SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


                                    FORM 10-K/A

[X]      Annual  report  pursuant  to  Section  13 or  15(d)  of the Securities
         Exchange   Act  of  1934   for   the    period  from  May 1, 2001
         (Commencement of Operations) to December 31, 2001

[  ]     Transition report pursuant to Section 13 or 15(d) of the
         Securities Exchange Act of 1934 for the transition period from   to


                        Commission File Number 333-49820-16

               CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
             (Exact name of registrant as specified in its charter)

         Delaware                                            13-3320910
(State or other jurisdiction of                           I.R.S. Employer
incorporation or organization)                            Identification No.)

11 Madison Ave.
New York, New York                                             10010
(Address of Principal Executive Offices)                      (Zip Code)

       Registrant's telephone number, including area code :(212)325-2000


         CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
                    CREDIT SUISSE FIRST BOSTON
        MORTGAGE-BACKED PASS-THROUGH CERTIFICATES, SERIES 2001-11
       (Title of each class of securities covered by this Form)

Securities registered pursuant to Section 12(b) of the Act:  None
Securities registered pursuant to Section 12(g) of the Act:  None

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  registrant  was
required  to file  such  reports),  and  (2) has  been  subject  to such  filing
requirements for the past 90 days. Yes [X] No [ ]

Indicate by check mark if disclosure of delinquent  filers  pursuant to Item 405
of Regulation  S-K is not contained  herein,  and will not be contained,  to the
best of registrant's  knowledge,  in definitive proxy or information  statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [X]

Documents incorporated by reference:  None

                                   Page 1 of 5
             This report consists 12 of consecutively numbered pages.

<PAGE>

                AMENDMENT NUMBER 1 OF 1

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<PAGE>

CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
CREDIT SUISSE FIRST BOSTON
MORTGAGE-BACKED PASS-THROUGH CERTIFICATES, SERIES 2001-11
-----------------------------------------------------------------------


PART IV

Item 14. Exhibits, Financial Statement Schedules and Reports on Form 8-K

(a) The following documents are filed as part of this report:

    (1) Financial Statements:
         Omitted.

    (2)  Financial Statement Schedules:
         Omitted.

    (3)  Exhibits:

   Annual  Servicer  Statement of  Compliance,  filed as Exhibit 99.1 hereto.
   Annual Statement of  Independent  Accountants  Report for the Servicer,
           filed as Exhibit 99.2 hereto.

(b)   Reports on Form 8-K: The  following  Current  Reports on Form 8-K were
      filed by the Registrant during the last quarter of 2001.

      Current  Reports   on Form 8-K,   dated   October 25,  2001,  November 26,
     2001,  and  December  26,  2001,  were filed for the  purpose of filing the
     Monthly  Statement  sent to the  Holders of the  Offered  Certificates  for
     payments made on the same dates.  The items reported in such Current Report
     were Item 5 (Other Events).


(c)   Exhibits to this report are listed in Item (14)(a)(3) above.

                                      -3-
<PAGE>


SIGNATURE

Pursuant to the  requirements of Section 13 or 15(d) of the Securities  Exchange
Act of 1934,  the  registrant  has duly  caused  this report to be signed on its
behalf by the undersigned thereunto duly authorized.


                                    JPMORGAN CHASE BANK,
                                    not in its individual capacity but solely
                                    as Trust Administrator
                                    under the Agreement referred to herein



Date:  August 22, 2002              By:  /s/ Thomas M. Britt
                                    -----------------------------
                                    Thomas M. Britt
                                    Trust Officer



                                      -4-
<PAGE>

                                 EXHIBIT INDEX

Exhibit     Description                                                 Page

 99.1       Servicer's Annual Statement of Compliance                    6
            and Officers' Certificate

 99.2       Servicer's Annual Independent Accountant's Report            10



                                      -5-
<PAGE>

                                EXHIBIT 99.1

        Servicer's Annual Statement of Compliance
        and Officers' Certification


                                      -6-

<PAGE>
Washington Mutual Mortgage Securities Corporation
75 North Fairway Drive
Vernon Hills, IL  60061

May 16, 2002

Chase Manhattan Bank of Connecticut, N.A.
300 Tice Boulevard 3rd Floor-North
WoodCliff, NJ  07675
Attn:  Fran Ambrosia, Docs Control

RE:      ANNUAL STATEMENT AS TO COMPLIANCE FOR WAMU MORTGAGE
         SECURITIES CORP. MORTGAGE PASS-THROUGH CERTIFICATES

Dear Ms. Ambrosia:

Please be advised that, in accordance with the pooling and servicing  agreements
(each,  an  "Agreement")  executed  in  connection  with the series of  mortgage
pass-through  certificates listed on the schedule attached to the correspondence
attached to this letter.  I have reviewed the  activities  of Washington  Mutual
Mortgage  Securities Corp.  (f/k/a PNC Mortgage  Securities  Corp.) (the "Master
Servicer"),  acting in its  capacity as master  servicer  under each  Agreement,
during the preceding calendar year and its performance under the Agreements and,
to the best of my  knowledge,  the  Master  Servicer  has  fulfilled  all of its
obligations under the Agreements during such year.

Please find  enclosed the "Report of  Independent  Auditors"  for the year ended
December 31, 2001.

Sincerely,



/s/ Richie Moore
Richie Moore
Vice President
Master Servicing Division
RM/aa

enclosures

WASHINGTON MUTUAL BANK, FA
SCHEDULE OF AGREEMENTS WITH THE CHSE MANHATTAN BANK COMPANY
Servicing in compliance with the terms of the agreement

Description

POOLING AND SERVICING AGREEMENT, dated May 1, 2001, Mortgage-Backed Pass-Through
Securities,   Series  2001-11,  between  Credit  Suisse  First  Boston  Mortgage
Securities Corp.  (Depositor),  DLJ Mortgage Capital, Inc. (Seller),  Greenpoint
Mortgage  Funding,  Inc.(Seller),  WMMSC (Seller and Servicer),  Chase Manhattan
Mortgage Corporation (Servicer),  Calmco Servicing L.P. (Special Servicer), Bank
One, N.A. (Trustee) and The Chase Manhattan Bank (Trust Administrator).


                                      -7-

<PAGE>
Chase Manhattan Mortgage Corporation
3415 Vision Drive
Columbus, OH  43219
1-800-848-9136 Customer Service
1-800-582-0542 TDD/ Text Telephone

Chase Manhattan Mortgage Corporation
Master Servicing
1400 East Newport Center Drive
Deerfield Beach, FL  33442

RE:  Annual Certification

Pursuant to the servicing  agreement,  the undersigned  Officer certifies to the
following:

a) All hazard (or mortgage  impairment,  if applicable)  flood or other casualty
insurance and primary mortgage guaranty insurance premiums, taxes, ground rents,
assessments and other changes have been paid by/in connection with the Mortgaged
Properties;

b) All property inspections have been completed;

c) Compliance relative to Adjustable Rate Mortgages have been met;

d) Compliance with IRS Foreclosure  reporting regulations enacted as IRS Section
6060J by the  Deficit  Reduction  Act,  regarding  Acquired  and/or  Abandonment
property have been completed;

e) All loans CMMC  services  in state that have  statutes  requiring  payment of
interest on escrow/impound accounts have been completed;

f) That such  officer  has  confirmed  that the  Fidelity  Bond,  the Errors and
Omissions  Insurance Policy, and any other bonds required under the terms of the
Servicing Agreement are in full force and effect.

g) Enclosed is a copy of our most recent independent audit statement.

CERTIFIED BY:  /s/ Lucy P. Gambino          Date:  March 29, 2002
                  ------------------------------

Lucy P. Gambino
Vice President
Chase Manhattan Mortgage Corporation
3415 Vision Drive
Columbus, OH  43219


                                      -8-


<PAGE>

Exhibit I

Management's Assertion Concerning Compliance
With USAP Minimum Servicing Standards



March 15, 2002

As of and for the  year  ended  December  31,  2001,  Chase  Manhattan  Mortgage
Corporation  ("CMMC") and Chase Mortgage Company ("CMC") and their  subsidiaries
(collectively,  the "Group")  have  complied in all material  respects  with the
mininum servicing  standards (the "Standards") set forth in the Mortgage Bankers
Association of America's Uniform Single Attestation Program for Mortgage Bankers
("USAP").  These  standards  are  applicable  only to Chase  Manhattan  Mortgage
Corporation's prime and subprime mortgage portfolios.

As of and for same period,  the Group had in effect fidelity bond and errors and
omissions policy in the amounts of $250,000,000 and $25,000,000 respectively.

/s/ Steve Rotella
--------------------------
Steve Rotella
Chief Executive Officer

/s/ Glenn Mouridy
--------------------------
Glenn Mouridy
Executive Vice President of Servicing

/s/ Terry L. Gentry
--------------------------
Terry L. Gentry
Senior Vice President of Servicing

/s/ Lucy Gambino
--------------------------
Lucy Gambino
Vice President of Risk Management


                                      -9-
<PAGE>

                                EXHIBIT 99.2

        Servicer's Annual Independent Accountant's Report


                                      -10-


<PAGE>
DELOITTE & TOUCHE LLP
700 Fifth Avenue, Suite 4500
Seattle, Washington  98104-5044

Tel:  206.292.1800
Fax:  206.343.7809
www.us.deloitte.com


INDEPENDENT AUDITORS' REPORT ON AGREEMENTS
WITH THE CHASE MANHATTAN BANK

Board of Directors
Washington Mutual Bank, FA

We have audited, in accordance with auditing standards generally accepted in the
United States of America,  the consolidated  statement of financial condition of
Washington  Mutual  Bank,  FA  and  subsidiaries  (including  Washington  Mutual
Mortgage  Securities  Corp.  (WMMSC)) as of December 31,  2001,  and the related
consolidated  statements  of  income,  stockholder's  equity  and  comprehensive
income,  and of cash flows for the year then  ended,  and have issued our report
thereon  dated  February  19, 2002  (March 1, 2002,  as to  Note2)(which  report
expresses an unqualified opinion and includes an explanatory  paragraph relating
to the  adoption  of  Statement  of  Financial  Accounting  Standards  No.  133,
Accounting for Derivative  Instruments and Hedging  Activities,  as amended,  on
January 1, 2001).

In connection  with our audit,  nothing came to our attention  that caused us to
believe that WMMSC failed to comply with the terms,  covenants,  provisions,  or
conditions  of the  sections  of the  agreements  between  WMMSC  and The  Chase
Manhattan Bank (Chase), as listed in the accompanying schedule,  insofar as they
relate to financial and accounting matters.  However, our audit was not directed
primarily toward obtaining knowledge of noncompliance.

This  report is  intended  solely  for the  information  and use of the Board of
Directors,  management  of  Washington  Mutual  Bank FA, and  Chase,  and is not
intended  to be and  should not be used by anyone  other  than  these  specified
parties.


/s/ Deloitte & Touche

February 19, 2002


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<PAGE>
PricewaterhouseCoopers LLP
1177 Avenue of the Americas
New York, NY  10036
Telephone (646) 471-4000
Facsimile (646) 471-4100


Report of Independent Accountants

To the Board of Directors and Stockholder
Of Chase Manhattan Mortgage Corporation:

We  have  examined   management's   assertion  about  Chase  Manhattan  Mortgage
Corporation's  (the "Company")  compliance with the minimum servicing  standards
("standards")  identified  in the  Mortgage  Bankers  Association  of  America's
Uniform Single  Attestation  Program for Mortgage Bankers ("USAP") as of and for
the year December 31, 2001  included in the  accompanying  management  assertion
(see  Exhibit I). The  Company  performs  loan  subservicing  functions  for the
residential  loan servicing  portfolios of its affiliates Chase Mortgage Company
and Chase Mortgage  Company West.  Management is  responsible  for the Company's
compliance with those minimum  servicing  standards.  Our  responsibility  is to
express an opinion on management's assertion about the entity's compliance based
on our examination.

Our  examination  was  made in  accordance  with  standards  established  by the
American  Institute of Certified Public Accountants and,  accordingly,  included
examining,  on a test basis,  evidence about the Company's  compliance  with the
standards and performing such other procedures as we considered necessary in the
circumstances.  We believe that our examination  provides a reasonable basis for
our  opinion.  Our  examination  does not provide a legal  determination  on the
Company's compliance with the standards.

In our  opinion,  management's  assertion  that the  Company  complied  with the
aforementioned  standards  as of and for the year  ended  December  31,  2001 is
fairly stated, in all material respects.


/s/ PricewaterhouseCoopers LLP

March 15, 2002


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