UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                                (Amendment No. _3__ )*

                             NetScout Systems, Inc.
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                                (Name of Issuer)

                                  Common Stock
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                         (Title of Class of Securities)

                                    64115T104
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                                 (CUSIP Number)

                                December 31, 2006
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             (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).

                                EXPLANATORY NOTE

This Schedule 13G/A, Amendment No. 2, is being filed to correct the information
reflected in the original Schedule 13G dated December 13, 2007, which
inadvertently included incorrect information regarding the shares owned by the
reporting persons.



                                  SCHEDULE 13G

CUSIP No. 64115T104

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      1.    Names of Reporting Persons. I.R.S. Identification Nos. of above
            persons (entities only).
            INVESCO Ltd.
                  Atlantic Trust Company, N.A.
                  PowerShares Capital Management LLC

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      2.    Check the Appropriate Box if a Member of a Group (see Instructions)
            (a)
            (b)

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      3.    SEC Use Only _______________________________________________

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      4.    Citizenship or Place of Organization
            INVESCO Ltd.: England
                  Atlantic Trust Company, N.A.: United States
                  PowerShares Capital Management LLC: United States

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                     5.    Sole Voting Power 1,651,383:
                           Such shares are held by the following
                           entities in the respective amounts
                           listed:
                             Atlantic Trust Company, N.A. 1,589,998
                             PowerShares Capital Management LLC 61,385

Number of Shares     -----------------------------------------------------------
Beneficially Owned
by Each Reporting    6.    Shared Voting Power -0-
Person With

                     -----------------------------------------------------------

                     7.    Sole Dispositive Power 1,651,383:
                           Such shares are held by the following
                           entities in the respective amounts
                           listed:
                             Atlantic Trust Company, N.A. 1,589,998
                             PowerShares Capital Management LLC 61,385

                     -----------------------------------------------------------

                     8.      Shared Dispositive Power -0-

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      9.   Aggregate Amount Beneficially Owned by Each Reporting Person
           1,651,383

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      10.  Check if the Aggregate Amount in Row (9) Excludes Certain Shares
           (See Instructions) N/A

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      11.  Percent of Class Represented by Amount in Row (9)        5.21%
                                                                   -----

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      12.  Type of Reporting Person (See Instructions)
           IA, HC. See Items 2 and 3 of this statement.



                                  SCHEDULE 13G

Item 1(a)     Name of Issuer:
              NetScout Systems, Inc.

Item 1(b)     Address of Issuer's Principal Executive Offices:
                       310 Littleton Road
                       Westford, MA  01886

Item 2(a)     Name of Person Filing:
              INVESCO Ltd.

              In accordance with Securities and Exchange Commission Release
              No. 34-39538 (January 12, 1998), this statement on Schedule
              13G or amendment thereto is being filed by INVESCO Ltd.
              ("INVESCO"), a U.K. entity, on behalf of itself and its
              subsidiaries listed in Item 4 of the cover of this statement.
              INVESCO through such subsidiaries provides investment
              management services to institutional and individual investors
              worldwide.

              Executive officers and directors of INVESCO or its
              subsidiaries may beneficially own shares of the securities of
              the issuer to which this statement relates (the "Shares"), and
              such Shares are not reported in this statement. INVESCO and
              its subsidiaries disclaim beneficial ownership of Shares
              beneficially owned by any of their executive officers and
              directors. Each of INVESCO's direct and indirect subsidiaries
              also disclaim beneficial ownership of Shares beneficially
              owned by INVESCO and any other subsidiary.

Item 2(b)     Address of Principal Business Office:
              30 Finsbury Square
              London EC2A 1AG
              England

Item 2(c)     Citizenship:
              See the response to Item 2(a) of this statement.

Item 2(d)     Title of Class of Securities:
              Common Stock, $.001 par value per share

Item 2(e)     CUSIP Number:
              64115T104

Item 3        If this statement is filed pursuant to ss240.13d-1(b) or
              240.13d-2(b) or (c), check whether the person filing is a:

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

          (g) [x] A parent holding company or control person in accordance with
section 240.13d-1(b)(1)(ii)(G)

              As noted in Item 2 above, INVESCO is making this filing on behalf
              of its subsidiaries listed herein. Each of these entities is
              either an investment adviser registered with the United States
              Securities and Exchange Commission under Section 203 of the
              Investment Advisers Act of 1940, as amended, or under similar laws
              of other jurisdictions. INVESCO is a holding company.



Item 4        Ownership:
              Please see responses to Items 5-8 on the cover of this statement,
              which are incorporated herein by reference.

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
              [ ]

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

Item 7        Identification and Classification of the Subsidiary Which Acquired
              the Security Being reported on By the Parent Holding Company:
              Please see Item 3 of this statement, which is incorporated herein
              by reference.

Item 8        Identification and Classification of Members of the Group:
              N/A

Item 9        Notice of Dissolution of a Group:
              N/A

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 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.

              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.

                                             12/10/2007
                                     -------------------------------------------
                                                Date

                                     INVESCO Ltd.

                                     By:      /s/ Lisa Brinkley
                                     -------------------------------------------

                                     Lisa Brinkley
                                     Chief Compliance Officer