Exhibit (a)(4)

                           OFFER TO PURCHASE FOR CASH

                     All Outstanding Shares of Common Stock
                                       of
               PUTNAM CALIFORNIA INVESTMENT GRADE MUNICIPAL TRUST
                                       at
                              $14.16 Net Per Share
                                       by
                            MILDRED B. HOREJSI TRUST


         THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT,
    NEW YORK CITY TIME, ON FEBRUARY 16, 2007, UNLESS THE OFFER IS EXTENDED.

                                                                January 22, 2007

To Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees:

     We have been  appointed by the Mildred B.  Horejsi  Trust,  an  irrevocable
grantor trust administered in accordance with Alaska administrative statutes and
governed  by  Alaska  trust law (the  "Trust")  to act as  information  agent in
connection  with the Trust's  offer to  purchase  up to 100% of the  outstanding
shares of common  stock,  par value $0.001 per share (the  "shares"),  of Putnam
California  Investment  Grade Municipal  Trust, a  Massachusetts  business trust
("PCA"),  at $14.16 per share,  net to the seller in cash (subject to applicable
withholding of United States federal,  state and local taxes),  on the terms and
subject to the  conditions  set forth in the Offer to Purchase dated January 22,
2007 (the "Offer to Purchase")  and the related  letter of  transmittal  (which,
together with any supplements or amendments thereto, collectively constitute the
"Offer").  Please  furnish  copies of the  enclosed  materials  to those of your
clients for whom you hold shares  registered in your name or in the name of your
nominee.

     Enclosed herewith are copies of the following documents:

          1.   Offer to Purchase dated January 22, 2007;

          2.   Letter of  transmittal  for your use in  accepting  the Offer and
               tendering shares and for the information of your clients;

          3.   A form of  letter  that  may be sent to your  clients  for  whose
               account you hold shares in your name or in the name of a nominee,
               with space provided for obtaining such client's instructions with
               regard to the Offer;

          4.   Notice of guaranteed delivery with respect to shares;

          5.   Guidelines for Certification of Taxpayer Identification Number on
               Substitute Form W-9; and

          6.   Return  envelope  addressed  to The  Colbent  Corporation  as the
               depositary.

     CERTAIN CONDITIONS TO THE OFFER ARE DESCRIBED IN SECTION 14 OF THE OFFER TO
PURCHASE.

     WE URGE YOU TO CONTACT YOUR  CLIENTS AS PROMPTLY AS  POSSIBLE.  PLEASE NOTE
THAT THE OFFER AND  WITHDRAWAL  RIGHTS WILL EXPIRE AT 12:00  MIDNIGHT,  NEW YORK
CITY TIME, ON FEBRUARY 16, 2007, UNLESS THE OFFER IS EXTENDED.

     In all cases, payment for shares accepted for payment pursuant to the Offer
will be made only after timely receipt by the depositary of (1) the certificates
for (or a timely  book-entry  confirmation (as defined in the Offer to Purchase)
with  respect  to) such  shares,  (2) a letter of  transmittal  (or a  facsimile
thereof),  properly  completed and duly  executed,  with any required  signature
guarantees,  or, in the case of a book-entry  transfer  effected pursuant to the
procedures set forth in Section 3 of the Offer to Purchase,  an agent's  message
(as defined in the Offer to Purchase),  and (3) any other documents  required by
the letter of transmittal.  Accordingly,  tendering  stockholders may be paid at
different  times  depending  on  when  certificates  for  shares  or  book-entry
confirmations  with respect to shares are actually  received by the  depositary.
UNDER NO CIRCUMSTANCES WILL INTEREST BE PAID ON THE PURCHASE PRICE OF THE SHARES
REGARDLESS  OF ANY EXTENSION OF OR AMENDMENT TO THE OFFER OR ANY DELAY IN PAYING
FOR SUCH SHARES.

     The Purchasers will not pay any fees or commissions to any broker or dealer
or other  person  (other  than the  information  agent  and the  depositary,  as
described in the Offer to  Purchase)  in  connection  with the  solicitation  of
tenders of shares  pursuant  to the Offer.  However,  the  Purchasers  will,  on
request,  reimburse you for customary  mailing and handling expenses incurred by
you in forwarding copies of the enclosed Offer materials to your clients.

     Questions and requests for additional  copies of the enclosed  material may
be directed to the  information  agent at its address and  telephone  number set
forth on the back cover of the Offer to Purchase.

                                     Very truly yours,

                                     Morrow & Co.

     Nothing  contained herein or in the enclosed  documents shall render you or
any other person the agent of the Purchasers,  the  depositary,  the information
agent or any  affiliate of any of them or  authorize  you or any other person to
give any  information or use any document or make any statement on behalf of any
of them with  respect to the Offer  other than the  enclosed  documents  and the
statements contained therein.