SC 13G/A 1 IdenixSC13G.txt BROOKSIDE 13G FOR IDENIX PHARMACEUTICALS, INC. AS OF DECEMBER 31, 2013 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A (Rule 13d-102) Information Statement Pursuant to Rules 13d-1 and 13d-2 Under the Securities Exchange Act of 1934 (Amendment No. 4)* Idenix Pharmaceuticals, Inc. (Name of Issuer) Common Stock, Par Value $0.001 (Title of Class of Securities) 45166R204 (CUSIP Number) December 31, 2013 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this schedule is filed: [ ] Rule 13d-1(b) [X] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting persons initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be filed for the purpose of Section 18 of the Securities Exchange Act of 1934 (Act) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 45166R204 13G/A Page 2 of 5 Pages 1. NAME OF REPORTING PERSON Brookside Capital Trading Fund, L.P. 2. (a) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (b) 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH 5. SOLE VOTING POWER 13,115,858 Shares 6. SHARED VOTING POWER 0 7. SOLE DISPOSITIVE POWER 13,115,858 Shares 8. SHARED DISPOSITIVE POWER 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,115,858 Shares 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 9.79% 12. TYPE OF REPORTING PERSON PN Item 1(a). Name of Issuer The name of the issuer to which this filing on Schedule 13G/A relates is Idenix Pharmaceuticals, Inc. (the Company). Item 1(b). Address of Issuers Principal Executive Offices The principal executive offices of the Company are located at 320 Bent Street, Cambridge, MA 02141. Item 2(a). Name of Person Filing This Statement is being filed on behalf of Brookside Capital Trading Fund, L.P., a Delaware limited partnership (Trading Fund), whose sole general partner is Brookside Capital Investors II, L.P., a Delaware limited partnership (Brookside Investors II), whose sole general partner is Brookside Capital Management, LLC, a Delaware limited liability company (Brookside Management). Item 2(b). Address of Principal Business Office or, if none, Residence The principal business address of each of Trading Fund, Brookside Investors II, and Brookside Management is John Hancock Tower, 200 Clarendon Street, Boston, MA 02116. Item 2(c). Citizenship Each of the Trading Fund, Brookside Investors II and Brookside Management is organized under the laws of the State of Delaware. Item 2(d). Title of Class of Securities The class of equity securities of the Company to which this filing on Schedule 13G/A relates is Common Stock, Par Value $0.001 (Common Stock). Item 2(e). CUSIP Number The CUSIP number of the Companys Common Stock is 45166R204. Item 3. If this statement is filed pursuant to 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: (a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o). (b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 73c). (c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c). (d) [ ] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) [ ] An investment adviser in accordance with 13d-1(b)(1)(ii)(E). (f) [ ] An employee benefit plan or endowment fund in accordance with 240.13d-1(b)(1)(ii)(F). (g) [ ] A parent holding company or control person in accordance with 240.13d-1(b)(1)(ii)(G). (h) [ ] A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) [ ] A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3). (j) [ ] Group, in accordance with 240.13d-1(b)(1)(ii)(J). [x] If this statement is filed pursuant to 240.13d-1(c), check this box. Item 4. Ownership Item 4(a). Amount beneficially owned As of the close of business on December 31, 2013, the Trading Fund beneficially owned 13,115,858 shares of the Common Stock of the Company. Item 4(b). Percent of Class As of the close of business on December 31, 2013, the Trading Fund was the beneficial owner of 9.79% of the Common Stock of the Company. The percentage of Common Stock reported owned by the Trading Fund is based upon 134,000,750 shares of Common Stock outstanding, which is the total number of shares of Common Stock outstanding as of October 18, 2013, based on representations made in the Companys 10Q filed with the Securities and Exchange Commission on October 30, 2013. Item 4(c). Number of shares as to which such person has: (i) sole power to vote or to direct the vote: 13,115,858 Shares (ii) shared power to vote or to direct the vote: 0 (iii) sole power to dispose or to direct the disposition of: 13,115,858 Shares (iv) shared power to dispose or to direct the disposition of: 0 Item 5. Ownership of Five Percent or Less of a Class Not Applicable. Item 6. Ownership of More than Five Percent on Behalf of Another Person Not Applicable. Item 7. Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company: Not Applicable. Item 8. Identification and Classification of Members of the Group Not Applicable. Item 9. Notice of Dissolution of Group Not Applicable. Item 10. Certification By signing below, the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. Dated: February 12, 2014 After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete, and correct. BROOKSIDE CAPITAL TRADING FUND, L.P. By: Brookside Capital Investors II, L.P., its general partner By: Brookside Capital Management, LLC, its general partner By: /s/ William E. Pappendick IV Name: William E. Pappendick IV Title: Managing Director