provided, that the Trustee or the Delaware Trustee, as applicable, shall remain
liable for all of its obligations and duties under this Agreement. If the Master Servicer shall not have joined in such appointment
within 15 days after the receipt by it of a request so to do, or in case an Event of Default shall have occurred and be continuing,
the Trustee or the Delaware Trustee, as applicable, alone shall have the power to make such appointment; provided, that such
trustee shall remain liable for all of its obligations and duties under this Agreement. No co-trustee or separate trustee hereunder
shall be required to meet the terms of eligibility as a successor trustee under Section 8.06 hereunder and no notice to
Certificateholders of the appointment of co-trustee(s) or separate trustee(s) shall be required under Section 8.08 hereof.


In the case of any appointment of a co-trustee or separate trustee
pursuant to this Section 8.10, all rights, powers, duties and obligations conferred or imposed upon the Trustee or the Delaware
Trustee, as applicable, shall be conferred or imposed upon and exercised or performed by the Trustee or the Delaware Trustee, as
applicable, and such separate trustee or co-trustee jointly and severally, except to the extent that under any law of any
jurisdiction in which any particular act or acts are to be performed by the Trustee or the Delaware Trustee, as applicable (whether
as Trustee or Delaware Trustee hereunder or as successor to the Master Servicer hereunder), such trustee shall be incompetent or
unqualified to perform such act or acts, in which event such rights, powers, duties and obligations (including the holding of title
to the assets of the Trust or any portion thereof in any such jurisdiction) shall be exercised and performed by such separate
trustee or co-trustee at the direction of the Trustee or the Delaware Trustee, as applicable.


Any notice, request or other writing given to the Trustee or the
Delaware Trustee shall be deemed to have been given to each of the then related separate trustee(s) and co-trustee(s), as
effectively as if given to each of them. Every instrument appointing any separate trustee(s) or co-trustee(s) shall refer to this
Agreement and the conditions of this Article VIII. Each separate trustee and co-trustee, upon its acceptance of the trusts
conferred, shall be vested with the estates or property specified in its instrument of appointment, either jointly with the Trustee
or the Delaware Trustee, as applicable, or separately, as may be provided therein, subject to all the provisions of this Agreement,
specifically including every provision of this Agreement relating to the conduct of, affecting the liability of, or affording
protection to, the Trustee or the Delaware Trustee, as applicable. Every such instrument shall be filed with the Trustee or the
Delaware Trustee, as applicable.


Any separate trustee or co-trustee may, at any time, constitute the
Trustee or the Delaware Trustee, as applicable, its agent or attorney-in-fact, with full power and authority, to the extent not
prohibited by law, to do any lawful act under or in respect of this Agreement on its behalf and in its name. If any separate
trustee or co-trustee shall die, become incapable of acting, resign or be removed, all of its estates, properties, rights, remedies
and the trust shall vest in and be exercised by the Trustee or the Delaware Trustee, as applicable, to the extent permitted by law,
without the appointment of a new or successor trustee.



Section 8.11.        Authenticating
Agents. The Trustee may appoint one or more Authenticating Agents which shall be authorized to act on behalf of the
Trustee in authenticating Certificates. Wherever reference is made in this Agreement to the authentication of Certificates by the
Trustee or the Trustee’s certificate of authentication, such reference shall be deemed to include authentication on behalf of
the Trustee by an Authenticating Agent and a certificate of authentication executed on behalf of the Trustee by an Authenticating
Agent. Each Authenticating Agent must be acceptable to the Master Servicer and must be a corporation, trust company or banking
association organized and doing business under the laws of the United States of America or of any state, having an office and place
of business in New York, New York, having a combined capital and surplus of at least $15,000,000, authorized under such laws to do
a trust business and subject to supervision or examination by federal or state authorities.


Any corporation into which any Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting from any merger, conversion or consolidation to which
any Authenticating Agent shall be a party, or any corporation succeeding to the corporate agency business of any Authenticating
Agent, shall continue to be the Authenticating Agent so long as it shall be eligible in accordance with the provisions of the first
paragraph of this Section 8.11 without the execution or filing of any paper or any further act on the part of the Trustee or the
Authenticating Agent.


Any Authenticating Agent may at any time resign by giving written
notice of resignation to the Trustee and the Master Servicer. The Trustee may, upon prior written approval of the Master Servicer,
at any time terminate the agency of any Authenticating Agent by giving written notice of termination to such Authenticating Agent
and to the Master Servicer. Upon receiving a notice of resignation or upon such a termination, or in case at any time any
Authenticating Agent shall cease to be eligible in accordance with the provisions of the first paragraph of this Section 8.11, the
Trustee may appoint, upon prior written approval of the Master Servicer, a successor Authenticating Agent, shall give written
notice of such appointment to the Master Servicer and shall mail notice of such appointment to all Certificateholders. Any
successor Authenticating Agent upon acceptance of its appointment hereunder shall become vested with all the rights, powers, duties
and responsibilities of its predecessor hereunder, with like effect as if originally named as Authenticating Agent. Any reasonable
compensation paid to an Authenticating Agent shall be a reimbursable expense pursuant to Section 8.05 if paid by the
Trustee.



Section 8.12.        Paying Agents.
The Trustee may appoint one or more Paying Agents which shall be authorized to act on behalf of the Trustee in making withdrawals
from the Certificate Account, and distributions to Certificateholders as provided in Section 4.01(a) and Section 9.01(b) to the
extent directed to do so by the Master Servicer. Wherever reference is made in this Agreement to the withdrawal from the
Certificate Account by the Trustee, such reference shall be deemed to include such a withdrawal on behalf of the Trustee by a
Paying Agent. Whenever reference is made in this Agreement to a distribution by the Trustee or the furnishing of a statement to
Certificateholders by the Trustee, such reference shall be deemed to include such a distribution or furnishing on behalf of the
Trustee by a Paying Agent. Each Paying Agent shall provide to the Trustee such information concerning the Certificate Account as
the Trustee shall request from time to time. Each Paying Agent must be reasonably acceptable to the Master Servicer and must be a
corporation, trust company or banking association organized and doing business under the laws of the United States of America or of
any state, having an office and place of business in New York, New York, having a combined capital and surplus of at least
$15,000,000, authorized under such laws to do a trust business and subject to supervision or examination by federal or state
authorities.


Any corporation into which any Paying Agent may be merged or converted
or with which it may be consolidated, or any corporation resulting from any merger, conversion or consolidation to which any Paying
Agent shall be a party, or any corporation succeeding to the corporate agency business of any Paying Agent, shall continue to be
the Paying Agent provided that such corporation after the consummation of such merger, conversion, consolidation or succession
meets the eligibility requirements of this Section 8.12.


Any Paying Agent may at any time resign by giving written notice of
resignation to the Trustee and to the Master Servicer; provided, that the Paying Agent has returned to the Certificate Account or
otherwise accounted, to the reasonable satisfaction of the Master Servicer, for all amounts it has withdrawn from the Certificate
Account. The Trustee may, upon prior written approval of the Master Servicer, at any time terminate the agency of any Paying Agent
by giving written notice of termination to such Paying Agent and to the Master Servicer. Upon receiving a notice of resignation or
upon such a termination, or in case at any time any Paying Agent shall cease to be eligible in accordance with the provisions of
the first paragraph of this Section 8.12, the Trustee may appoint, upon prior written approval of the Master Servicer, a successor
Paying Agent, shall give written notice of such appointment to the Master Servicer and shall mail notice of such appointment to all
Certificateholders. Any successor Paying Agent upon acceptance of its appointment hereunder shall become vested with all the
rights, powers, duties and responsibilities of its predecessor hereunder, with like effect as if originally named as Paying Agent.
Any reasonable compensation paid to any Paying Agent shall be a reimbursable expense pursuant to Section 8.05 if paid by the
Trustee.



Section 8.13.        Duties of Delaware
Trustee.


(a)        The Delaware Trustee is
appointed to serve as the trustee of the Trust in the State of Delaware for the sole purpose of satisfying the requirement of
Section 3807(a) of the Statutory Trust Statute that the Trust have at least one trustee with a principal place of business in
Delaware.  It is understood and agreed by the parties hereto that the Delaware Trustee shall have none of the duties or
liabilities of the Trustee.


(b)        The duties of the
Delaware Trustee shall be limited to (i) accepting legal process served on the Trust in the State of Delaware, (ii) the execution
of any certificates with respect to the Trust required to be filed with the Secretary of State which the Delaware Trustee is
required to execute under Section 3811 of the Statutory Trust Statute and (iii) such other duties as are set forth in this Article
VIII.  To the extent that, at law or in equity, the Delaware Trustee has duties (including fiduciary duties) and liabilities
relating thereto to the Trust or the Holders of the Certificates, it is hereby understood and agreed by the parties hereto that
such duties and liabilities are replaced by the duties and liabilities of the Delaware Trustee expressly set forth in this
Agreement.



Section 8.14.        Amendment to Certificate of
Trust.  If at any time required by Section 3810 of the Statutory Trust Statute, the Trustee, the Delaware
Trustee and any other trustee of the Trust shall cause an amendment to the Certificate of Trust to be filed with the Secretary of
State in accordance with the provisions of such Section 3810.



Section 8.15.        Limitation of
Liability.            It is expressly understood and agreed
by the parties hereto that (a) each of the representations, undertakings and agreements herein made on the part of the Trust is
made and intended not as personal representations, undertakings and agreements by the Trustee but is made and intended for the
purpose of binding only the Trust and (b) under no circumstances shall the Trustee be personally liable for the payment of any
indebtedness or expenses of the Trust or be liable for the breach or failure of any obligation, representation, warranty or
covenant made or undertaken by the Trust under this Agreement.



ARTICLE
IX



Termination 



Section 9.01.        Termination Upon Purchase by
the Master Servicer or Liquidation of All Mortgage Loans.


(i)                 
(a)        Except as otherwise set forth in this Article IX, including, without limitation, the
obligation of the Master Servicer to make payments to Certificateholders as hereafter set forth, the Trust and the respective
obligations and responsibilities of the Company, the Master Servicer, the Trustee and the Delaware Trustee created hereby shall
terminate in accordance with Section 3808 of the Statutory Trust Statute upon (i) the purchase by the Master Servicer pursuant to
the following paragraph of this Section 9.01(a) of all Mortgage Loans (other than Liquidated Mortgage Loans), all property acquired
in respect of any Mortgage Loan remaining in the Trust and all other property included in any REMIC formed under this Agreement at
a price equal, after the deduction of related advances, to the sum of (x) the excess of (A) 100% of the aggregate outstanding
Principal Balance of such Mortgage Loans (other than Liquidated Mortgage Loans) plus accrued interest at the applicable
Pass-Through Rate with respect to such Mortgage Loan (other than a Liquidated Mortgage Loan) through the last day of the month of
such purchase, over (B) with respect to any Mortgage Loan which is not a Liquidated Mortgage Loan, the amount of the Bankruptcy
Loss incurred with respect to such Mortgage Loan as of the date of such purchase by the Master Servicer to the extent that the
Principal Balance of such Mortgage Loan has not been previously reduced by such Bankruptcy Loss, and (y) without duplication, the
appraised fair market value as of the effective date of the termination of the Trust of (A) all property in the Trust which secured
a Mortgage Loan and which was acquired by foreclosure or deed in lieu of foreclosure after the Cut-Off Date, including related
Insurance Proceeds, and (B) all other property included in any REMIC formed under this Agreement, any such appraisal to be
conducted by an appraiser mutually agreed upon by the Master Servicer and the Trustee, less the sum of all unreimbursed advances
made by the Master Servicer pursuant to this Agreement or by a Servicer pursuant to its Selling and Servicing Contract, other than
advances made with respect to Mortgage Loans as to which the Master Servicer expects at the time of such purchase, in its sole
judgment, that foreclosure is not imminent, or (ii) the later of the final payment or other liquidation (or any advance with
respect thereto) of the last Mortgage Loan remaining in the Trust or the disposition of all property acquired upon foreclosure in
respect of any Mortgage Loan, and the payment to the Certificateholders of all amounts required to be paid to them hereunder;
provided, however, that in no event shall the Trust continue beyond the expiration of 21 years from the death of the survivor of
the issue of Joseph P. Kennedy, the late ambassador of the United States to the Court of St. James’, living on the date
hereof. Neither the Master Servicer nor any Servicer shall have any further right to reimbursement by the Trust for any advance
that is used to reduce the purchase price of the Mortgage Loans pursuant to the immediately preceding sentence.


On any Distribution Date after the Clean-Up Call Option Date, the
Master Servicer may purchase the outstanding Mortgage Loans (other than Liquidated Mortgage Loans), all property acquired in
respect of any Mortgage Loan remaining in the Trust and all other property included in any REMIC formed under this Agreement at the
price stated in clause (i) of the preceding paragraph; provided, that the Master Servicer may not so purchase
the outstanding Mortgage Loans (other than Liquidated Mortgage Loans), all property acquired in respect of any Mortgage Loan
remaining in the Trust and all other property included in any REMIC formed under this Agreement if the price stated in
clause (i) of the preceding paragraph exceeds the fair market value, determined in accordance with prudent industry practices, of
all outstanding Mortgage Loans (other than Liquidated Mortgage Loans), all property acquired in respect of any Mortgage Loan
remaining in the Trust and all other property included in any REMIC formed under this Agreement. If
such right is exercised, the Master Servicer shall provide to the Trustee (and to the Company, if the Company is no longer acting
as Master Servicer) the written certification of an officer of the Master Servicer (which certification shall include a statement
to the effect that all amounts required to be paid in order to purchase the Mortgage Loans have been deposited in the Certificate
Account) and the Trustee on behalf of the Trust shall promptly execute all instruments as may be necessary to release and assign to
the Master Servicer the Mortgage Loans (other than Liquidated Mortgage Loans), all property acquired in respect of any Mortgage
Loan remaining in the Trust and all other property included in any REMIC formed under this Agreement.


In no event shall the Master Servicer be required to expend any
amounts other than those described in the first paragraph of this Section 9.01(a) in order to terminate the Trust or purchase the
Mortgage Loans under this Section 9.01, and in no event shall the Company be required to expend any amounts in connection with such
termination or purchase.


(b)        Notice of any
termination, specifying the date upon which the Certificateholders may surrender their Certificates to the Trustee for payment and
cancellation, shall be given promptly by letter from the Trustee to Certificateholders mailed not less than 30 days prior to such
final distribution, specifying (i) the date upon which final payment of the Certificates will be made upon presentation and
surrender of Certificates at the office of the Certificate Registrar therein designated (the “Termination
Date”), (ii) the amount of such final payment (the “Termination Payment”) and (iii) that the Record
Date otherwise applicable to the Distribution Date upon which the Termination Date occurs is not applicable, payments being made
only upon presentation and surrender of the Certificates at the office of the Certificate Registrar therein specified. Upon any
such notice, the Certificate Account shall terminate subject to the Master Servicer’s obligation to hold all amounts payable
to Certificateholders in trust without interest pending such payment. The Master Servicer shall provide the Trustee with written
notice of its intent to terminate the Trust upon purchase at least five Business Days, or such lesser time as is acceptable to the
Trustee, such acceptance not to be unreasonably withheld, prior to the time that the Trustee is required to mail notice to the
Certificateholders.


In the event that all of the Certificateholders shall not surrender
their Certificates for cancellation within six months after the Termination Date, the Master Servicer shall give a second written
notice to the remaining Certificateholders to surrender their Certificates for cancellation and receive the Termination Payment
with respect thereto. If within one year after the second notice all the Certificates shall not have been surrendered for
cancellation, the Master Servicer may take appropriate steps to contact the remaining Certificateholders concerning surrender of
their Certificates, and the cost thereof shall be paid out of the funds and other assets which remain in trust
hereunder.


Upon the completion of winding up of the Trust, including the payment
or the making reasonable provision for payment of all obligations of the Trust in accordance with Section 3808(e) of the Statutory
Trust Statute, the Delaware Trustee shall prepare, the Trustee, the Delaware Trustee and any other trustee hereunder shall sign,
and the Delaware Trustee (upon the Trustee’s consent acting at the direction of the Master Servicer) shall file, a
certificate of cancellation with the Secretary of State in accordance with Section 3810 of the Statutory Trust Statute, at which
time the Trust and this Agreement shall terminate.  The Master Servicer shall act as the liquidator of the Trust and shall be
responsible for taking all actions in connection with winding up the Trust, in accordance with the requirements of this Agreement
(including this Section 9.01 and Section 9.02) and applicable law.



Section 9.02.        Additional Termination
Requirements.


(a)        In the event the Master
Servicer exercises its purchase option as provided in Section 9.01, REMIC I shall be terminated in accordance with the following
additional requirements, unless the Master Servicer, at its own expense, obtains for the Trustee an Opinion of Counsel to the
effect that the failure of REMIC I to comply with the requirements of this Section 9.02 will not (i) result in the imposition of
taxes on “prohibited transactions” of REMIC I as described in Section 860F of the Code, or (ii) cause REMIC I to
fail to qualify as a REMIC at any time that any Certificates are outstanding:


(i)                  Within
90 days prior to the final Distribution Date set forth in the notice given by the Trustee under Section 9.01, the Tax Matters
Person shall prepare the documentation required and the Tax Matters Person and the Trustee shall adopt a plan of complete
liquidation on behalf of REMIC I meeting the requirements of a qualified liquidation under Section 860F of the Code and any
regulations thereunder, as evidenced by an Opinion of Counsel obtained at the expense of the Master Servicer, on behalf of REMIC I;
and


(ii)                At or after the
time of adoption of such a plan of complete liquidation and at or prior to the final Distribution Date, the Master Servicer on
behalf of the Trust shall sell all of the assets of REMIC I to the Master Servicer for cash in the amount specified in Section
9.01.


(b)        By its acceptance of any
Residual Certificate, the Holder thereof hereby agrees to authorize the Tax Matters Person and the Trustee to adopt such a plan of
complete liquidation upon the written request of the Tax Matters Person and the Trustee and to take such other action in connection
therewith as may be reasonably requested by the Tax Matters Person or the Trustee.



Section 9.03.        Trust
Irrevocable. Except as expressly provided herein, the trust created hereby is irrevocable.



ARTICLE
X



Miscellaneous Provisions 



Section 10.01.    Amendment.


(a)        This Agreement may be
amended from time to time by the Master Servicer, the Company and the Trustee, without the consent of any of the
Certificateholders:


(i)        
to cure any ambiguity;


(ii)        to
correct or supplement any provision herein which may be defective or inconsistent with any other provisions herein;


(iii)       to comply
with any requirements imposed by the Code or any regulations thereunder;


(iv)       to correct
the description of any property at any time included in REMIC I, or to assure the conveyance to the Trust of any property
included in REMIC I;


(v)       
pursuant to Section 5.01(c)(v); and


(vi)       to add any
provision to, or amend any provision in, this Agreement, provided that such amendment or addition does not adversely affect in any
material respect the interests of any Certificateholder;



provided, however, that any such
amendment which modifies the rights or obligations of the Delaware Trustee hereunder shall require the consent of the Delaware
Trustee. No such amendment (other than one entered into pursuant to clause (iii) of the preceding sentence) shall change the powers
of the Master Servicer. Prior to entering into any amendment (other than one entered into pursuant to clause (iii) of the second
preceding sentence) without the consent of Certificateholders pursuant to this paragraph, the Trustee shall require an Opinion of
Counsel addressed to the Trust and the Trustee to the effect that such amendment is permitted under this Agreement and has no
material adverse effect on the interests of the Certificateholders; provided, however, that no such Opinion of
Counsel shall be required if the Company obtains a letter from each Rating Agency stating that the amendment would not result in
the downgrading or withdrawal of the respective ratings then assigned to the Certificates.  Prior to entering into any
amendment pursuant to clause (iii) of the third preceding sentence without the consent of Certificateholders pursuant to this
paragraph, the Trustee shall require an Opinion of Counsel to the effect that such action is necessary or helpful to comply with
the requirements imposed by the Code or any regulations thereunder and shall not cause any REMIC formed under this Agreement to
fail to qualify as such under the Code.  The cost of any opinion required by this Section 10.01 shall be borne by the
party requesting such amendment.


(b)        This Agreement may also
be amended from time to time by the Master Servicer, the Company and the Trustee with the consent of the Holders of Certificates
evidencing Percentage Interests aggregating not less than 66% of REMIC I for the purpose of adding any provisions to, or changing
in any manner or eliminating any of the provisions of, this Agreement or of modifying in any manner the rights of the
Certificateholders; provided, however, that no such amendment shall, without the consent of the Holder of each Certificate
affected thereby (i) reduce in any manner the amount of, or delay the timing of, distributions of principal or interest required to
be made hereunder or reduce the Certificateholder’s Percentage Interest, the Certificate Interest Rate or the Termination
Payment with respect to any of the Certificates, (ii) reduce the percentage of Percentage Interests specified in this Section 10.01
which are required to amend this Agreement, (iii) create or permit the creation of any lien against any part of REMIC I, or (iv)
modify any provision in any way which would permit an earlier retirement of the Certificates; provided, further, that any
such amendment which modifies the rights or obligations of the Delaware Trustee hereunder shall require the consent of the Delaware
Trustee.


Promptly after the execution of any such amendment, the Trustee shall
furnish written notification of the substance of such amendment to the Delaware Trustee and each Certificateholder. Any failure to
provide such notice, or any defect therein, shall not, however, in any way impair or affect the validity of any such
amendment.


It shall not be necessary for the consent of Certificateholders under
this Section 10.01 to approve the particular form of any proposed amendment, but it shall be sufficient if such consent shall
approve the substance thereof. The manner of obtaining such consents and of evidencing the authorization of the execution thereof
by Certificateholders shall be subject to such reasonable regulations as the Trustee may prescribe.



Section 10.02.    Recordation of Agreement. To the
extent permitted by applicable law, this Agreement is subject to recordation in all appropriate public offices for real property
records in all the counties or the comparable jurisdictions in which any Mortgaged Property is situated, and in any other
appropriate public recording office or elsewhere, such recordation to be effected by the Company and at its expense on direction by
the Trustee, but only upon direction accompanied by an Opinion of Counsel to the effect that such recordation materially and
beneficially affects the interests of the Certificateholders.



Section 10.03.    Limitation on Rights of
Certificateholders. The death or incapacity of any Certificateholder shall not operate to terminate this Agreement
or the Trust, nor entitle such Certificateholder’s legal representatives or heirs to claim an accounting or to take any
action or proceeding in any court for a partition or winding-up of the Trust, nor otherwise affect the rights, obligations and
liabilities of the parties hereto or any of them.


No Certificateholder shall have any right to vote or in any manner
otherwise to control the operation and management of the Trust or the obligations of the parties hereto (except as provided in
Section 5.09, Section 7.01, Section 8.01, Section 8.02, Section 8.07, Section 10.01 and this Section 10.03), nor shall anything
herein set forth, or contained in the terms of the Certificates, be construed so as to constitute the Certificateholders from time
to time as partners or members of an association; nor shall any Certificateholder be under any liability to any third person by
reason of any action taken by the parties to this Agreement pursuant to any provision hereof.


No Certificateholder shall have any right by virtue or by availing of
any provision of this Agreement to institute any suit, action or proceeding in equity or at law upon or under or with respect to
this Agreement, unless such Holder previously shall have given to the Trustee a written notice of default and of the continuance
thereof, as hereinbefore provided, and unless also the Holders of Certificates evidencing Percentage Interests aggregating not less
than 25% of REMIC I shall have made written request upon the Trustee to institute such action, suit or proceeding in its own name
as Trustee hereunder and shall have offered to the Trustee such reasonable indemnity as it may require against the costs, expenses
and liabilities to be incurred therein or thereby, and the Trustee, for 60 days after its receipt of such notice, request and offer
of indemnity, shall have neglected or refused to institute any such action, suit or proceeding. However, the Trustee is under no
obligation to exercise any of the extraordinary trusts or powers vested in it by this Agreement or to make any investigation of
matters arising hereunder or to institute, conduct or defend any litigation hereunder or in relation hereto at the request, order
or direction of any of the Certificateholders unless such Certificateholders have offered to the Trustee reasonable security or
indemnity against the costs, expenses and liabilities which may be incurred therein or thereby. It is understood and intended, and
expressly covenanted by each Certificateholder with every other Certificateholder and the Trustee, that no one or more Holders of
Certificates shall have any right in any manner whatever by virtue or by availing of any provision of this Agreement to affect,
disturb or prejudice the rights of the Holders of any other of such Certificates, or to obtain or seek to obtain priority over or
preference to any other such Holder, or to enforce any right under this Agreement, except in the manner herein provided and for the
equal, ratable and common benefit of all Certificateholders. For the protection and enforcement of the provisions of this Section
10.03, each and every Certificateholder and the Trustee shall be entitled to such relief as can be given either at law or in
equity.



Section 10.04.    Access to List of Certificateholders.
The Certificate Registrar shall furnish or cause to be furnished to the Trustee, within 30 days after receipt of a request by the
Trustee in writing, a list, in such form as the Trustee may reasonably require, of the names and addresses of the
Certificateholders as of the most recent Record Date for payment of distributions to such Certificateholders.


If three or more Certificateholders (hereinafter referred to as
“applicants”) apply in writing to the Trustee, and such application states that the applicants desire to
communicate with other Certificateholders with respect to their rights under this Agreement or under the Certificates and is
accompanied by a copy of the communication which such applicants propose to transmit, then the Trustee shall, within five Business
Days after the receipt of such list from the Certificate Registrar, afford such applicants access during normal business hours to
the most recent list of Certificateholders held by the Trustee. If such a list is as of a date more than 90 days prior to the date
of receipt of such applicants’ request, the Trustee shall promptly request from the Certificate Registrar a current list as
provided above, and shall afford such applicants access to such list promptly upon receipt.


Every Certificateholder, by receiving and holding the same, agrees
with the Master Servicer, the Trust, the Trustee and the Delaware Trustee that none of the Master Servicer, the Trust, the Trustee
or the Delaware Trustee shall be held accountable by reason of the disclosure of any such information as to the names and addresses
of the Certificateholders hereunder, regardless of the source from which such information was derived.



Section 10.05.    Governing Law. This Agreement shall be
construed in accordance with the laws of the State of Delaware without giving effect to its conflict of laws provisions and the
obligations, rights and remedies of the parties hereunder shall be determined in accordance with such laws without giving effect to
conflict of laws provisions.



Section 10.06.    Notices. All demands, notices and
communications hereunder shall be in writing and shall be deemed to have been duly given if personally delivered at or mailed by
registered or certified mail or overnight courier to the applicable Notice Address. Notices to the Rating Agencies shall also be
deemed to have been duly given if mailed by first class mail, postage prepaid, to the above listed addresses of the Rating
Agencies. Any notice required or permitted to be mailed to a Certificateholder shall be given by first class mail, postage prepaid,
at the address of such Holder as shown in the Certificate Register. Any notice so mailed within the time prescribed in this
Agreement shall be conclusively presumed to have been duly given, whether or not the Certificateholder receives such notice.



Section 10.07.    Severability of Provisions. If any one
or more of the covenants, agreements, provisions or terms of this Agreement shall be for any reason whatsoever held invalid, then
such covenants, agreements, provisions or terms shall be deemed severable from the remaining covenants, agreements, provisions or
terms of this Agreement and shall in no way affect the validity or enforceability of the other provisions of this Agreement or of
the Certificates or the rights of the Holders thereof.



Section 10.08.    Counterpart Signatures. For the
purpose of facilitating the recordation of this Agreement as herein provided and for other purposes, this Agreement may be executed
simultaneously in any number of counterparts, each of which counterparts shall be deemed to be an original, and such counterparts
shall constitute but one and the same instrument.



Section 10.09.    Benefits of Agreement. Nothing in this
Agreement or in any Certificate, expressed or implied, shall give to any Person, other than the parties hereto and their respective
successors hereunder, any separate trustee or co-trustee appointed under Section 8.10 and the Certificateholders, any benefit or
any legal or equitable right, remedy or claim under this Agreement.



Section 10.10.    Notices and Copies to Rating
Agencies.


(a)        The Trustee shall notify
the Rating Agencies of the occurrence of any of the following events, in the manner provided in Section 10.06:


(i)        
the occurrence of an Event of Default pursuant to Section 7.01, subject to the provisions of Section 8.01(d); and


(ii)        the
appointment of a successor Master Servicer pursuant to Section 7.02;


(b)        The Master Servicer
shall notify the Rating Agencies of the occurrence of any of the following events, or in the case of clauses (iii), (iv), (vii) and
(viii) promptly upon receiving notice thereof, in the manner provided in Section 10.06:


(i)        
any amendment of this Agreement pursuant to Section 10.01;


(ii)        the
appointment of a successor Trustee or successor Delaware Trustee pursuant to Section 8.08;


(iii)       the filing
of any claim under or the cancellation or modification of any fidelity bond and errors and omissions coverage pursuant to Section
3.01 and Section 3.06 with respect to the Master Servicer or any Servicer;


(iv)       any change
in the location of the Certificate Account, any Custodial Account for P&I or any Custodial Account for Reserves;


(v)        the
purchase of any Mortgage Loan pursuant to a Purchase Obligation or as permitted by this Agreement or the purchase of the
outstanding Mortgage Loans pursuant to Section 9.01;


(vi)       the
occurrence of the final Distribution Date or the termination of the trust pursuant to Section 9.01(a)(ii);


(vii)      the failure of
the Master Servicer to make a Monthly P&I Advance following a determination on the Determination Date that the Master Servicer
would make such advance pursuant to Section 4.02; and


(viii)      the failure of
the Master Servicer to make a determination on the Determination Date regarding whether it would make a Monthly P&I Advance
when a shortfall exists between (x) payments scheduled to be received in respect of the Mortgage Loans and (y) the amounts actually
deposited in the Certificate Account on account of such payments, pursuant to Section 4.02.


The Master Servicer shall provide copies of the statements
pursuant to Section 4.02, Section 4.04, Section 3.12, Section 3.13 or Section 3.15 or any other statements or reports to the Rating
Agencies in such time and manner that such statements or determinations are required to be provided to Certificateholders. With
respect to the reports described in the second paragraph of Section 4.04, the Master Servicer shall provide such reports to the
Rating Agencies in respect of each Distribution Date, without regard to whether any Certificateholder or the Trustee or the
Delaware Trustee has requested such report for such Distribution Date.











 



IN WITNESS WHEREOF, the Company, the Trustee and
the Delaware Trustee have caused their names to be signed hereto by their respective officers, thereunto duly authorized, all as of
the day and year first above written.


	

WASHINGTON MUTUAL MORTGAGE SECURITIES
CORP.


	

By /s/ Thomas G. Lehmann


	

        Name:
Thomas G. Lehmann

         Title: First Vice President


	
LASALLE BANK NATIONAL ASSOCIATION,


	

as Trustee


	

By: /s/ Cynthia Reis


	

       
Name: Cynthia Reis

         Title: Senior Vice President


	
CHRISTIANA BANK & TRUST COMPANY,


	

as Delaware
Trustee


	

By:  /s/ James M. Young


	

       
Name: James M. Young

         Title:  Assistant Vice President






[Signature page to Pooling and Servicing Agreement for WaMu Series 2005-AR3]









 



Exhibit A

CUSIP 939336 Z3 0


WaMu MORTGAGE PASS-THROUGH
CERTIFICATE


Class A-1


Evidencing a beneficial interest in a pool of assets consisting of, among
other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL MORTGAGE
SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended. The issue date of this Certificate is February 23, 2005.


Unless this Certificate is presented by an authorized representative of
The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer,
exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by
an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an
authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
inasmuch as the registered owner hereof, Cede & Co., has an interest herein.


 


Series
2005-AR3                                                                                    
Portion of the Class A-1 Principal Balance as of


                                                                                                               
the Cut-Off Date Evidenced by this Certificate:


                                                                                                               
$400,000,000.00


Class A-1 Certificate Interest Rate:
Variable


Cut-Off Date:
February 1, 2005


First Distribution
Date: March 25, 2005


Last Scheduled
Distribution Date: March 25, 2035


Class A-1
Principal Balance

as of the Cut-Off Date: $400,000,000.00


Cede & Co.


Registered Owner


 













 


Exhibit A

CUSIP 939336 Z4 8


WaMu MORTGAGE PASS-THROUGH
CERTIFICATE


Class A-2


Evidencing a beneficial interest in a pool of assets consisting of, among
other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL MORTGAGE
SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended. The issue date of this Certificate is February 23, 2005.


Unless this Certificate is presented by an authorized representative of
The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer,
exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by
an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an
authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
inasmuch as the registered owner hereof, Cede & Co., has an interest herein.


 


Series
2005-AR3                                                                                    
Portion of the Class A-2 Principal Balance as of


                                                                                                               
the Cut-Off Date Evidenced by this Certificate:


                                                                                                               
$304,500,000.00


Class A-2 Certificate Interest Rate:
Variable


Cut-Off Date:
February 1, 2005


First Distribution
Date: March 25, 2005


Last Scheduled
Distribution Date: March 25, 2035


Class A-2
Principal Balance

as of the Cut-Off Date: $304,500,000.00


Cede & Co.


Registered Owner


 













 




 


Exhibit A

CUSIP 939336 Z5 5


WaMu MORTGAGE PASS-THROUGH
CERTIFICATE


Class A-3


Evidencing a beneficial interest in a pool of assets consisting of, among
other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL MORTGAGE
SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended. The issue date of this Certificate is February 23, 2005.


Unless this Certificate is presented by an authorized representative of
The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer,
exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by
an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an
authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
inasmuch as the registered owner hereof, Cede & Co., has an interest herein.


 


Series
2005-AR3                                                                                    
Portion of the Class A-3 Principal Balance as of


                                                                                                               
the Cut-Off Date Evidenced by this Certificate:


                                                                                                               
$14,019,000.00


Class A-3 Certificate Interest Rate:
Variable


Cut-Off Date:
February 1, 2005


First Distribution
Date: March 25, 2005


Last Scheduled
Distribution Date: March 25, 2035


Class A-3
Principal Balance

as of the Cut-Off Date: $14,019,000.00


Cede & Co.


Registered Owner


 


 













 




 


Exhibit A

CUSIP 939336 Z6 3


 WaMu
MORTGAGE PASS-THROUGH CERTIFICATE


Class
B-1


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON
MUTUAL MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


Unless this Certificate
is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the
Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of
Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co.
or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest
herein.


NO TRANSFER OF THIS CLASS B-1
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


NOTWITHSTANDING THE FOREGOING PARAGRAPH,
WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY
INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S
CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE FOREGOING PARAGRAPH, SHALL NOT BE REQUIRED, AND (II)
THE FOLLOWING CONDITIONS SHALL APPLY:


1.             ANY TRANSFEREE OF THIS CERTIFICATE WILL BE DEEMED
TO HAVE REPRESENTED, BY VIRTUE OF ITS ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN), THAT EITHER (A) SUCH
TRANSFEREE IS NOT AN EMPLOYEE BENEFIT OR OTHER PLAN SUBJECT TO THE PROHIBITED TRANSACTION PROVISIONS OF ERISA OR SECTION 4975 OF
THE CODE, OR ANY PERSON (INCLUDING AN INVESTMENT MANAGER, A NAMED FIDUCIARY OR A TRUSTEE OF ANY SUCH PLAN) ACTING, DIRECTLY OR
INDIRECTLY, ON BEHALF OF OR PURCHASING THIS CERTIFICATE WITH “PLAN ASSETS” OF ANY SUCH PLAN (A “PLAN
INVESTOR”), (B) SUCH TRANSFEREE IS AN INSURANCE COMPANY, THE SOURCE OF FUNDS TO BE USED BY IT TO ACQUIRE OR HOLD THIS
CERTIFICATE IS AN “INSURANCE COMPANY GENERAL ACCOUNT” (WITHIN THE MEANING OF DEPARTMENT OF LABOR PROHIBITED TRANSACTION
CLASS EXEMPTION (“PTCE”) 95-60), AND THE CONDITIONS IN SECTIONS I AND III OF PTCE 95-60 HAVE BEEN SATISFIED (EACH
ENTITY THAT SATISFIES THIS CLAUSE (B), A “COMPLYING INSURANCE COMPANY”) OR (C) THIS CERTIFICATE WAS RATED
“BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES AT THE TIME OF SUCH TRANSFEREE’S
ACQUISITION OF THIS CERTIFICATE (OR INTEREST HEREIN); AND


2.             IF THIS CERTIFICATE (OR ANY INTEREST HEREIN) IS
ACQUIRED OR HELD IN VIOLATION OF THE PROVISIONS OF THE PRECEDING PARAGRAPH, THEN THE LAST PRECEDING TRANSFEREE THAT EITHER (I) IS
NOT A PLAN INVESTOR, (II) IS A COMPLYING INSURANCE COMPANY OR (III) ACQUIRED THIS CERTIFICATE AT A TIME WHEN THIS CERTIFICATE WAS
RATED “BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES SHALL BE RESTORED, TO THE EXTENT
PERMITTED BY LAW, TO ALL RIGHTS AND OBLIGATIONS AS BENEFICIAL HOLDER THEREOF RETROACTIVE TO THE DATE OF TRANSFER OF THIS
CERTIFICATE BY SUCH PRECEDING TRANSFEREE.  NEITHER THE TRUST NOR THE TRUSTEE SHALL BE UNDER ANY LIABILITY TO ANY PERSON FOR
MAKING ANY PAYMENTS DUE ON THIS CERTIFICATE TO SUCH PRECEDING TRANSFEREE.


ANY PURPORTED BENEFICIAL HOLDER WHOSE
ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN) WAS EFFECTED IN VIOLATION OF THE RESTRICTIONS IN SECTION 5.01(g) OF
THE POOLING AGREEMENT SHALL INDEMNIFY AND HOLD HARMLESS THE COMPANY, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER, THE
TRUST AND THE UNDERWRITERS FROM AND AGAINST ANY AND ALL LIABILITIES, CLAIMS, COSTS OR EXPENSES INCURRED BY SUCH PARTIES AS A RESULT
OF SUCH ACQUISITION OR HOLDING.


The Class B-1 Certificates will be subordinate
in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling
Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:

$17,260,000.00


Class B-1 Certificate Interest Rate: Variable


Cut-Off Date: February 1, 2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date: March 25,
2035


Class B-1
Principal Balance

as of the Cut-Off Date: $17,260,000.00


 


Cede & Co.


Registered Owner


 


 













 




 


Exhibit A

CUSIP 939336 Z7 1


 WaMu
MORTGAGE PASS-THROUGH CERTIFICATE


Class
B-2


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON
MUTUAL MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


Unless this Certificate
is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the
Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of
Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co.
or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest
herein.


NO TRANSFER OF THIS CLASS B-2
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


NOTWITHSTANDING THE FOREGOING PARAGRAPH,
WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY
INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S
CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE FOREGOING PARAGRAPH, SHALL NOT BE REQUIRED, AND (II)
THE FOLLOWING CONDITIONS SHALL APPLY:


1.             ANY TRANSFEREE OF THIS CERTIFICATE WILL BE DEEMED
TO HAVE REPRESENTED, BY VIRTUE OF ITS ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN), THAT EITHER (A) SUCH
TRANSFEREE IS NOT AN EMPLOYEE BENEFIT OR OTHER PLAN SUBJECT TO THE PROHIBITED TRANSACTION PROVISIONS OF ERISA OR SECTION 4975 OF
THE CODE, OR ANY PERSON (INCLUDING AN INVESTMENT MANAGER, A NAMED FIDUCIARY OR A TRUSTEE OF ANY SUCH PLAN) ACTING, DIRECTLY OR
INDIRECTLY, ON BEHALF OF OR PURCHASING THIS CERTIFICATE WITH “PLAN ASSETS” OF ANY SUCH PLAN (A “PLAN
INVESTOR”), (B) SUCH TRANSFEREE IS AN INSURANCE COMPANY, THE SOURCE OF FUNDS TO BE USED BY IT TO ACQUIRE OR HOLD THIS
CERTIFICATE IS AN “INSURANCE COMPANY GENERAL ACCOUNT” (WITHIN THE MEANING OF DEPARTMENT OF LABOR PROHIBITED TRANSACTION
CLASS EXEMPTION (“PTCE”) 95-60), AND THE CONDITIONS IN SECTIONS I AND III OF PTCE 95-60 HAVE BEEN SATISFIED (EACH
ENTITY THAT SATISFIES THIS CLAUSE (B), A “COMPLYING INSURANCE COMPANY”) OR (C) THIS CERTIFICATE WAS RATED
“BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES AT THE TIME OF SUCH TRANSFEREE’S
ACQUISITION OF THIS CERTIFICATE (OR INTEREST HEREIN); AND


2.             IF THIS CERTIFICATE (OR ANY INTEREST HEREIN) IS
ACQUIRED OR HELD IN VIOLATION OF THE PROVISIONS OF THE PRECEDING PARAGRAPH, THEN THE LAST PRECEDING TRANSFEREE THAT EITHER (I) IS
NOT A PLAN INVESTOR, (II) IS A COMPLYING INSURANCE COMPANY OR (III) ACQUIRED THIS CERTIFICATE AT A TIME WHEN THIS CERTIFICATE WAS
RATED “BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES SHALL BE RESTORED, TO THE EXTENT
PERMITTED BY LAW, TO ALL RIGHTS AND OBLIGATIONS AS BENEFICIAL HOLDER THEREOF RETROACTIVE TO THE DATE OF TRANSFER OF THIS
CERTIFICATE BY SUCH PRECEDING TRANSFEREE.  NEITHER THE TRUST NOR THE TRUSTEE SHALL BE UNDER ANY LIABILITY TO ANY PERSON FOR
MAKING ANY PAYMENTS DUE ON THIS CERTIFICATE TO SUCH PRECEDING TRANSFEREE.


ANY PURPORTED BENEFICIAL HOLDER WHOSE
ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN) WAS EFFECTED IN VIOLATION OF THE RESTRICTIONS IN SECTION 5.01(g) OF
THE POOLING AGREEMENT SHALL INDEMNIFY AND HOLD HARMLESS THE COMPANY, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER, THE
TRUST AND THE UNDERWRITERS FROM AND AGAINST ANY AND ALL LIABILITIES, CLAIMS, COSTS OR EXPENSES INCURRED BY SUCH PARTIES AS A RESULT
OF SUCH ACQUISITION OR HOLDING.


The Class B-2 Certificates will be subordinate
in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling
Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:

$5,253,000.00


Class B-2 Certificate Interest Rate: Variable


Cut-Off Date: February 1, 2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date: March 25,
2035


Class B-2
Principal Balance

as of the Cut-Off Date: $5,253,000.00


 


Cede & Co.


Registered Owner


 













 




 


Exhibit A

CUSIP 939336 Z8 9


 WaMu
MORTGAGE PASS-THROUGH CERTIFICATE


Class
B-3


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON
MUTUAL MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through Certificates
Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage
investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of
1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


Unless this Certificate
is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the
Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of
Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co.
or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest
herein.


NO TRANSFER OF THIS CLASS B-3
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


NOTWITHSTANDING THE FOREGOING PARAGRAPH,
WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY
INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S
CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE FOREGOING PARAGRAPH, SHALL NOT BE REQUIRED, AND (II)
THE FOLLOWING CONDITIONS SHALL APPLY:


1.             ANY TRANSFEREE OF THIS CERTIFICATE WILL BE DEEMED
TO HAVE REPRESENTED, BY VIRTUE OF ITS ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN), THAT EITHER (A) SUCH
TRANSFEREE IS NOT AN EMPLOYEE BENEFIT OR OTHER PLAN SUBJECT TO THE PROHIBITED TRANSACTION PROVISIONS OF ERISA OR SECTION 4975 OF
THE CODE, OR ANY PERSON (INCLUDING AN INVESTMENT MANAGER, A NAMED FIDUCIARY OR A TRUSTEE OF ANY SUCH PLAN) ACTING, DIRECTLY OR
INDIRECTLY, ON BEHALF OF OR PURCHASING THIS CERTIFICATE WITH “PLAN ASSETS” OF ANY SUCH PLAN (A “PLAN
INVESTOR”), (B) SUCH TRANSFEREE IS AN INSURANCE COMPANY, THE SOURCE OF FUNDS TO BE USED BY IT TO ACQUIRE OR HOLD THIS
CERTIFICATE IS AN “INSURANCE COMPANY GENERAL ACCOUNT” (WITHIN THE MEANING OF DEPARTMENT OF LABOR PROHIBITED TRANSACTION
CLASS EXEMPTION (“PTCE”) 95-60), AND THE CONDITIONS IN SECTIONS I AND III OF PTCE 95-60 HAVE BEEN SATISFIED (EACH
ENTITY THAT SATISFIES THIS CLAUSE (B), A “COMPLYING INSURANCE COMPANY”) OR (C) THIS CERTIFICATE WAS RATED
“BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES AT THE TIME OF SUCH TRANSFEREE’S
ACQUISITION OF THIS CERTIFICATE (OR INTEREST HEREIN); AND


2.             IF THIS CERTIFICATE (OR ANY INTEREST HEREIN) IS
ACQUIRED OR HELD IN VIOLATION OF THE PROVISIONS OF THE PRECEDING PARAGRAPH, THEN THE LAST PRECEDING TRANSFEREE THAT EITHER (I) IS
NOT A PLAN INVESTOR, (II) IS A COMPLYING INSURANCE COMPANY OR (III) ACQUIRED THIS CERTIFICATE AT A TIME WHEN THIS CERTIFICATE WAS
RATED “BBB-” OR BETTER (OR ITS EQUIVALENT) BY AT LEAST ONE OF THE RATING AGENCIES SHALL BE RESTORED, TO THE EXTENT
PERMITTED BY LAW, TO ALL RIGHTS AND OBLIGATIONS AS BENEFICIAL HOLDER THEREOF RETROACTIVE TO THE DATE OF TRANSFER OF THIS
CERTIFICATE BY SUCH PRECEDING TRANSFEREE.  NEITHER THE TRUST NOR THE TRUSTEE SHALL BE UNDER ANY LIABILITY TO ANY PERSON FOR
MAKING ANY PAYMENTS DUE ON THIS CERTIFICATE TO SUCH PRECEDING TRANSFEREE.


ANY PURPORTED BENEFICIAL HOLDER WHOSE
ACQUISITION OR HOLDING OF THIS CERTIFICATE (OR INTEREST HEREIN) WAS EFFECTED IN VIOLATION OF THE RESTRICTIONS IN SECTION 5.01(g) OF
THE POOLING AGREEMENT SHALL INDEMNIFY AND HOLD HARMLESS THE COMPANY, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER, THE
TRUST AND THE UNDERWRITERS FROM AND AGAINST ANY AND ALL LIABILITIES, CLAIMS, COSTS OR EXPENSES INCURRED BY SUCH PARTIES AS A RESULT
OF SUCH ACQUISITION OR HOLDING.


The Class B-3 Certificates will be subordinate
in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling
Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:

$3,377,000.00


Class B-3 Certificate Interest Rate: Variable


Cut-Off Date: February 1, 2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date: March 25,
2035


Class B-3
Principal Balance

as of the Cut-Off Date: $3,377,000.00


 


Cede & Co.


Registered Owner


 




 




 


 

 Exhibit A

CUSIP 939336 2A 0


 WaMu MORTGAGE
PASS-THROUGH CERTIFICATE


Class B-4


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL
MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through
Certificates Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real
estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal
Revenue Code of 1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


NO TRANSFER OF THIS CLASS B-4
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


THE SECURITIES REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED,
PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT.


The Class B-4 Certificates will be subordinate in right of
payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:


$2,626,000.00


Class B-4 Certificate Interest Rate:
Variable


Cut-Off Date: February 1,
2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date:
March 25, 2035


Class B-4
Principal Balance


as of the Cut-Off Date:
$2,626,000.00


_____________________

Registered Owner


 


                                                                                                         













 




 


Exhibit A

CUSIP 939336 2B 8


 WaMu MORTGAGE
PASS-THROUGH CERTIFICATE


Class B-5


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL
MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through
Certificates Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real
estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal
Revenue Code of 1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


NO TRANSFER OF THIS CLASS B-5
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


THE SECURITIES REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED,
PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT.


The Class B-5 Certificates will be subordinate in right of
payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:


$1,876,000.00


Class B-5 Certificate Interest Rate:
Variable


Cut-Off Date: February 1,
2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date:
March 25, 2035


Class B-5
Principal Balance


as of the Cut-Off Date:
$1,876,000.00


_____________________

Registered Owner


 













 




 


Exhibit A

CUSIP 939336 2C 6


 WaMu MORTGAGE
PASS-THROUGH CERTIFICATE


Class B-6


Evidencing a beneficial interest in a pool of
assets consisting of, among other things, conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL
MORTGAGE SECURITIES CORP.


This Certificate is issued by WaMu Mortgage Pass-Through
Certificates Series 2005-AR3 Trust. This Certificate represents ownership of a “regular interest” in a “real
estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal
Revenue Code of 1986, as amended (the “Code”). The issue date of this Certificate is February 23, 2005.


NO TRANSFER OF THIS CLASS B-6
CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION
5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO
AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS
CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER
SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER
SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION
4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE
TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


THE SECURITIES REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED,
PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT.


The Class B-6 Certificates will be subordinate in right of
payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement.


Series
2005-AR3                                                                                    
Portion of the Class B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate:


$1,500,908.71


Class B-6 Certificate Interest Rate:
Variable


Cut-Off Date: February 1,
2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date:
March 25, 2035


Class B-6
Principal Balance


as of the Cut-Off Date:
$1,500,908.71


_____________________

Registered Owner


 













 




 


Exhibit A

CUSIP 939336 Z9 7


 WaMu MORTGAGE PASS-THROUGH CERTIFICATE


Class R


Evidencing a Percentage Interest in certain distributions with
respect to a pool of conventional one- to four-family mortgage loans formed and administered by


WASHINGTON MUTUAL
MORTGAGE SECURITIES CORP.


ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE
MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE
IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL
ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN
SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE
TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON
DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR
(D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT
OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED
TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R
CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF
NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER,
INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE
OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH.


IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR
REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN
SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL
ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF
A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION
UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE
CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE MASTER SERVICER OR THE COMPANY TO ANY OBLIGATION OR
LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE
UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE
TRUSTEE, THE MASTER SERVICER OR THE COMPANY.


This Certificate is issued by WaMu Mortgage Pass-Through
Certificates Series 2005-AR3 Trust. Solely for U.S. federal income tax purposes, this Certificate represents a “residual
interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D,
respectively, of the Internal Revenue Code of 1986, as amended.


Series
2005-AR3                                                                                    
Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates:
                                     
%


Class R Certificate Interest Rate: 4.6608%.  Additionally the Class R Certificates are entitled to Excess
Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement.


Cut-Off Date: February 1,
2005


First Distribution Date: March 25,
2005


Last Scheduled Distribution Date:
March 25, 2035


Class R Principal Balance as of the
Cut-Off Date: $100.00


__________________

Registered Owner


Certificate No.
___















 




 



Exhibit B


[Reserved]















 




 



Exhibit C


ANTI-PREDATORY LENDING CATEGORIZATION


 


I.              High-Cost Loan Categorization


 


                                                                               
                                                       


	
State/Jurisdiction

	
Name of Anti-Predatory Lending
Law/Effective Date

	

Category under Applicable

Anti-Predatory Lending Law


	
Arkansas

	
Arkansas Home Loan Protection Act, Ark.
Code Ann. §§ 23-53-101 et seq.


Effective July 16, 2003

	
High Cost Home Loan


	
Cleveland Heights, OH

	
Ordinance No. 72-2003 (PSH), Mun. Code §§ 757.01 et seq.


Effective June 2, 2003

	
Covered Loan


	
Colorado

	
Consumer Equity Protection, Colo. Stat. Ann.
§§ 5-3.5-101 et seq.


Effective for covered loans offered or entered
into on or after January 1, 2003. Other provisions of the Act took effect on June 7, 2002

	
Covered Loan


	
Connecticut

	
Connecticut Abusive Home Loan Lending Practices
Act, Conn. Gen. Stat. §§ 36a-746 et seq.


Effective October 1, 2001

	
High Cost Home Loan


	
District of Columbia

	
Home Loan Protection Act, D.C. Code
§§ 26-1151.01 et seq.


Effective for loans closed on or after January
28, 2003

	
Covered Loan


	
Florida

	
Fair Lending Act, Fla. Stat. Ann. §§ 494.0078 et seq.


Effective October 2, 2002

	
High Cost Home Loan


	
Georgia (Oct 1, 2002 – Mar 6, 2003)

	
Georgia Fair Lending Act, Ga. Code Ann. §§ 7-6A-1 et seq.


Effective October 1, 2002 – March 6,
2003

	
High Cost Home Loan


	
Georgia as amended (Mar 7, 2003 – current)

	
Georgia Fair Lending Act, Ga. Code Ann. §§ 7-6A-1 et seq.


Effective for loans closed on or after March 7,
2003

	
High Cost Home Loan


	
HOEPA Section 32

	
Home Ownership and Equity Protection Act of
1994, 15 U.S.C. § 1639, 12 C.F.R. §§ 226.32 and 226.34


Effective October 1, 1995, amendments October
1, 2002

	
High Cost Loan


	
Illinois

	
High Risk Home Loan Act, Ill. Comp. Stat. tit. 815, §§ 137/5 et seq.


Effective January 1, 2004 (prior to this date,
regulations under Residential Mortgage License Act effective from May 14, 2001)

	
High Risk Home Loan


	
Kansas

	
Consumer Credit Code, Kan. Stat. Ann. §§ 16a-1-101 et seq.


Sections 16a-1-301 and 16a-3-207 became
effective April 14, 1999; Section 16a-3-308a became effective July 1, 1999

	
High Loan to Value Consumer Loan (id. § 16a-3-207) and;


 


High APR Consumer Loan (id. § 16a-3-308a)


 


	
Kentucky

	
2003 KY H.B. 287 – High Cost Home Loan
Act, Ky. Rev. Stat. §§ 360.100 et seq.


Effective June 24, 2003

	
High Cost Home Loan


	
Maine

	
Truth in Lending, Me. Rev. Stat. tit. 9-A,
§§ 8-101 et seq.


Effective September 29, 1995 and as amended
from time to time

	
High Rate High Fee Mortgage


	
Massachusetts

	
Part 40 and Part 32, 209 C.M.R. §§
32.00 et seq. and 209 C.M.R. §§ 40.01 et seq.


Effective March 22, 2001 and amended from time
to time

	
High Cost Home Loan


	
Nevada

	
Assembly Bill No. 284, Nev. Rev. Stat. §§ 598D.010 et seq.


Effective October 1, 2003

	
Home Loan


	
New Jersey

	
New Jersey Home Ownership Security Act of 2002,
N.J. Rev. Stat. §§ 46:10B-22 et seq.


Effective for loans closed on or after November
27, 2003

	
High Cost Home Loan


	
New York

	
Home Loan Protection Act, N.M. Rev.
Stat. §§ 58-21A-1 et seq.


Effective as of January 1, 2004; Revised as of
February 26, 2004

	
High Cost Home Loan


	
New Mexico

	
N.Y. Banking Law Article 6-l


Effective for applications made on or after
April 1, 2003

	
High Cost Home Loan


	
North Carolina

	
Restrictions and Limitations on High Cost Home
Loans, N.C. Gen. Stat. §§ 24-1.1E et seq.


Effective July 1, 2000; amended October 1, 2003
(adding open-end lines of credit)

	
High Cost Home Loan


	
Ohio

	
H.B. 386 (codified in various sections of the
Ohio Code), Ohio Rev. Code Ann. §§ 1349.25 et seq.


Effective May 24, 2002

	
Covered Loan


	
Oklahoma

	
Consumer Credit Code (codified in various
sections of Title 14A)


Effective July 1, 2000; amended effective
January 1, 2004

	
Subsection 10 Mortgage


	
South Carolina

	
South Carolina High Cost and Consumer Home
Loans Act, S.C. Code Ann. §§ 37-23-10 et seq.


Effective for loans taken on or after January
1, 2004

	
High Cost Home Loan


	
West Virginia

	
West Virginia Residential Mortgage Lender,
Broker and Servicer Act, W. Va. Code Ann. §§ 31-17-1 et seq.


Effective June 5, 2002

	
West Virginia Mortgage Loan Act Loan





 


 


 


II.            Covered
Loan Categorization


                                                                               
                    


	
State/Jurisdiction

	
Name of Anti-Predatory Lending
Law/Effective Date

	

Category under Applicable

Anti-Predatory Lending Law


	
Georgia (Oct 1, 2002 – Mar 6, 2003)

	
Georgia Fair Lending Act, Ga. Code Ann. §§ 7-6A-1 et seq.


Effective October 1, 2002 – March 6,
2003

	
Covered Loan


	
New Jersey

	
New Jersey Home Ownership Security Act of 2002,
N.J. Rev. Stat. §§ 46:10B-22 et seq.


Effective November 27, 2003 – July 5,
2004

	
Covered Home Loan





 















 




 



Exhibit D



Mortgage Loan
Schedule


 




Copies of the Mortgage Loan Schedule (which has been intentionally
omitted from this filing) may be obtained from Washington Mutual Mortgage Securities Corp. or LaSalle Bank National Association by
contacting:


 


	
 

	
      in the case of Washington Mutual
Mortgage Securities Corp.,





 


	
 

	
        Laura Kelsey

         Master Servicing Department

         Washington Mutual Mortgage Securities Corp.

         75 N. Fairway Drive,VHF2A01

         Vernon Hills, IL 60061

         Telephone:  (847) 393-5198

         Facsimile:     (847) 549-2997





 


	
 

	
      in the case of LaSalle Bank National
Association,





 


	
 

	
        Stefanie Edwards

         LaSalle Bank National Association

         135 S. LaSalle Street, Suite 2910

         Chicago, IL  60603

         Telephone:  (312) 904-8975

         Facsimile:    (312) 904-2084





 


















 




 



Exhibit E






SELLING AND
SERVICING


CONTRACT



 












This Selling and
Servicing Contract (this “Agreement”) is made and entered into by Washington Mutual Mortgage Securities Corp. and its
successors and assigns (“Washington Mutual Mortgage”) and the entity identified below and its successors and assigns
(the “Company”).


 


WITNESSETH:


            WHEREAS, this Company wishes to sell first lien
residential mortgage loans to, and service first lien residential mortgage loans on behalf of, Washington Mutual Mortgage;
and


            WHEREAS, the Company has
submitted a Seller Application to Washington Mutual Mortgage and has been approved by Washington Mutual Mortgage for participation
in the Washington Mutual Mortgage Purchase Programs; and


            WHEREAS, the Company has
received and reviewed the Washington Mutual Mortgage Purchase Programs Seller Guide (the “Seller Guide”), as well as
the Washington Mutual Mortgage Servicing Guide (the “Servicing Guide” and, together with the Seller Guide, the
“Guides”), and understands each and every provision thereof;


            NOW, THEREFORE, in
consideration of the premises and of the mutual agreements herein contained, Washington Mutual Mortgage and the Company hereby
agree as follows:


            1.        
Guides.  The Guides, which set forth the terms and conditions under which Washington Mutual Mortgage may elect to
purchase mortgage loans from the Company, and the Company shall service mortgage loans on behalf of Washington Mutual Mortgage, are
a supplement to this Agreement and such Guides, as may be amended or supplemented from time to time by Washington Mutual Mortgage,
are incorporated into this Agreement in full by reference and made a part hereof as fully as if set forth at length herein. 
All capitalized terms used and not defined herein have the meanings ascribed to them in the Guides.


            2.        
Company’s Duties.  The Company shall diligently perform all duties incident to the origination, sale and servicing
of the mortgage loans subject to this Agreement.  In the performance of its servicing duties, the Company shall exercise the
same degree of care it exercises when servicing mortgage loans for its own account, but in no event shall the Company exercise less
care than a reasonable prudent servicer would exercise under similar circumstances.  In addition, the Company shall comply
with all of the provisions of the Guides and with all other requirements and instructions of Washington Mutual Mortgage.  The
Company shall perform such duties at its sole expense, except as otherwise expressly provided in the Guides.


            3.        
Representations, Warranties and Covenants of the Company; Remedies of Washington Mutual Mortgage.  With respect to each
mortgage loan sold by the Company to Washington Mutual Mortgage pursuant to the terms of this Agreement, the Company shall make all
of the representations, warranties and covenants set forth in the Guide and, in the event of the breach of any of such
representations, warranties and covenants, Washington Mutual Mortgage shall have all of the remedies available at law or in equity,
as well as all of the remedies set forth in the Guide, including, but not limited to, repurchase and indemnification.  The
representations and warranties made by the Company with respect to any mortgage loan subject to this Agreement, as well as the
remedies available to Washington Mutual Mortgage upon the breach thereof, shall survive:  (a) any investigation regarding the
mortgage loan conducted by Washington Mutual Mortgage, its assignees or designees, (b) the liquidation of the mortgage loan, (c)
the purchase of the mortgage loan by Washington Mutual Mortgage, its assignee or designee, (d) the repurchase of the mortgage loan
by the Company and (e) the termination of this Agreement.


            4.        
Compensation.  The Company shall be compensated for its services hereunder as specified in the Guides.


            5.         No
Assignment.  This Agreement may not be assigned by the Company without the prior written consent of Washington Mutual
Mortgage.  The Company hereby consents to the assignment by Washington Mutual Mortgage of all or any part of its rights and
obligations under this Agreement to any affiliate designated by Washington Mutual Mortgage.  Any other transfer by Washington
Mutual Mortgage will be allowed and be effective upon written notice by Washington Mutual Mortgage to the Company.


            6.        
Prior Agreements.  This Agreement supersedes any prior agreements and understandings between Washington Mutual Mortgage
and the Company governing the subject matter hereof; provided, however, the Company shall not be released from any responsibility
or liability that may have arisen under such agreements and understanding.


            7.        
Effective Date of Agreement.  This Agreement is not effective until it is executed and accepted by Washington Mutual
Mortgage at its home office in Illinois.


            8.        
Notices.  All notices, requests, demands or other communications that are to be given under this Agreement shall be in
writing, addressed to the appropriate parties, and shall be sent by certified mail, return receipt requested, postage prepaid, if
to the Company, at the address below and, if to Washington Mutual Mortgage, to the appropriate address or facsimile number
specified in the Guides.  Any such notice, request, demand or other communication shall be deemed effective upon
receipt.


            9.        
Independent Contractor.  At no time shall the Company represent that it is acting as an agent, partner or joint
venturer of Washington Mutual Mortgage.  The Company shall at all times act as an independent contracting party.


            10.       
Amendment.  This Agreement may not be amended or modified orally, and no provision of this Agreement may be waived or
amended, except in writing signed by the party against whom enforcement is sought.  Such a written waiver or amendment must
expressly reference this Agreement.  However, by their terms the Guides may be amended or supplemented by Washington Mutual
Mortgage from time to time.  Any such amendment(s) to the Guides shall be in writing and be binding upon the parties hereto on
and after the effective date specified therein.


            11.       
Miscellaneous.  This Agreement, including all documents incorporated by reference herein, constitutes the entire
understanding between the parties hereto and supersedes all other agreements, covenants, representations, warranties,
understandings and communications between the parties, whether written or oral, with respect to the transactions contemplated by
this Agreement.  All section headings contained herein are for convenience only and shall not be construed as part of this
Agreement.  Any provision of this Agreement that is prohibited or unenforceable in any jurisdiction shall as to such
jurisdiction be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining portions
hereof or affecting the validity or enforceability of such provision in any other jurisdiction, and to this end, the provisions
hereof are severable.  This Agreement shall be governed by, and construed and enforced in accordance with, applicable federal
laws and laws of the State of Illinois, without reference to conflict of laws principles. This Agreement may be executed in one or
more counterparts, each of which shall constitute an original and all of which shall constitute the same Agreement.


            IN WITNESS WHEREOF, the parties have executed this
Agreement by proper officials duly authorized on the dates hereinafter set forth.  This Agreement shall take effect as of the
date of its execution in original or facsimile signature by a duly authorized officer of Washington Mutual Mortgage.


 


	
__________________________________________

	
___________________________________


	
Name of the
Company

	
Company I.D.
Number


	
__________________________________________

	
___________________________________


	
Type of
organization

	
Organized under laws
of


	
________________________________________________________________________________


	
Principal place of
business:  street address, city, state, zip code


	
________________________________________________________________________________


	
Typed name and title of
the Company’s authorized officer


	
_______________________________________________________

	
_______________________


	
Signature of the
Company’s authorized officer

	
Date


	
 


Agreed to and
accepted by Washington Mutual Mortgage Securities Corp.


	
________________________________________________________________________________


	
Typed name and title of
authorized representative


	
_______________________________________________________

	
_______________________


	
Signature of authorized
representative

	
Date


			



 


 















 




 



                 Exhibit F






FORM OF TRANSFEROR CERTIFICATE FOR


JUNIOR SUBORDINATE CERTIFICATES


 


[Date]


LaSalle Bank
National Association, as Trustee


135
South LaSalle Street, Suite 1625


Chicago, Illinois 60603


Attention: Global Securitization Trust Services


 


Re:       Purchase of Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through
Certificates Series 2005-AR3, Class [   ]  (the “Certificates”)


Ladies and Gentlemen:


In connection with our disposition of
the above Certificates we certify that (a) we understand the Certificates have not been registered under the Securities Act of
1933, as amended (the “Act”) and are being disposed by us in a transaction that is exempt from the registration
requirements of the Act, and (b) we have not offered or sold any certificates to, or solicited offers to buy any Certificates from,
any person, or otherwise approached or negotiated with any person with respect thereto, or taken any other action which would
result in a violation of Section 5 of the Act.


 


Very truly yours,


[Name of Transferor]


 



By:                                                      


                   Authorized
Officer


 















 




 



                Exhibit G






FORM OF TRANSFEREE'S AGREEMENT FOR


JUNIOR SUBORDINATE
CERTIFICATES


[Date]


LaSalle Bank
National Association, as Trustee


135
South LaSalle Street, Suite 1625


Chicago, Illinois 60603


Attention: Global Securitization Trust Services


 


Washington
Mutual Mortgage Securities Corp.


75 N. Fairway
Drive


Vernon Hills,
Illinois  60061


 


The undersigned (the
“Purchaser”) proposes to purchase Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through Certificates,
Series 2005-AR3, Class [   ] (the “Purchased Certificates”) in the principal amount of $______________. In
doing so, the Purchaser hereby acknowledges and agrees as follows:


Section 1. Definitions. Each
capitalized term used herein and not otherwise defined herein shall have the meaning ascribed to it in the Pooling and Servicing
Agreement, dated as of February 1, 2005 (the “Pooling Agreement”), by and among Washington Mutual Mortgage Securities
Corp. (“Washington Mutual”), LaSalle Bank National Association., as trustee (the “Trustee”), and Christiana
Bank & Trust Company, as Delaware trustee, of the Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through
Certificates, Series 2005-AR3.


Section 2. Representations and
Warranties of the Purchaser. In connection with the proposed transfer, the Purchaser represents and warrants to Washington Mutual,
the Trustee and the Trust that:


(a)        The Purchaser is duly organized, validly existing and in good standing under
the laws of the jurisdiction in which the Purchaser is organized, is authorized to invest in the Purchased Certificates, and to
enter into this Agreement, and duly executed and delivered this Agreement;


(b)        The Purchaser is acquiring the Purchased Certificates for its own account as
principal and not with a view to the distribution thereof, in whole or in part;


(c)        The Purchaser is an “accredited investor” as such term is defined
in paragraph (a)(1), (a)(2), (a)(3), (a)(7) or (a)(8) of Section 501 of Regulation D under the Securities Act of 1933, as amended
(the “Act”), has knowledge of financial and business matters and is capable of evaluating the merits and risks of an
investment in the Purchased Certificates; the Purchaser has sought such accounting, legal and tax advice as it has considered
necessary to make an informed investment decision; and the Purchaser is able to bear the economic risk of an investment in the
Purchased Certificates and can afford a complete loss of such investment;


(d)        The Purchaser is not affiliated with the Trustee;


(e)        The Purchaser confirms that Washington Mutual has made available to the
Purchaser the opportunity to ask questions of, and receive answers from Washington Mutual concerning the trust created pursuant to
the Pooling Agreement (the “Trust”), the purchase by the Purchaser of the Purchased Certificates and all matters
relating thereto that Washington Mutual possesses or can acquire without unreasonable effort or expense; and


(f)        If applicable, the Purchaser has complied, and will continue to comply, with
the guidelines established by Thrift Bulletin 13a issued April 23, 1998, by the Office of Regulatory Activities of the Federal Home
Loan Bank System.


Section 3. Transfer of Purchased
Certificates.


(a)        The Purchaser understands that the Purchased Certificates have not been
registered under the Act, or any state securities laws and that no transfer may be made unless the Purchased Certificates are
registered under the Act and under applicable state law or unless an exemption from registration is available. The Purchaser
further understands that neither Washington Mutual nor the Trust is under any obligation to register the Purchased Certificates or
make an exemption available. In the event that such a transfer is to be made within two years from the Closing Date without
registration under the Act or applicable state securities laws, (i) the Trustee shall require, in order to assure compliance with
such laws, that the Certificateholder's prospective transferee each certify to Washington Mutual, the Trustee and the Trust as to
the factual basis for the registration or qualification exemption relied upon, and (ii) the Trustee or Washington Mutual may
require an Opinion of Counsel that such transfer may be made pursuant to an exemption from the Act and state securities laws, which
Opinion of Counsel shall not be an expense of the Trust, the Trustee or Washington Mutual. Any such Certificateholder desiring to
effect such transfer shall, and does hereby agree to, indemnify the Trust, the Trustee and Washington Mutual against any liability
that may result if the transfer is not so exempt or is not made in accordance with such federal and state laws.


(b)        No transfer of a Purchased Certificate shall be made unless the transferee
provides Washington Mutual and the Trustee with (i) a Transferee's Agreement, substantially in the form of this Agreement, (ii) an
affidavit substantially in the form of Exhibit N to the Pooling Agreement and (iii) if so indicated in such affidavit, a Benefit
Plan Opinion (as defined in Section 1.01 of the Pooling Agreement).


(c)        The Purchaser acknowledges that its Purchased Certificates bear a legend
setting forth the applicable restrictions on transfer.











IN WITNESS WHEREOF, the undersigned
has caused this Agreement to be validly executed by its duly authorized representative as of the day and the year first above
written.



[Purchaser]


 



 



By:
                                                                 


Its:


 















 




 



                 Exhibit H






FORM OF ADDITIONAL MATTER INCORPORATED INTO


THE FORM OF THE
CERTIFICATES


This Certificate does not represent an
obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the
underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States.


This certifies that the above-named
Registered Owner is the registered owner of certain interests in a pool of assets (“REMIC I”) consisting of, among
other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed and administered by
Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling
Agreement referred to below. REMIC I was created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated
above (the “Pooling Agreement”), among the Company, LaSalle Bank National Association, as Trustee (the
“Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent
provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings
assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict
between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued
under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of
this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound.


Distributions will be made, pursuant to
the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately
following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose
name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the
Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the
“Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the
portion of the Available Distribution Amount for such Distribution Date then distributable on the Certificates of this Class, as
specified in Section 4.01 of the Pooling Agreement.


Distributions on this Certificate will
be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address
shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after
due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the
Certificate Registrar.


Reference is hereby made to the further
provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set
forth at this place.


Unless the certificate of
authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled
to any benefit under the Pooling Agreement or be valid for any purpose.











IN WITNESS WHEREOF, the Trust has
caused this Certificate to be duly executed.


WaMu MORTGAGE PASS-THROUGH
CERTIFICATES SERIES 2005-AR3 TRUST


 


By:    LASALLE BANK NATIONAL ASSOCIATION,


as Trustee


 


By:
                                                                          


 


 


(TRUSTEE'S CERTIFICATE
OF AUTHENTICATION)


This is one of the Certificates
referred to in the within-mentioned Pooling Agreement.


LASALLE BANK
NATIONAL ASSOCIATION, as Trustee


 


By:
                                                     


Dated:
                                                


 











WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.


 WaMu MORTGAGE
PASS-THROUGH CERTIFICATE


This Certificate is one of a duly authorized issue of Certificates
designated as WaMu Mortgage Pass-Through Certificates of the Series and Class specified hereon (herein called the
“Certificates”) and representing certain interests in REMIC I.


The Certificates do not represent an obligation of, or an interest in,
the Company or any of its affiliates and are not insured or guaranteed by any governmental agency. The Certificates are limited in
right of payment to certain collections and recoveries respecting the Mortgage Loans, all as more specifically set forth herein and
in the Pooling Agreement. In the event funds are advanced with respect to any Mortgage Loan, such advance is reimbursable to the
Master Servicer from the related recoveries on such Mortgage Loan or from other cash deposited in the Certificate Account to the
extent that such advance is not otherwise recoverable.


As provided in the Pooling Agreement, withdrawals from the Certificate
Account may be made from time to time for purposes other than distributions to Certificateholders, such purposes including
reimbursement to the Master Servicer of advances made, or certain expenses incurred, by it.


The Pooling Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and obligations of the Company and the rights of the
Certificateholders under the Pooling Agreement at any time by the Company, the Master Servicer and the Trustee with the consent of
the Holders of the Certificates evidencing Percentage Interests aggregating not less than 66% of REMIC I. Any such consent by the
Holder of this Certificate shall be conclusive and binding on such Holder and upon all future Holders of this Certificate and of
any Certificate issued upon the transfer hereof or in exchange herefor or in lieu hereof whether or not notation of such consent is
made upon this Certificate. The Pooling Agreement also permits the amendment thereof, in certain limited circumstances, without the
consent of the Holders of any of the Certificates.


As provided in the Pooling Agreement and subject to certain
limitations therein set forth, the transfer of this Certificate is registrable in the Certificate Register upon surrender of this
Certificate for registration of transfer at the offices of the Certificate Registrar or the office maintained by the Trustee in the
City and State of New York, duly endorsed by, or accompanied by an assignment in the form below or other written instrument of
transfer in form satisfactory to the Trustee or any Authenticating Agent duly executed by, the Holder hereof or such Holder's
attorney duly authorized in writing, and thereupon one or more new Certificates of Authorized Denominations evidencing the same
Percentage Interest set forth hereinabove will be issued to the designated transferee or transferees.


[to be used only in the case of the Junior Subordinate Certificates:]
[No transfer of a Certificate will be made unless such transfer is exempt from or is made in accordance with the registration
requirements of the Securities Act of 1933, as amended (the “Securities Act”) and any applicable state securities laws.
In the event that a transfer is to be made without registration or qualification under applicable laws, (i) in the event such
transfer is made pursuant to Rule 144A under the Securities Act, the Company and the Trustee shall require the transferee to
execute an investment letter in substantially the form attached as Exhibit L to the Pooling Agreement, which investment letter
shall not be an expense of the Company, the Master Servicer, the Trust or the Trustee and (ii) in the event that such a transfer is
not made pursuant to Rule 144A under the Securities Act, the Trustee may require an Opinion of Counsel satisfactory to the Trustee
that such transfer may be made without such registration or qualification, which Opinion of Counsel shall not be an expense of the
Company, the Master Servicer, the Trust or the Trustee. Neither the Company nor the Trust will register the Certificate under the
Securities Act, qualify the Certificate under any state securities law or provide registration rights to any purchaser. Any Holder
desiring to effect such transfer shall, and does hereby agree to, indemnify the Trust, the Trustee, the Company and the Master
Servicer against any liability that may result if the transfer is not so exempt or is not made in accordance with such federal and
state laws.]


The Certificates are issuable only as registered Certificates without
coupons in Authorized Denominations specified in the Pooling Agreement. As provided in the Pooling Agreement and subject to certain
limitations therein set forth, Certificates are exchangeable for new Certificates of Authorized Denominations of like Certificate
Principal Balance or Percentage Interest, as applicable, as requested by the Holder surrendering the same.


A reasonable service charge may be made for any such registration of
transfer or exchange, and the Trustee may require payment of a sum sufficient to cover any tax or other governmental charge payable
in connection therewith.


The Company, the Trustee and the Certificate Registrar and any agent
of the Company, the Trustee or the Certificate Registrar may treat the Person in whose name this Certificate is registered as the
owner hereof for all purposes, and neither the Company, the Trustee, the Certificate Registrar nor any such agent shall be affected
by notice to the contrary.


The obligations created by the Pooling Agreement and the Trust created
thereby shall terminate upon (i) the later of the maturity or other liquidation (including purchase by the Master Servicer) of the
last Mortgage Loan remaining in the Trust or the disposition of all property acquired upon foreclosure or deed in lieu of
foreclosure of any Mortgage Loan, and (ii) the payment to Certificateholders of all amounts held by the Trustee and required to be
paid to them pursuant to the Pooling Agreement. In the event that the Company or the Master Servicer purchases any Mortgage Loan
pursuant to the Pooling Agreement, the Pooling Agreement generally requires that the Trustee distribute to the Certificateholders
in the aggregate an amount equal to 100% of the unpaid Principal Balance of such Mortgage Loan, plus unpaid accrued interest
thereon at the applicable Pass-Through Rate to the last day of the month in which such purchase occurs. The Pooling Agreement
permits, but does not require, the Master Servicer to purchase from the Trust all Mortgage Loans at the time subject thereto and
all property acquired in respect of any Mortgage Loan upon payment to the Certificateholders of the amounts specified in the
Pooling Agreement. The exercise of such right will effect early retirement of the Certificates, the Master Servicer’s right
to purchase being subject to the aggregate Principal Balance of the Mortgage Loans at the time of purchase being less than the
Clean-Up Call Percentage of the aggregate Principal Balance of the Mortgage Loans as of the Cut-Off Date.











ASSIGNMENT


 


FOR VALUE RECEIVED the undersigned hereby sell(s) and assign(s) and transfer(s)
unto                                
                                                                                                                                                                                   
                                                                                               


(Please print or typewrite name and address, including postal
zip code of assignee. Please insert social security or other identifying number of assignee.)


the within WaMu
Mortgage Pass-Through Certificate and hereby irrevocably constitutes and appoints


                                                                                                                                                           


Attorney to transfer said Certificate on the
Certificate Register, with full power of substitution in the premises.


Dated:
                        
           
                                                                                                           


Signature Guaranteed



                                                                                                           


NOTICE:    The signature to this assignment must correspond with the name as written upon the face of the
within instrument in every particular, without alteration or enlargement or any change whatever.  This Certificate does not
represent an obligation of or an interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates.  Neither
this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States.


 















 




 



                  Exhibit I






TRANSFEROR
CERTIFICATE


[Date]


LaSalle Bank
National Association, as Trustee


111 Wall Street,
14th Floor, Zone 3


New York, New
York 10005


Attn: Structured Finance Group, Washington Mutual
2005-AR3


Re:
     Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through Certificates, Series 2005-AR3,
Class R


Ladies and Gentlemen:


This letter is delivered to you in
connection with the sale from
                                        
 (the “Seller”) to           
                                   
(the “Purchaser”) of $____________________ initial Certificate Principal Balance of WaMu Mortgage Pass-Through
Certificates, Series 2005-AR3, Class R (the “Certificate”), pursuant to Section 5.01 of the Pooling and Servicing
Agreement (the “Pooling Agreement”), dated as of February 1, 2005 among Washington Mutual Mortgage Securities Corp., as
depositor and master servicer (the “Company”), LaSalle Bank National Association, as trustee (the
“Trustee”), and Christiana Bank & Trust Company, as Delaware trustee. All terms used herein and not otherwise
defined shall have the meanings set forth in the Pooling Agreement. The Seller hereby certifies, represents and warrants to, and
covenants with, the Company, the Trustee and the Trust that:


1.         No purpose of the Seller relating to the sale of the Certificate by the
Seller to the Purchaser is or will be to enable the Seller to impede the assessment or collection of tax.


2.         The Seller understands that the Purchaser has delivered to the Trustee
and the Company a transferee affidavit and agreement in the form attached to the Pooling Agreement as Exhibit J. The Seller does
not know or believe that any representation contained therein is false.


3.         The Seller has no actual knowledge that the proposed Transferee is not a
Permitted Transferee.


4.         The Seller has no actual knowledge that the Purchaser would be unwilling
or unable to pay taxes due on its share of the taxable income attributable to the Certificates.


5.         The Seller has conducted a reasonable investigation of the financial
condition of the Purchaser and, as a result of the investigation, found that the Purchaser has historically paid its debts as they
came due, and found no significant evidence to indicate that the Purchaser will not continue to pay its debts as they come due in
the future.











6.         The Purchaser has represented to the Seller that, if the Certificates
constitute a noneconomic residual interest, it (i) understands that as holder of a noneconomic residual interest it may incur tax
liabilities in excess of any cash flows generated by the interest, and (ii) intends to pay taxes associated with its holding of the
Certificates as they become due.



Very truly yours,



 



[Seller]



 



By:
                                                                             



      Name:
                  
                                               



      Title:
                                                                     


 















 




 



Exhibit J






TRANSFEREE AFFIDAVIT
AND AGREEMENT


 


STATE
OF                  )

                                      )   ss:

COUNTY
OF               )


 


[NAME OF OFFICER], being first duly
sworn, deposes and says:


1.         That he is [Title of Officer] of [Name of Owner] (record or beneficial
owner of the Class R Certificate (the “Owner”)), a [savings institution] [corporation] duly organized and existing
under the laws of [the State of
                  ] [the United
States], on behalf of which he makes this affidavit and agreement.


2.         That the Owner (i) is not and will not be a “disqualified
organization” as of [date of transfer] within the meaning of Section 860E(e)(5) of the Internal Revenue Code of 1986, as
amended (the “Code”) and will endeavor to remain other than a disqualified organization for so long as it retains its
ownership interest in the Class R Certificates, and (ii) is acquiring the Class R Certificates for its own account or for the
account of another Owner from which it has received an affidavit and agreement in substantially the same form as this affidavit and
agreement. (For this purpose, a disqualified organization” means the United States, any state or political subdivision
thereof, or any agency or instrumentality of any of the foregoing (other than an instrumentality all of the activities of which are
subject to tax and, except for the Federal Home Loan Mortgage Corporation, a majority of whose board of directors is not selected
by any such governmental entity), or any foreign government or international organization, or any agency or instrumentality of such
foreign government or organization, any rural electric or telephone cooperative, or any organization (other than certain farmers'
cooperatives) that is generally exempt from federal income tax unless such organization is subject to the tax on unrelated business
taxable income).


3.         That the Owner is aware (i) of the tax that would be imposed on transfers
of the Class R Certificates after March 31, 1988; (ii) that such tax would be on the transferor, or, if such transfer is through an
agent (which person includes a broker, nominee or middle-man) for a disqualified organization, on the agent; (iii) that the person
otherwise liable for the tax shall be relieved of liability for the tax if the transferee furnishes to such person an affidavit
that the transferee is not a disqualified organization and, at the time of transfer, such person does not have actual knowledge
that the affidavit is false; and (iv) that the Class R Certificates may be a “noneconomic residual interest” within the
meaning of Treasury regulations promulgated pursuant to the Code and that the transferor of a noneconomic residual interest will
remain liable for any taxes due with respect to the income on such residual interest, if a significant purpose of the transfer was
to enable the transferor to impede the assessment or collection of tax.


4.         That the Owner is aware of the tax imposed on a “pass-through
entity” holding the Class R Certificates if at any time during the taxable year of the pass-through entity a disqualified
organization is the record holder of an interest in such entity. (For this purpose, a “pass through entity” includes a
regulated investment company, a real estate investment trust or common trust fund, a partnership, trust or estate, and certain
cooperatives.)


5.         That the Owner is aware that the Trustee will not register the Transfer
of the Class R Certificates unless the transferee, or the transferees' agent, delivers to it an affidavit and agreement, among
other things, in substantially the same form as this affidavit and agreement. The Owner expressly agrees that it will not
consummate any such transfer if it knows or believes that any of the representations contained in such affidavit and agreement are
false.


6.         That the Owner has reviewed the restrictions set forth on the face of the
Class R Certificates and the provisions of Section 5.01 of the Pooling Agreement under which the Class R Certificates were issued
(in particular, clauses (iii)(A) and (iii)(B) of Section 5.01(c) which authorize the Trustee to deliver payments to a person other
than the Owner and negotiate a mandatory sale by the Trustee in the event the Owner holds such Certificates in violation of Section
5.01). The Owner expressly agrees to be bound by and to comply with such restrictions and provisions.


7.         That the Owner consents to any additional restrictions or arrangements
that shall be deemed necessary upon advice of counsel to constitute a reasonable arrangement to ensure that the Class R
Certificates will only be owned, directly or indirectly, by an Owner that is not a disqualified organization.


8.         The Owner's Taxpayer Identification Number is
                              
..


9.         That no purpose of the Owner relating to the purchase of the Class R
Certificates by the Owner is or will be to enable the transferor to impede the assessment or collection of tax, and that in making
this representation, the Owner warrants that the Owner is familiar with Treasury Regulation 1.860E-1(c) and with the preamble to
the adoption of amendments to that regulation as of July 19, 2002, attached hereto as Exhibit 1.


10.        That the Owner anticipates that it will, so long as it holds the Class R
Certificates, have sufficient assets to pay any taxes owed by the holder of such Certificates, and hereby represents to and for the
benefit of the person from whom it acquired the Class R Certificates that the Owner intends to pay taxes associated with holding
such Certificates as they become due, fully understanding that it may incur tax liabilities in excess of any cash flows generated
by the Class R Certificates. That the Owner has provided financial statements or other financial information requested by the
transferor in connection with the transfer of the Class R Certificates to permit the transferor to assess the financial capability
of the Owner to pay such taxes.


11.        That the Owner has no present knowledge or expectation that it will be unable
to pay any United States taxes owed by it so long as any of the Class R Certificates remain outstanding.


12.        That the Owner has no present knowledge or expectation that it will become
insolvent or subject to a bankruptcy proceeding for so long as any of the Class R Certificates remain outstanding.


13.        That the Owner is familiar with Treasury Regulation 1.860E-1(c) and with the
preamble to the adoption of amendments to that regulation as of July 19, 2002, attached hereto as Exhibit 1, and that no purpose of
the Owner relating to any sale of the Class R Certificates by the Owner will be to impede the assessment or collection of
tax.


14.        The Owner is a citizen or resident of the United States, a corporation,
partnership or other entity treated as a partnership or corporation for U.S. federal income tax purposes created or organized in,
or under the laws of, the United States or any state thereof or the District of Columbia, or an estate or trust whose income from
sources without the United States is includible in gross income for United States federal income tax purposes regardless of its
connection with the conduct of a trade or business within the United States.


15.        The Owner hereby agrees that it will not cause income from the Class R
Certificates to be attributable to a foreign permanent establishment or fixed base (within the meaning of an applicable income tax
treaty) of the Owner or another United States taxpayer.


16.        The Owner hereby agrees to cooperate with the Company and to take any action
required of it by the Code or Treasury regulations thereunder (whether now or hereafter promulgated) in order to create or maintain
the REMIC status of REMIC I (the “REMIC”).


17.        The Owner hereby agrees that it will not take any action that could endanger
the REMIC status of the REMIC or result in the imposition of tax on the REMIC unless counsel for, or acceptable to, the Company has
provided an opinion that such action will not result in the loss of such REMIC status or the imposition of such tax, as
applicable.


18.        The Owner as transferee of the Class R Certificates has represented to the
transferor that, if the Class R Certificates constitute a noneconomic residual interest, the Owner (i) understands that as holder
of a noneconomic residual interest it may incur tax liabilities in excess of any cash flows generated by the interest, and (ii)
intends to pay taxes associated with its holding of the Class R Certificates as they become due.


            19.        That the Owner satisfies the condition in the paragraph marked below [mark one
paragraph only]:


___      The
Owner is not an employee benefit or other plan subject to the prohibited transaction provisions of the Employee Retirement Income
Security Act of 1974, as amended, or Section 4975 of the Internal Revenue Code of 1986, as amended (a “Plan”), or any
other person (including an investment manager, a named fiduciary or a trustee of any Plan) acting, directly or indirectly, on
behalf of, or purchasing the Class R Certificates with “plan assets” of, any Plan within the meaning of the Department
of Labor (“DOL”) regulation at 29 C.F.R. Section 2510.3-101.


___      The Owner has delivered a Benefit Plan Opinion (as defined in Section 1.01 of the Pooling
Agreement under which the Class R Certificates were issued).


IN WITNESS WHEREOF, the Owner has
caused this instrument to be executed on its behalf, pursuant to the authority of its Board of Directors, by its [Title of Officer]
and its corporate seal to be hereunto attached, attested by its [Assistant] Secretary, this
          day of          ,
20 __ .


[Name of Owner]



By:                                                      



                  [Name of
Officer]


                   [Title of
Officer]


[Corporate Seal]


ATTEST:


 


 


[Assistant] Secretary


Personally appeared before me the
above-named [Name of Officer], known or proved to me to be the same person who executed the foregoing instrument and to be the
[Title of Officer] of the Owner, and Acknowledged to me that he executed the same as his free act and deed and the free act and
deed of the Owner.


Subscribed and sworn before me this ___
day of __________________, 20__.


 


 



NOTARY PUBLIC



 



COUNTY OF



STATE OF



My Commission expires the     day



of
                     ,
20     















 




 



        Exhibit 1 to Transferee Affidavit


 


DEPARTMENT OF THE TREASURY

Internal Revenue Service

26 CFR Parts 1 and 602

[TD 9004]

RIN 1545-AW98


Real Estate Mortgage Investment Conduits


AGENCY: Internal Revenue Service (IRS), Treasury.


 


ACTION: Final regulations.


 


-----------------------------------------------------------------------


 


SUMMARY: This document contains final regulations relating to safe harbor transfers of noneconomic residual interests in
real estate mortgage investment conduits (REMICs). The final regulations provide additional limitations on the circumstances under
which transferors may claim safe harbor treatment.


 


DATES:           Effective Date: These regulations are effective July 19,
2002.


Applicability
Date: For dates of applicability, see Sec. 1.860E-


(1)(c)(10).


 


FOR FURTHER INFORMATION CONTACT: Courtney Shepardson at (202) 622-3940 (not a toll-free number).


 


SUPPLEMENTARY INFORMATION:


 


Paperwork Reduction Act


 


The collection of information in this final rule has been reviewed and, pending receipt and evaluation of public comments,
approved by the Office of Management and Budget (OMB) under 44 U.S.C. 3507 and assigned control number 1545-1675.  The
collection of information in this regulation is in Sec. 1.860E-1(c)(5)(ii). This information is required to enable the IRS to
verify that a taxpayer is complying with the conditions of this regulation. The collection of information is mandatory and is
required. Otherwise, the taxpayer will not receive the benefit of safe harbor treatment as provided in the regulation. The likely
respondents are businesses and other for-profit institutions.


 


Comments on the collection of information should be sent to the Office of Management and Budget, Attn: Desk Officer for the
Department of the Treasury, Office of Information and Regulatory Affairs, Washington, DC, 20503, with copies to the Internal
Revenue Service, Attn: IRS Reports Clearance Officer, W:CAR:MP:FP:S, Washington, DC 20224. Comments on the collection of
information should be received by September 17, 2002. Comments are specifically requested concerning: 


 


Whether the
collection of information is necessary for the proper performance of the functions of the Internal Revenue Service, including
whether the information will have practical utility; 


 


The accuracy of the
estimated burden associated with the collection


of information (see below);


 


How the quality,
utility, and clarity of the information to be collected may be enhanced;


 


How the burden of
complying with the collection of information may be minimized, including through the application of automated collection techniques
or other forms of information technology; and


 


Estimates of
capital or start-up costs and costs of operation,


maintenance, and purchase of service to provide information.


 


An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it
displays a valid control number assigned by the Office of Management and Budget.   


 


The estimated total annual reporting burden is 470 hours, based on an estimated number of respondents of 470 and an
estimated average annual burden hours per respondent of one hour.


 


Books or records relating to a collection of information must be retained as long as their contents may become material in
the administration of any internal revenue law. Generally, tax returns and tax return information are confidential, as required by
26 U.S.C. 6103.


 


Background


 


This document contains final regulations regarding the proposed amendments to 26 CFR part 1 under section 860E of the
Internal Revenue Code (Code). The regulations provide the circumstances under which a transferor of a noneconomic REMIC residual
interest meeting the investigation and representation requirements may avail itself of the safe harbor by satisfying either the
formula test or the asset test.


 


Final regulations governing REMICs, issued in 1992, contain rules governing the transfer of noneconomic REMIC residual
interests. In general, a transfer of a noneconomic residual interest is disregarded for all tax purposes if a significant purpose
of the transfer is to enable the transferor to impede the assessment or collection of tax. A purpose to impede the assessment or
collection of tax (a wrongful purpose) exists if the transferor, at the time of the transfer, either knew or should have known that
the transferee would be unwilling or unable to pay taxes due on its share of the REMIC's taxable income.


 


Under a safe harbor, the transferor of a REMIC noneconomic residual interest is presumed not to have a wrongful purpose if
two requirements are satisfied: (1) the transferor conducts a reasonable investigation of the transferee's financial condition (the
investigation requirement); and (2) the transferor secures a representation from the transferee to the effect that the transferee
understands the tax obligations associated with holding a residual interest and intends to pay those taxes (the representation
requirement).


 


The IRS and Treasury have been concerned that some transferors of noneconomic residual interests claim they satisfy the safe
harbor even in situations where the economics of the transfer clearly indicate the transferee is unwilling or unable to pay the tax
associated with holding the interest. For this reason, on February 7, 2000, the IRS published in the Federal Register (65 FR 5807)
a notice of proposed rulemaking (REG-100276-97; REG-122450-98) designed to clarify the safe harbor by adding the ``formula test,''
an economic test. The proposed regulation provides that the safe harbor is unavailable unless the present value of the anticipated
tax liabilities associated with holding the residual interest does not exceed the sum of: (1) The present value of any
consideration given to the transferee to acquire the interest; (2) the present value of the expected future distributions on the
interest; and (3) the present value of the anticipated tax savings associated with holding the interest as the REMIC generates
losses.


 


The notice of proposed rulemaking also contained rules for FASITs. Section 1.860H-6(g) of the proposed regulations provides
requirements for transfers of FASIT ownership interests and adopts a safe harbor by reference to the safe harbor provisions of the
REMIC regulations.   


 


In January 2001, the IRS published Rev. Proc. 2001-12 (2001-3 I.R.B. 335) to set forth an alternative safe harbor that
taxpayers could use while the IRS and the Treasury considered comments on the proposed regulations. Under the alternative safe
harbor, if a transferor meets the investigation requirement and the representation requirement but the transfer fails to meet the
formula test, the transferor may invoke the safe harbor if the transferee meets a two-prong test (the asset test). A transferee
generally meets the first prong of this test if, at the time of the transfer, and in each of the two years preceding the year of
transfer, the transferee's gross assets exceed $100 million and its net assets exceed $10 million. A transferee generally meets the
second prong of this test if it is a domestic, taxable corporation and agrees in writing not to transfer the interest to any person
other than another domestic, taxable corporation that also satisfies the requirements of the asset test. A transferor cannot rely
on the asset test if the transferor knows, or has reason to know, that the transferee will not comply with its written agreement to
limit the restrictions on subsequent transfers of the residual interest.


 


Rev. Proc. 2001-12 provides that the asset test fails to be satisfied in the case of a transfer or assignment of a
noneconomic residual interest to a foreign branch of an otherwise eligible transferee. If such a transfer or assignment were
permitted, a corporate taxpayer might seek to claim that the provisions of an applicable income tax treaty would resource excess
inclusion income as foreign source income, and that, as a consequence, any U.S. tax liability attributable to the excess inclusion
income could be offset by foreign tax credits. Such a claim would impede the assessment or collection of U.S. tax on excess
inclusion income, contrary to the congressional purpose of assuring that such income will be taxable in all events. See, e.g.,
sections 860E(a)(1), (b), (e) and 860G(b) of the Code.


 


The Treasury and the IRS have learned that certain taxpayers transferring noneconomic residual interests to foreign branches
have attempted to rely on the formula test to obtain safe harbor treatment in an effort to impede the assessment or collection of
U.S. tax on excess inclusion income. Accordingly, the final regulations provide that if a noneconomic residual interest is
transferred to a foreign permanent establishment or fixed base of a U.S. taxpayer, the transfer is not eligible for safe harbor
treatment under either the asset test or the formula test. The final regulations also require a transferee to represent that it
will not cause income from the noneconomic residual interest to be attributable to a foreign permanent establishment or fixed
base.


 


Section 1.860E-1(c)(8) provides computational rules that a taxpayer may use to qualify for safe harbor status under the
formula test. Section 1.860E-1(c)(8)(i) provides that the transferee is presumed to pay tax at a rate equal to the highest rate of
tax specified in section 11(b). Some commentators were concerned that this presumed rate of taxation was too high because it does
not take into consideration taxpayers subject to the alternative minimum tax rate. In light of the comments received, this
provision has been amended in the final regulations to allow certain transferees that compute their taxable income using the
alternative minimum tax rate to use the alternative minimum tax rate applicable to corporations.


 


Additionally, Sec. 1.860E-1(c)(8)(iii) provides that the present values in the formula test are to be computed using a
discount rate equal to the applicable Federal short-term rate prescribed by section 1274(d). This is a change from the proposed
regulation and Rev. Proc. 2001-12. In those publications the provision stated that “present values are computed using a
discount rate equal to the applicable Federal rate prescribed in section 1274(d) compounded semiannually” and that “[a]
lower discount rate may be used if the transferee can demonstrate that it regularly borrows, in the course of its trade or
business, substantial funds at such lower rate from an unrelated third party.”  The IRS and the Treasury Department have
learned that, based on this provision, certain taxpayers have been attempting to use unrealistically low or zero interest rates to
satisfy the formula test, frustrating the intent of the test. Furthermore, the Treasury Department and the IRS believe that a rule
allowing for a rate other than a rate based on an objective index would add unnecessary complexity to the safe harbor. As a result,
the rule in the proposed regulations that permits a transferee to use a lower discount rate, if the transferee can demonstrate that
it regularly borrows substantial funds at such lower rate, is not included in the final regulations; and the Federal short-term
rate has been substituted for the applicable Federal rate. To simplify taxpayers' computations, the final regulations allow use of
any of the published short-term rates, provided that the present values are computed with a corresponding period of compounding.
With the exception of the provisions relating to transfers to foreign branches, these changes generally have the proposed
applicability date of February 4, 2000, but taxpayers may choose to apply the interest rate formula set forth in the proposed
regulation and Rev. Proc. 2001-12 for transfers occurring before August 19, 2002.


 


It is anticipated that when final regulations are adopted with respect to FASITs, Sec. 1.860H-6(g) of the proposed
regulations will be adopted in substantially its present form, with the result that the final regulations contained in this
document will also govern transfers of FASIT ownership interests with substantially the same applicability date as is contained in
this document.


 


Effect on Other Documents


 


Rev. Proc. 2001-12 (2001-3 I.R.B. 335) is obsolete for transfers of noneconomic residual interests in REMICs occurring on or
after August 19, 2002.


 


Special Analyses


 


It is hereby certified that these regulations will not have a significant economic impact on a substantial number of small
entities. This certification is based on the fact that it is unlikely that a substantial number of small entities will hold REMIC
residual interests. Therefore, a Regulatory Flexibility Analysis under the Regulatory Flexibility Act (5 U.S.C. chapter 6) is not
required. It has been determined that this Treasury decision is not a significant regulatory action as defined in Executive Order
12866. Therefore, a regulatory assessment is not required. It also has been determined that sections 553(b) and 553(d) of the
Administrative Procedure Act (5 U.S.C. chapter 5) do not apply to these regulations.


 


Drafting Information


 


The principal author of these regulations is Courtney Shepardson. However, other personnel from the IRS and Treasury
Department participated in their development.


 


List of Subjects


 


26 CFR Part 1


 


Income taxes, Reporting and record keeping requirements.


 


26 CFR Part 602


 


Reporting and record keeping requirements.


 


Adoption of Amendments to the Regulations


 


Accordingly, 26 CFR parts 1 and 602 are amended as follows:


 


PART 1--INCOME TAXES


 


Paragraph 1. The
authority citation for part 1 continues to read in part as follows:


 


    Authority: 26 U.S.C. 7805 * * *


 


 


 















 




 



Exhibit K


[Reserved]


 


 






 




 












                 Exhibit L






[FORM OF RULE 144A
INVESTMENT REPRESENTATION]


Description of Rule
144A Securities, including numbers:


                                                  


                                                  


                                                  


                                                  


 


The undersigned  seller, as
registered holder (the “Seller”), intends to transfer the Rule 144A Securities described above to the undersigned buyer
(the “Buyer”).


1.         In connection with such transfer and in accordance with the agreements
pursuant to which the Rule 144A Securities were issued, the Seller hereby certifies the following facts: Neither the Seller nor
anyone acting on its behalf has offered, transferred, pledged, sold or otherwise disposed of the Rule 144A Securities, any interest
in the Rule 144A Securities or any other similar security to, or solicited any offer to buy or accept a transfer, pledge or other
disposition of the Rule 144A Securities, any interest in the Rule 144A Securities or any other similar security from, or otherwise
approached or negotiated with respect to the Rule 144A Securities, any interest in the Rule 144A Securities or any other similar
security with, any person in any manner, or made any general solicitation by means of general advertising or in any other manner,
or taken any other action, that would constitute a distribution of the Rule 144A Securities under the Securities Act of 1933, as
amended (the “1933 Act”), or that would render the disposition of the Rule 144A Securities a violation of Section 5 of
the 1933 Act or require registration pursuant thereto, and that the Seller has not offered the Rule 144A Securities to any person
other than the Buyer or another “qualified institutional buyer” as defined in Rule 144A under the 1933 Act.


2.         The Buyer warrants and represents to, and covenants with, the Seller, the
Trustee, the Trust and the Master Servicer (as defined in Section 1.01 of the Pooling and Servicing Agreement (the
“Agreement”) dated as of February 1, 2005 among Washington Mutual Mortgage Securities Corp., as Depositor and Master
Servicer, LaSalle Bank National Association, as Trustee, and Christiana Bank & Trust Company, as Delaware Trustee) pursuant to
Section 5.01(f) of the Agreement, as follows:


a.         The Buyer understands that the Rule 144A Securities have not been
registered under the 1933 Act or the securities laws of any state.


b.         The Buyer considers itself a substantial, sophisticated institutional
investor having such knowledge and experience in financial and business matters that it is capable of evaluating the merits and
risks of investment in the Rule 144A Securities.


c.         The Buyer has received and reviewed the Private Placement Memorandum
dated as of February 23, 2005 relating to the Rule 144A Securities and has been furnished with all information regarding the Rule
144A Securities that it has requested from the Seller, the Trustee, the Company or the Master Servicer.


d.         Neither the Buyer nor anyone acting on its behalf has offered,
transferred, pledged, sold or otherwise disposed of the Rule 144A Securities, any interest in the Rule 144A Securities or any other
similar security to, or solicited any offer to buy or accept a transfer, pledge or other disposition of the Rule 144A Securities,
any interest in the Rule 144A Securities or any other similar security from, or otherwise approached or negotiated with respect to
the Rule 144A Securities, any interest in the Rule 144A Securities or any other similar security with, any person in any manner, or
made any general solicitation by means of general advertising or in any other manner, or taken any other action, that would
constitute a distribution of the Rule 144A Securities under the 1933 Act or that would render the disposition of the Rule 144A
Securities a violation of Section 5 of the 1933 Act or require registration pursuant thereto, nor will it act, nor has it
authorized or will it authorize any person to act, in such manner with respect to the Rule 144A Securities.


e.         The Buyer is a “qualified institutional buyer” as that term
is defined in Rule 144A under the 1933 Act and has (1) completed either of the forms of certification to that effect attached
hereto as Annex 1 or Annex 2, or (2) obtained the waiver of the Company with respect to Annex 1 and Annex 2 pursuant to
Section 5.01(f) of the Agreement. The Buyer is aware that the sale to it is being made in reliance on Rule 144A. The Buyer is
acquiring the Rule 144A Securities for its own account or the accounts of other qualified institutional buyers, understands that
such Rule 144A Securities may be resold, pledged or transferred only (i) to a person reasonably believed to be a qualified
institutional buyer that purchases for its own account or for the account of a qualified institutional buyer to whom notice is
given that the resale, pledge or transfer is being made in reliance on Rule 144A, or (ii) pursuant to another exemption from
registration under the 1933 Act.


f.          The Buyer is not affiliated with (i) the Trustee or
(ii) any Rating Agency that rated the Rule 144A Securities.


g.         If applicable, the Buyer has complied, and will continue to comply, with
the guidelines established by Thrift Bulletin 13a issued April 23, 1998, by the Office of Regulatory Activities of the Federal Home
Loan Bank System.


3.         This document may be executed in one or more counterparts and by the
different parties hereto on separate counterparts, each of which, when so executed, shall be deemed to be an original; such
counterparts, together, shall constitute one and the same document.











IN WITNESS WHEREOF, each of the parties
has executed this document as of the date set forth below.


 


                                                                       
           
                                                                       


                    
Print Name of
Seller                                                    
Print Name of Buyer


By:
                                                                 
            By:
                                                                 



Name:                                                                         
Name:      



Title:
                                                                           
Title:


 


Taxpayer
Identification:
                                   
            Taxpayer Identification:
                                   


No.:
                                                                
            No.:
                                                                


Date:
                                                              
            Date:
                                                              


 















 




 



   Annex 1 to
Exhibit L


QUALIFIED
INSTITUTIONAL BUYER STATUS UNDER SEC RULE 144A


[For Buyers Other Than
Registered Investment Companies]


 


The undersigned hereby certifies as
follows in connection with the Rule 144A Investment Representation to which this Certification is attached:


1.         As indicated below, the undersigned is the President, Chief Financial
Officer, Senior Vice President or other executive officer of the Buyer.


2.         In connection with purchases by the Buyer, the Buyer is a
“qualified institutional buyer” as that term is defined in Rule 144A under the Securities Act of 1933 (“Rule
144A”) because (i) the Buyer owned and/or invested on a discretionary basis $______________________ (the Buyer
must own and/or invest on a discretionary basis at least $100,000,000 in securities unless the Buyer is a dealer, and, in that
case, the Buyer must own and/or invest on a discretionary basis at least $10,000,000 in securities) in securities
(except for the excluded securities referred to below) as of the end of the Buyer's most recent fiscal year (such amount being
calculated in accordance with Rule 144A) and (ii) the Buyer satisfies the criteria in the category marked below.


___     
Corporation, etc. The Buyer is a corporation (other than a bank, savings and loan association or similar institution),
Massachusetts or similar business trust, partnership, or charitable organization described in Section 501(c)(3) of the Internal
Revenue Code.


___     
Bank. The Buyer (a) is a national bank or banking institution organized under the laws of any State, territory or the
District of Columbia, the business of which is substantially confined to banking and is supervised by the State or territorial
banking commission or similar official or is a foreign bank or equivalent institution, and (b) has an audited net worth of at least
$25,000,000 as demonstrated in its latest annual financial statements, a copy of which is attached hereto.


___     
Savings and Loan. The Buyer (a) is a savings and loan association, building and loan association, cooperative bank,
homestead association or similar institution, which is supervised and examined by a State or Federal authority having supervision
over any such institutions or is a foreign savings and loan association or equivalent institution and (b) has an audited net worth
of at least $25,000,000 as demonstrated in its latest annual financial statements.


___     
Broker-Dealer. The Buyer is a dealer registered pursuant to Section 15 of the Securities Exchange Act of 1934.


___     
Insurance Company. The Buyer is an insurance company whose primary and predominant business activity is the writing of
insurance or the reinsuring of risks underwritten by insurance companies and which is subject to supervision by the insurance
commissioner or a similar official or agency of a State or territory or the District of Columbia.


___     
State or Local Plan. The Buyer is a plan established and maintained by a State, its political subdivisions, or any agency or
instrumentality of the State or its political subdivisions, for the benefit of its employees.


___     
ERISA Plan. The Buyer is an employee benefit plan within the meaning of Section 3(3) of the Employee Retirement Income
Security Act of 1974, as amended (“ERISA”) and is subject to the fiduciary responsibility provisions of
ERISA.


___     
Investment Adviser. The Buyer is an investment adviser registered under the Investment Advisers Act of 1940.


___     
SBIC. The Buyer is a Small Business Investment Company licensed by the U.S. Small Business Administration under Section
301(c) or (d) of the Small Business Investment Act of 1958.


___     
Business Development Company. The Buyer is a business development company as defined in Section 202(a)(22) of the Investment
Advisers Act of 1940.


___     
Trust Fund. The Buyer is a trust fund whose trustee is a bank or trust company and whose participants are exclusively (a)
plans established and maintained by a State, its political subdivisions, or any agency or instrumentality of the State or its
political subdivisions, for the benefit of its employees, or (b) employee benefit plans within the meaning of Title I of the
Employee Retirement Income Security Act of 1974, but is not a trust fund that includes as participants individual retirement
accounts or H.R. 10 plans.


3.         The term “securities” as used herein does not
include (i) securities of issuers that are affiliated with the Buyer, (ii) securities that are part of an unsold
allotment to or subscription by the Buyer, if the Buyer is a dealer, (iii) bank deposit notes and certificates of deposit,
(iv) loan participations, (v) repurchase agreements, (vi) securities owned but subject to a repurchase agreement and
(vii) currency, interest rate and commodity swaps.


4.         For purposes of determining the aggregate amount of securities owned
and/or invested on a discretionary basis by the Buyer, the Buyer used the cost of such securities to the Buyer and did not include
any of the securities referred to in the preceding paragraph. Further, in determining such aggregate amount, the Buyer may have
included securities owned by subsidiaries of the  Buyer,  but only if such subsidiaries are consolidated with the Buyer
in its financial statements prepared in accordance with generally accepted accounting principles and if the investments of such
subsidiaries are managed under the Buyer's direction. However, such securities were not included if the Buyer is a majority-owned,
consolidated subsidiary of another enterprise and the Buyer is not itself a reporting company under the Securities Exchange Act of
1934.


5.         The Buyer acknowledges that it is familiar with Rule 144A and understands
that the seller to it and other parties related to the Certificates are relying and will continue to rely on the statements made
herein because one or more sales to the Buyer may be in reliance on Rule 144A.











                                   
           
            Will the Buyer be purchasing the Rule 144A

                                Yes 
                 
No                       
Securities only for the Buyer's own account?


6.         If the answer to the foregoing question is “no”, the Buyer
agrees that, in connection with any purchase of securities sold to the Buyer for the account of a third party (including any
separate account) in reliance on Rule 144A, the Buyer will only purchase for the account of a third party that at the time is
a “qualified institutional buyer” within the meaning of Rule 144A. In addition, the Buyer agrees that the Buyer
will not purchase securities for a third party unless the Buyer has obtained a current representation letter from such third party
or taken other appropriate steps contemplated by Rule 144A to conclude that such third party independently meets the
definition of “qualified institutional buyer” set forth in Rule 144A.


7.         The Buyer will notify each of the parties to which this certification is
made of any changes in the information and conclusions herein. Until such notice is given, the Buyer's purchase of Rule 144A
Securities will constitute a reaffirmation of this certification as of the date of such purchase.


 


                                                                                   
                                                                       


                                                                                                        
Print Name of Buyer


            By:
                                                                 



                                                                                   
Name:      


                                                                                   
Title:


Date:
                                                              


 















 




 



Annex 2 to Exhibit
L


QUALIFIED INSTITUTIONAL
BUYER STATUS UNDER SEC RULE 144A


[For Buyers That Are
Registered Investment Companies]


 


The undersigned hereby certifies as
follows in connection with the Rule 144A Investment Representation to which this Certification is attached:


1.         As indicated below, the undersigned is the President, Chief Financial
Officer or Senior Vice President of the Buyer or, if the Buyer is a “qualified institutional buyer” as that term is
defined in Rule 144A under the Securities Act of 1933 (“Rule 144A”) because Buyer is part of a Family of Investment
Companies (as defined below), is such an officer of the Adviser.


2.         In connection with purchases by Buyer, the Buyer is a “qualified
institutional buyer” as defined in SEC Rule 144A because (i) the Buyer is an investment company registered under the
Investment Company Act of 1940, and (ii) as marked below, the Buyer alone, or the Buyer's Family of Investment Companies, owned at
least $100,000,000 in securities (other than the excluded securities referred to below) as of the end of the Buyer's most recent
fiscal year. For purposes of determining the amount of securities owned by the Buyer or the Buyer's Family of Investment Companies,
the cost of such securities was used.


____    The Buyer owned
$___________________ in securities (other than the excluded securities referred to below) as of the end of the Buyer's most recent
fiscal year (such amount being calculated in accordance with Rule 144A).


____    The Buyer is
part of a Family of Investment Companies which owned in the aggregate $______________ in securities (other than the excluded
securities referred to below) as of the end of the Buyer's most recent fiscal year (such amount being calculated in accordance with
Rule 144A).


3.         The term “Family of Investment Companies” as used
herein means two or more registered investment companies (or series thereof) that have the same investment adviser or investment
advisers that are affiliated (by virtue of being majority owned subsidiaries of the same parent or because one investment adviser
is a majority owned subsidiary of the other).


4.         The term “securities” as used herein does not include
(i) securities of issuers that are affiliated with the Buyer or are part of the Buyer's Family of Investment Companies, (ii) bank
deposit notes and certificates of deposit, (iii) loan participations, (iv) repurchase agreements, (v) securities owned but subject
to a repurchase agreement and (vi) currency, interest rate and commodity swaps.


5.         The Buyer is familiar with Rule 144A and understands that each of the
parties to which this certification is made are relying and will continue to rely on the statements made herein because one or more
sales to the Buyer will be in reliance on Rule 144A. In addition, the Buyer will only purchase for the Buyer's own
account.


6.         The undersigned will notify each of the parties to which this
certification is made of any changes in the information and conclusions herein. Until such notice, the Buyer's purchase of Rule
144A Securities will constitute a reaffirmation of this certification by the undersigned as of the date of such
purchase.


 


                                                                                   
                                                                       


                                                                                                        
Print Name of Buyer


            By:
                                                                 



                                                                                   
Name:      


                                                                                   
Title:


Date:
                                                              


IF AN
ADVISER:


                                                                       


                    
Print Name of Buyer


            By:
                                                                 



                                                                                   
Name:      


                                                                                   
Title:


Date:
                                                              


(SEAL)















 




 



                Exhibit M






 


[Date]


[Company]


Re:       Pooling and Servicing Agreement dated as of February 1, 2005 by and among Washington
Mutual Mortgage Securities Corp., as Depositor and Master Servicer, LaSalle Bank National Association, as Trustee, and Christiana
Bank & Trust Company, as Delaware Trustee, relating to Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through
Certificates, Series 2005-AR3


Ladies and Gentlemen:


In accordance with Section 2.07 of the
above-captioned Pooling and Servicing Agreement, the undersigned, as [Trustee] [Initial Custodian], hereby certifies that, except
as noted on the attachment hereto, as to each Mortgage Loan listed in the Mortgage Loan Schedule (other than any Mortgage Loan paid
in full or listed on the attachment hereto) it has reviewed the documents delivered to it pursuant to Section 2.04 of the Pooling
and Servicing Agreement and has determined that (i) all documents required (in the case of instruments described in clauses
(X)(ii), (X)(iv) and (Y)(ix) of the definition of “Mortgage File,” known by it to be required) pursuant to the
definition of “Mortgage File” and Section 2.05 of the Pooling and Servicing Agreement to have been executed and
received as of the date hereof are in its possession and (ii) all such documents have been executed and relate to the Mortgage
Loans identified in the Mortgage Loan Schedule. The [Trustee] [Initial Custodian] has made no independent examination of such
documents beyond the review specifically required in the above referenced Pooling and Servicing Agreement and has relied upon the
purported genuineness and due execution of any such documents and upon the purported genuineness of any signature thereon. The
[Trustee] [Initial Custodian] makes no representations as to: (i) the validity, legality, enforceability or genuineness of any of
the documents contained in each Mortgage File or any of the Mortgage Loans identified on the Mortgage Loan Schedule, or (ii) the
collectability, insurability, effectiveness or suitability of any such Mortgage Loan.


Capitalized words and phrases used
herein shall have the respective meanings assigned to them in the above-captioned Pooling and Servicing Agreement.


 


                                                                                   
                                                                       


                                                                                   
as [Trustee] [Initial Custodian]


            By:
                                                                 



                                                                                   
Name:      


                                                                                   
Title:














                















 




 



Exhibit N


BENEFIT PLAN
AFFIDAVIT


LaSalle Bank
National Association, as Trustee (the “Trustee”)

135 South
LaSalle Street, Suite 1625

Chicago, Illinois 60603

Attention: Global Securitization Trust
Services


Washington Mutual Mortgage Securities Corp. (“Washington Mutual”)

75
North Fairway Drive

Vernon Hills, IL  60061


 


RE:       CLASS [B-4][B-5][B-6] CERTIFICATES (THE “PURCHASED CERTIFICATES”) ISSUED
BY WaMu MORTGAGE PASS-THROUGH CERTIFICATES SERIES 2005-AR3 TRUST (THE “TRUST”)


Under penalties of perjury, I,
_____________________, declare that, to the best of my knowledge and belief, the following representations are true, correct and
complete; and


1.         That I am the _______________ of __________________ (the
“Purchaser”), whose taxpayer identification number is  ___________, and on behalf of which I have the authority to
make this affidavit.


2.         That the Purchaser is acquiring a Purchased Certificate representing an
interest in the assets of the Trust.


3.         That the Purchaser satisfies the condition in the paragraph marked below
[mark one paragraph only]:


___      The
Purchaser is not an employee benefit plan or other plan subject to the prohibited transaction provisions of the Employee Retirement
Income Security Act of 1974, as amended, or Section 4975 of the Internal Revenue Code of 1986, as amended (a “Plan”),
or any other person (including an investment manager, a named fiduciary or a trustee of any Plan) acting, directly or indirectly,
on behalf of, or purchasing any of the Purchased Certificates with “plan assets” of, any Plan within the meaning of the
Department of Labor (“DOL”) regulation at 29 C.F.R. Section 2510.3-101.


___      The Purchaser is an insurance company, the source of funds to be used by it to acquire or
hold the Purchased Certificate is an “insurance company general account” (within the meaning of DOL Prohibited
Transaction Class Exemption (“PTCE”) 95-60), and the conditions in Sections I and III of PTCE 95-60 have been
satisfied.


___      The
Purchaser has delivered to Washington Mutual and the Trustee a Benefit Plan Opinion (as defined in Section 1.01 of the Pooling and
Servicing Agreement, dated as of February 1, 2005, by and among Washington Mutual, the Trustee and the Delaware Trustee thereunder,
and relating to the Trust).











IN WITNESS WHEREOF, the Purchaser has caused this instrument to be duly executed on its behalf, by its duly authorized officer this _____
day of __________________, 20__.


[Purchaser]


By:
                                                     


      Its:

Personally appeared before me ______________________, known or proved to me to be the same person who executed the foregoing
instrument and to be a ________________ of the Purchaser, and acknowledged to me that (s)he executed the same as his/her free act
and deed and as the free act and deed of the Purchaser.


SUBSCRIBED and SWORN to before me this
day of ____________, 20__.



                                                                                   


            Notary Public


 















 




 



   Exhibit O


BENEFIT PLAN
AFFIDAVIT


LaSalle Bank
National Association, as Trustee (the “Trustee”)

135 South
LaSalle Street, Suite 1625

Chicago, Illinois 60603

Attention: Global Securitization Trust
Services


Washington Mutual Mortgage Securities Corp. (“Washington Mutual”)

75
North Fairway Drive

Vernon Hills, IL  60061


 


RE:       CLASS [B-1][B-2][B-3] CERTIFICATES (THE “PURCHASED CERTIFICATES”) ISSUED
BY WaMu MORTGAGE PASS-THROUGH CERTIFICATES SERIES 2005-AR3 TRUST (THE “TRUST”)


 


Under penalties of perjury, I,
_____________________, declare that, to the best of my knowledge and belief, the following representations are true, correct and
complete; and


1.         That I am the _______________ of __________________ (the
“Purchaser”), whose taxpayer identification number is  ___________, and on behalf of which I have the authority to
make this affidavit.


2.         That the Purchaser is acquiring a Purchased Certificate representing an
interest in the assets of the Trust.


3.         That the Purchaser satisfies the condition in the paragraph marked below
[mark one paragraph only]:


­­___
     The Purchaser is not an employee benefit or other plan subject to the prohibited transaction provisions of
the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), or Section 4975 of the Internal Revenue Code
of 1986, as amended (a “Plan”), or any other person (including an investment manager, a named fiduciary or a trustee of
any such Plan) acting, directly or indirectly, on behalf of or purchasing the Purchased Certificate with “plan assets”
of, any Plan within the meaning of the Department of Labor (“DOL”) regulation at 29 C.F.R. Section
2510.3-101.


___      The Purchaser is an insurance company, the source of funds to be used by it to acquire or
hold the Purchased Certificate is an “insurance company general account” (within the meaning of DOL Prohibited
Transaction Class Exemption (“PTCE”) 95-60), and the conditions in Sections I and III of PTCE 95-60 have been
satisfied.


___      The Purchased Certificate was rated “BBB-” or better (or its equivalent) by at
least one of the Rating Agencies (as defined in Section 1.01 of the Pooling and Servicing Agreement (the “the Pooling and
Servicing Agreement”), dated as of February 1, 2005, by and among Washington Mutual, the Trustee and the Delaware Trustee
thereunder, and relating to the Trust) at the time of Purchaser’s acquisition of the Purchased Certificate (or interest
therein).


___      The
Purchaser has delivered to Washington Mutual and the Trustee a Benefit Plan Opinion (as defined in Section 1.01 of the Pooling and
Servicing Agreement).


IN WITNESS WHEREOF, the Purchaser has caused this instrument to be duly executed on its behalf, by its duly authorized officer this _____
day of __________________, 20__.


[Purchaser]


By:
                                                     


      Its:

Personally appeared before me ______________________, known or proved to me to be the same person who executed the foregoing
instrument and to be a ________________ of the Purchaser, and acknowledged to me that (s)he executed the same as his/her free act
and deed and as the free act and deed of the Purchaser.


SUBSCRIBED and SWORN to before me this
day of ____________, 20__.



                                                                                   


           
Notary Public