----

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION****Washington, D.C. 20549**

----

**FORM 10-K**

----

**(Mark One)**
| **x** | **ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934** |
|-------|------------------------------------------------------------------------------------------|

**For the fiscal year ended: December 31, 2007****or**
| ** ̈** | **TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934** |
|-----------|----------------------------------------------------------------------------------------------|

**For Transition period                     **

|   |                                                                                                                  |
|--------|-----------------------------------------------------------------------------------------------------------------------|
|   | **Commission File Number of issuing entity: 333-130795-44**

**WaMu Asset-Backed Certificates, WaMu Series 2007-HE1** |
|   | **(Exact name of issuing entity as specified in its charter)**                                                        |

**Commission File Number of depositor:  333-130795**

----

**WAMU ASSET ACCEPTANCE CORP.**

**(Exact name of depositor as specified in its charter)**

----

**WASHINGTON MUTUAL BANK**

**(Exact name of sponsor as specified in its charter)**

----

|   |                                                                                          |
|--------|-----------------------------------------------------------------------------------------------|
|   | **Delaware**                                                                                  |
|   | **(State or other jurisdiction of Incorporation**

**or organization of the issuing entity)** |
|   |
|   | **1301 Second Avenue, WMC 3501A Seattle, Washington  98101**                             |
|   | **(Address of principal executive offices**

**of issuing entity)**                           |
|   |
|   | **(206) 500-4418**                                                                            |
|   | **(Telephone number, including area code)**                                                   |
|   |
|   | **54-2190610**                                                                                |
|   | **(I.R.S. Employer Identification No.)**                                                      |
|   |
|   | **N/A**                                                                                       |
|   | **(Former name, former address, if changed since last report)**                               |

----

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 if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes   ̈    No  x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes   ̈    No  x

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 suchshorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    x  Yes     ̈  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 definitiveproxy or information statements incorporated by reference in Part II of the Form 10-K or any amendment to this Form 10-K.     ̈  [Item 405 of Regulation S-K is notapplicable.]

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule12b-2 of the Exchange Act. (Check one):

Large accelerated filer   ̈    Accelerated filer   ̈    Non-accelerated filer  x

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes   ̈    No  x

Registrant has no voting or non-voting common equity outstanding held by non-affiliates.

 

----

 

**PART I**

**The following Items have been omitted in accordance with General Instruction J to Form 10–K:**

|          |         |                                                 |
|---------------|--------------|------------------------------------------------------|
| Item 1:  |    | Business.                                            |
| Item 1A: |    | Risk Factors.                                        |
| Item 2:       |    | Properties.                                          |
| Item 3:       |    | Legal Proceedings.                                   |
| Item 4:       |    | Submission of Matters to a Vote of Security Holders. |

**Item 1B. Unresolved Staff Comments.**

Not Applicable.

**Substitute information provided in accordance with General Instruction J to Form 10–K:**

**Item 1112(b) of Regulation AB: Significant Obligors of Pool Assets (Financial Information). **

No single obligor represents more than 10% of the pool assets held by WaMu Asset-Backed Certificates, WaMu Series 2007-HE1 (the “Trust”).

**Item 1114(b)(2) of Regulation AB: Credit Enhancement and Other Support, Except for Certain Derivatives Instruments (Information Regarding Significant Enhancement Providers: FinancialInformation). **

No entity or group of affiliated entities that provides (1) any external credit enhancement designed to ensure that the asset-backed securities or pool assets will pay in accordance with their terms, (2) anymechanisms to ensure that payments on the asset-backed securities are timely or (3) any derivatives whose primary purpose is to provide credit enhancement related to pool assets or the asset-backed securities is either liable or contingently liable to providepayments representing 10% or more of the cash flow supporting any offered class of asset-backed securities of the Trust.

**Item 1115(b) of Regulation AB: Certain Derivatives Instruments (Financial Information). **

The “aggregate significance percentage” (as defined in Item 1115 of Regulation AB) related to any entity or group of affiliated entities providing derivative instruments that are used to alter thepayment characteristics of the cashflows from the Trust and whose primary purpose is not to provide credit enhancement related to the pool assets or the asset-backed securities of the Trust does not equal or exceed 10%. 

**Item 1117 of Regulation AB: Legal Proceedings. **

None. 

----

**PART II**

**The following Items have been omitted in accordance with General Instruction J to Form 10–K:**

 

|          |   |                                                                                                                |
|---------------|--------|---------------------------------------------------------------------------------------------------------------------|
| Item 5:  |   | Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities. |
| Item 6:  |   | Selected Financial Data.                                                                                            |
| Item 7:  |   | Management’s Discussion and Analysis of Financial Condition and Results of Operations.                        |
| Item 7A: |   | Quantitative and Qualitative Disclosures about Market Risk.                                                         |
| Item 8:  |   | Financial Statements and Supplementary Data.                                                                        |
| Item 9:  |   | Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.                               |
| Item 9A: |   | Controls and Procedures.                                                                                            |

 

**Item 9B: Other Information.**

None.

----

**PART III**

**The following Items have been omitted in accordance with General Instruction J to Form 10–K:**

 

|          |   |                                                                                            |
|---------------|--------|-------------------------------------------------------------------------------------------------|
| Item 10: |   | Directors and Executive Officers of the Registrant.                                             |
| Item 11:      |   | Executive Compensation.                                                                         |
| Item 12:      |   | Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters. |
| Item 13:      |   | Certain Relationships and Related Transactions.                                                 |
| Item 14:      |   | Principal Accountant Fees and Services.                                                         |

**Substitute information provided in accordance with General Instruction J to Form 10–K:**

 

**Item 1119 of Regulation AB: Affiliations and Certain Relationships and Related Transactions**

Pursuant to the Instructions to Item 1119 of Regulation AB, information required by Item 1119 has been omitted from this annual report on Form 10-K because it is substantially the same information as has beenprovided previously in a prospectus timely filed pursuant to Rule 424 of the General Rules and Regulations Promulgated under the Securities Act of 1933 under the same Central Index Key (CIK) as this annual report on Form 10-K.

**Item 1122 of Regulation AB: Compliance with Applicable Servicing Criteria.**

WaMu Asset Acceptance Corp.(in its role as depositor), Washington Mutual Bank (in its role as servicer) (“WMB”), Washington Mutual Mortgage Securities Corp. (in its role asadministrative agent) (“WMMSC”), American Security Insurance Company and Standard Guaranty Insurance Company (together, in the role as hazard insurance servicer, “ASIC”), and Deutsche Bank National Trust Company (inits roles as bond administrator and custodian) (collectively, the “Servicing Parties”) have each been identified by the registrant as parties participating in the servicing function with respect to the asset pool held by the Trust. Each of the ServicingParties has completed a report on assessment of compliance with the servicing criteria applicable to it (each a “Servicing Report”), which Servicing Reports are attached as exhibits to this Form 10-K.  Each of the Servicing Parties have provided anattestation report (each an “Attestation Report”) by one or more public accounting firms, which reports are also attached as exhibits to this Form 10-K.  None of the Servicing Reports or Attestation Reports has identified any material instance ofnoncompliance with the servicing criteria as applicable to the respective Servicing Party except that, with respect to:

1.  WMB and its compliance with:

a.  Item 1122(d)(2)(vii)(D). Approximately 532 account reconciliations out of approximately 60,000 statements (or approximately 0.9%) with reconciling items were not resolved within 90 days oftheir identification, due to the migration of functions to personnel in a separate geographic location.  All such reconciling items have been resolved in the meantime and processes and procedures are in place to provide for on-going compliance with thisrequirement;

b.  Item 1122(d)(3)(i)(B) and (3)(ii). A programming change resulted in the miscalculation of some liquidation proceeds and the failure to include other liquidation proceeds, in the aggregateamount of approximately $9,694,614, in the September 2007 distribution with respect to 13 securitizations subject to Regulation AB.  WMB in each of the securitizations remitted the applicable shortfall amount on October 1, 2007 to the applicable Trustee asrequired by the applicable pooling and servicing agreement.  The programming error was corrected in October 2007;

c.  Item 1122(d)(3)(ii).  Prepayment fees due to investors in 16 or more securitizations subject to Regulation AB were calculated incorrectly on certain loans with deferred interest,resulting in a shortfall in the distributions to those investors in an aggregate amount that is not expected to exceed $500,000.  In addition, WMB has determined that, under certain circumstances, WMB’s automated loan servicing system calculates theapplicable interest to be used to determine prepayment premiums inconsistently with the requirements of certain mortgage loan notes, which could result in the underpayment of prepayment premiums due to certificateholders in prepayment premium classes under the termsof the applicable transaction agreements.  Approximately 15 loans in 8 securitizations subject to Regulation AB have been identified that may have been affected in 2007. Any amounts due as the result of these miscalculations will be delivered to the applicabletrustee for distribution to the affected investors once analysis of these matters has been completed and the amounts due in the case of each securitization have been determined.   Processes and procedures are currently being implemented to provide for moreaccurate calculation of prepayment fees and WMB is making changes to its automated servicing system to provide for some of the identified variations in the terms of mortgage note prepayment requirements;

d.  Item 1122(d)(4)(vii). With respect to 4 series of mortgage-backed securities, WMB recently self-identified foreclosure cases initiated in connection with approximately 175 loans where WMB didnot expressly disclose the interests in the loans of the applicable trustees.  To the extent necessary under applicable law and court rules, WMB will promptly move to amend those foreclosure pleadings.  Investors will be made whole if any direct losses oradditional costs and expenses are incurred as a result of the failure to identify the interests of the trusts in the loans in any proceeding in which applicable law or court rules the trusts’ interests must be disclosed.  WMB will conduct further researchand if additional loans are identified that were treated similarly, WMB will make the applicable trusts whole if any losses arise from such treatment; and

e.  Item 1122(d)(4)(xiv).  Delinquent second lien mortgage loans were not charged off at 180 days as required by the applicable pooling and servicing agreements in the case of twosecuritizations subject to Regulation AB.  All such mortgage loans were charged off as required upon identification of the non-compliance.  Processes and procedures have been put in place to provide for on-going compliance with this requirement.

2.  WMMSC and its compliance with:

a.  Item 1122(d)(2)(vii)(D).  One reconciling item was not resolved within 90 days of its original identification.  This reconciling item was resolved within 124 days of its originalidentification and processes and procedures are in place to provide for on-going compliance with this requirement;

b.  Item 1122(d)(3)(ii).  Prepayment fees due to investors in 16 or more securitizations subject to Regulation AB were calculated incorrectly on certain loans with deferred interest,resulting in a shortfall in the distributions to those investors in an aggregate amount that is not expected to exceed  $1,500,000, of which not more than  $1,000,000 is expected to be attributable to incorrect calculations performed by the Asserting Partyand not more than  $500,000 is expected to be attributable to incorrect calculations performed by Washington Mutual Bank, an affiliate of the Asserting Party.    The amounts due as the result of these miscalculations will be delivered to theapplicable Trustee for distribution to the affected investors once analysis of the matter has been completed and the amounts due in the case of each securitization have been determined.  Processes and procedures have been implemented and are currently beingvalidated to provide for more accurate calculation of prepayment fees; and

c.  Item 1122(d)(3)(ii).  Certain LIBOR values were incorrectly determined for the December, 2007 distribution with respect to certain classes of securities subject to pooling andservicing agreements which require that LIBOR values be determined on the second day on which banks in London are open for foreign exchange transactions prior to the 25th day of the prior calendar month.  In the referenced month, the specified LIBORvaluation day was Thanksgiving Day, not a day in the United States of America in which banks are open for transactions in foreign exchange but a day on which banks in London are.  LIBOR was established on the day immediately preceding Thanksgiving Day ratherthan Thanksgiving Day as required under the applicable pooling and servicing agreements.  The difference in LIBOR values was .00562 percentage points.  Accordingly certain classes of securities were overpaid interest and certain classes of securities wereunderpaid interest by the same amount.  In December, 2007, interest was reallocated to investors using the correct LIBOR values and total interest reallocated in each affected series of securities ranged from approximately $304 to $3,050.  The aggregateoriginal interest payments distributed to the affected series of securities ranged from approximately $1,124,821 to $11,126,217.  Procedures have been implemented to provide for accurate determinations of LIBOR.

3.  ASIC and its compliance with Item 1122(d)(4)(xii).  During the reporting period covered by this 10-K Annual Report, ASIC did not have sufficientpolicies and procedures in place to capture the information necessary to determine its compliance with Item 1122(d)(4)(xii).  As stated in a letter dated January 30, 2008 and attached hereto as Exhibit 33.4, ASIC has implemented policies and procedures tocapture the information required to comply with this provision.

**Item 1123 of Regulation AB: Servicer Compliance Statement**.

Washington Mutual Bank (in its role as servicer) and WMMSC (in its role as administrative agent) have been identified by the registrant as servicers with respect to the asset pool held by the Trust.  Each of WashingtonMutual Bank and WMMSC has completed a statement of compliance with applicable servicing criteria (each a “Compliance Statement”), in each case signed by an authorized officer of Washington Mutual Bank and WMMSC, respectively.  The ComplianceStatements are attached as exhibits to this Form 10-K.  None of the Compliance Statements has identified any material instance of noncompliance with the respective servicer's obligation under the applicable servicing agreement, except that WMB reported thefollowing:  A programming change resulted in the miscalculation of some liquidation proceeds, and the failure to include other liquidation proceeds in the September 2007 distribution resulted in a shortfall of $345,944.00, which was subsequently remitted to theTrustee on October 1, 2007.  The programming error was corrected in October 2007.

 

----

**PART IV**

**Item 15. Exhibits, Financial Statement Schedules.**
|         | (a)(1) | Not Applicable. |
|--------------|--------|-----------------|
|         | (a)(2) | Not Applicable. |
|    | (a)(3) | Not Applicable. |
|    | (b)    | Exhibits        |
|              |        |                 |  |  |

 

**WaMu Asset-Backed Certificates, WaMu Series 2007-HE1**

 
| **Exhibit No.** | **Description**                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 4.1             | Pooling and Servicing Agreement (incorporated herein by reference from Exhibit 4.1 to the Form 8-K filed by the issuing entity on January 31, 2007)                                                                                                                                                                                                                                                         |
| 4.2             | Mortgage Loan Purchase Agreement (incorporated herein by reference from Exhibit 4.2 to the Form 8-K filed by the issuing entity on January 31, 2007)                                                                                                                                                                                                                                                        |
| 4.3             | ISDA Long Form Swap Confirmation, Credit Support Annex and Novation Agreement each dated as of January 16, 2007 between The Bank of New York and Deutsche Bank National Trust Company, not in its individualcapacity but solely as Trustee on behalf of the Supplemental Interest Trust (incorporated herein by reference from Exhibit 4.3 to the Form 8-K filed by the issuing entity on January 31, 2007) |
| 4.4             | Administrative Agent Agreement between WMB, as servicer, and Washington Mutual Mortgage Securities Corp., and its successors and assigns, in its capacity as Administrative Agent, effective as of April 1, 2006(incorporated by reference from Exhibit 4.4 to Form 8-K filed under File No. 131-131252 on July 26, 2006).                                                                                  |
| 31              | Certification of David Beck pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                      |
| 33.1            | Report on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.                                                                                                                                                                                                                                                                                                                  |
| 33.2            | Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank                                                                                                                                                                                                                                                                                                                       |
| 33.3            | Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.                                                                                                                                                                                                                                |
| 33.4            | Letter dated January 30, 2008 regarding Restated Assessment for the Reporting Period of January 1, 2006 through December 31, 2006 for American Security Insurance Company, Standard Guaranty Insurance Companyand TrackSure Insurance Agency, Inc.                                                                                                                                                          |
| 33.5            | Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                                                                  |
| 33.6            | Report on Assessment of Compliance with Servicing Criteria for Deutsche Bank National Trust Company.                                                                                                                                                                                                                                                                                                        |
| 34.1            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.                                                                                                                                                                                                                                                                         |
| 34.2            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank.                                                                                                                                                                                                                                                                             |
| 34.3            | Attestation Report of PriceWaterhouseCoopers LLP on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure InsuranceAgency, Inc                                                                                                                                                                                        |
| 34.4            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                         |
| 34.5            | Attestation Report of KPMG LLP on Assessment of Compliance with Servicing Criteria for Deutsche Bank National Trust Company.                                                                                                                                                                                                                                                                                |
| 35.1            | Servicer Compliance Statement of Washington Mutual Bank                                                                                                                                                                                                                                                                                                                                                     |
| 35.2            | Servicer Compliance Statement of Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                                                                                                |
| 99.1            | Certain information concerning the mortgage loans prepared in connection with the Registrant's WaMu Asset-Backed Certificates, WaMu Series 2007-HE1 (incorporated herein by reference from Exhibit 99.1 to theForm 8-K filed by the issuing entity on January 12, 2007)                                                                                                                                     |

 

 

----

**SIGNATURES**

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 dulyauthorized.

 

|                            |   |                                   |   |                                                                      |
|---------------------------------|--------|----------------------------------------|--------|---------------------------------------------------------------------------|
| **WAMU ASSET ACCEPTANCE CORP.** |
|                            |   |
|                            |   |                                   |
|                            |   | By:                                    |   |  /s/ David Beck                                                      |
|                            |   | Name:                                  |   |  David Beck                                                          |
|                            |   | Title:                                 |   | President and Senior Officer in Charge of Securitization of the Depositor |
|                            |   |
|                            |   | Date:    March 24, 2008 |

 

 

----

EXHIBIT INDEX

**WaMu Asset-Backed Certificates, WaMu Series 2007-HE1**

 

| **Exhibit No.** | **Description**                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 4.1             | Pooling and Servicing Agreement (incorporated herein by reference from Exhibit 4.1 to the Form 8-K filed by the issuing entity on January 31, 2007)                                                                                                                                                                                                                                                         |
| 4.2             | Mortgage Loan Purchase Agreement (incorporated herein by reference from Exhibit 4.2 to the Form 8-K filed by the issuing entity on January 31, 2007)                                                                                                                                                                                                                                                        |
| 4.3             | ISDA Long Form Swap Confirmation, Credit Support Annex and Novation Agreement each dated as of January 16, 2007 between The Bank of New York and Deutsche Bank National Trust Company, not in its individualcapacity but solely as Trustee on behalf of the Supplemental Interest Trust (incorporated herein by reference from Exhibit 4.3 to the Form 8-K filed by the issuing entity on January 31, 2007) |
| 4.4             | Administrative Agent Agreement between WMB, as servicer, and Washington Mutual Mortgage Securities Corp., and its successors and assigns, in its capacity as Administrative Agent, effective as of April 1, 2006(incorporated by reference from Exhibit 4.4 to Form 8-K filed under File No. 131-131252 on July 26, 2006).                                                                                  |
| 31              | Certification of David Beck pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                      |
| 33.1            | Report on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.                                                                                                                                                                                                                                                                                                                  |
| 33.2            | Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank                                                                                                                                                                                                                                                                                                                       |
| 33.3            | Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.                                                                                                                                                                                                                                |
| 33              | Letter dated January 30, 2008 regarding Restated Assessment for the Reporting Period of January 1, 2006 through December 31, 2006 for American Security Insurance Company, Standard Guaranty Insurance Companyand TrackSure Insurance Agency, Inc.                                                                                                                                                          |
| 33.5            | Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                                                                  |
| 33.6            | Report on Assessment of Compliance with Servicing Criteria for Deutsche Bank National Trust Company.                                                                                                                                                                                                                                                                                                        |
| 34.1            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.                                                                                                                                                                                                                                                                         |
| 34.2            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank.                                                                                                                                                                                                                                                                             |
| 34.3            | Attestation Report of PriceWaterhouseCoopers LLP on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure InsuranceAgency, Inc                                                                                                                                                                                        |
| 34.4            | Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                         |
| 34.5            | Attestation Report of KPMG LLP on Assessment of Compliance with Servicing Criteria for Deutsche Bank National Trust Company.                                                                                                                                                                                                                                                                                |
| 35.1            | Servicer Compliance Statement of Washington Mutual Bank                                                                                                                                                                                                                                                                                                                                                     |
| 35.2            | Servicer Compliance Statement of Washington Mutual Mortgage Securities Corp.                                                                                                                                                                                                                                                                                                                                |
| 99.1            | Certain information concerning the mortgage loans prepared in connection with the Registrant's WaMu Asset-Backed Certificates, WaMu Series 2007-HE1 (incorporated herein by reference from Exhibit 99.1 to theForm 8-K filed by the issuing entity on January 12, 2007)                                                                                                                                     |