<PAGE>

                                                                     EXHIBIT 4.1

                             STOCKHOLDERS' AGREEMENT

                                      Among

                         CALAMOS ASSET MANAGEMENT, INC.,

                              CALAMOS HOLDINGS LLC,

                         CALAMOS FAMILY PARTNERS, INC.,

                                JOHN P. CALAMOS,

                                NICK P. CALAMOS,

                              JOHN P. CALAMOS, JR.,

                JOHN P. CALAMOS 1985 TRUST DATED AUGUST 21, 1985,

              THE JOHN P. CALAMOS ANNUITY TRUST DATED JUNE 21, 1998

                                       AND

           THE JOHN P. CALAMOS ANNUITY TRUST II DATED NOVEMBER 1, 1998

                          Dated as of October 28, 2004

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                                Table of Contents

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                                          ARTICLE I

                                         DEFINITIONS

SECTION 1.01  Definitions ............................................................    1

SECTION 1.02  Other Definitions ......................................................    4

SECTION 1.03  Interpretation, Certain Definitions ....................................    5

                                          ARTICLE II

                                    TRANSFER RESTRICTIONS

SECTION 2.01  General Restrictions and Exceptions in LLC Agreement ...................    5

SECTION 2.02  First Year Post-IPO Restrictions .......................................    5

SECTION 2.03  Restrictions Following First Anniversary of IPO ........................    6

SECTION 2.04  Certain Exceptions to Transfer Restrictions ............................    6

SECTION 2.05  Requirements for Transfer to Independent CFP Transferee ................    7

SECTION 2.06  Transfers to Persons other than CFP Permitted Transferees ..............    7

SECTION 2.07  Change of Control ......................................................    8

SECTION 2.08  Additional Agreements ..................................................    8

SECTION 2.09  Termination of Article .................................................    8

                                         ARTICLE III

                                    ADDITIONAL AGREEMENTS

SECTION 3.01  Effectiveness of Agreement .............................................    8

SECTION 3.02  Observer Rights ........................................................    8

SECTION 3.03  Reinvestment ...........................................................    9

SECTION 3.04  Further Action .........................................................    9
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                                          ARTICLE IV

                              TERMINATION, AMENDMENT AND WAIVER

SECTION 4.01  Termination ............................................................    9

SECTION 4.02  Effect of Termination ..................................................    9

                                          ARTICLE V

                                        MISCELLANEOUS

SECTION 5.01  Severability ...........................................................   10

SECTION 5.02  Notices ................................................................   10

SECTION 5.03  Amendment; Waiver; Cumulative Remedies .................................   11

SECTION 5.04  Binding Effect .........................................................   12

SECTION 5.05  Counterparts ...........................................................   12

SECTION 5.06  Entire Agreement .......................................................   12

SECTION 5.07  Governing Law; Submission to Jurisdiction; WAIVER OF JURY TRIAL ........   12

SECTION 5.08  Specific Performance ...................................................   13

SECTION 5.09  Expenses ...............................................................   13

SECTION 5.10  No Third Party Beneficiaries ...........................................   13

SECTION 5.11  Assignment .............................................................   13

SECTION 5.12  Headings ...............................................................   13
</TABLE>

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            STOCKHOLDERS' AGREEMENT, dated as of October 28, 2004 (the
"Agreement"), among Calamos Asset Management, Inc., a Delaware corporation (the
"Company"), Calamos Holdings LLC, a Delaware limited liability company ("Calamos
LLC"), Calamos Family Partners, Inc., a Delaware corporation (f/k/a Calamos
Holdings Inc. "Calamos Family Partners"), John P. Calamos, Nick P. Calamos, John
P. Calamos, Jr. (together with John P. Calamos and Nick P. Calamos, the
"Founders" and each, a "Founder"), John P. Calamos, as Trustee of the John P.
Calamos 1985 Trust dated August 21, 1985, Nick P. Calamos, as Trustee of The
John P. Calamos Annuity Trust dated June 21, 1998 and John P. Calamos Jr., as
Trustee of The John P. Calamos Annuity Trust II dated November 1, 1998 (together
with John P. Calamos 1985 Trust dated August 21, 1985 and The John P. Calamos
Annuity Trust dated June 21, 1998, the "Founder Trusts" and each, a "Founder
Trust" and each of John P. Calamos, Nick P. Calamos and John P. Calamos Jr., in
his capacity as Trustee, is hereinafter referred to as a "Initial Founder Trust
Trustee" and collectively they are referred to in such capacity as the "Initial
Founder Trust Trustees").

            WHEREAS, in connection with the IPO (as defined herein), Calamos
Family Partners caused a reorganization of the business conducted by its
subsidiaries as described in the Registration Statement on Form S-1
(Registration No. 333-117847) (the "IPO Registration Statement");

            WHEREAS, the Founders and the Founder Trust Trustees are the
Beneficial Owners (as defined herein) of all the shares of Class A voting common
stock and the shares of Class B non-voting common stock of Calamos Family
Partners;

            WHEREAS, Calamos Family Partners and John P. Calamos are the record
owners of all of the membership units of Calamos LLC and, immediately following
the IPO Closing, Calamos Family Partners and John P. Calamos shall be the record
holders of all of the membership units of Calamos LLC not held of record by the
Company, all as described in the IPO Registration Statement; and

            WHEREAS, in connection with the IPO, Calamos Family Partners, the
Founders and the Founder Trust Trustees have agreed to certain restrictions on
the transfer of their individual or such Founder Trust's interests, as the case
may be, in the Company and Calamos LLC;

            NOW, THEREFORE, in consideration of the premises and the mutual
agreements and covenants hereinafter set forth, the parties hereto hereby agree
as follows:

                                    ARTICLE I

                                   DEFINITIONS

            SECTION 1.01 Definitions. As used in this Agreement, the following
terms shall have the following meanings:

            "Affiliate" has the meaning given such term in the LLC Agreement.

<PAGE>

            "Beneficial Owner" (including the terms "Beneficially Own" and
      "Beneficial Ownership") has the meaning given such term in the LLC
      Agreement. For purposes of this Agreement, a Founder Trust Trustee shall
      be deemed to be the Beneficial Owner of any securities held in such
      Founder Trust until such time as the Founder Trust Trustee ceases to act
      as trustee of such Founder Trust by reason of his death, incapacity,
      resignation or removal.

            "Business Day" has the meaning given such term in the LLC Agreement.

            "CFP Permitted Transferee" has the meaning given such term in the
      LLC Agreement.

            "CFP Transferee" means any CFP Permitted Transferee that becomes the
      Owner of Founders Equity as a result of a Transfer of Ownership of any
      security permitted under this Agreement after the IPO Closing.

            "Class A Common Stock" has the meaning given such term in the
      Company's Certificate of Incorporation, as amended.

            "Class B Common Stock" has the meaning given such term in the
      Company's Certificate of Incorporation, as amended.

            "Class B Directors" has the meaning given such term in the Company's
      Certificate of Incorporation, as amended.

            "Common Stock" means the Class A Common Stock and the Class B Common
      Stock.

            "Control" (including the terms "Controlled by" and "under common
      Control with") has the meaning given such term in the LLC Agreement.

            "Exchange Act" means the Securities Exchange Act of 1934, as
      amended, and all rules and regulations promulgated thereunder.

            "Founders Equity" means with respect to any (i) Founder or Initial
      Founder Trust Trustee, the aggregate number of Membership Units and shares
      of Common Stock Indirectly Beneficially Owned by such Person (whether in
      his individual capacity or as trustee of a Founder Trust) as of the IPO
      Closing plus, in the case of John P. Calamos, the aggregate number of
      Membership Units and shares of Common Stock held of record by him as of
      the IPO Closing (and, in each case, including for purposes hereof any
      shares of Class A Common Stock issued after the date hereof in exchange
      for the surrender of Membership Units or shares of Class B Common Stock
      constituting such Person's Founders Equity) and (ii) with respect to any
      Successor Founder Trust Trustee, the aggregate number of Membership Units
      and shares of Common Stock Indirectly Beneficially Owned by the trustee in
      his capacity as the trustee of such Founder Trust as of the IPO Closing
      (and including for purposes hereof any shares of Class A Common Stock
      issued after the date hereof in exchange for the surrender of Membership
      Units or shares of Class B Common Stock constituting such Person's
      Founders Equity), which in

                                       2
<PAGE>

      the case of clauses (i) and (ii) the parties hereto acknowledge and agree
      shall, as of the date of this Agreement, be as set forth next to their
      name or otherwise indicated on Schedule I hereto. Any Membership Units or
      shares of Common Stock constituting Founders Equity of a Successor Founder
      Trust Trustee Transferred pursuant to a distribution or other payment by
      the Founder Trust to a Founder that was the Initial Founder Trust Trustee
      of such Founder Trust shall be deemed to be "Founders Equity" of such
      Founder effective as of the date that such Founder receives Indirect
      Beneficial Ownership of such securities.

            "Founder Trust Trustee" means with respect to any Founder Trust, the
      Initial Founder Trust Trustee or the Successor Founder Trust Trustee of
      such Founder Trust.

            "Independent CFP Transferee" means, in connection with any Transfer,
      any CFP Transferee that is not Controlled by or under common Control with
      the Person effecting such Transfer. For purposes of this Agreement, a CFP
      Transferee that is Transferred Ownership of securities in his individual
      capacity who, acting in his capacity as trustee, is also the transferor of
      Ownership of such securities shall not be deemed an Independent CFP
      Transferee.

            "Indirect Beneficial Owner" (including the term "Indirectly
      Beneficially Own") means a natural person (including in his capacity as
      trustee) or ultimate parent entity, with respect to Membership Units or
      shares of Common Stock that are not held of record by such Person, that
      Beneficially Owns equity interests (regardless of whether voting or
      non-voting interests) (i) directly in any entity that is the holder of
      record of Membership Units or shares of Common Stock or (ii) indirectly
      through one or more entities that own equity interests (regardless of
      whether voting or non-voting interests) in the entity that is the holder
      of record of Membership Units or shares of Common Stock, and the number of
      Membership Units or shares of Common Stock that such Person shall be
      deemed to "Indirectly Beneficially Own" (even if such Person Beneficially
      Owns (directly or indirectly) less than all the equity interests of the
      record holder of Membership Units or shares of Common Stock but
      nevertheless Controls such record holder) shall be equal to (x) the number
      of Membership Units or shares of Common Stock held by the record holder
      thereof multiplied by (y) such Person's direct or indirect equity interest
      in such record holder.

            "Involuntary Transfer" means a Transfer of Ownership of Membership
      Units or shares of Common Stock to a CFP Permitted Transferee as a result
      of or in connection with the death, disability, termination, bankruptcy,
      insolvency of the transferor or the occurrence of any other event that is
      outside the reasonable control of the transferor (including in connection
      with a CFP Permitted Transferee's exercise of an option to acquire
      securities that is triggered by the occurrence of such death, disability,
      bankruptcy, insolvency or other event).

            "IPO" means the initial public offering of shares of Class A Common
      Stock pursuant to the IPO Registration Statement.

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            "IPO Closing" means the closing of the IPO pursuant to the terms of
      the underwriting agreement entered into by the Company and the
      underwriters referred to in the IPO Registration Statement, as a result of
      which the underwriters shall acquire the shares of Class A Common Stock
      registered pursuant to the IPO Registration Statement (other than any
      shares of Class A Common Stock subject to the underwriters' overallotment
      option), a form of which underwriting agreement is filed as an exhibit to
      the IPO Registration Statement.

            "Law" has the meaning given such term in the LLC Agreement.

            "LLC Agreement" means the Second Amended and Restated Limited
      Liability Company Agreement of Calamos LLC to be effective as of the date
      of the IPO Closing.

            "Membership Unit" has the meaning given such term in the LLC
      Agreement.

            "Observers" means the two individuals identified from time to time
      by Calamos Family Partners (or such other Person as may be designated by
      Calamos Family Partners (or any such designee) in a written notice
      delivered to the Company) pursuant to a written notice delivered to the
      Company to act as observers at meetings of the board of directors of the
      Company pursuant to Section 3.02 of this Agreement.

            "Ownership" (including the term "Own") means Beneficial Ownership or
      Indirect Beneficial Ownership.

            "Person" has the meaning given such term in the LLC Agreement.

            "Restricted Person" means any Person that is not a CFP Permitted
      Transferee.

            "Successor Founder Trust Trustee" means with respect to any Founder
      Trust, any successor trustee or co-trustee appointed after the date hereof
      by reason of the death, incapacity, resignation or removal of the Initial
      Founder Trust Trustee of such Founder Trust.

            "Transfer" (including the term "Transferred") has the meaning given
      such term in the LLC Agreement, provided, that for purposes of this
      Agreement, (i) the appointment of a Successor Founder Trust Trustee shall
      not be considered a Transfer and such Successor Founder Trust Trustee
      shall be subject to the terms of this Agreement as if originally named
      herein, and (ii) a transfer of Beneficial Ownership of securities by a
      Founder to a trust of which such Founder serves as a trustee shall not be
      considered a Transfer of such securities and such securities shall
      continue to be deemed Beneficially Owned by him following such transfer to
      such trust.

            SECTION 1.02 Other Definitions. The meanings of the following terms
can be found in the Sections of this Agreement indicated below:

                                       4
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<TABLE>
<CAPTION>
         TERM                                            SECTION
         ----                                            -------
<S>                                                      <C>
Agreement                                                Preamble
Calamos Family Partners                                  Recitals
Calamos Family Holders                                   5.03
Calamos LLC                                              Preamble
Company                                                  Preamble
Founder                                                  Preamble
Founder Trust                                            Preamble
Initial Founder Trust Trustee                            Preamble
IPO Registration Statement                               Recitals
</TABLE>

            SECTION 1.03 Interpretation, Certain Definitions. When a reference
is made in this Agreement to an Article, Section or Schedule, such reference
shall be to an Article or Section of, or a Schedule to, this Agreement unless
otherwise indicated. The table of contents and headings for this Agreement are
for reference purposes only and shall not affect in any way the meaning or
interpretation of this Agreement. Whenever the words "include", "includes" or
"including" are used in this Agreement, they shall be deemed to be followed by
the words "without limitation." The words "hereof," "herein" and "hereunder" and
words of similar import when used in this Agreement shall refer to this
Agreement as a whole and not to any particular provision of this Agreement. All
terms defined in this Agreement shall have the defined meanings when used in any
certificate or other document made or delivered pursuant hereto unless otherwise
defined therein. The definitions contained in this Agreement are applicable to
the singular as well as the plural forms of such terms and to the masculine as
well as to the feminine and neuter genders of such term. Any statute defined or
referred to herein or in any agreement or instrument that is referred to herein
means such statute as from time to time amended, modified or supplemented,
including (in the case of statutes) by succession of comparable successor
statutes. References to a Person are also to its permitted successors and
assigns. The use of "or" is not intended to be exclusive unless expressly
indicated otherwise.

                                   ARTICLE II

                              TRANSFER RESTRICTIONS

            SECTION 2.01 General Restrictions and Exceptions in LLC Agreement.
(a) Each of Calamos Family Partners, the Founders and the Founder Trust Trustees
and any Independent CFP Transferee, acknowledges the restrictions set forth in
Section 8.08 of the LLC Agreement and covenants and agrees not to take any
action that would be reasonably likely to result in a breach of such section.

            (b) The Company acknowledges and agrees that each of the Founders,
the Founder Trusts and the Founder Trust Trustees (and any CFP Transferee) are
CFP Permitted Transferees for purposes of the LLC Agreement, including Sections
8.08 and 8.09 of the LLC Agreement.

            SECTION 2.02 First Year Post-IPO Restrictions. Except as otherwise
provided in this Agreement and notwithstanding the proviso set forth in Section
8.08 of the LLC Agreement, each of the Founders and the Founder Trust Trustees
covenants and agrees that from

                                       5
<PAGE>

the IPO Closing through the first anniversary of the IPO Closing he shall not
Transfer (i) any of his Founders Equity Beneficially Owned by him or (ii) any
other securities Beneficially Owned by him that represent an Indirect Beneficial
Ownership interest in his Founders Equity.

            SECTION 2.03 Restrictions Following First Anniversary of IPO. (a)
Except as otherwise provided in this Agreement, each of the Founders and the
Founder Trust Trustees covenants and agrees that following the first anniversary
of the IPO Closing until the tenth anniversary of the IPO Closing Date he shall
not Transfer (i) any of his Founders Equity Beneficially Owned by him or (ii)
any other securities Beneficially Owned by him that represent an Indirect
Beneficial Ownership interest in his Founders Equity; provided that
notwithstanding the foregoing each of the Founders and the Founder Trust
Trustees may Transfer to one or more third parties or Independent CFP
Transferees during any 12-month period commencing after the first anniversary of
the IPO Closing Ownership of such number of Membership Units or shares of Common
Stock (subject to Section 2.01) that in the aggregate does not exceed 20% of his
Founders Equity (and in connection therewith Calamos Family Partners or any
other Person, in each case to the extent an Owner of the relevant Founders
Equity, may Transfer Ownership of such Membership Units or shares of Common
Stock) and the parties hereto acknowledge that any such transferees shall take
such securities free and clear of the Transfer restrictions set forth in
Sections 2.02 and 2.03(a) of this Agreement.

            (b) Notwithstanding the proviso set forth in Section 2.03(a), each
of the Founders and the Founder Trust Trustees covenants and agrees that so long
as either John P. Calamos or Nick P. Calamos is employed in the business of
Calamos LLC and its Subsidiaries, he shall not Transfer (i) any Founders Equity
Beneficially Owned by him or (ii) any other securities Beneficially Owned by him
that represent an Indirect Beneficial Ownership interest in Founders Equity, in
each case if such Transfer would result in the Founders and the Founder Trust
Trustees, taken as a whole, Owning less than 30% of the aggregate Founders
Equity; provided that no Founder or Founder Trust Trustee shall be deemed in
breach of this Section 2.03(b) to the extent an Involuntary Transfer of Founders
Equity results in the Founders and the Founder Trust Trustees, taken as a whole,
Owning less than 30% of the aggregate Founders Equity, in which case each of the
Founders covenants and agrees not to Transfer thereafter to a Person other than
one of the other Founders or Founder Trust Trustees Ownership of (x) any
Founders Equity Beneficially Owned by him or (y) any other securities
Beneficially Owned by him that represent an Indirect Beneficial Ownership
interest in Founders Equity

            SECTION 2.04 Certain Exceptions to Transfer Restrictions.
Notwithstanding anything in this Agreement to the contrary, each of Calamos
Family Partners, the Founders and the Founder Trust Trustees and any CFP
Transferee may at any time Transfer any or all Founders Equity Beneficially
Owned by such Person or any or all other securities Beneficially Owned by such
Person that represent an Indirect Beneficial Ownership interest in Founders
Equity:

            (a) to (i) the Company in exchange for shares of Class A Common
      Stock in accordance with the Certificate of Incorporation or (ii) a CFP
      Permitted Transferee (other than an Independent CFP Transferee);

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<PAGE>

            (b) to an Independent CFP Transferee as part of an Involuntary
      Transfer and such Independent CFP Transferee shall take such securities
      free and clear of the Transfer restrictions set forth in Sections 2.02 and
      2.03 of this Agreement;

            (c) in the case of any Founder Trust Trustee or other trustee or
      fiduciary that is a CFP Permitted Transferee, pursuant to the terms of the
      trust agreements governing such Founders Trust or other trusts or
      applicable Law and any Independent CFP Transferee (other than the Initial
      Founder Trust Trustee of such Founder Trust) that is the transferee of
      such securities shall take such securities free and clear of the Transfer
      restrictions set forth in Sections 2.02 and 2.03(a) of this Agreement (any
      such securities Transferred to the Initial Founder Trust Trustee of such
      Founder Trust shall be deemed Founders Equity of such Founder and subject
      to the Transfer restrictions set forth in Sections 2.02 and 2.03 of this
      Agreement);

            (d) in connection with any merger or consolidation of Calamos LLC or
      the Company, or any transaction having the same effect, that is approved
      in accordance with the By-Laws, as amended, of the Company; and

            (e) with the prior written consent of the Company, which must be
      authorized by a resolution of the board of directors of the Company
      adopted by a majority of the independent directors.

            SECTION 2.05 Requirements for Transfer to Independent CFP
Transferee. Each Transfer of Ownership of Founders Equity to an Independent CFP
Transferee shall be subject to the following requirements:

            (a) such intended transferee complies with applicable Law; and

            (b) (i) such intended transferee delivers to the parties hereto
      written notice of such Transfer and (ii) if such intended transferee is
      not a signatory to this Agreement, such intended transferee executes and
      delivers an instrument in form and substance reasonably satisfactory to
      the Company accepting and agreeing to be bound by all the terms and
      conditions of this Agreement as if such intended transferee in its
      capacity as an Independent CFP Transferee had been a signatory to this
      Agreement.

Following satisfaction of such requirements, such Independent CFP Transferee
shall be deemed a party to this Agreement as if such Independent CFP Transferee
had been a signatory to this Agreement, and such Independent CFP Transferee
shall be entitled to all applicable rights under this Agreement.

            SECTION 2.06 Transfers to Persons other than CFP Permitted
Transferees. In the event that Beneficial Ownership of Membership Units or
shares of Class B Common Stock is Transferred to any Person that is not a CFP
Permitted Transferee, each of the parties to this Agreement covenants and agrees
to use its reasonable best efforts to ensure that such Membership Units or
shares of Class B Common Stock cease to be Beneficially Owned by a Restricted
Person, including using its reasonable best efforts to cause (a) any such
Membership Units or shares of Class B Common Stock that may be owned of record
by Calamos Family Partners (or such other Person through which a Restricted
Person may Beneficially Own

                                       7
<PAGE>

Membership Units or shares of Class B Common Stock) to be exchanged promptly for
shares of Class A Common Stock and (b) Calamos Family Partners (or such other
Person through which a Restricted Person may Beneficially Own Membership Units
or shares of Class B Common Stock) to distribute such shares of Class A Common
Stock to such Restricted Person. Until such time as any such Membership Units or
shares of Class B Common Stock cease to be Beneficially Owned by a Restricted
Person, the record holder of such Membership Units or shares of Class B Common
Stock that are Beneficially Owned by such Restricted Person shall not be
entitled to vote any such securities and such securities shall not be taken into
account for purposes of determining the number of votes to which such holder is
entitled pursuant to the Certificate of Incorporation or the By-Laws, as
amended, of the Company.

            SECTION 2.07 Change of Control. Notwithstanding anything in this
Agreement to the contrary, each of Calamos Family Partners, the Founders and the
Founder Trust Trustees (and any CFP Transferee) may at any time (whether acting
separately or as a group) in any transaction or series of related transactions
Transfer Beneficial Ownership of 40% or more of the aggregate Founders Equity to
any Person or group that is not Controlled by or under common Control with a CFP
Permitted Transferee so long as such Founders Equity is Transferred in the form
of shares of Class A Common Stock consistent with the terms of the LLC Agreement
and the Certificate of Incorporation, as amended, of the Company, and such
Person shall take such securities free and clear of the Transfer restrictions
set forth in this Agreement.

            SECTION 2.08 Additional Agreements. Each party hereto that Controls
any Person that is the Beneficial Owner of Founders Equity Indirectly
Beneficially Owned by another party to this Agreement covenants and agrees not
to take any action that would be reasonably likely to result in a breach of this
Article II by such other party.

            SECTION 2.09 Termination of Article. All rights and obligations of
the parties under this Article II shall terminate upon the earlier of (a) 10:00
a.m. New York time on the tenth anniversary of the IPO Closing and (b) the
termination of this Agreement in accordance with Section 4.01.

                                   ARTICLE III

                              ADDITIONAL AGREEMENTS

            SECTION 3.01 Effectiveness of Agreement. Articles II and III of this
Agreement shall become effective only upon the IPO Closing.

            SECTION 3.02 Observer Rights. The parties hereto covenant and agree
that for so long as shares of Class B Common Stock remain outstanding the
Company shall use its reasonable best efforts to ensure that each of the
Observers be provided with notice of all meetings of the board of directors of
the Company as if such Observer was a director and be permitted to attend all
meetings of the board of directors to the same extent and as if such Observer
was a Class B Director (including telephonic or similar meetings). The parties
hereto acknowledge that the Observers shall not attend any meeting of the
Company's board of directors (or portion thereof) to the extent such meeting is
restricted to the independent directors

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<PAGE>

and that under no circumstances shall the Observers be entitled to vote at any
meeting of the Company's board of directors.

            SECTION 3.03 Reinvestment. Each of Calamos Family Partners, the
Founders and the Founder Trust Trustees covenants and agrees (a) to invest, or
use its reasonable best efforts to cause to be invested, in investment products
offered or managed by the Company, Calamos LLC or any of their subsidiaries at
least 50% of the net proceeds (after taking into account all taxes, including
distributions made by Calamos Family Partners in respect thereof, and fees or
expenses incurred by such parties and their Affiliates in connection with the
IPO) from Calamos Family Partners' sale of Membership Units to the Company in
connection with the IPO (including any Membership Units sold as a result of the
exercise by the underwriters of their overallotment option) and (b) to maintain
invested, or use its reasonable best efforts to cause to be maintained invested,
such proceeds in investment products offered or managed by the Company, Calamos
LLC or any of their subsidiaries through the second anniversary of the IPO
Closing.

            SECTION 3.04 Further Action. Each party hereto shall use its
reasonable best efforts to take, or cause to be taken, all appropriate action,
do or cause to be done all things necessary, proper or advisable under
applicable Law, and execute and deliver such documents and other papers as may
be reasonably required to carry out the provisions of this Agreement.

                                   ARTICLE IV

                        TERMINATION, AMENDMENT AND WAIVER

            SECTION 4.01 Termination. This Agreement shall terminate only on the
earlier to occur of:

            (a) the expiration of (i) all rights created hereunder and (ii) all
      statutes of limitations applicable to the enforcement of claims hereunder;

            (b) execution and delivery of a written agreement to that effect by
      (i) the Founders, Founder Trust Trustees, and Independent CFP Transferees
      (if any) that have any rights or obligations under this Agreement and (ii)
      the Company (which must be authorized by a resolution of the board of
      directors of the Company adopted by a majority of the independent
      directors); and

            (c) November 5, 2004, if the IPO Closing shall not have occurred for
      any reason on or prior to such date.

            SECTION 4.02 Effect of Termination. In the event of termination of
this Agreement as provided in Section 4.01, this Agreement shall forthwith
become void and there shall be no liability on the part of any party hereto,
except with respect to Section 5.09, which shall survive any termination of this
Agreement, and except that nothing herein shall relieve any party from liability
for any breach of this Agreement occurring prior to such termination.

                                       9
<PAGE>

                                    ARTICLE V

                                  MISCELLANEOUS

            SECTION 5.01 Severability. If any term or other provision of this
Agreement is held to be invalid, illegal or incapable of being enforced by any
rule of Law, or public policy, all other conditions and provisions of this
Agreement shall nevertheless remain in full force and effect so long as the
economic or legal substance of the transactions is not affected in any manner
materially adverse to any party. Upon a determination that any term or other
provision is invalid, illegal or incapable of being enforced, the parties hereto
shall negotiate in good faith to modify this Agreement so as to effect the
original intent of the parties as closely as possible in a mutually acceptable
manner in order that the transactions contemplated hereby be consummated as
originally contemplated to the fullest extent possible.

            SECTION 5.02 Notices. All notices, requests, claims, demands and
other communications hereunder shall be in writing and shall be given (and shall
be deemed to have been duly given upon receipt) by delivery in person, by
courier service, by fax or by registered or certified mail (postage prepaid,
return receipt requested) to the respective parties at the following addresses
(or at such other address for a party as shall be specification notice given in
accordance with this Section 5.02):

            (a) if to the Company:

            Calamos Asset Management, Inc
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: James S. Hamman, Jr.

            (b) if to Calamos LLC:

            Calamos Holdings LLC
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: James S. Hamman, Jr.

            (c) if to Calamos Family Partners:

            Calamos Family Partners
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

                                       10
<PAGE>

            (d) if to John P. Calamos:

            John P. Calamos
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

            (e) if to Nick P. Calamos:

            Nick P. Calamos
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

            (f) if to John P. Calamos, Jr.:

            John P. Calamos, Jr.
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

            (g) if to John P. Calamos 1985 Trust dated August 21, 1985:

            John P. Calamos 1985 Trust dated August 21, 1985
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

            (h) if to The John P. Calamos Annuity Trust dated June 21, 1998:

            The John P. Calamos Annuity Trust dated June 21, 1998
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

            (i) if to The John P. Calamos Annuity Trust II dated November 1,
            1998:

            The John P. Calamos Annuity Trust II dated November 1, 1998
            1111 E. Warrenville Road
            Naperville, Illinois
            Facsimile: (630) 245-7511
            Attention: John P. Calamos

                                       11
<PAGE>

            SECTION 5.03 Amendment; Waiver; Cumulative Remedies. This Agreement
may be amended, and any provision hereof may be waived, only by an instrument in
writing signed by the Company (which must be authorized by a resolution of the
board of directors of the Company adopted by a majority of the independent
directors); provided, however, that if any amendment, or waiver of any provision
hereof, would adversely affect the rights of any of the Founders, the Founder
Trust Trustees or any Independent CFP Transferee (collectively, the "Calamos
Family Holders"), such amendment, or waiver of any provision hereof, shall not
be effective as to any Calamos Family Holder unless consented to in writing by a
majority in interest of the Calamos Family Holders (based on such Persons'
Indirect Beneficial Ownership of Membership Units). Each of the parties hereto
shall be bound by any amendment or waiver effected in accordance with this
Section 5.03, whether or not such Person has consented to such amendment or
waiver. Upon the effectuation of each such waiver or amendment, the Company
shall promptly give written notice thereof to the parties hereto who have not
previously consented thereto in writing. Any waiver of any term or condition
shall not be construed as a waiver of any subsequent breach or a subsequent
waiver of the same term or condition, or a waiver of any other term or condition
of this Agreement. The failure of any party to assert any of its rights
hereunder shall not constitute a waiver of any of such rights. The rights and
remedies provided by this Agreement are cumulative and the use of any one right
or remedy by any party shall not preclude or waive its right to use any or all
other remedies. Said rights and remedies are given in addition to any other
rights the parties may have by Law.

            SECTION 5.04 Binding Effect. This Agreement shall be binding upon
and inure to the benefit of all of the parties and, to the extent permitted or
contemplated by this Agreement, their successors, executors, administrators,
heirs, legal representatives and assigns.

            SECTION 5.05 Counterparts. This Agreement may be executed and
delivered (including by facsimile transmission) in one or more counterparts, and
by the different parties hereto in separate counterparts, each of which when
executed and delivered shall be deemed to be an original but all of which taken
together shall constitute one and the same agreement. Copies of executed
counterparts transmitted by telecopy or other electronic transmission service
shall be considered original executed counterparts for purposes of this Section
5.05.

            SECTION 5.06 Entire Agreement. This Agreement and the LLC Agreement
constitute the entire agreement among the parties hereto pertaining to the
subject matter hereof and thereof and supersede all prior agreements and
undertakings pertaining thereto.

            SECTION 5.07 Governing Law: Submission to Jurisdiction: WAIVER OF
JURY TRIAL, (a) This Agreement shall be governed by, and construed in accordance
with, the laws of the State of Illinois.

            (b) Any claim, action, suit or proceeding seeking to enforce any
provision of, or based on any matter arising out of or in connection with, this
Agreement or the transactions contemplated hereby shall be heard and determined
in any Illinois state or federal court sitting in Chicago, Illinois, Cook
County, and each of the parties hereto hereby consents to the exclusive
jurisdiction of such courts (and of the appropriate appellate courts therefrom
in any such claim, action, suit or proceeding) and irrevocably waives, to the
fullest extent permitted by law, any

                                       12
<PAGE>

objection which it may now or hereafter have to the laying of venue of any such
claim, action, suit or proceeding in any such court or that any such claim,
action, suit or proceeding which is brought in any such court has been brought
in an inconvenient forum.

            (c) EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES ALL RIGHT TO TRIAL
BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM (WHETHER BASED IN CONTRACT,
TORT OR OTHERWISE) ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE ACTIONS
OF ANY PARTY IN THE NEGOTIATION, ADMINISTRATION, PERFORMANCE AND ENFORCEMENT
THEREOF.

            SECTION 5.08 Specific Performance. The parties hereto agree that
irreparable damage would occur in the event any provision of this Agreement was
not performed in accordance with the terms hereof and that the parties hereto
shall be entitled to specific performance of the terms hereof, in addition to
any other remedy at Law or in equity.

            SECTION 5.09 Expenses. The Company shall pay all reasonable expenses
and legal fees incurred by the parties hereto in connection with the
negotiation, execution and delivery of this Agreement.

            SECTION 5.10 No Third Party Beneficiaries. This Agreement shall be
binding upon and inure solely to the benefit of the parties hereto and their
permitted assigns and successors, and nothing herein, express or implied, is
intended to or shall confer upon any other Person, any legal or equitable right,
benefit or remedy of any nature whatsoever under or by reason of this Agreement.

            SECTION 5.11 Assignment. This Agreement may not be assigned by any
party hereto, by operation of Law or otherwise, without the express written
consent of each party hereto, except in connection with any Transfer permitted
under Article II of Ownership of Founders Equity to an Independent CFP
Transferee.

            SECTION 5.12 Headings. The headings and subheadings in this
Agreement are included for convenience and identification only and are in no way
intended to describe, interpret, define or limit the scope, extent or intent of
this Agreement or any provision hereof.

                                       13
<PAGE>

            IN WITNESS WHEREOF, the parties hereto have entered into this
Agreement or have caused this Agreement to be duly executed by their respective
authorized officers, in each case as of the date first above stated.

                                   CALAMOS ASSET MANAGEMENT, INC.

                                   By: /s/ James S. Hamman Jr.
                                      -------------------------------
                                   Name: James S. Hamman Jr.
                                   Title: Executive Vice President

                                   CALAMOS HOLDINGS LLC
                                   By Calamos Family Partners, Inc., as Manager

                                   By: /s/ John P. Calamos
                                      -------------------------------------
                                   Name : John P. Calamos
                                   Title: President

                                   CALAMOS FAMILY PARTNERS, INC.

                                   By: /s/ Nick P. Calamos
                                      --------------------------------------
                                   Name: Nick P. Calamos
                                   Title: Senior Executive Vice President

                                   /s/ John P. Calamos
                                   -----------------------------------------
                                   John P. Calamos

                                   /s/ Nick P. Calamos
                                   -----------------------------------------
                                   Nick P. Calamos

<PAGE>

                                   /s/ John P. Calamos Jr.
                                   ----------------------------------------
                                   John P. Calamos Jr.

                                   /s/ John P. Calamos
                                   ----------------------------------------
                                   John P. Calamos, as Trustee of the
                                   John P. Calamos 1985 Trust Dated August 21,
                                   1985, and not individually

                                   /s/ Nick P. Calamos
                                   ----------------------------------------
                                   Nick P. Calamos, as Trustee of The John
                                   P. Calamos Annuity Trust Dated June 21, 1998,
                                   and not individually

                                   /s/ John P. Calamos
                                   ----------------------------------------
                                   John P. Calamos, Jr., as Trustee of The
                                   John P. Calamos Annuity Trust II Dated
                                   November 1, 1998, and not individually

<PAGE>

SCHEDULE I

                                FOUNDERS EQUITY

<TABLE>
<CAPTION>
                                                                                 TOTAL MEMBERSHIP
                                                                                UNITS AND SHARES OF
                                                       SHARES OF CLASS B           CLASS B COMMON
         NAME                      MEMBERSHIP UNITS      COMMON STOCK                  STOCK
         ----                      ----------------    -----------------        -------------------
<S>                                <C>                 <C>                      <C>
John P. Calamos(1)                       48,534,080               62.935             48,534,142.935
                                   ----------------    -----------------        -------------------
Nick P. Calamos(2)                       24,929,280               32.460             24,929,312.460
                                   ----------------    -----------------        -------------------
John P. Calamos, Jr.(3)                   3,536,640                4.605              3,536,644.605
                                   ----------------    -----------------        -------------------
Total ..................                 77,000,000              100.000             77,000,100.000
                                   ================    =================        ===================
</TABLE>

-------------------
(1)   Includes 200,000 Membership Units held of record by John P. Calamos and
      40,227,840 Membership Units and 52.38 shares of Common Stock Indirectly
      Beneficially Owned by John P. Calamos as the Initial Founder Trust Trustee
      of the John P. Calamos 1985 Trust Dated August 21, 1985.

(2)   Includes 3,421,440 Membership Units and 4,455 shares of Common Stock
      Indirectly Beneficially Owned by Nick P. Calamos as the Initial Founder
      Trust Trustee of The John P. Calamos Annuity Trust Dated June 21, 1998.

(3)   Includes 3,421,440 Membership Units and 4,455 shares of Common Stock
      Indirectly Beneficially Owned by John P. Calamos, Jr. as the Initial
      Founder Trust Trustee of The John P. Calamos Annuity Trust II Dated
      November 1, 1998.