SNDE Sundance Energy Inc

CUSIP NO. 86725N102   13G


1     Name of Reporting Person:
      Advisory Research, Inc.

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2     Check the Appropriate Box if a Member of a Group    (a)  [ ]
                                                          (b)  [ ]

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3     SEC Use Only

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4     Citizenship or Place of Organization
      Delaware

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   Number of
                   5     Sole Voting Power
    Shares               432,217 Shares
                   -----------------------------------------------
 Beneficially
                   6     Shared Voting Power
   Owned By              0 Shares
                   -----------------------------------------------
     Each
                   7     Sole Dispositive Power
   Reporting             432,217 Shares
                   -----------------------------------------------
    Person
                   8     Shared Dispositive Power
     With                0 Shares
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9     Aggregate Amount Beneficially Owned by Each Reporting Person
      432,217 Shares

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10    Check if the Aggregate Amount in Row (9) Excludes Certain
      Shares  [ ]

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11    Percent of Class Represented by Amount in Row (9)
      6.3%

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12    Type of Reporting Person
      IA

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Item 1     (a)  Name of Issuer:
                Sundance Energy Inc.

           (b)  Name of Issuer's Principal Executive Offices:
                1050 17th Street, Suite 700
                Denver, CO 80265

Item 2     (a)  Person Filing:
                Advisory Research, Inc.

           (b)  Address:
                Advisory Research, Inc.
                180 N. Stetson Ave., Suite 5500
                Chicago, IL 60601

           (c)  Citizenship:
                Advisory Research, Inc is a Delaware Corporation

           (d)  Title of Class of Securities:
                Common Stock

           (e)  CUSIP Number:
                86725N102


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

           (i) Advisory Research, Inc. is an investment advisor in
               accordance with section 240.13d-1(b)(1)(ii)(E)


Item 4     Ownership

           (a)  Amount Beneficially Owned:
                (i) Advisory Research, Inc.:    432,217 Shares

           (b)  Percent of Class:
                (i) Advisory Research, Inc:     6.3%

           (c)  Number of shares as to which reporting person has:
                (i)    Sole Voting Power            432,217 Shares
                (ii)   Shared Voting Power          0 Shares
                (iii)  Sole Dispositive Power       432,217 Shares
                (iv)   Shared Dispositive Power     0 Shares



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:

           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 if Members of
           the Group:

           Not Applicable

Item 9     Notice of Dissolution of 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 and are
           not held in connection with or as a participant
           in any transaction having such purposes or effect.


           In accordance with Rule 13d-4 of the Securities Exchange
           Act of 1934, each of the persons filing this statement
           expressly disclaim the beneficial ownership of the securities
           covered by this statement and the filing of this report
           shall not be construed as an admission by such persons that
           they are the beneficial owners of such securities.


                                SIGNATURE

           The undersigned certify, after reasonable inquiry
           and to the best knowledge and belief of the undersigned,
           that the information set forth in this Statement is true,
           complete and correct.  The undersigned agree to the
           filing of this single Statement on Schedule 13G.


                           Advisory Research, Inc.

Date:  February 13, 2020   By:  /s/ Matthew K. Swaim
                           Name: Matthew K. Swaim
                           Title: Chief Executive Officer