UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 10-K/A

Amendment No. 1





(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, 2015

OR



| ̈ | 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:
001-36131





Endurance International Group Holdings, Inc.

(Exact name of registrant as specified in its charter)







|                                                               |  |                                     
|-------------------------------------------------------------- |  | ------------------------------------
|Delaware                                                       |  | 46-3044956                          
|(State or other jurisdiction of
incorporation or organization) |  | (I.R.S. Employer
Identification No.)
|                                                               | 
|10 Corporate Drive, Suite 300
Burlington, Massachusetts        |  | 01803                               
|(Address of principal executive offices)                       |  | (Zip code)                          

(781) 852-3200

(Registrants telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:



|                                          |  |                                     
|----------------------------------------- |  | ------------------------------------
|Title of each class                       |  | Name of exchange on which
registered
|Common Stock, par value $0.0001 per share |  | The NASDAQ Global Select Market     

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 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 whether the registrant has submitted electronically and posted on its corporate Website, if any, every Interactive Data
File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such
files).    Yes  x    No   ̈

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) 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.     ̈

Indicate by check mark whether the registrant is a large
accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of
the Exchange Act. (Check one)



|                        |  |                                                  |  |                           |  |  
|----------------------- |  | ------------------------------------------------ |  | ------------------------- |  | -
|Large accelerated filer |  | x                                                |  | Accelerated filer         |  |  ̈
|                        |  |                                                  | 
|Non-accelerated filer   |  |  ̈  (Do not check if a smaller reporting company) |  | Smaller reporting company |  |  ̈

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

The aggregate market value of common stock held by non-affiliates of the registrant based on the closing price of the registrants common
stock as reported on the NASDAQ Global Select Market on June 30, 2015, was $1,250,205,625.

As of June 28, 2016 there were
140,897,191 shares of the registrants common stock, $0.0001 par value per share, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrants definitive proxy statement for its 2016 Annual Meeting of Stockholders, which was filed pursuant to
Regulation 14A with the Securities and Exchange Commission on April 12, 2016, are incorporated by reference into Part III of this Annual Report on Form 10-K.









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EXPLANATORY NOTE

This Amendment No. 1 to Form 10-K (this Amendment) amends the Annual Report on Form 10-K for the fiscal year ended
December 31, 2015, originally filed on February 29, 2016 (the Original 10-K), of Endurance International Group Holdings, Inc. (the Company). The Company is filing this Amendment to include in Item 15 the
separate financial statements of WZ (UK) Limited (WZ UK) as required by Rule 3-09 of Regulation S-X, which were not included in the Original 10-K and are due within six months of December 31, 2015.

As of December 31, 2015, the Company held a 49% interest in WZ UK and WZ UK met the significance test of an equity investee for the
Companys fiscal year ended December 31, 2015. In accordance with Rule 3-09 of Regulation S-X, the WZ UK financial statements as of and for the year ended December 31, 2015 were audited in accordance with United Kingdom Accounting
Standards (United Kingdom Generally Accepted Accounting Practice). The WZ UK financial statements as of and for the period ended December 31, 2014 are unaudited.

This Amendment should be read in conjunction with the Original 10-K and the Companys other filings made with the Securities and Exchange
Commission subsequent to the filing of the Original 10-K on February 29, 2016. The Original 10-K has not been amended or updated to reflect events occurring after February 29, 2016, except as specifically set forth in this Amendment.



|ITEM 15. | EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
|-------- | ------------------------------------------



| | (1) | Financial Statements
| | --- | --------------------

For a list of the consolidated financial statements included
herein, which are incorporated into this Item by reference, see Index to Consolidated Financial Statements on page 90 of the Original 10-K.



| | (2) | Financial Statement Schedules
| | --- | -----------------------------

The financial statements of WZ UK are provided as Exhibit
99.1 to this Amendment.



| | (3) | Exhibits
| | --- | --------

The exhibits listed in the Exhibit Index of the Original 10-K and this
Amendment are filed with, or incorporated by reference in, this report.



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SIGNATURE

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



|                    |  |  |  |                                              |  |                        
|------------------- |  |  |  | -------------------------------------------- |  | -----------------------
|                    |  |  |  | ENDURANCE INTERNATIONAL GROUP HOLDINGS, INC.
|                    |  |  | 
|Date: June 28, 2016 |  |  |  | By:                                          |  | /s/ Marc Montagner     
|                    |  |  |  |                                              |  | Marc Montagner         
|                    |  |  |  |                                              |  | Chief Financial Officer



---

EXHIBIT INDEX



|           |  |                                                                                                                                                
|---------- |  | -----------------------------------------------------------------------------------------------------------------------------------------------
|ExhibitNo. |  | Description of Exhibit                                                                                                                         
|           | 
|23.2       |  | Consent of BDO LLP                                                                                                                             
|           | 
|31.3       |  | Certification of Principal Executive Officer Pursuant to Rule 13a-14(a)/15d-14(a) of the Securities Exchange Act of 1934, as amended           
|           | 
|31.4       |  | Certification of Principal Financial Officer Pursuant to Rule 13a-14(a)/15d-14(a) of the Securities Exchange Act of 1934, as amended           
|           | 
|32.3       |  | Certification of Principal Executive Officer Pursuant to 18 U.S.C. § 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
|           | 
|32.4       |  | Certification of Principal Financial Officer Pursuant to 18 U.S.C. § 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
|           | 
|99.1       |  | Financial Statements of WZ (UK) Limited