<PAGE>
                                                                   Exhibit 10.66

--------------------------------------------------------------------------------




                                 HSBC BANK USA


                                      AND


                       THE NEW YORK MORTGAGE COMPANY LLC




                          ---------------------------


                                 FIFTH AMENDED
                                    GUARANTY

                                 STEVEN SCHNALL

                          ---------------------------





                           Dated as of April 29, 2002



--------------------------------------------------------------------------------
<PAGE>
                             FIFTH AMENDED GUARANTY

                                 STEVEN SCHNALL

     In consideration of any extension of credit whether heretofore or hereafter
made by HSBC BANK USA, a banking corporation organized under the laws of the
State of New York ("Secured Party") to THE NEW YORK MORTGAGE COMPANY LLC, a New
York limited liability company (the "Company"), the undersigned hereby
guarantees (a) the full and prompt payment to Secured Party when due, whether by
acceleration or otherwise, of any and all indebtedness and other liabilities of
the Company to Secured Party arising out of a Fifth Amended Credit and Security
Agreement between Secured Party and the Company dated as of even date herewith
("Credit Agreement") governing a mortgage warehousing line of credit in the
maximum principal amount of FORTY MILLION DOLLARS (40,000,000.00), whether now
existing or hereafter incurred, of every kind and character, direct or indirect,
and whether such indebtedness is from time to time reduced and thereafter
increased, or entirely extinguished and thereafter reincurred ("Indebtedness"),
and (b) the full and complete performance of all the Company's obligations and
compliance with all the Company's covenants set forth in the Credit Agreement.
The undersigned further agrees to pay all costs and expenses, including, without
limitation, attorneys' fees, at any time paid or incurred by Secured Party in
endeavoring to collect the Indebtedness or any part thereof and in enforcing
this Guaranty.

     This Guaranty is, and is intended to be, a continuing guaranty of the
payment of the Indebtedness (irrespective of the aggregate amount thereof)
independent of and in addition to any other guaranty, indorsement or collateral
held by Secured Party therefor whether or not furnished by the undersigned. The
undersigned shall have no right of subrogation with respect to any payments made
by the undersigned hereunder until all of the Indebtedness is paid in full.

     If any default shall be made in the payment of any Indebtedness, the
undersigned hereby agrees to pay the same to the extent above specified: (i)
without requiring protest or notice of nonpayment or notice of default to the
undersigned, to the Company, or to any other person; (ii) without proof of
demand; (iii) without requiring Secured Party to resort first to the Company or
to any other guaranty or any collateral which Secured Party may hold; (iv)
without requiring notice of acceptance hereof or assent hereto by Secured Party;
and (v) without requiring notice that any indebtedness has been incurred, all of
which the undersigned hereby waives.

     The undersigned authorizes Secured Party, without notice or demand and
without releasing, impairing or affecting the undersigned's obligations
hereunder, from time to time: (i) to take from any party and hold collateral for
the payment of the Indebtedness or any part thereof, and to exchange, enforce or
release such collateral or any part thereof; (ii) to accept and hold any
indorsement or guaranty of payment of the Indebtedness or any part thereof and
to release or substitute any such indorser or guarantor, or any party who has
given any security interest in any collateral as security for the payment of the
Indebtedness or any part thereof, or any other party in any way obligated to pay
the Indebtedness or any part thereof; (iii) to direct the order or manner of the
disposition of any and all collateral and the enforcement of any and all
indorsements and
<PAGE>
                                      -2-

guaranties relating to the Indebtedness or any part thereof as Secured Party,
in its sole discretion, may determine; and (iv) to determine how, when and what
application of payments and credits, if any, shall be made on the Indebtedness
or any part thereof, and to apply the same upon principal or interest or the
portion thereof, if any, in excess of the amount of this Guaranty.

     No delay or omission by Secured Party in exercising any right or remedy
hereunder shall operate as a waiver thereof or of any other right or remedy, and
no single or partial exercise thereof shall preclude any other or further
exercise thereof or the exercise of any other right or remedy. All rights and
remedies of Secured Party hereunder are cumulative.

     This Guaranty is absolute and unconditional and shall not be affected by
any act or thing whatsoever, except as herein provided. No modification or
amendment of any provision of this Guaranty shall be effective unless in
writing and subscribed by a duly authorized officer of Secured Party.

     This Guaranty shall be governed by and construed under the laws of the
State of New York, whose laws the undersigned expressly elects to apply to this
Guaranty. The undersigned agrees that any action or proceeding brought to
enforce or arising out of this Guaranty may be commenced in the New York
Supreme Court for the County of Erie, or in the District Court of the United
States for the Western District of New York, and the undersigned waives
personal service of process and agrees that a summons and complaint commencing
an action or proceeding in any such court shall be properly served and shall
confer personal jurisdiction if served by registered mail to the undersigned,
or as otherwise provided by the laws of the State of New York or the United
States.

     The undersigned hereby knowingly, voluntarily, unconditionally and
irrevocably waives the right to a trial by jury in every jurisdiction in any
action, proceeding or counterclaim brought by or against the undersigned, its
personal representatives, successors or assigns, in respect of any matter
arising out of this Guaranty or the Indebtedness, including without limitation
any exercise of rights hereunder, any attempt to cancel, void, or rescind this
Guaranty, and any course of conduct or course of dealing in connection herewith.

     Secured Party and the undersigned as used herein shall include the
estates, executors or administrators, or successors or assigns, of those
parties.

     This Fifth Amended Guaranty replaces the Fourth Amended Guaranty by the
undersigned dated as of January 16, 2002.

     IN WITNESS WHEREOF this Guaranty has been signed by the undersigned at
          , this 3rd day of May, 2002.


Signature of Guarantor                       Address

/s/ Steven Schnall                           304 East 65th Street, #18A
-------------------------                    -------------------------------
STEVEN SCHNALL                               New York, NY 10021
                                             -------------------------------


<PAGE>
                                      -3-


STATE OF NEW YORK  )
                   ) SS.:
COUNTY OF QUEENS   )

     On the 6 day of May 2002 before me, the undersigned, a notary public in
and for said state, personally appeared STEVEN SCHNALL, personally known to me
or proved to me on the basis of satisfactory evidence to be the individual
whose name is subscribed to the within instrument and acknowledged to me that
he executed the same in his capacity, and that by his signature on the
instrument, the individual, or the person upon behalf of which the individual
acted, executed the instrument.


                                                      /s/ Anna Marin
                                              -------------------------------
                                                       Notary Public

                                                         Anna Marin
                                              Notary Public State of New York
                                                       No. 01MA5039882
                                                   Qualified in Queens County
                                               Commission Expires March 6, 2003