<DOCUMENT>
<TYPE>SC 13D/A
<SEQUENCE>1
<FILENAME>sch13d-a.txt
<DESCRIPTION>SC 13D/A
<TEXT>
<PAGE>


CUSIP No. 45031W 10 7                                               Page 1 of 11

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

                                 SCHEDULE 13D/A
                               AMENDMENT NUMBER 4

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934

                              I-Sector Corporation
 ------------------------------------------------------------------------------
                                (Name of Issuer)

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

                                   45031W 10 7
                    ----------------------------------------
                                 (CUSIP Number)

                          PEAK6 Capital Management, LLC
                        209 S. LaSalle Street, Suite 200
                             Chicago, Illinois 60604
 ------------------------------------------------------------------------------
   (Name, Address and Telephone Number of Person Authorized to Receive Notices
                               and Communications)

                               September 25, 2003
          ------------------------------------------------------------
             (Date of Event which Requires Filing of this Statement

If the filing person has previously filed a statement on Schedule 13G to report
the acquisitions which is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(b)(3) or (4), check the following box / /.

NOTE: Six copies of this statement, including all exhibits, should be filed with
the Commission. See Rule 13d-1(a) for other parties to whom copies are to be
sent.

*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
disclosures provided in a prior cover page.

The information required on 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>

CUSIP No. 45031W 10 7                                               Page 2 of 11

                                  SCHEDULE 13D

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

                                Jennifer J. Just
================================================================================
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  [x]
                                                                 (b)  [_]

================================================================================
3    SEC USE ONLY



================================================================================
4    SOURCE OF FUNDS*


     WC
================================================================================
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(E)                                   [_]



================================================================================
6    CITIZENSHIP OR PLACE OF ORGANIZATION


     United States citizen
================================================================================
               7    SOLE VOTING POWER

  NUMBER OF

   SHARES      =================================================================
               8    SHARED VOTING POWER
BENEFICIALLY

  OWNED BY     258,500 shares
               =================================================================
    EACH       9    SOLE DISPOSITIVE POWER

  REPORTING

   PERSON      =================================================================
               10   SHARED DISPOSITIVE POWER
    WITH

               258,500 shares
================================================================================
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON


     258,500 shares
================================================================================
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [_]

================================================================================
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)


     7.1%
================================================================================
14   TYPE OF REPORTING PERSON


     IN







<PAGE>


CUSIP No. 45031W 10 7                                               Page 3 of 11

                                  SCHEDULE 13D

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

                               Matthew N. Hulsizer
================================================================================
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  [x]
                                                                 (b)  [_]

================================================================================
3    SEC USE ONLY



================================================================================
4    SOURCE OF FUNDS*


     WC
================================================================================
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(E)                                   [_]



================================================================================
6    CITIZENSHIP OR PLACE OF ORGANIZATION


     United States citizen
================================================================================
               7    SOLE VOTING POWER

  NUMBER OF

   SHARES      =================================================================
               8    SHARED VOTING POWER
BENEFICIALLY

  OWNED BY     258,500 shares
               =================================================================
    EACH       9    SOLE DISPOSITIVE POWER

  REPORTING

   PERSON      =================================================================
               10   SHARED DISPOSITIVE POWER
    WITH

               258,500 shares
================================================================================
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON


     258,500 shares
================================================================================
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [_]

================================================================================
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)


     7.1%
================================================================================
14   TYPE OF REPORTING PERSON


     IN





<PAGE>


CUSIP No. 45031W 10 7                                               Page 4 of 11

                                  SCHEDULE 13D

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

                          PEAK6 Capital Management, LLC
================================================================================
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  [x]
                                                                 (b)  [_]

================================================================================
3    SEC USE ONLY



================================================================================
4    SOURCE OF FUNDS*


     WC
================================================================================
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(E)                                   [_]



================================================================================
6    CITIZENSHIP OR PLACE OF ORGANIZATION


     Delaware
================================================================================
               7    SOLE VOTING POWER

  NUMBER OF
                    258,500 shares
   SHARES      =================================================================
               8    SHARED VOTING POWER
BENEFICIALLY

  OWNED BY
               =================================================================
    EACH       9    SOLE DISPOSITIVE POWER

  REPORTING
                    258,500 shares
   PERSON      =================================================================
               10   SHARED DISPOSITIVE POWER
    WITH


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


     258,500 shares
================================================================================
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [_]

================================================================================
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)


     7.1%
================================================================================
14   TYPE OF REPORTING PERSON


     BD





<PAGE>


CUSIP No. 45031W 10 7                                               Page 5 of 11

                                  SCHEDULE 13D

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

                             PEAK6 Investments, L.P.
================================================================================
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  [x]
                                                                 (b)  [_]

================================================================================
3    SEC USE ONLY



================================================================================
4    SOURCE OF FUNDS*


     WC
================================================================================
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(E)                                   [_]



================================================================================
6    CITIZENSHIP OR PLACE OF ORGANIZATION


     Delaware
================================================================================
               7    SOLE VOTING POWER

  NUMBER OF

   SHARES      =================================================================
               8    SHARED VOTING POWER
BENEFICIALLY

  OWNED BY          258,500 shares
               =================================================================
    EACH       9    SOLE DISPOSITIVE POWER

  REPORTING

   PERSON      =================================================================
               10   SHARED DISPOSITIVE POWER
    WITH

                    258,500 shares
================================================================================
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON


     258,500 shares
================================================================================
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [_]

================================================================================
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)


     7.1%
================================================================================
14   TYPE OF REPORTING PERSON


     PN








<PAGE>


CUSIP No. 45031W 10 7                                               Page 6 of 11

                                  SCHEDULE 13D

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

                                   PEAKS6, LLC
================================================================================
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  [x]
                                                                 (b)  [_]

================================================================================
3    SEC USE ONLY



================================================================================
4    SOURCE OF FUNDS*


     WC
================================================================================
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDING IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(E)                                   [_]



================================================================================
6    CITIZENSHIP OR PLACE OF ORGANIZATION


     Delaware
================================================================================
               7    SOLE VOTING POWER

  NUMBER OF

   SHARES      =================================================================
               8    SHARED VOTING POWER
BENEFICIALLY

  OWNED BY          258,500 shares
               =================================================================
    EACH       9    SOLE DISPOSITIVE POWER

  REPORTING

   PERSON      =================================================================
               10   SHARED DISPOSITIVE POWER
    WITH

                    258,500 shares
================================================================================
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON


     258,500 shares
================================================================================
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [_]

================================================================================
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)


     7.1%
================================================================================
14   TYPE OF REPORTING PERSON


     OO







<PAGE>

CUSIP No. 45031W 10 7                                               Page 7 of 11


                                 SCHEDULE 13-D/A
                               Amendment Number 4
                              I Sector Corporation
                Filed by PEAK6 Capital Management, LLC ("PEAK6"),
               PEAK6 Investments, L.P. ("LP"), PEAK6, LLC ("LLC"),
         Jennifer J. Just ("Just"), and Matthew N. Hulsizer ("Hulsizer")


Items 3-5 Inclusive for PEAK6:

Item 3.           Source and Amount of Funds or Other Considerations:

                  All acquisitions of the common stock of the Issuer were
                  acquired by PEAK6 using working capital funds.

Item 4.           Purpose of Transaction:

                  Investment purposes. PEAK6 does have an intent to acquire
                  additional securities of the Issuer if such additional
                  securities become available at a price PEAK6 considers
                  reasonable.

Item 5.           Interest in Securities of the Issuer.

                  (a) PEAK6 owns 258,500 shares of Issuer directly, which is
                      7.1% of the outstanding common stock of Issuer.

                  (b) PEAK6 has sole voting power and sole dispositive power
                      with respect to such 258,500 shares of common stock of
                      Issuer.

                  (c) In the past sixty days, PEAK6 has made the following open
                      market transactions in the Issuer's stock, all effectuated
                      in their own account located in Chicago, Illinois:

                  Sales
                  DATE - 2003               # OF SHARES            SHARE PRICE
                  -----------               -----------            -----------

                  September 17              2,200                  $2.99
                  September 17              100                    $2.99
                  September 17              100                    $2.99
                  September 17              400                    $2.99
                  September 17              100                    $2.99
                  September 23              24,300                 $3.1976
                  September 24              50,000                 $3.6146
                  September 25              500                    $4.2
                  September 25              500                    $4.2
                  September 25              500                    $4.2
                  September 25              500                    $4.2
                  September 25              300                    $4.2
                  September 25              6,000                  $4.4
                  September 25              1,000                  $4.25
                  September 25              1,000                  $4.25
                  September 25              1,000                  $4.25
                  September 25              700                    $4.33
                  September 25              200                    $4.33



<PAGE>

CUSIP No. 45031W 10 7                                               Page 8 of 11




Items 3-5 Inclusive for the LP.

Item 3.           Source and Amount of Funds or Other Considerations.

                  The LP indirectly owns the 258,500 shares of Issuer owned by
                  PEAK6 by virtue of directly owning 100.00% of the membership
                  interests of PEAK6 and being the managing member of PEAK6. See
                  PEAK6's response to Item 3 herein.

Item 4.           Purpose of Transaction.

                  The LP acquired its shares of common stock of Issuer for the
                  same purposes as PEAK6. See PEAK6's response to Item 4 herein.

Item 5.           Interest in Securities of the Issuer.

                  (a)      By virtue of owning 100.00% of the outstanding
                           membership interests of PEAK6, the LP beneficially
                           owns the 258,500 shares of common stock of Issuer
                           owned by PEAK6, which is 7.1% of the outstanding
                           shares of Issuer.

                  (b)      By virtue of owning 100.00% of the outstanding
                           membership interests of PEAK6, the LP has shared
                           voting power and shared dispositive power with
                           respect to the 258,500 shares of common stock of
                           Issuer owned by PEAK6.

                  (c)      See PEAK6's response to Item 5(c) herein.

Items 3-5 Inclusive for the LLC.

Item 3.           Source and Amount of Funds or Other Considerations.

                  The LLC indirectly owns the 258,500 shares of Issuer owned by
                  PEAK6 by virtue of directly owning 82% of the LP and being the
                  general partner of the LP. See PEAK6's response to Item 3
                  herein.

Item 4.           Purpose of Transaction.

                  The LLC acquired its shares of common stock of Issuer for the
                  same purposes as PEAK6. See PEAK6's response to Item 4 herein.

Item 5.           Interest in Securities of the Issuer.

                  (a)      By virtue of owning 82% of the LP, and all votes of
                           the LP, the LLC beneficially controls the 258,500
                           shares of common stock of Issuer owned by PEAK6,
                           which is 7.1% of the outstanding shares of Issuer.

                  (b)      By virtue of owning 82% of the LP, the LLC has shared
                           voting power and shared dispositive power with
                           respect to the 258,500 shares of common stock of
                           Issuer owned by PEAK6.

                  (c)      See PEAK6's response to Item 5(c) herein.



<PAGE>

CUSIP No. 45031W 10 7                                               Page 9 of 11



Items 3-5 Inclusive for Just.

Item 3.           Source and Amount of Other Considerations.

                  Just is a managing member of the LLC. See PEAK6's and LP's
                  responses to Item 3 herein.

Item 4.           Purpose of Transaction.

                  Just acquired her shares of common stock of Issuer for the
                  same purposes as PEAK6. See response of PEAK6 to Item 4
                  herein.

Item 5.           Interest in Securities of the Issuer.

                  (a)      By virtue of being a managing member of LLC, Just
                           beneficially controls the 258,500 shares of common
                           stock of Issuer owned by PEAK6. The LLC is the
                           general partner of the LP, which owns 100.00% of the
                           membership interests of PEAK6.

                  (b)      By virtue of being a managing member of the LLC, Just
                           has shared voting power and shared dispositive power
                           with respect to the 258,500 shares of common stock of
                           Issuer owned by PEAK6.

Items 3-5 Inclusive for Hulsizer.

Item 3.           Sources and Amount of Funds or Other Consideration.

                  Hulsizer is a managing member of the LLC. See
                  responses of PEAK6 to Item 3 herein.

Item 4.           Purpose of the Transaction.

                  Hulsizer acquired the shares of common stock of Issuer for the
                  same purposes as PEAK6. See response of PEAK6 to Item 4
                  herein.

Item 5.           Interest in Securities of the Issuer.

                  (a)      By virtue of being a managing member of the LLC,
                           Hulsizer beneficially controls the 258,500 shares of
                           common stock of Issuer owned by PEAK6. The LLC is the
                           general partner of the LP, which owns 100.00% of
                           PEAK6.

                  (b)      By virtue of being a managing member of the LLC,
                           Hulsizer has shared voting power and shared
                           dispositive power with respect to the 258,500 shares
                           of common stock of Issuer owned by PEAK6.

                  (c)      See PEAK6's response to Item 5(c) herein.


A joint filing statement is filed as an exhibit to this Schedule 13D/A.





<PAGE>


CUSIP No. 45031W 10 7                                              Page 10 of 11


Signatures.

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

October 9, 2003

                                        PEAK6 CAPITAL MANAGEMENT, LLC


                                        By:  PEAK6 Investments, L.P.,
                                             its managing member

                                        By:  PEAK6, LLC, its general partner

                                        By:    /s/ Jennifer J. Just
                                             --------------------------
                                               Jennifer J. Just
                                               Managing Member

                                        By:    /s/ Matthew N. Hulsizer
                                             --------------------------
                                               Matthew N. Hulsizer
                                               Managing Member

                                        PEAK6 INVESTMENTS, L.P.

                                        By:  PEAK6, LLC, its general partner

                                        By:    /s/ Jennifer J. Just
                                             --------------------------
                                               Jennifer J. Just
                                               Managing Member

                                        By:     /s/ Matthew N. Hulsizer
                                             --------------------------
                                               Matthew N. Hulsizer
                                               Managing Member


                                        PEAK6, LLC

                                        By:     /s/ Jennifer J. Just
                                             --------------------------
                                               Jennifer J. Just
                                               Managing Member

                                        By:     /s/ Matthew N. Hulsizer
                                             --------------------------
                                               Matthew N. Hulsizer
                                               Managing Member



                                          /s/  Jennifer J. Just
                                        -------------------------------
                                        Jennifer J. Just


                                          /s/  Matthew N. Hulsizer
                                        -------------------------------
                                        Matthew N. Hulsizer



<PAGE>


CUSIP No. 45031W 10 7                                              Page 11 of 11


                            EXHIBIT TO SCHEDULE 13D/A
                               AMENDMENT NUMBER 4
                                       OF
                      JENNIFER J. JUST, MATTHEW N. HULSIZER
                    PEAK6, LLC, PEAK6 CAPITAL MANAGEMENT, LLC
                           AND PEAK6 INVESTMENTS, L.P.

                             JOINT FILING AGREEMENT

         PEAK6 Capital Management, LLC ("PEAK6"), PEAK6 Investments, L.P.
("LP"), PEAK6, LLC ("LLC"), Jennifer J. Just ("Just"), and Matthew N. Hulsizer
("Hulsizer") hereby agree that the Schedule 13D (as amended to date) to which
this statement is attached is filed on behalf of PEAK6, the LP, the LLC, Just,
and Hulsizer, and that any amendments to this Schedule 13D may be filed on
behalf of PEAK6, the LP, the LLC, Just and Hulsizer.

                                          PEAK6 CAPITAL MANAGEMENT, LLC

                                          By:  PEAK6 INVESTMENTS, L.P.,
                                                its managing member

                                          By:  PEAK6, LLC, its general partner

                                          By:    /s/ Jennifer J. Just
                                               -------------------------
                                                Jennifer J. Just
                                                Managing Member

                                          By:    /s/ Matthew N. Hulsizer
                                               -------------------------
                                                Matthew N. Hulsizer
                                                Managing Member

                                          PEAK6 INVESTMENTS, L.P.

                                          By:  PEAK6, LLC, its general partner

                                          By:    /s/ Jennifer J. Just
                                               -------------------------
                                                Jennifer J. Just
                                                Managing Member

                                          By:    /s/ Matthew N. Hulsizer
                                               -------------------------
                                                Matthew N. Hulsizer
                                                Managing Member

                                          PEAK6, LLC

                                          By:    /s/ Jennifer J. Just
                                               -------------------------
                                                Jennifer J. Just
                                                Managing Member

                                          By:    /s/ Matthew N. Hulsizer
                                               -------------------------
                                                Matthew N. Hulsizer
                                                Managing Member

                                            /s/ Jennifer J. Just
                                          ------------------------------
                                          Jennifer J. Just

                                            /s/ Matthew N. Hulsizer
                                          ------------------------------
                                          Matthew N. Hulsizer








</TEXT>
</DOCUMENT>