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

                                  SCHEDULE 13G

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

                                   Viacom Inc.
                                (Name of Issuer)

                                 Common-Class B
                         (Title of Class of Securities)

                                    92553P201
                                 (CUSIP Number)

                                December 31, 2007
             (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

<PAGE>

--------------------------------------------------------------------------------
 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) [_]
--------------------------------------------------------------------------------
 3     SEC USE ONLY

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

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

                            27,670,281
      NUMBER OF      -----------------------------------------------------------
        SHARES       6      SHARED VOTING POWER
     BENEFICIALLY
       OWNED BY             0
         EACH        -----------------------------------------------------------
      REPORTING      7      SOLE DISPOSITIVE POWER
       PERSON
         WITH               31,886,366
                     -----------------------------------------------------------
                     8      SHARED DISPOSITIVE POWER

                            0
--------------------------------------------------------------------------------
 9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
       31,886,366
--------------------------------------------------------------------------------
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
       5.33%
--------------------------------------------------------------------------------
12     TYPE OF REPORTING PERSON*
       IA
--------------------------------------------------------------------------------


                                PAGE 2 OF 4 PAGES

<PAGE>

              Item 1(a) Name of Issuer:
                        Viacom Inc.

              Item 1(b) Address of Issuer's Principal Executive Offices:
                         1515 Broadway
                         New York, NY 10036
                         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-Class B

              Item 2(e) CUSIP Number:
                        92553P201

              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:
                31,886,366
            (b) Percent of Class:
                5.33%
            (c) Number of shares as to which such person has:
             (i)   sole power to vote or direct the vote:
                   27,670,281
             (ii)  shared power to vote or direct the vote:
                   0
             (iii) sole power to dispose or to direct the disposition of:
                   31,886,366
             (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.


                                PAGE 3 OF 4 PAGES

<PAGE>

  Item 6    Ownership of More than Five Percent on Behalf of Another Person:

            Securities reported on this Schedule 13G are beneficially owned
            by clients which may include investment companies
            registered under the Investment Company Act and/or employee
            benefit plans, pensions, Charitable funds or other institutional
            and high net worth clients.

  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.

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: February 14, 2008

                                 NWQ Investment Management Company, LLC

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


                                PAGE 4 OF 4 PAGES