[CALAMOS INVESTMENTS(R) letterhead]

March 15, 2007

Securities and Exchange Commission
100 F Street, NE
Washington, DC 20549

                              FIDELITY BOND FILING

             Calamos Investment Trust - 1940 Act File No. 811-05443
              Calamos Advisors Trust - 1940 Act File No. 811-09237
 Calamos Convertible Opportunities and Income Fund - 1940 Act File No. 811-21080
     Calamos Convertible and High Income Fund - 1940 Act File No. 811-21319
        Calamos Strategic Total Return Fund - 1940 Act File No. 811-21484
         Calamos Global Total Return Fund - 1940 Act File No. 811-21547

On behalf of Calamos Investment Trust, Calamos Advisors Trust, Calamos
Convertible Opportunities and Income Fund, Calamos Convertible and High Income
Fund, Calamos Strategic Total Return Fund and Calamos Global Total Return Fund
(the "Trusts"), I am enclosing the following documents for filing under Rule
17g-1(g) of the Investment Company Act of 1940:

     1.   One copy of the Trusts' joint fidelity bond for the year ending
          January 31, 2008;

     2.   One copy of the resolutions adopted by the Trusts' board of trustees,
          including the trustees who are not "interested persons" of the Trusts
          approving the amount, type, form and coverage of the bond;

     3.   One copy of the fidelity bond insurance allocation agreement among the
          Trusts, Calamos Advisors LLC, Calamos Asset Management, Inc., Calamos
          Family Partners, Inc., Calamos Financial Services LLC, Calamos
          Holdings LLC, Calamos Partners LLC and the Calamos Profit Sharing
          401(k) Plan.

The premium on the bond has been paid for the period ending January 31, 2008. In
addition, please note that the minimum amount of bond that each trust would have
been required to provide, as set forth in Rule 17g-1(d), under a single insured
bond is as follows:


                                                 
Calamos Investment Trust                            $2,500,000
Calamos Advisors Trust                              $  350,000
Calamos Convertible Opportunities and Income Fund   $1,250,000
Calamos Convertible and High Income Fund            $1,250,000
Calamos Strategic Total Return Fund                 $2,100,000



Fidelity Bond Filing
March 15, 2007
Page 2



                                                 
Calamos Global Total Return Fund                    $  600,000


Please acknowledge receipt of this filing by stamping the accompanying copy of
this letter and returning it in the enclosed postage-paid, self-addressed
enveloped.

Sincerely,

CALAMOS INVESTMENT TRUST, CALAMOS ADVISORS TRUST, CALAMOS CONVERTIBLE
OPPORTUNITIES AND INCOME FUND, CALAMOS CONVERTIBLE AND HIGH INCOME FUND, CALAMOS
STRATEGIC TOTAL RETURN FUND, CALAMOS GLOBAL TOTAL RETURN FUND


/s/ James S. Hamman, Jr.
-------------------------------------
James S. Hamman, Jr.
Secretary