UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





Form 10-K/A

(Amendment No. 1)







|þ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------

For the fiscal year ended December 31, 2013

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 000-28018





Yahoo! Inc.

(Exact name of Registrant as specified in its charter)



|                                                               |  |                                     
|-------------------------------------------------------------- |  | ------------------------------------
|Delaware                                                       |  | 77-0398689                          
|(State or other jurisdiction of
incorporation or organization) |  | (I.R.S. Employer Identification No.)

701 First Avenue

Sunnyvale, California 94089

(Address of principal executive offices,
including zip code)

Registrants telephone number, including area code: (408) 349-3300

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



|                              |  |                                                          
|----------------------------- |  | ---------------------------------------------------------
|Title of Each Class           |  | Name of Each Exchange on Which
Registered                
|Common stock, $.001 par value |  | The NASDAQ Stock Market LLC (NASDAQ Global Select Market)

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

(Title of Class)





Indicate by check mark if the
Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities
Act.    Yes  þ    No   ̈

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  þ

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  þ    No   ̈

Indicate by check mark whether the Registrant has submitted electronically and posted on its
corporate Web site, 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  þ    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 definitions of large accelerated filer, accelerated filer, and smaller reporting company in Rule 12b-2 of the Exchange Act.



|                        |  |                                                  |  |                           |  |  
|----------------------- |  | ------------------------------------------------ |  | ------------------------- |  | -
|Large accelerated filer |  | þ                                                |  | 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 by Rule 12b-2 of the Exchange
Act).    Yes   ̈    No  þ

As of June 28, 2013, the aggregate market value of voting stock held by non-affiliates of the Registrant, based upon the closing sales price for the Registrants common stock, as reported on the
NASDAQ Global Select Market, was $21,982,938,411. Shares of common stock held by each officer and director and by each person who owns 10 percent or more of the outstanding common stock have been excluded in that such persons may be deemed to be
affiliates. This determination of affiliate status is not necessarily a conclusive determination for any other purpose.

The number of shares
of the Registrants common stock outstanding as of February 14, 2014 was 1,009,392,339.

DOCUMENTS INCORPORATED BY
REFERENCE

The following documents (or parts thereof) are incorporated by reference into the following parts of this Form 10-K:

Proxy Statement for the 2014 Annual Meeting of ShareholdersPart III Items 10, 11, 12, 13, and 14.









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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, 2013, originally filed on February 28, 2014 (the Original 10-K), of Yahoo! Inc., a Delaware corporation (Yahoo, the Company, or we). We are filing this Amendment to amend
Item 15 to include the separate financial statements of Yahoo Japan Corporation and Consolidated Subsidiaries (Yahoo Japan) as required by Regulation S-X Rule 3-09 (the Rule 3-09 financial statements), which were not
included in the Original 10-K because Yahoo Japans fiscal year ended after the date of the filing of the Original 10-K. The Rule 3-09 financial statements include consolidated balance sheets of Yahoo Japan as of March 31, 2014 and 2013,
and the related consolidated statements of income, comprehensive income, changes in equity, and cash flows for each of the three years in the period ended March 31, 2014. In accordance with Rule 3-09 of Regulation S-X, only the financial
statements as of March 31, 2014 and for the years ended March 31, 2014 and 2012 are required to be audited. The Rule 3-09 financial statements as of and for the year ended March 31, 2013 are unaudited. The Rule 3-09 financial
statements were prepared and provided to the Company by Yahoo Japan.

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 28, 2014. The Original 10-K has not been amended or updated to reflect events
occurring after February 28, 2014, except as specifically set forth in this Amendment.



|Item 15. | Exhibits and Financial Statement Schedules
|-------- | ------------------------------------------

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

1. Consolidated Financial
Statements:

The consolidated financial statements of the Company, as listed in Item 15 of the Original 10-K, are included in
Item 8 of the Original 10-K.



|2. | Financial Statement Schedules:
|-- | ------------------------------

The financial statement schedules and supplementary financial data of the Company, as listed in Item 15 of the Original 10-K, are included in Item 8 of the Original 10-K.

The financial statements of Yahoo Japan Corporation and its consolidated subsidiaries required by Rule 3-09 of Regulation S-X 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, on the 19th day of September 2014.



YAHOO! INC.By:

/s/ KEN GOLDMANKen GoldmanChief Financial Officer(Principal Financial Officer)




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INDEX TO EXHIBITS

The following exhibits are included, or incorporated by reference, in this Amendment (and are numbered in accordance with Item 601 of Regulation S-K). Pursuant to Item 601(a)(2) of
Regulation S-K, this Exhibit Index immediately precedes the exhibits.



|               |  |                                                                                                                                                                                                                                      
|-------------- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Exhibit Number |  | Description                                                                                                                                                                                                                          
|23.2*          |  | Consent of Deloitte Touche Tohmatsu LLC, Independent Auditors of Yahoo Japan Corporation and Consolidated Subsidiaries.                                                                                                              
|               | 
|31.3*          |  | Certificate of Chief Executive Officer Pursuant to Securities Exchange Act Rules 13a-14(a) and 15d-14(a) as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002,
dated September 19, 2014.                             
|               | 
|31.4*          |  | Certificate of Chief Financial Officer Pursuant to Securities Exchange Act Rules 13a-14(a) and 15d-14(a) as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002,
dated September 19, 2014.                             
|               | 
|32.2**         |  | Certificate of Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of
2002, dated September 19, 2014.                               
|               | 
|99.1*          |  | Financial Statements of Yahoo Japan Corporation and Consolidated Subsidiaries as of March 31, 2014 (audited) and March 31, 2013 (unaudited) and for the years ended
March 31, 2014 and 2012 (audited) and March 31, 2013 (unaudited).



|* | Filed herewith.
|- | ---------------

|** | Furnished herewith.
|-- | -------------------