<PAGE>   1
                                                                    Exhibit 10.4

                        FORM OF WHOLESALING AGREEMENT

         THIS WHOLESALING AGREEMENT (this "Agreement") dated as of _____________
2001, by and between CORPORATE PROPERTY ASSOCIATES 15 INCORPORATED, a Maryland
corporation (the "Company"), and CAREY FINANCIAL CORPORATION, a Delaware
corporation ("Carey Financial").

         WHEREAS, the Company proposes to raise up to $400,000,000 through the
sale of shares of common stock of the Company (the "Shares") for investment in
real property as described in a Registration Statement on Form S-11 (No.
333-_____) filed with the Securities and Exchange Commission (the "Registration
Statement"); and

         WHEREAS, the Company desires to retain Carey Financial and Carey
Financial desires to undertake to coordinate the performance of certain
wholesaling services for the Company pursuant to this Agreement on the terms and
subject to the conditions hereinafter set forth and subject to the limitations,
if any, set forth in the final Prospectus which will be included in the
Registration Statement.

         NOW THEREFORE, in consideration of the mutual promises herein made and
for other good and valuable consideration, and intending to be legally bound
hereby, the parties hereto agree as follows:

         1. The Company hereby retains Carey Financial to provide the following
services for the Company:

         (a) Carey Financial shall develop and prepare sales literature to be
         used by the Company in the offer and sale of the Shares (the
         "Offering"), which sales literature shall comply with the Securities
         Act of 1933, as amended ("the "Securities Act"), and the regulations
         thereunder, the Rules of Fair Practice of the National Association of
         Securities Dealers, Inc. (the "RFP") and the "blue sky" laws of any
         jurisdiction in which such material is used ("Blue Sky Law"). The sales
         literature may include, but not be limited to, a slide presentation, a
         property acquisition report, a brochure and seminar invitations for
         presentation and distribution to the public and an audio program, a
         video program and a brochure for presentation and distribution to
         broker-dealers.

         (b) Carey Financial shall assist broker-dealers and registered
         investment advisors participating in the Offering by coordinating
         broker-dealer and registered investment advisor seminars, informational
         meetings, preparing and distributing brochures and other sales
         literature designed for broker-dealers and registered investment
         advisors and providing information and answering any questions with
         regard to the Offering.

         (c) Carey Financial shall assist the Company in enlisting
         broker-dealers and registered investment advisors to participate in the
         Offering as selected dealers.
<PAGE>   2
         2. In consideration for providing the above services, Carey Financial
shall receive reimbursement for identified expenses incurred in connection with
its wholesaling activities described in Section 1 above, including but not
limited to: (a) travel and entertainment expenses; (b) the cost of compensation
paid to employees of Carey Financial in connection with wholesaling activities;
(c) expenses incurred in coordinating broker-dealer and registered investment
advisor seminars and meetings; and (d) wholesaling fees and wholesaling expense
reimbursements paid to it or its Affiliates or other entities.

         3. The Company shall, at the direction of Carey Financial, reimburse
directly all other entities for marketing and wholesaling expenses of the type
described in clauses (a), (b) and (c) of Section 2 hereof incurred directly by
those entities at the request of Carey Financial.

         4. Carey Financial shall adopt procedures which it, in its sole
discretion, deems adequate to monitor compliance with the limitation in Rule
2740 of the RFP and IM 2740 thereto on aggregate compensation to it and all
broker-dealers participating in the Offering. In no event will the amounts paid
hereunder, when combined with all other underwriting compensation paid in
connection with the offering, exceed 10% of Gross Offering Proceeds plus 0.5%
for bona fide due diligence expenses.

         5. The Company hereby represents and warrants to Carey Financial that
the representations and warranties of it set forth in Section 2 of the Sales
Agency Agreement, dated the date hereof, between the Company and Carey
Financial, as Sales Agent (the "Sales Agency Agreement"), are true and correct
in all respects, and that such representations and warranties are hereby
incorporated by reference herein (together with all related definitions and
cross-references) as if set forth in full herein.

         6. The Company hereby covenants to Carey Financial that it will honor
and perform each of the covenants made by it in Section 4 of the Sales Agency
Agreement, and agrees that such covenants are incorporated by reference herein
(together with all related definitions and cross-references) as if set forth in
full herein.

         7. The term of this Agreement shall commence on the date hereof and
shall continue until such time as the Offering is completed. Notwithstanding the
foregoing, this Agreement may be terminated without the payment of any penalty
by either party upon not less than 60 days' notice in writing to the other
party, except for the payment to Carey Financial of unreimbursed expenses
incurred by it prior to the date of termination.

         8. Carey Financial may assign any of its rights or delegate the
performance of any of its obligations hereunder to its Affiliates or any other
entity, provided, however, that no such delegation shall relieve Carey Financial
of its obligations hereunder.

         9. The parties hereto agree that they have not created a joint venture
or partnership relationship between them, that Carey Financial shall be deemed
to be an independent contractor and not for any purpose to be an employee of the
Company.



                                      -2-
<PAGE>   3
         10. This Agreement represents the entire agreement of the parties
hereto relating to the subject matter hereof and may not be amended, modified or
changed except in a writing signed by the parties hereto.

         11. Subject to the limitations on assignment contained herein, the
provisions of this Agreement shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and assigns.

         12. This Agreement shall be governed by the laws of the State of New
York applicable to agreements made and to be performed entirely within such
state.

         13. This Agreement may be executed simultaneously in two or more
counterparts, each of which shall be deemed an original, and all such
counterparts together shall constitute but one and the same instrument.

         14. Any provision of this Agreement which is invalid or unenforceable
in any jurisdiction shall be ineffective to the extent of such invalidity or
unenforceability without invalidating or rendering unenforceable the remaining
provisions hereof, and any such invalidity or unenforceability in any
jurisdiction shall not invalidate or render unenforceable such provisions in any
other jurisdiction.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.

                                   CORPORATE PROPERTY ASSOCIATES 15
                                   INCORPORATED


                                   By:
                                      --------------------------------
                                       ---------------,
                                       ---------------



                                   CAREY FINANCIAL CORPORATION


                                   By:
                                      --------------------------------
                                       ---------------,
                                       ---------------







                                      -3-