<PAGE>

                                                                     EXHIBIT 4.5


                                  $65,000,000

                              CBRE Holding, Inc.

                           16% Senior Notes Due 2011

                    339,820 Shares of Class A Common Stock

                              PURCHASE AGREEMENT
                              ------------------

June 29, 2001

Credit Suisse First Boston Corporation
Eleven Madison Avenue
New York, New York  10010-3629

Dear Sirs:

          1.  Introductory.  CBRE Holding, Inc., a Delaware corporation (the
              ------------
"Company"), proposes, subject to the terms and conditions stated herein, to
issue and sell to Credit Suisse First Boston Corporation ("CSFBC" or the
"Initial Purchaser") $65,000,000 aggregate principal amount of its 16% Senior
Notes Due 2011 (the "Notes") and 339,820 shares of Class A common stock (the
"Common Stock") of the Company, par value $0.01 per share (the "Shares" and
together with the Notes, the "Offered Securities"). The Notes are to be issued
pursuant to an indenture (the "Indenture") to be dated as of the Closing Date
(as defined below), between the Company and State Street Bank and Trust Company
of California, N.A., as trustee (the "Trustee"). As part of the transactions
(the "Transactions") as defined in the "Description of the Notes" and as
described under the heading "The Transactions" in the Offering Document (as
defined herein), BLUM CB Corp. will merge with and into CB Richard Ellis
Services, Inc., a Delaware corporation ("CBRESI"), with CBRESI as the surviving
corporation in such merger (the "Merger"). Concurrently with the consummation of
the Merger, (1) the Company will execute a Notes Registration Rights Agreement
(the "Notes Registration Rights Agreement"), a Securityholders' Agreement (the
"Securityholders Agreement"), and an Anti-Dilution Agreement (the "Anti-Dilution
Agreement") and (2) CBRESI will enter into a credit agreement (together with the
related guaranties and security documents, the "Credit Agreement") among itself,
the guarantors named therein, Credit Suisse First Boston, New York branch, as
administrative agent, and the lenders named therein.
<PAGE>

                                      -2-


          This Agreement, the Indenture, the Offered Securities, the Exchange
Securities (as defined in the Notes Registration Rights Agreement), the Notes
Registration Rights Agreement, the Securityholders Agreement and the Anti-
Dilution Agreement are sometimes referred to in this Agreement collectively as
the "Operative Documents".  All material agreements and instruments relating to
the Transactions (including, but not limited to, the Merger Agreement and the
Credit Agreement) are sometimes referred to in this Agreement collectively as
the "Transaction Agreements".  The Operative Documents and the Transaction
Agreements are sometimes referred to in this Agreement collectively as the
"Transaction Documents".  References in this Agreement to the subsidiaries of
the Company shall include all direct and indirect subsidiaries of the Company
after the consummation of the Merger.

          Capitalized terms used but not defined herein shall have the meanings
given to such terms in the Offering Document (as defined below).

          The Company hereby agrees with the Initial Purchaser as follows:

          2.  Representations and Warranties of the Company.  The Company
              ---------------------------------------------
represents and warrants to, and agrees with, the Initial Purchaser that:

              (a)  An offering circular dated the date of this Agreement
     relating to the Offered Securities to be purchased by the Initial Purchaser
     has been prepared by the Company. Such offering circular, as the same may
     be supplemented prior to the closing of the offering is hereinafter
     referred to as the "Offering Document". On the date of this Agreement, the
     Offering Document does not include any untrue statement of a material fact
     or omit to state any material fact necessary in order to make the
     statements therein, in the light of the circumstances under which they were
     made, not misleading. The preceding sentence does not apply to statements
     or omissions from the Offering Document based upon written information
     furnished to the Company by the Initial Purchaser specifically for use
     therein, it being understood and agreed that the only such information is
     that described in Section 7(b) hereof.

              (b)  The Company has been duly incorporated and is an existing
     corporation in good standing under the laws of the jurisdiction of its
     incorporation, with corporate power and authority to own its properties and
     conduct its business as described in the Offering Document, and the Company
     is duly qualified to do business as a foreign corporation in good standing
     in all other jurisdictions in which its ownership or lease of property or
     the conduct of its business requires such qualification, except to the
     extent that the failure to be so qualified or to be in good standing would
     not have a material adverse effect on the business, financial condition or
     results of operation of the Company and its subsidiaries, taken as a whole
     (a "Material Adverse Effect").
<PAGE>

                                      -3-

              (c)  Each subsidiary of the Company has been duly incorporated and
     is an existing corporation, limited liability company or limited
     partnership, as the case may be, in good standing (if applicable) under the
     laws of the jurisdiction of its incorporation or organization, with power
     and authority to own its properties and conduct its business as described
     in the Offering Document, and each subsidiary of the Company is duly
     qualified to do business as a foreign corporation, limited liability
     company or limited partnership, as the case may be, in good standing (if
     applicable) in all other jurisdictions in which its ownership or lease of
     property or the conduct of its business requires such qualification, except
     to the extent that the failure to be so qualified or to be in good standing
     would not have a Material Adverse Effect; all of the issued and outstanding
     capital stock, ownership interests or partnership interests, as the case
     may be, of each subsidiary of the Company have been, and immediately
     following the Merger will be, duly authorized and validly issued and, in
     the case of capital stock, is fully paid and nonassessable; and except as
     disclosed in the Offering Document and for pledges in favor of Credit
     Suisse First Boston, New York branch, as collateral agent under the Credit
     Agreement, the capital stock, ownership interests or partnership interests,
     as the case may be, of the Company and each subsidiary owned by the
     Company, directly or through subsidiaries, will be owned free from liens,
     encumbrances and defects immediately following the Merger and the other
     Transactions.

              (d)  The Indenture has been duly authorized by the Company; the
     Notes have been duly authorized by the Company; and when the Notes are
     delivered and paid for pursuant to this Agreement and the Indenture on the
     Closing Date (as defined below), assuming due authorization, execution and
     delivery of the Indenture by the Trustee, the Indenture will have been duly
     executed and delivered by the Company, such Notes will have been duly
     executed, authenticated, issued and delivered by the Company (assuming
     authentication by the Trustee in accordance with the provisions of the
     Indenture) and the Indenture and such Notes will constitute valid and
     legally binding obligations of the Company, enforceable in accordance with
     their terms and entitled to the benefits of the Indenture (assuming that
     the Indenture is a valid and legally binding obligation of the Trustee),
     subject to (i) the effects of bankruptcy, insolvency, fraudulent transfer,
     reorganization, moratorium or similar laws of general applicability
     relating to or affecting creditors' rights, (ii) general principles of
     equity (regardless of whether enforceability is considered in a proceeding
     at law or in equity) and (iii) an implied covenant of good faith and fair
     dealing.

              (e)  The Exchange Securities have been duly authorized by the
     Company. When the Exchange Securities are issued, executed and
     authenticated in accordance with the terms of the Exchange Offer and the
     Indenture, the Ex-
<PAGE>

                                      -4-

     change Securities (assuming authentication by the Trustee in accordance
     with the provisions of the Indenture) will be entitled to the benefits of
     the Indenture and will be the valid and binding obligations of the Company,
     enforceable against the Company in accordance with their terms (assuming
     that the Indenture is a valid and legally binding obligation of the
     Trustee), subject to (i) the effects of bankruptcy, insolvency, fraudulent
     transfer, reorganization, moratorium or similar laws of general
     applicability relating to or affecting creditors' rights, and (ii) general
     principles of equity (regardless of whether enforceability is considered in
     a proceeding at law or in equity).

              (f)  The Indenture conforms in all material respects to the
     requirements of the Trust Indenture Act of 1939, as amended (the "TIA" or
     the "Trust Indenture Act"), and the rules and regulations of the Securities
     and Exchange Commission (the "Commission") applicable to an indenture which
     is qualified thereunder.

              (g)  The Shares have been duly reserved for issuance by the
     Company, the issuance of the Shares has been duly authorized by the
     Company, and the Shares, when delivered pursuant to the terms of this
     Agreement, will be validly issued, fully paid and nonassessable, and except
     as set forth in the Offering Document no holder of any securities of the
     Company has any preemptive or other similar rights to subscribe for or to
     purchase any common stock of the Company arising by operation of the
     General Corporation Law of the State of Delaware, under the Certificate of
     Incorporation or bylaws of the Company or pursuant to the terms of any
     agreement or instrument to which the Company is a party.

              (h)  Except as disclosed in the Offering Document, there are no
     contracts, agreements or understandings between the Company and any person
     that would give rise to a valid claim against the Company or the Initial
     Purchaser for a brokerage commission, finder's fee or other like payment in
     connection with the Offered Securities.

              (i)  No consent, approval, authorization or order of, or filing
     with, any governmental agency or body or any court is required for the
     consummation of the transactions contemplated by this Agreement, the
     Registration Rights Agreement, the Anti-Dilution Agreement, the
     Securityholders Agreement or any other Transaction Document, in each case,
     in connection with the consummation of the transactions contemplated
     therein, except as may be required under the Securities Act, the TIA and
     the rules and regulations of the Commission thereunder with respect to the
     Exchange Offer Registration Statement or the Shelf Registration Statement
     (each as defined in the Notes Registration Rights Agreement) or the
     transactions contemplated by the Notes Registration Rights Agree-
<PAGE>

                                      -5-

     ment, the Anti-Dilution Agreement, the Securityholders Agreement or any
     state or foreign securities laws or by the regulations of the National
     Association of Securities Dealers, Inc.

              (j)  Assuming the accuracy of the representations of the other
     parties thereto and the performance by those parties of their agreements
     therein, the execution, delivery and performance by the Company and the
     subsidiaries of the Company (to the extent a party thereto) of each of the
     Transaction Documents and their compliance with the terms and provisions
     thereof and the consummation of the Transactions will not result in a
     breach or violation of any of the terms and provisions of, or constitute a
     default under, (i) any statute, rule, regulation or order of any
     governmental agency or body or any court, domestic or foreign, that has
     jurisdiction over the Company, or any of the Company's subsidiaries or any
     of their properties, (ii) the Transaction Documents or any agreement or
     instrument to which the Company or any of the Company's subsidiaries is a
     party or by which the Company or any of the Company's subsidiaries is bound
     or to which any of the properties of the Company or the Company's
     subsidiaries is subject or (iii) the charter, by-laws or similar governing
     documents of the Company or any of the Company's subsidiaries, except, with
     respect to clauses (i) and (ii), where such breach, violation or default
     would not have a Material Adverse Effect or would not have a material
     adverse effect on the Company's power or ability to consummate the
     Transactions; the Company has full corporate power and authority to
     authorize, issue and sell the Offered Securities as contemplated by this
     Agreement.

              (k)  None of the Company or any of the subsidiaries of the Company
     is in breach or violation of any of the terms and provisions of, or in
     default under, (i) any statute, rule, regulation or order of any
     governmental agency or body or any court, domestic or foreign, that has
     jurisdiction over the Company or any of the Company's subsidiaries or any
     of their properties, (ii) any agreement or instrument to which the Company
     or any of the Company's subsidiaries is a party or by which the Company or
     any of the Company's subsidiaries is bound or to which any of the
     properties of the Company or the Company's subsidiaries is subject or (iii)
     the charter, by-laws or similar governing document of the Company or any of
     the Company's subsidiaries, except with respect to clauses (i) and (ii) for
     any breaches, violations or defaults that would not have a Material Adverse
     Effect or would not have a material adverse effect on the Company's power
     or ability to consummate the Transactions.

              (l)  This Agreement has been duly authorized, executed and
     delivered by the Company. Each of the other Operative Documents has been,
     or
<PAGE>

                                      -6-

     as of the Closing Date will have been, duly authorized, executed and
     delivered by the Company. All of the Transaction Agreements have been, or
     will be as of or on the Closing Date, duly authorized, executed and
     delivered by each of the Company and the Company's subsidiaries (to the
     extent a party thereto). Each Transaction Document conforms or, at the
     Closing Date, will conform in all material respects to the descriptions
     thereof contained in the Offering Document and each Operative Document
     (other than this Agreement) is or will constitute valid and legally binding
     obligations of the Company and each Transaction Agreement constitutes or
     will, at the Closing Date, constitute valid and legally binding obligations
     of the Company to the extent it is a party thereto, enforceable in
     accordance with its respective terms, except that any rights to indemnity
     and contribution may be limited by federal and state securities laws and
     public policy considerations and subject to (i) bankruptcy, insolvency,
     fraudulent transfer, reorganization, moratorium and similar laws of general
     applicability relating to or affecting creditors' rights, (ii) general
     principles of equity (regardless of whether enforceability is considered in
     a proceeding at law or in equity) and (iii) an implied covenant of good
     faith and fair dealing.

              (m)  Except as disclosed in the Offering Document, the Company and
     its subsidiaries have good and marketable title to all real properties and
     all other properties and assets owned by them that are material to the
     Company and its subsidiaries taken as a whole, in each case free from
     liens, encumbrances and defects that would materially affect the value
     thereof or materially interfere with the use made or proposed to be made
     thereof by them; and except as disclosed in the Offering Document, the
     Company and its subsidiaries hold any leased real or personal property that
     is material to the Company and its subsidiaries taken as a whole under
     valid and enforceable leases with no exceptions that would materially
     interfere with the use made or proposed to be made thereof by them.

              (n)  The Company and its subsidiaries possess adequate
     certificates, authorities or permits issued by appropriate governmental
     agencies or bodies necessary to conduct the business now operated by them
     and have not received any notice of proceedings relating to the revocation
     or modification of any such certificate, authority or permit that, if
     determined adversely to the Company or any of its subsidiaries, would
     individually or in the aggregate have a Material Adverse Effect.

              (o)  No labor dispute with the employees of the Company or any
     subsidiary exists or, to the knowledge of the Company, is imminent that
     would reasonably be expected to have a Material Adverse Effect.
<PAGE>

                                      -7-

              (p)  The Company and its subsidiaries own, possess or can acquire
     on reasonable terms, adequate trademarks, trade names and other rights to
     inventions, know-how, patents, copyrights, confidential information and
     other intellectual property (collectively, "intellectual property rights")
     necessary to conduct the business now operated by them, or presently
     employed by them, and have not received any notice of infringement of or
     conflict with asserted rights of others with respect to any intellectual
     property rights that, if determined adversely to the Company or any of its
     subsidiaries, would individually or in the aggregate have a Material
     Adverse Effect.

              (q)  Except as disclosed in the Offering Document, neither the
     Company nor any of its subsidiaries is in violation of any statute, rule,
     regulation, decision or order of any governmental agency or body or any
     court, domestic or foreign, relating to the use, disposal or release of
     hazardous or toxic substances or relating to the protection or restoration
     of the environment or human exposure to hazardous or toxic substances
     (collectively, "environmental laws"), owns or operates any real property
     contaminated with any substance that is subject to any environmental laws,
     is liable for any off-site disposal or contamination pursuant to any
     environmental laws, or is subject to any claim relating to any
     environmental laws, which violation, contamination, liability or claim
     would individually or in the aggregate have a Material Adverse Effect; and
     the Company is not aware of any pending investigation which might lead to
     such a claim.

              (r)  Except as disclosed in the Offering Document, there are no
     pending actions, suits or proceedings against or affecting the Company, any
     of the Company's subsidiaries or any of their respective properties that
     (i) if determined adversely to the Company or any of its subsidiaries,
     would individually or in the aggregate have a Material Adverse Effect, (ii)
     would materially and adversely affect the ability of the Company to perform
     its obligations under the Transaction Documents or (iii) are otherwise
     material in the context of the sale of the Offered Securities; and no such
     actions, suits or proceedings are, to the knowledge of the Company,
     threatened or contemplated.

              (s)  The historical financial statements included in the Offering
     Document present fairly the financial position of the Company and its
     consolidated subsidiaries as of the dates shown and their results of
     operations and cash flows for the periods shown, and such financial
     statements have been prepared in conformity with the generally accepted
     accounting principles in the United States applied on a consistent basis
     and the assumptions used in preparing the pro forma financial statements
     included in the Offering Document provide a reasonable basis for presenting
     the significant effects directly attributable to the transactions or
<PAGE>

                                      -8-

     events described therein, the related pro forma adjustments give
     appropriate effect to those assumptions, and the pro forma columns therein
     reflect the proper application of those adjustments to the corresponding
     historical financial statement amounts.

              (t)  To our knowledge, no "nationally recognized statistical
     rating organization" as such term is defined for purposes of Rule 436(g)(2)
     under the Securities Act (i) has imposed (or has informed the Company or
     any of the Company's subsidiaries that it is considering imposing) any
     condition (financial or otherwise) on the Company's or any of the Company's
     subsidiaries retaining any rating assigned to the Company or any securities
     of the Company or any of the Company's subsidiaries or (ii) has indicated
     to the Company that it is considering (a) the downgrading, suspension or
     withdrawal of, or any review for a possible change that does not indicate
     the direction of the possible change in, any rating so assigned or (b) any
     change in the outlook for any rating of the Company or any of the Company's
     subsidiaries or any securities of the Company or any of the Company's
     subsidiaries.

              (u)  Except as disclosed in the Offering Document, since the date
     of the latest audited financial statements of the Company included in the
     Offering Document, there has been no material adverse change, nor any
     development or event involving a prospective material adverse change, in
     the financial condition, business, properties or results of operations of
     the Company and its subsidiaries taken as a whole, and, except as disclosed
     in or contemplated by the Offering Document, there has been no dividend or
     distribution of any kind declared, paid or made by the Company on any class
     of its capital stock.

              (v)  The Company is not, and following the consummation of the
     Merger, the Company will not be, an open-end investment company, unit
     investment trust or face-amount certificate company that is or is required
     to be registered under Section 8 of the Investment Company Act of 1940 (the
     "Investment Company Act"); and the Company is not and, after giving effect
     to the offering and sale of the Offered Securities, the other Transactions
     and the application of the proceeds thereof as described in the Offering
     Document, will not be an "investment company" as defined in the Investment
     Company Act.

              (w)  No securities of the same class (within the meaning of Rule
     144A(d)(3) under the Securities Act) as the Offered Securities are listed
     on any national securities exchange registered under Section 6 of the
     Securities Exchange Act of 1934 ("Exchange Act") or quoted in a U.S.
     automated inter-dealer quotation system.
<PAGE>

                                      -9-

              (x)  Assuming the accuracy of the representations and the
     performance by the Initial Purchaser of its agreements contained herein,
     the offer and sale of the Offered Securities in the manner contemplated by
     this Agreement will be exempt from the registration requirements of the
     Securities Act by reason of Section 4(2) thereof and Regulation S
     thereunder.

              (y)  None of the Company, nor any of its respective affiliates,
     nor any person acting on its or their behalf has offered or will offer or
     sell the Offered Securities by means of any form of general solicitation or
     general advertising within the meaning of Rule 502(c) under the Securities
     Act. None of the Company nor any of the Company's subsidiaries has entered
     or will enter into any contractual arrangement with respect to the
     distribution of the Offered Securities except for this Agreement.

              (z)  The Offering Document, as of its date, contains all the
     information specified in, and meeting the requirements of, Rule 144A(d)(4)
     under the Securities Act.

          3.  Purchase, Sale and Delivery of Offered Securities.  On the basis
              -------------------------------------------------
of the representations, warranties and agreements herein contained, but subject
to the terms and conditions set forth herein, the Company agrees to sell to the
Initial Purchaser, and the Initial Purchaser agrees to purchase from the
Company, all of the Offered Securities at a purchase price of $63,525,020 in the
aggregate.

          The Company and the Initial Purchaser agree that the issue price of
the Offered Securities for U.S. Federal Income tax purposes is $916.35 per
$1,000 principal amount of Notes and $16.00 per Share.

          The Company will deliver against payment of the purchase price the
Notes in the form of one or more permanent global securities in definitive form
(the "Global Securities") deposited with the Trustee as custodian for The
Depository Trust Company ("DTC") and registered in the name of Cede & Co., as
nominee for DTC.  Interests in any permanent Global Securities will be held only
in book-entry form through DTC, except in the limited circumstances described in
the Offering Document.  The Company will deliver against payment of the purchase
price of the Shares, one or more certificates for the Shares in definitive form
in such denominations and registered in such names as the Initial Purchaser may
request in writing at least three full business days before the Closing Date.
Payment for the Offered Securities shall be made by the Initial Purchaser in
Federal (same day) funds by official check or checks or wire transfer to an
account at a bank acceptable to CSFBC drawn to the order of CBRE Holding, Inc.
at the office of Simpson Thacher & Bartlett, Palo Alto, California at 12:00 P.M.
(California time), on July 20, 2001, or at such other time not later than seven
full business days thereafter as CSFBC and the Company determine, such time
being herein re-
<PAGE>

                                      -10-

ferred to as the "Closing Date", against delivery to the Trustee as custodian
for DTC of the Global Securities representing all of the Offered Securities. The
Global Securities will be made available for checking at the office of Simpson
Thacher & Bartlett, Palo Alto, Calfornia at least 24 hours prior to the Closing
Date.

          4.  Representations by Initial Purchaser; Resale by Initial Purchaser.
              -----------------------------------------------------------------

              (a)  The Initial Purchaser represents and warrants to the Company
     that it is an "accredited investor" within the meaning of Regulation D
     under the Securities Act .

              (b)  The Initial Purchaser acknowledges that the Offered
     Securities have not been registered under the Securities Act and may not be
     offered or sold within the United States or to, or for the account or
     benefit of, U.S. persons except pursuant to an exemption from the
     registration requirements of the Securities Act. The Initial Purchaser
     represents and agrees that it has offered and sold the Offered Securities,
     and will offer and sell the Offered Securities, only (i) in accordance with
     Rule 144A under the Securities Act ("Rule 144A") and (ii) to a limited
     number of institutional investors reasonably believed by the Initial
     Purchaser to be "Accredited Investors" (as defined in Rule 501(a)(1), (2),
     (3) or (7) under Regulation D of the Securities Act), in private sales
     exempt from registration under the Securities Act, in each case who have
     executed or have agreed to execute the Securityholders Agreement.
     Accordingly, none of the Initial Purchaser or its affiliates, or any person
     acting on their behalf, has engaged or will engage in any directed selling
     efforts with respect to the Offered Securities, and the Initial Purchaser,
     its affiliates and all persons acting on their behalf have complied and
     will comply with the offering restrictions requirement of Rule 144A.

              (c)  The Initial Purchaser agrees that it and each of its
     affiliates has not entered and will not enter into any contractual
     arrangement with respect to the distribution of the Offered Securities
     except with the prior consent of the Company.

              (d)  The Initial Purchaser agrees that it and each of its
     affiliates will not offer or sell the Offered Securities in the United
     States by means of any form of general solicitation or general advertising
     within the meaning of Rule 502(c) under the Securities Act, including, but
     not limited to (i) any advertisement, article, notice or other
     communication published in any newspaper, magazine or similar media or
     broadcast over television or radio, or (ii) any seminar or meeting whose
     attendees have been invited by any general solicitation or general
     advertising. The Initial Purchaser agrees, with respect to resales made in
     reliance on Rule 144A of any of the Offered Securities, to deliver either
     with the confir-
<PAGE>

                                      -11-

     mation of such resale or otherwise prior to settlement of such resale a
     notice to the effect that the resale of such Offered Securities has been
     made in reliance upon the exemption from the registration requirements of
     the Securities Act provided by Rule 144A.

              (e)  The Initial Purchaser agrees that it will not offer, sell or
     deliver any of the Offered Securities in any jurisdiction outside of the
     United States.

          5.  Certain Agreements of the Company.  The Company agrees with the
              ---------------------------------
Initial Purchaser that:

              (a)  The Company will advise CSFBC promptly of any proposal to
     amend or supplement the Offering Document and will not effect such
     amendment or supplementation without CSFBC's consent, which consent shall
     not be unreasonably withheld or delayed. If, at any time prior to the
     completion of the resale of the Offered Securities by the Initial
     Purchaser, any event occurs as a result of which the Offering Document as
     then amended or supplemented would include an untrue statement of a
     material fact or omit to state any material fact necessary in order to make
     the statements therein, in the light of the circumstances under which they
     were made, not misleading, the Company promptly will notify CSFBC of such
     event and promptly will prepare, at its own expense, an amendment or
     supplement which will correct such statement or omission. Neither CSFBC's
     consent to, nor its delivery to offerees or investors of, any such
     amendment or supplement shall constitute a waiver of any of the conditions
     set forth in Section 6.

              (b)  The Company will furnish to CSFBC copies of any Offering
     Document and all amendments and supplements to any such document, in each
     case as soon as available and in such quantities as CSFBC reasonably
     requests. Subject to the terms of the Securityholders Agreement with
     respect to the Shares, at any time when the Company is not subject to
     Section 13 or 15(d) of the Exchange Act, the Company will promptly furnish
     or cause to be furnished to CSFBC and, upon request of holders and
     prospective purchasers of the Offered Securities, to such holders and
     purchasers, copies of the additional information required to be delivered
     to holders and prospective purchasers of the Offered Securities pursuant to
     Rule 144A(d)(4) under the Securities Act (or any successor provision
     thereto) in order to permit compliance with Rule 144A in connection with
     resales by such holders of the Offered Securities (the "Additional Company
     Information"). The Company will pay the expenses of printing and
     distributing to the Initial Purchaser all such documents.
<PAGE>

                                      -12-

              (c)  The Company will arrange for the qualification of the Offered
     Securities for sale and the determination of their eligibility for
     investment under the laws of such jurisdictions in the United States as
     CSFBC designates and will continue such qualifications in effect so long as
     required for the resale of the Offered Securities by the Initial Purchaser;
     provided, however, that the Company will not be required to qualify as a
     --------  -------
     foreign corporation or to file a general consent to service of process or
     to subject itself to taxation in respect of doing business in any such
     state where it is not then required to be so qualified or subject to
     taxation.

              (d)  During the period of three years hereafter, the Company will
     furnish to CSFBC as soon as practicable after the end of each fiscal year,
     a copy of its annual report to shareholders for such year; and the Company
     will furnish to CSFBC, as soon as available, a copy of each report and any
     definitive proxy statement of it filed with the Commission under the
     Exchange Act or mailed to holders of Offered Securities or of any
     securities of the Company which have been registered under Section 12 of
     the Exchange Act.

              (e)  During the period of two years after the Closing Date, the
     Company will, upon request, furnish to CSFBC, and upon request, furnish to
     any holder of Offered Securities, a copy of the restrictions on transfer
     applicable to the Offered Securities.

              (f)  During the period of two years after the Closing Date, the
     Company will not and will not permit any of its affiliates (as defined in
     Rule 144 under the Securities Act) to, resell any of the Offered Securities
     that have been reacquired by any of them.

              (g)  During the period of two years after the Closing Date, the
     Company will not become an open-end investment company, unit investment
     trust or face-amount certificate company that is or is required to be
     registered under Section 8 of the Investment Company Act.

              (h)  The Company will pay all expenses of the Company and its
     subsidiaries incidental to the performance of the obligations of the
     Company and the Company's subsidiaries under this Agreement, the Indenture,
     the Registration Rights Agreement, the Anti-Dilution Agreement, the
     Securityholders Agreement and the other Transaction Documents, including
     (i) the fees and expenses of counsel and accountants for the Company, and
     of the Trustee and its professional advisers; provided, however, that the
                                                   --------  -------
     Company shall not be responsible for the payment of fees and expenses of
     Arthur Anderson LLP, to the extent attributable to the preparation and
     delivery of a comfort letter to the Initial Purchaser; (ii) all ex-
<PAGE>

                                      -13-

     penses in connection with the execution, issue, authentication, packaging
     and initial delivery of the Offered Securities and, as applicable, the
     Exchange Securities, and the printing of the Offering Document and
     amendments and supplements thereto, and any other document relating to the
     issuance, offer, sale and delivery of the Offered Securities and as
     applicable, the Exchange Securities; (iii) the cost of listing the Offered
     Securities and qualifying the Offered Securities for trading in The
     PortalSM Market ("PORTAL") and any expenses incidental thereto; (iv) the
     cost of any advertising approved by the Company in connection with the
     issue of the Offered Securities; and (v) expenses incurred in printing and
     distributing any Offering Document (including any amendments and
     supplements thereto) to or at the direction of the Initial Purchaser. In
     addition, the Company will pay the reasonable fees and expenses of Cahill
     Gordon & Reindel, special counsel to the Initial Purchaser. Each party will
     pay its own expenses in connection with attending or hosting meetings with
     prospective purchasers of the Offered Securities from the Initial
     Purchaser.

              (i)  In connection with the offering, until CSFBC shall have
     notified the Company of the completion of the resale of the Offered
     Securities, none of the Company or any of its respective affiliates has or
     will, either alone or with one or more other persons, bid for or purchase
     for any account in which it or any of its affiliates has a beneficial
     interest any Offered Securities or attempt to induce any person to purchase
     any Offered Securities; and none of them nor any of their affiliates will
     make bids or purchases for the purpose of creating actual, or apparent,
     active trading in, or of raising the price of, the Offered Securities.

              (j)  For a period of 120 days after the date of the initial
     offering of the Offered Securities by the Initial Purchaser, except as
     described in the section entitled "The Transactions" in the Offering
     Document, the Company will not offer, sell, contract to sell, pledge or
     otherwise dispose of, directly or indirectly, any United States dollar-
     denominated debt securities issued or guaranteed by the Company and having
     a maturity of more than one year from the date of issue. The Company will
     not at any time offer, sell, contract to sell, pledge or otherwise dispose
     of, directly or indirectly, any securities under circumstances where such
     offer, sale, pledge, contract or disposition would cause the exemption
     afforded by Section 4(2) of the Securities Act to cease to be applicable to
     the offer and sale of the Offered Securities.

              (k)  The Company will use the net proceeds from the sale of the
     Offered Securities in substantially the manner described in the Offering
     Document under the caption "Use of Proceeds".
<PAGE>

                                      -14-

              (l)  None of the Company or any of its subsidiaries will sell,
     offer for sale or solicit offers to buy or otherwise negotiate in respect
     of any security (as defined in the Securities Act) that would be integrated
     with the sale of the Offered Securities in a manner that would require the
     registration under the Securities Act of the sale to the Initial Purchaser
     of the Offered Securities or to take any other action that would result in
     the resale of the Offered Securities not being exempt from registration
     under the Securities Act.

              (m)  None of the Company or any of its subsidiaries will take,
     directly or indirectly, any action designed to, or that might reasonably be
     expected to, cause or result in stabilization or manipulation of the price
     of any security of the Company to facilitate the resale of the Offered
     Securities. Except as permitted by the Securities Act, the Company will not
     distribute any (i) preliminary offering memorandum or offering memorandum,
     including without limitation, the Offering Document, or (ii) other offering
     material in connection with the offering and sale of the Offered
     Securities.

              (n)  On the Closing Date, the Company shall deliver to the Initial
     Purchaser Secretary's Certificates reasonably satisfactory to the Initial
     Purchaser which shall include the following documents with respect to the
     Company and each of the Company's U.S. subsidiaries: (1) certificates of
     incorporation or formation, as applicable, (2) by-laws or other similar
     governing documents, (3) resolutions and (4) certificates of good standing
     and/or qualification to do business as a foreign corporation in such
     jurisdictions as the Initial Purchaser may reasonably request.

              (o)  On the Closing Date, the Company shall cause the Initial
     Purchaser to receive a copy of the opinions delivered in connection with
     the consummation of the Credit Agreement, which opinions shall expressly
     state that the Initial Purchaser is justified in relying upon the opinions
     therein.

          6.  Conditions to the Obligations of the Initial Purchaser.  The
              ------------------------------------------------------
obligations of the Initial Purchaser to purchase and pay for the Offered
Securities will be subject to the accuracy of the representations and warranties
on the part of the Company herein, to the accuracy of the statements of officers
of the Company made pursuant to the provisions hereof, to the performance by the
Company of its obligations hereunder and to the following additional conditions
precedent:

              (a)  The Initial Purchaser shall have received a letter, dated the
     date of this Agreement, of Arthur Andersen LLP in a form satisfactory to
     the Initial Purchaser in all respects.
<PAGE>

                                      -15-

              (b)  Subsequent to the execution and delivery of this Agreement,
     there shall not have occurred (i) a change in U.S. or international
     financial, political or economic conditions or currency exchange rates or
     exchange controls that would, in the reasonable judgment of CSFBC, be
     likely to prejudice materially the success of the proposed issue, sale or
     distribution of the Offered Securities, whether in the primary market or in
     respect of dealings in the secondary market, or (ii) (A) any change, or any
     development or event involving a prospective change, in the financial
     condition, business, properties or results of operations of the Company or
     its subsidiaries which, in the reasonable judgment of CSFBC, is material
     and adverse and makes it impractical or inadvisable to proceed with
     completion of the offering or the sale of and payment for the Offered
     Securities; (B) any downgrading in the rating of any debt securities of the
     Company by any "nationally recognized statistical rating organization" (as
     defined for purposes of Rule 436(g) under the Securities Act), or any
     public announcement that any such organization has under surveillance or
     review its rating of any debt securities of the Company (other than an
     announcement with positive implications of a possible upgrading, and no
     implication of a possible downgrading, of such rating); (C) any suspension
     or limitation of trading in securities generally on the New York Stock
     Exchange, or any setting of minimum prices for trading on such exchange, or
     any suspension of trading of any securities of the Company on any exchange
     or in the over-the-counter market; (D) any banking moratorium declared by
     U.S. Federal or New York authorities; or (E) any outbreak or escalation of
     major hostilities in which the United States is involved, any declaration
     of war by Congress or any other substantial national or international
     calamity or emergency if, in the judgment of CSFBC, the effect of any such
     outbreak, escalation, declaration, calamity or emergency makes it
     impractical or inadvisable to proceed with completion of the offering or
     sale of and payment for the Offered Securities.

              (c)  There shall exist at and as of the Closing Date no condition
     that would constitute a default (or an event that with notice or lapse of
     time, or both, would constitute a default) under any Transaction Agreement
     as in effect or as in draft form at the Closing Date.

              (d)  The Initial Purchaser shall have received an opinion and a
     letter, each dated the Closing Date, of Simpson Thacher & Bartlett, counsel
     to the Company, substantially in the form of Exhibit A attached hereto. The
                                                  ---------
     Initial Purchaser shall have received an opinion, dated the Closing Date,
     of Walter Stafford, Esq., Senior Vice President, Secretary and General
     Counsel of CBRESI, substantially in the form of Exhibit B attached hereto.
                                                     ---------
<PAGE>

                                      -16-

              (e)  The Initial Purchaser shall have received (i) a letter from
     Cravath Swaine & Moore, counsel for the Initial Purchaser, dated the
     Closing Date and in form and substance reasonably satisfactory to the
     Initial Purchaser and (ii) an opinion and a letter from Cahill Gordon &
     Reindel, special counsel for the Initial Purchaser, each dated the Closing
     Date, as to the validity of the Securities and in form and substance
     reasonably satisfactory to the Initial Purchaser.

              (f)  The Initial Purchaser shall have received a certificate,
     dated the Closing Date, of the Chief Executive Officer or any Vice
     President and a principal financial or accounting officer of the Company in
     which such officers, to the best of their knowledge after reasonable
     investigation, shall state that the representations and warranties made by
     the Company in this Agreement are true and correct and that, subsequent to
     the respective date of the most recent financial statements in the Offering
     Document, there has been no material adverse change, nor any development or
     event involving a prospective material adverse change, in the financial
     condition, business, properties or results of operations of the Company and
     its subsidiaries taken as a whole except as set forth in or contemplated by
     the Offering Document or as described in such certificate.

              (g)  The Initial Purchaser shall have received a letter, dated the
     Closing Date, of Arthur Anderson LLP which meets the requirements of
     subsection (a) of this Section, except that the specified date referred to
     in such subsection will be a date not more than three days prior to the
     Closing Date for the purposes of this subsection.

              (h)  Substantially concurrent with the closing in respect of the
     Offered Securities, the Merger shall be consummated and the proceeds from
     the sale of the BLUM CB Corp. 11 1/4% Senior Subordinated Notes due June
     15, 2011 shall be released from escrow.

              (i)  The Company and the Trustee shall have entered into the
     Indenture and you shall have received counterparts, conformed as executed,
     thereof.

              (j)  The Company shall have entered into the Notes Registration
     Rights Agreement and you shall have received counterparts, conformed as
     executed, thereof.

              (k)  The Company shall have entered into the Anti-Dilution
     Agreement and you shall have received counterparts, conformed as executed,
     thereof.
<PAGE>

                                      -17-

              (l)  The Company shall have entered into the Securityholders
     Agreement and you shall have received counterparts, conformed as executed,
     thereof.

              (m)  The Notes shall have been designated PORTAL securities in
     accordance with the rules and regulations adopted by the NASD relating to
     trading in the PORTAL market.

              (n)  On or prior to the Closing Date, the Company shall have
     provided to the Initial Purchaser and counsel to the Initial Purchaser
     copies of all Transaction Documents executed and delivered on or prior to
     such date, including but not limited to legal opinions relating to the
     Transactions.

              (o)  On or prior to the Closing Date, the Company shall have paid
     in full all fees and expenses owing pursuant to the Commitment Letter dated
     February 23, 2001, as amended through the Closing Date, between DLJ
     Investment Funding II, L.P. and CBRE Holding, Inc.

          7.  Indemnification and Contribution.
              --------------------------------

              (a)  The Company will indemnify and hold harmless the Initial
     Purchaser, its partners, directors and officers and each person, if any,
     who controls the Initial Purchaser within the meaning of Section 15 of the
     Securities Act, against any losses, claims, damages or liabilities, joint
     or several, to which the Initial Purchaser may become subject, under the
     Securities Act or the Exchange Act or otherwise, insofar as such losses,
     claims, damages or liabilities (or actions in respect thereof) arise out of
     or are based upon any breach of any untrue statement or alleged untrue
     statement of any material fact contained in the Offering Document, or any
     amendment or supplement thereto, or arise out of or are based upon the
     omission or alleged omission to state therein a material fact necessary in
     order to make the statements therein, in the light of the circumstances
     under which they were made, not misleading, including any losses, claims,
     damages or liabilities arising out of or based upon the Company's failure
     to perform its obligations under Section 5(a) of this Agreement, and will
     reimburse the Initial Purchaser for any legal or other expenses reasonably
     incurred by the Initial Purchaser in connection with investigating or
     defending any such loss, claim, damage, liability or action as such
     expenses are incurred; provided, however, that the Company will not be
                            --------  -------
     liable in any such case to the extent that any such loss, claim, damage or
     liability arises out of or is based upon an untrue statement or alleged
     untrue statement in or omission or alleged omission from any of such
     documents in reliance upon and in conformity with written information
     furnished to the Company by the Initial Purchaser specifically for use
     therein, it being understood and agreed that the only such information
     consists of the information described as such in subsection (b) below.
<PAGE>

                                      -18-

              (b)  The Initial Purchaser will indemnify and hold harmless the
     Company, its directors and officers and each person, if any, who controls
     the Company within the meaning of Section 15 of the Securities Act, against
     any losses, claims, damages or liabilities to which the Company may become
     subject, under the Securities Act or the Exchange Act or otherwise, insofar
     as such losses, claims, damages or liabilities (or actions in respect
     thereof) arise out of or are based upon any untrue statement or alleged
     untrue statement of any material fact contained in the Offering Document or
     any amendment or supplement thereto or arise out of or are based upon the
     omission or the alleged omission to state therein a material fact necessary
     in order to make the statements therein, in the light of the circumstances
     under which they were made, not misleading, in each case to the extent, but
     only to the extent, that such untrue statement or alleged untrue statement
     or omission or alleged omission was made in reliance upon and in conformity
     with written information furnished to the Company by CSFBC specifically for
     use therein, and will reimburse any legal or other expenses reasonably
     incurred by the Company in connection with investigating or defending any
     such loss, claim, damage, liability or action as such expenses are
     incurred, it being understood and agreed that the only such information
     furnished by the Initial Purchaser consists of (i) the following
     information in the Offering Document: under the caption "Plan of
     Distribution", the seventh, eighth, ninth, tenth and eleventh paragraphs,
     and the fourth sentence of the sixth paragraph; provided, however, that the
                                                     --------  -------
     Initial Purchaser shall not be liable for any losses, claims, damages or
     liabilities arising out of or based upon the Company's failure to perform
     its obligations under Section 5(a) of this Agreement.

              (c)  Promptly after receipt by an indemnified party under this
     Section of notice of the commencement of any action, such indemnified party
     will, if a claim in respect thereof is to be made against the indemnifying
     party under subsection (a) or (b) above, notify the indemnifying party of
     the commencement thereof; but the omission so to notify the indemnifying
     party will not relieve it from any liability which it may have to any
     indemnified party otherwise than under subsection (a) or (b) above. In case
     any such action is brought against any indemnified party and it notifies
     the indemnifying party of the commencement thereof, the indemnifying party
     will be entitled to participate therein and, to the extent that it may
     wish, jointly with any other indemnifying party similarly notified, to
     assume the defense thereof, with counsel reasonably satisfactory to such
     indemnified party (who shall not, except with the consent of the
     indemnified party, be counsel to the indemnifying party), and after notice
     from the indemnifying party to such indemnified party of its election so to
     assume the defense thereof, the indemnifying party will not be liable to
     such indemnified party under this Section for any legal or other expenses
     subsequently incurred by such indemnified party in connection with the
     defense thereof other than reasonable costs of investigation. No
     indemnifying party shall, without the prior written consent of the
     indemnified party, effect any settlement of any pending or threatened
     action in respect of which any indemnified party is or could have been a
     party
<PAGE>

                                      -19-

     and indemnity could have been sought hereunder by such indemnified party
     unless such settlement includes an unconditional release of such
     indemnified party from all liability on any claims that are the subject
     matter of such action and does not include a statement as to or an
     admission of fault, culpability or failure to act by or on behalf of any
     indemnified party.

              (d)  If the indemnification provided for in this Section is
     unavailable or insufficient to hold harmless an indemnified party under
     subsection (a) or (b) above, then each indemnifying party shall contribute
     to the amount paid or payable by such indemnified party as a result of the
     losses, claims, damages or liabilities referred to in subsection (a) or (b)
     above (i) in such proportion as is appropriate to reflect the relative
     benefits received by the Company on the one hand and the Initial Purchaser
     on the other from the offering of the Offered Securities or (ii) if the
     allocation provided by clause (i) above is not permitted by applicable law,
     in such proportion as is appropriate to reflect not only the relative
     benefits referred to in clause (i) above but also the relative fault of the
     Company on the one hand and the Initial Purchaser on the other in
     connection with the statements or omissions which resulted in such losses,
     claims, damages or liabilities as well as any other relevant equitable
     considerations. The relative benefits received by the Company on the one
     hand and the Initial Purchaser on the other shall be deemed to be in the
     same proportion as the total net proceeds from the offering (before
     deducting expenses) received by the Company bear to the total discounts and
     commissions received by the Initial Purchaser from the Company under this
     Agreement. The relative fault shall be determined by reference to, among
     other things, whether the untrue or alleged untrue statement of a material
     fact or the omission or alleged omission to state a material fact relates
     to information supplied by the Company or the Initial Purchaser and the
     parties' relative intent, knowledge, access to information and opportunity
     to correct or prevent such untrue statement or omission. The amount paid by
     an indemnified party as a result of the losses, claims, damages or
     liabilities referred to in the first sentence of this subsection (d) shall
     be deemed to include any legal or other expenses reasonably incurred by
     such indemnified party in connection with investigating or defending any
     action or claim which is the subject of this subsection (d).
     Notwithstanding the provisions of this subsection (d), the Initial
     Purchaser shall not be required to contribute any amount in excess of the
     amount by which the total discounts and commissions received by the Initial
     Purchaser exceeds the amount of any damages which the Initial Purchaser
     would have otherwise been required to pay by reason of such untrue or
     alleged untrue statement or omission or alleged omission.

              (e)  The obligations of the Company under this Section shall be in
     addition to any liability which the Company may otherwise have and shall
     extend, upon the same terms and conditions, to each person, if any, who
     controls such Initial Purchaser within the meaning of the Securities Act or
     the Exchange Act; and the obligations
<PAGE>

                                      -20-

     of the Initial Purchaser under this Section shall be in addition to any
     liability which the Initial Purchaser may otherwise have and shall extend,
     upon the same terms and conditions, to each person, if any, who controls
     the Company within the meaning of the Securities Act or the Exchange Act.

          8.  Survival of Certain Representations and Obligations.  The
              ---------------------------------------------------
respective indemnities, agreements, representations, warranties and other
statements of the Company or any of its officers and of the Initial Purchaser
set forth in or made pursuant to this Agreement will remain in full force and
effect, regardless of any investigation, or statement as to the results thereof,
made by or on behalf of the Initial Purchaser, the Company or any of its
respective representatives, officers or directors or any controlling person, and
will survive delivery of and payment for the Offered Securities. If for any
reason the purchase of the Offered Securities by the Initial Purchaser is not
consummated, the Company and the Initial Purchaser shall remain responsible for
their respective expenses to be paid or reimbursed by them pursuant to Section
5(h), except that the Company shall not be responsible for the fees and expenses
of counsel to the Initial Purchaser, and the respective obligations of the
Company and the Initial Purchaser pursuant to Section 7 shall remain in effect.

          9.  Notices.  All communications hereunder will be in writing and, if
              -------
sent to the Initial Purchaser, will be mailed, delivered or telegraphed and
confirmed to the Initial Purchaser at Eleven Madison Avenue, New York, New York
10010-3629, Attention: Investment Banking Department - Transactions Advisory
Group, or, if sent to the Company, will be mailed, delivered or telegraphed and
confirmed to it at CBRE Holding, Inc., 909 Montgomery Street, Suite 400, San
Francisco, California 94133, Attention: Claus Moller.

          10.  Successors.  This Agreement will inure to the benefit of and be
               ----------
binding upon the parties hereto and their respective successors and the
controlling persons referred to in Section 7, and no other person will have any
right or obligation hereunder, except that holders of Offered Securities shall
be entitled to enforce the agreements for their benefit contained in the second
and third sentences of Section 5(b) hereof against the Company as if such
holders were parties thereto.

          11.  Counterparts.  This Agreement may be executed in any number of
               ------------
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute one and the same Agreement.

          12.  Applicable Law.  This Agreement shall be governed by, and
               --------------
construed in accordance with, the laws of the State of New York.

          The Company hereby submits to the non-exclusive jurisdiction of the
Federal and state courts in the Borough of Manhattan in The City of New York in
any suit or proceeding arising out of or relating to this Agreement or the
transactions contemplated hereby.
<PAGE>

                                      -21-

          If the foregoing is in accordance with the Initial Purchaser's
understanding of our agreement, kindly sign and return to us one of the
counterparts hereof, whereupon it will become a binding agreement between the
Company and the Initial Purchaser in accordance with its terms.

                              Very truly yours,

                              CBRE HOLDING, INC.

                              By:  /s/ Claus J. Moller
                                  --------------------------------
                                  Name: Claus J. Moller
                                  Title: President



The foregoing Purchase Agreement
is hereby confirmed and accepted
as of the date first above written.

Credit Suisse First Boston Corporation

By:  /s/ Malcolm Price
   -------------------------------------------
   Name: Malcolm Price
   Title: Managing Director