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

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934

                                (Amendment No. 5)

                      American Medical Security Group, Inc.
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                                (Name of Issuer)

                           Common Stock, no par value
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                         (Title of Class of Securities)

                                   027 44P 101
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                                 (CUSIP Number)

                               Stephen E. Bablitch
                      President and Chief Operating Officer
                               Cobalt Corporation
                            401 West Michigan Street
                           Milwaukee, Wisconsin 53203

                 (Name, Address and Telephone Number of Persons
               Authorized to Receive Notices and Communications)

                               September 13, 2002
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             (Date of Event which Requires Filing of this Statement)


If the filing person has previously filed a statement on Schedule 13G to report
the acquisition which is the subject of this Schedule 13D, and is filing this
schedule because of ss. 240.13d-1(e), 240.13d-1(f) or 240.13(g), check the
following box [ ].

Note: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See ss.240.13d-7(b) for other
parties to whom copies are to be sent.





                                  SCHEDULE 13D

CUSIP No. 027 44P 101

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

          Wisconsin United for Health Foundation, Inc.
          Cobalt Corporation
          Blue Cross & Blue Shield United of Wisconsin
--------  ----------------------------------------------------------------------
    2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP               (a) [X]
          (SEE INSTRUCTIONS)                                             (b) [ ]
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    3     SEC USE ONLY

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    4     SOURCE OF FUNDS (SEE INSTRUCTIONS)

          Not applicable
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    5     CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
          PURSUANT TO ITEMS 2(d) OR 2(e)                                     [ ]

--------  ----------------------------------------------------------------------
    6     CITIZENSHIP OR PLACE OF ORGANIZATION

          Wisconsin United for Health Foundation, Inc. - Wisconsin
          Cobalt Corporation - Wisconsin
          Blue Cross & Blue Shield United of Wisconsin - Wisconsin
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 NUMBER OF        7     SOLE VOTING POWER

                        Wisconsin United for Health Foundation, Inc. - 0
   SHARES               Cobalt Corporation - 0
                        Blue Cross & Blue Shield United of Wisconsin - 1,759,325
              --------  --------------------------------------------------------
BENEFICIALLY      8     SHARED VOTING POWER

                        Wisconsin United for Health Foundation, Inc. - 0
  OWNED BY              Cobalt Corporation - 0
                        Blue Cross & Blue Shield United of Wisconsin - 0
              --------  --------------------------------------------------------
    EACH          9     SOLE DISPOSITIVE POWER

                        Wisconsin United for Health Foundation, Inc. - 0
 REPORTING              Cobalt Corporation - 0
                        Blue Cross & Blue Shield United of Wisconsin - 1,759,325
              --------  --------------------------------------------------------
   PERSON        10     SHARED DISPOSITIVE POWER

                        Wisconsin United for Health Foundation, Inc. - 0
    WITH                Cobalt Corporation - 0
                        Blue Cross & Blue Shield United of Wisconsin - 0
--------------------------------------------------------------------------------

                                       2


--------------------------------------------------------------------------------
   11     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          Wisconsin United for Health Foundation, Inc. - 1,759,325
          Cobalt Corporation - 1,759,325
          Blue Cross & Blue Shield United of Wisconsin - 1,759,325
--------  ----------------------------------------------------------------------
   12     CHECK BOX IF THE AGGREGATE AMOUNT IN
          ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)                [ ]
--------  ----------------------------------------------------------------------
   13     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

          13.6%
--------  ----------------------------------------------------------------------
   14     TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

          Wisconsin United for Health Foundation, Inc. - CO
          Cobalt Corporation - CO
          Blue Cross & Blue Shield United of Wisconsin - CO
================================================================================


ITEM 1.   Security and Issuer.

     This statement on Schedule 13D (this "Schedule 13D") relates to the shares
of common stock, no par value per share ("Common Stock"), of American Medical
Security Group, Inc., a Wisconsin corporation (the "Issuer"). The principal
executive offices of the Issuer are located at 3100 AMS Boulevard, Green Bay, WI
54313.

ITEM 2.   Identity and Background.

     (a)-(c)  This statement is being filed by

          (i)   Wisconsin United for Health Foundation, Inc. (the "Foundation")
                10 E. Doty Street, Madison, WI 53703

                The Foundation is a Wisconsin social welfare organization and a
                Wisconsin non-stock corporation.

          (ii)  Cobalt Corporation ("Cobalt") 401 West Michigan Street,
                Milwaukee, WI 53203

                Cobalt is a publicly traded managed care company and a Wisconsin
                corporation.

          (iii) Blue Cross & Blue Shield United of Wisconsin ("BCBSUW") 401 West
                Michigan Street, Milwaukee, WI 53203

                BCBSUW is an insurance company and a Wisconsin corporation.


                                       3



     (d)  During the past five years, none of the reporting persons has been
          convicted in a criminal proceeding.

     (e)  During the past five years, none of the reporting persons has been a
          party to a civil proceeding of a judicial or administrative body of
          competent jurisdiction and as a result of such proceeding was or is
          subject to a judgment, decree or final order enjoining future
          violations of, or prohibiting or mandating activities subject to,
          federal or state securities laws or finding any violation with respect
          to such laws.

ITEM 3.   Source and Amount of Funds or Other Consideration.

     The Foundation and Cobalt became beneficial owners of the Common Stock in
connection with the conversion of BCBSUW from a Wisconsin service insurance
corporation to a Wisconsin stock insurance corporation. BCBSUW previously owned
1,908,025 shares of Common Stock prior to the sale of shares of Common Stock by
BCBSUW described in Item 5(c) hereof, and subsequent to such sale owns 1,759,325
shares of Common Stock, or approximately 13.6% of the issued and outstanding
shares of Common Stock. In connection with the conversion, Cobalt became the
owner of 100% of the issued and outstanding common stock of BCBSUW and the
Foundation became the owner of 77.5% of the issued and outstanding common stock
of Cobalt. Consequently, both the Foundation and Cobalt are deemed to be
beneficial owners of the 1,759,325 shares of Common Stock now owned by BCBSUW.

ITEM 4.   Purpose of Transaction.

     The information set forth in Item 5(c) hereof is incorporated by reference
in response to this Item 4.

     Depending on market conditions and other factors that Cobalt and/or BCBSUW
may deem material to its investment decision, Cobalt and/or BCBSUW may sell
additional shares of Common Stock in the open market or in private transactions
or may otherwise dispose of all or a portion of the shares of Common Stock now
owned by them.

     Except as otherwise set forth herein, none of the reporting persons has any
plans that would result in the occurrence of any of the events set forth in Item
4 of Schedule 13D.

     The Foundation received no proceeds from the sale of shares of Common Stock
by BCBSUW described herein. The Foundation is not responsible for the
completeness or accuracy of the information contained herein regarding Cobalt or
BCBSUW, and has no reason to believe that such information is inaccurate.

ITEM 5. Interests in Securities of the Company.

     (a)  Each member of the Group is deemed to be the beneficial owner of the
          1,759,325 shares of Common Stock owned by BCBSUW which represents
          13.6% of the issued and outstanding Common Stock.

                                       4


     (b)  (i)   Number of shares as to which the Foundation has:

                sole voting power - 0
                shared voting power - 0
                sole dispositive power - 0
                shared dispositive power - 0

          (ii)  Number of shares as to which Cobalt has:

                sole voting power - 0
                shared voting power - 0
                sole dispositive power - 0
                shared dispositive power - 0

          (iii) Number of shares as to which BCBSUW has:

                sole voting power - 1,759,325
                shared voting power - 0
                sole dispositive power - 1,759,325
                shared dispositive power - 0

     (c)  The following is a list of all transactions in the Common Stock by
          BCBSUW during the 60 days preceding the date of Amendment No. 5 to
          this Schedule 13D.

-------------------   ----------------   ---------------   -------------------
Date of Transaction   Number of Shares   Price Per Share   Type of Transaction
-------------------   ----------------   ---------------   -------------------
      9/11/02                 200             $14.97               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02              49,600             $15.00               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02               1,700             $15.01               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02               1,000             $15.02               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02                 800             $15.03               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02                 500             $15.04               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02                 100             $15.05               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02                 200             $15.07               Sale
-------------------   ----------------   ---------------   -------------------
      9/11/02                 900             $15.08               Sale
-------------------   ----------------   ---------------   -------------------
      9/12/02              40,000             $15.00               Sale
-------------------   ----------------   ---------------   -------------------
      9/12/02              13,500             $15.05               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02              15,200             $15.02               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02               4,900             $15.03               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02               3,300             $15.04               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02                 700             $15.05               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02                 600             $15.08               Sale
-------------------   ----------------   ---------------   -------------------
      9/13/02                 500             $15.09               Sale
-------------------   ----------------   ---------------   -------------------
      9/16/02              15,000             $15.00               Sale
-------------------   ----------------   ---------------   -------------------

                                       5


          Following these sales, BCBSUW beneficially owned approximately 13.6%
          of the issued and outstanding Common Stock.

          Except as reported in this Item 5(c), no member of the Group has made
          any transaction in the Common Stock during the past sixty days.

     (d)  Not applicable.

     (e)  Not applicable.


ITEM 6.   Contracts, Arrangements, Understandings or Relationships with Respect
          to Securities of the Company.

     General. On March 22, 2002, BCBSUW sold 1,400,000 shares of Common Stock to
the Issuer pursuant to the terms of a Stock Purchase Agreement, dated as of
March 19, 2002, by and among Cobalt, BCBSUW and the Issuer (the "Purchase
Agreement").

     Board Representation. Pursuant to the Purchase Agreement, the Issuer
appointed Thomas R. Hefty and Kenneth L. Evason to become directors of the
Issuer, effective on March 22, 2002. Mr. Hefty was appointed to the class of
directors whose terms expire at the Issuer's second annual meeting of
shareholders following the Closing Date, and Mr. Evason was appointed to the
class of directors whose terms expire at the Issuer's third annual meeting of
shareholders following the Closing Date. Mr. Hefty resigned effective upon
closing of the June 4, 2002 public offering by BCBSUW of 3,001,500 shares of
Common Stock, and Mr. Evason (or his successor) will resign effective
immediately upon the date that BCBSUW owns less than 10% of the then issued and
outstanding shares of Common Stock.

     The Purchase Agreement also provides that Cobalt and BCBSUW will be
entitled to designate (i) two nominees to the Issuer's Board of Directors (the
"Board") for so long as BCBSUW beneficially owns 20% or more of the then
outstanding shares of Common Stock and (ii) one nominee to the Board for so long
as BCBSUW beneficially owns 10% or more, but less than 20%, of the then issued
and outstanding shares of Common Stock. In each case, such nominee(s) must be
reasonably acceptable to the Issuer, and the Issuer will use its best efforts to
take all action necessary so that such BCBSUW nominees will be nominated for
election or re-election to the Board, as the case may be. If BCBSUW at any time
beneficially owns less than 10% of the then issued and outstanding shares of
Common Stock, then BCBSUW will not be entitled to designate any directors to the
Board, and BCBSUW will cause each BCBSUW-nominated director to immediately
resign from the Board.

     Certain Agreements. In addition to the Board representation rights
described above, and subject to the right of BCBSUW and Cobalt to earlier
terminate such covenants as described below under "Right to Terminate Certain
Covenants," the Purchase Agreement provides that, for so long as BCBSUW shall
have at least one BCBSUW-nominated director on the Board, Cobalt


                                       6


and BCBSUW will not, and will cause their respective directors, officers,
affiliates and, on their behalf, representatives, agents and advisors not to,
directly or indirectly:

o    purchase, offer to purchase or otherwise acquire or offer or agree to
     acquire any shares of Common Stock or other securities of the Issuer which
     are entitled to vote generally for the election of directors, or any
     securities which are convertible or exchangeable into or exercisable for
     any securities of the Issuer which are entitled to vote generally for the
     election of directors (the Common Stock, together with such other
     securities, are referred to herein as "Voting Securities");

o    (i) (a) make, or in any way participate, directly or indirectly, in any
     solicitation of proxies or consents, (b) seek to advise, encourage or
     influence any person with respect to the voting of any Voting Securities,
     or (c) initiate, propose or otherwise solicit shareholders of the Issuer,
     in each case for (1) the election of persons to the Board or (2) the
     approval of shareholder proposals; or (ii) induce or attempt to induce any
     other person to initiate any such solicitation or otherwise communicate
     with the Issuer's shareholders pursuant to Rule 14a-2(a) or (b) under the
     Securities Exchange Act of 1934, as amended;

o    without the prior consent of the Issuer, seek, propose, or make any
     statement that is critical of management of the Issuer or reasonably likely
     to be publicly disclosed with respect to, certain extraordinary corporate
     transactions involving the Issuer;

o    call or seek to have called any meeting of the shareholders of the Issuer;

o    otherwise act to control or seek to control or influence or seek to
     influence the management, Board or policies of the Issuer (other than with
     respect to their Board representation rights under the Purchase Agreement),
     or make any statement that is critical of any of the persons nominated by
     the Board for election as directors of the Issuer;

o    seek representation on the Board, or seek the removal of any member of the
     Board or a change in the composition or size of the Board (other than with
     respect to their Board representation rights under the Purchase Agreement);

o    make any publicly disclosed proposal, comment, statement or communication,
     or make any proposal, comment, statement or communication in a manner that
     would require any public disclosure by the Issuer, BCBSUW, Cobalt or any
     other person, or enter into any discussion with any person, regarding any
     of the foregoing; or

o    have any discussions or communications, or enter into any arrangements,
     understandings or agreements (whether written or oral) with, or advise,
     finance, assist, encourage or act in concert with, any other person in
     connection with any of the foregoing or make any investment in any person
     for the purpose of engaging in any of the foregoing, or take any action
     inconsistent with the foregoing.

                                       7


     Voting. BCBSUW and Cobalt also agreed that, until the date on which BCBSUW
beneficially owns less than 10% of the then issued and outstanding shares of
Common Stock and each BCBSUW-nominated director shall have resigned from the
Board, all of the additional shares of Common Stock beneficially owned by BCBSUW
("Additional Shares") will be present, in person or by proxy, at all meetings of
shareholders of the Issuer at which directors will be elected in order to
participate in a quorum at such meetings, and will be voted on the election of
directors at any such meeting in favor of each of the nominees recommended by
the Board. Notwithstanding the foregoing, (i) BCBSUW may vote Additional Shares
as it determines, in its sole discretion, on any matter other than the election
of directors, and (ii) BCBSUW may vote Additional Shares as it determines, in
its sole discretion, on the election of directors in the event that the Issuer
shall then be in material breach of its obligations under Section 6.01 of the
Purchase Agreement.

     Right to Terminate Certain Covenants. Notwithstanding anything to the
contrary contained in the Purchase Agreement, BCBSUW has the right, effective at
any time after December 31, 2002, upon thirty (30) days' prior written notice to
the Issuer, to terminate the covenants and agreements set forth in Sections 4.01
and 4.02 of the Purchase Agreement and described above under "Certain
Agreements" (other than certain covenants and agreements with respect to the
election of directors, which may not be terminated in any case until after
December 31, 2003). However, if the Issuer is at any time in material breach of
the Purchase Agreement, BCBSUW has the right at any time after the date of the
Purchase Agreement, upon thirty (30) days' prior written notice to the Issuer,
to terminate the covenants and agreements set forth in Sections 4.01 and 4.02 of
the Purchase Agreement and described above under "Certain Agreements" (other
than those covenants which may not be terminated in any case until after
December 31, 2003). Additionally, in the event of any termination of such
covenants under the provisions described in this paragraph, each
BCBSUW-nominated director then serving as a director on the Board will resign
from the Board, effective immediately on the date on which such notice of
termination is given, and BCBSUW's rights to continued Board representation
under the Purchase Agreement will terminate.

     The Foundation is not a party to and did not participate in the negotiation
of the Purchase Agreement. The Foundation is not responsible for the
completeness or accuracy of the information contained herein regarding Cobalt or
BCBSUW, and has no reason to believe that such information is inaccurate.


ITEM 7.   Material to be Filed as Exhibits.

          None.

                                       8


                                    SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, the
undersigned certify that the information set forth in this statement is true,
complete and correct.

                                    WISCONSIN UNITED FOR HEALTH FOUNDATION, INC.



                                    By:   /s/ David Meissner
                                         ---------------------------------------
                                          David Meissner
                                          Vice President

                                    COBALT CORPORATION



                                    By:   /s/ Gail L. Hanson
                                         ---------------------------------------
                                          Gail L. Hanson
                                          Chief Financial Officer

                                    BLUE CROSS & BLUE SHIELD UNITED OF WISCONSIN



                                    By:   /s/ Gail L. Hanson
                                         ---------------------------------------
                                          Gail L. Hanson
                                          Chief Financial Officer


Dated:  September 20, 2002


                                       9