UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

(AMENDMENT NO. 1)

For the Fiscal Year Ended December 31, 2017

OR

Commission File Number 000-28271

XO GROUP INC.

(Exact Name of Registrant as Specified in Its Charter)

195 Broadway, 25th Floor

New York, New York 10007

(Address of Principal Executive Offices and Zip Code)

(212) 219-8555

(Registrant’s Telephone Number, Including Area Code)

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

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 Exchange 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 Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T 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 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

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

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

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 voting common stock held by non-affiliates of the registrant as of June 30, 2017 was approximately $370,141,472. The number of shares outstanding of the registrant’s common stock as of February 28, 2018 was 25,706,590. The registrant does not have any non-voting stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive proxy statement for the 2018 Annual Meeting of Stockholders are incorporated by reference into Part III. 

EXPLANATORY NOTE

This Amendment No. 1 on Form 10-K/A (“Form 10-K/A”) to our Annual Report on Form 10-K for the year ended December 31, 2017, initially filed with the Securities and Exchange Commission on March 2, 2018 (the “Original Filing”), is being filed solely to revise Part II, Item 9A. “Controls and Procedures” in response to a comment received from the staff of the Division of Corporation Finance. This Form 10-K/A amends and restates in its entirety Part II, Item 9A of the Original Filing. Except as stated above, this Form 10-K/A does not reflect events occurring after the Original Filing and does not modify or update in any way the disclosures contained in the Original Filing. Accordingly, this Form 10-K/A should be read in conjunction with the Original Filing.

As required by Rule 12b-15 under the Securities Exchange Act of 1934, as amended, new certifications by our principal executive officer and principal financial officer are filed as exhibits to this Amendment under Item 15 of Part IV hereof.

Item 9A. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

The Company has established disclosure controls and procedures that are designed to ensure that information required to be disclosed in reports filed or submitted under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), is recorded, processed, summarized and reported within the time periods specified in the rules and forms of the Securities and Exchange Commission and, as such, is accumulated and communicated to the Company’s management, including our Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”), as appropriate to allow timely decisions regarding required disclosure. Based on our evaluation, our management, including the CEO and the CFO, has concluded that as of December 31, 2017 the Company’s disclosure controls and procedures are effective to ensure that information required to be disclosed by us in the reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms, and to ensure that such information is accumulated and communicated to our management, as appropriate to allow timely decisions regarding required disclosure.

Report of Management on Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Exchange Act Rule 13a-15(f). Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles.

Under the supervision and with the participation of our management, we conducted an evaluation of the effectiveness of its internal control over financial reporting as of December 31, 2017 based upon Internal Control-Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”). Based on our evaluation, our management, including the CEO and CFO, has concluded that our internal control over financial reporting is effective as of December 31, 2017.

As previously described in “Part II. Item 9A. Controls and Procedures” of the Company’s 2016 Form 10-K, we had identified a material weakness, which is defined as a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the Company’s annual or interim financial statements will not be prevented or detected on a timely basis.

Specifically, certain controls over national online advertising did not operate effectively as they did not ensure that revenue is recognized based on the targeting of impressions ordered by our customers. As a result, in some instances, the controls did not prevent the recognition of revenue for impressions ordered by our customers that we did not deliver to the correct targeting. The errors arising from the underlying deficiency were not material to the Consolidated Financial Statements reported in any interim or annual period and therefore, did not result in a revision to previously filed Consolidated Financial Statements. However, this control deficiency could have resulted in a material misstatement to the annual or interim Consolidated Financial Statements that would not be prevented or detected in a timely manner. Accordingly, we determined that this control deficiency constituted a material weakness.

In response to the material weakness, we implemented a remediation plan that included the following:

Our enhanced review procedures and access standards were in place during 2017. We have tested the enhanced internal controls and related procedures and accesses. We have concluded, through testing, that the newly implemented controls have operated for a sufficient period of time and are operating effectively, and that the material weakness previously identified has been remediated.

The independent registered public accounting firm, Ernst & Young LLP, has audited the consolidated financial statements included in this Form 10-K and, as part of the audit, has issued a report on the effectiveness of our internal control over financial reporting as of December 31, 2017, which is included in this Form 10-K in Item 8, “Financial Statements and Supplementary Data.”

Changes in Internal Control over Financial Reporting

There were no changes in the Company’s internal control over financial reporting during the quarter ended December 31, 2017, that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

Inherent Limitations on Effectiveness of Controls

The Company’s management, including the Company’s CEO and CFO, does not expect that the Company’s disclosure controls and procedures or the Company’s internal control over financial reporting will prevent or detect all error and all fraud. A control system, regardless of how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system will be met. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, have been detected.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, XO Group Inc. has duly caused this Report to be signed on its behalf by the undersigned, thereunto duly authorized in the City of New York, State of New York, on this 2nd day of August 2018.

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