UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 SCHEDULE 13G/A

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934
                               (AMENDMENT NO. 3)*

                                   UNUM GROUP
                      ------------------------------------
                                (Name of Issuer)

                                  Common Stock
                      ------------------------------------
                         (Title of Class of Securities)

                                   91529Y106
                              --------------------
                                 (CUSIP Number)

                                 July 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:

[x] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in 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).


                                PAGE 1 OF 4 PAGES


--------------------------------------------------------------------------------
 1     NAME OF REPORTING PERSON
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       NWQ Investment Management Company, LLC                   47-0875103
--------------------------------------------------------------------------------
 2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*                 (a) [_]
                                                                         (b) [_]
       N/A
--------------------------------------------------------------------------------
 3     SEC USE ONLY


--------------------------------------------------------------------------------
 4     CITIZENSHIP OR PLACE OF ORGANIZATION

       Delaware -- U.S.A.
--------------------------------------------------------------------------------
                     5      SOLE VOTING POWER

                            10,186,521
      NUMBER OF      -----------------------------------------------------------
        SHARES       6      SHARED VOTING POWER
     BENEFICIALLY
       OWNED BY             0
         EACH        -----------------------------------------------------------
      REPORTING      7      SOLE DISPOSITIVE POWER
       PERSON
         WITH               11,461,473
                     -----------------------------------------------------------
                     8      SHARED DISPOSITIVE POWER

                            0
--------------------------------------------------------------------------------
 9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       11,461,473
--------------------------------------------------------------------------------
10     CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

       N/A
--------------------------------------------------------------------------------
11     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

       4.29%
--------------------------------------------------------------------------------
12     TYPE OF REPORTING PERSON*

       IA
--------------------------------------------------------------------------------


                                PAGE 2 OF 4 PAGES


              Item 1(a) Name of Issuer:
                        UNUM GROUP

              Item 1(b) Address of Issuer's Principal Executive Offices:
                        1 Fountain Square
                        Chattanooga, TN 37402
                        UNITED STATES

              Item 2(a) Name of Person Filing:
                        NWQ Investment Management Company, LLC

              Item 2(b) Address of the Principal Office or, if none, Residence:
                        2049 Century Park East, 16th Floor
                        Los Angeles, CA 90067

              Item 2(c) Citizenship:
                        Delaware  -- U.S.A.

              Item 2(d) Title of Class of Securities:
                        Common Stock

              Item 2(e) CUSIP Number:
                        91529Y106

              Item 3 If the Statement is being filed pursuant to Rule
                     13d-1(b), or 13d-2(b), check whether the person filing
                     is a:

                        (e)      [X] An investment advisor in accordance with
                                 section 240.13d-1(b)(1)(ii)(E)

              Item 4    Ownership:
                         a)  Amount Beneficially Owned:
                             11,461,473

                        (b)  Percent of Class:
                             4.29%

                        (c)  Number of shares as to which such person has:

                        (i)  sole power to vote or direct the vote:   10,186,521

                       (ii)  shared power to vote or direct the vote:         0

                      (iii)  sole power to dispose or to direct the
                             disposition of:                          11,461,473

                       (iv)  shared power to dispose or to direct the
                             disposition of:                                  0


                                PAGE 3 OF 4 PAGES


              Item 5    Ownership of Five Percent or Less of a Class:

                        If this statement is being filed to report the fact that
                        as of the date hereof the reporting person has ceased to
                        be the beneficial owner of more than five percent of the
                        class of securities, check the following [ X ].


              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 a Group:
                        Not applicable.

              Item 10   Certification:
                        By signing below I certify that, to the best of my
                        knowledge and belief, the securities referred to above
                        were acquired and are held in the ordinary course of
                        business and 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 such securities and were
                        not acquired in connection with or as a participant
                        in any transaction having such purpose or effect.

                                    SIGNATURE

              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.

Dated: August 9, 2013

                                 NWQ Investment Management Company, LLC

                                 By:   /s/ Jon D. Bosse
                                       --------------------------------
                                       Jon D. Bosse, CFA
                                       Title: Chief Investment Officer


                                PAGE 4 OF 4 PAGES