As filed with the Securities and Exchange Commission on November 2, 2011

Registration No. 333-174661

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Amendment No. 8
to
FORM S-1
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

Groupon, Inc.
(Exact name of Registrant as specified in its charter)

Andrew D. Mason
Chief Executive Officer
Groupon, Inc.
600 West Chicago Avenue, Suite 620
Chicago, Illinois 60654
312-676-5773
(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

        Approximate date of commencement of proposed sale to the public:    As soon as practicable after this Registration Statement becomes effective.

          If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act, check the following box. o

          If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

          If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

          If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

          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. (Check one):

          The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission acting pursuant to said Section 8(a) may determine.

EXPLANATORY NOTE

        This pre-effective amendment is being filed solely for the purpose of amending "Part II-Information Not Required in Prospectus."

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13.    OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

        The following table sets forth all expenses to be paid by the registrant, other than estimated underwriting discounts and commissions, in connection with this offering. All expenses will be borne by the registrant (except any underwriting discounts and commissions). All amounts shown are estimates except for the SEC registration fee, the FINRA filing fee and the NASDAQ Global Select Market listing fee.

ITEM 14.   INDEMNIFICATION OF DIRECTORS AND OFFICERS.

        Section 145 of the Delaware General Corporation Law authorizes a corporation's board of directors to grant, and authorizes a court to award, indemnity to officers, directors and other corporate agents.

        As permitted by Section 102(b)(7) of the Delaware General Corporation Law, or DGCL, the registrant's certificate of incorporation to be in effect prior to the closing of this offering includes provisions that eliminate the personal liability of its directors and officers for monetary damages for breach of their fiduciary duty as directors and officers, except for liability (i) for any breach of the director's duty of loyalty to the corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) for unlawful payments of dividends or unlawful stock repurchases, redemptions or other distributions or (iv) for any transaction from which the director derived an improper personal benefit. The registrant's amended and restated certificate of incorporation provides for such limitation of liability.

        In addition, as permitted by Section 145 of the DGCL, the by-laws of the registrant to be effective upon completion of this offering provide that:

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The registrant shall indemnify its directors and officers for serving the registrant in those capacities or for serving other business enterprises at the registrant's request, to the fullest extent permitted by Delaware law. Delaware law provides that a corporation may indemnify such person if such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the registrant and, with respect to any criminal action or proceeding, had no reasonable cause to believe such person's conduct was unlawful.



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The registrant may, in its discretion, indemnify employees and agents in those circumstances where indemnification is permitted by applicable law.



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The registrant is required to advance expenses, as incurred, to its directors and officers in connection with defending a proceeding, except that such director or officer shall undertake to

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repay such advances if it is ultimately determined that such person is not entitled to indemnification.

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The registrant will not be obligated pursuant to the by-laws to indemnify a person with respect to proceedings initiated by that person, except with respect to proceedings authorized by the registrant's board of directors or brought to enforce a right to indemnification.



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The rights conferred in the by-laws are not exclusive, and the registrant is authorized to enter into indemnification agreements with its directors, officers, employees and agents and to obtain insurance to indemnify such persons.



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The registrant may not retroactively amend the by-law provisions to reduce its indemnification obligations to directors, officers, employees and agents.

        The registrant's policy is to enter into separate indemnification agreements with each of its directors and officers that provide the maximum indemnity allowed to directors and executive officers by Section 145 of the DGCL and certain additional procedural protections. The registrant will also maintain directors and officers insurance to insure such persons against certain liabilities.

        These indemnification provisions and the indemnification agreements entered into between the registrant and its officers and directors may be sufficiently broad to permit indemnification of the registrant's officers and directors for liabilities (including reimbursement of expenses incurred) arising under the Securities Act.

        The underwriting agreement to be filed as Exhibit 1.1 to this registration statement provides for indemnification by the underwriters of the registrant and its officers and directors for certain liabilities arising under the Securities Act and otherwise.

ITEM 15.    RECENT SALES OF UNREGISTERED SECURITIES.

        We sold the following shares of our Series D preferred stock, Series E preferred stock, Series F preferred stock, Series G preferred stock, voting common stock and non-voting common stock to the following entities and individuals on the dates set forth below. The issuances of these securities were deemed to be exempt from registration under the Securities Act of 1933, as amended, in reliance on Section 4(2) of the Securities Act as transactions not involving a public offering. The information set forth below with respect to our voting common stock and non-voting common stock gives effect to (i) the three-for-one forward stock split of our voting common stock and non-voting common stock that was completed in August 2010; (ii) the two-for-one forward stock split of our voting common stock and non-voting common stock that was completed in January 2011; and (iii) the two-for-one forward stock split of our voting common stock and non-voting common stock that was completed in October 2011.

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        Since January 1, 2008, we have granted options to 664 of our employees or consultants to purchase an aggregate of 37,710,400 shares of our common stock, of which 11,084,412 have been exercised, 8,218,478 have expired and 18,407,510 remain either unvested or unexercised. The weighted average exercise price for the unvested and/or unexercised options is $1.11 per share. In addition, since January 1, 2008, we have granted 20,106,714 restricted stock units to 346 of our employees or consultants, 10,575,100 of which remain unvested. Each of the option and restricted stock unit grants were awarded under either the Company's 2011 Incentive Plan, 2010 Stock Plan or 2008 Stock Option Plan and, subject to the terms of those plans, vest and allow for exercise, as applicable, in accordance with the terms of each individual grant.

        Other than the transactions listed immediately above, we have not issued and sold any unregistered securities in the three years preceding the filing of this registration statement.

ITEM 16.    EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

(a)

Exhibits. The following exhibits are included herein or incorporated herein by reference:

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(b)

Financial Statement Schedules.

Report of Independent Registered Public Accounting Firm

        The Board of Directors and Stockholders of Groupon, Inc.

        We have audited the consolidated financial statements of Groupon, Inc. as of December 31, 2009 and 2010, and for each of the three years in the period ended December 31, 2010, and have issued our report thereon dated June 2, 2011 (included elsewhere in this Registration Statement). Our audits also included the financial statement schedule listed in Item 16(b) of Form S-1 of this Registration Statement. This schedule is the responsibility of the Company's management. Our responsibility is to express an opinion based on our audits.

        In our opinion, the financial statement schedule referred to above, when considered in relation to the basic financial statements taken as a whole, presents fairly in all material respects the information set forth therein.

/s/ Ernst & Young LLP
Chicago, Illinois
June 2, 2011

Schedule II—Valuation and Qualifying Accounts

        All other schedules have been omitted because they are either inapplicable or the required information has been given in the consolidated financial statements or the notes thereto.

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ITEM 17.    UNDERTAKINGS.

        The undersigned registrant hereby undertakes to provide to the underwriters at the closing specified in the underwriting agreement certificates in such denominations and registered in such names as required by the underwriters to permit prompt delivery to each purchaser.

        Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

        The undersigned registrant hereby undertakes that:

        (1)   For purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this registration statement as of the time it was declared effective.

        (2)   For the purpose of determining any liability under the Securities Act of 1933, each post effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

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SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Chicago, Illinois, on the 2nd day of November, 2011.

        Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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EXHIBIT INDEX

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QuickLinks

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES.
ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

ITEM 17. UNDERTAKINGS.