<PAGE>   1
                                                                   EXHIBIT 10.19



                            [SUN MICROSYSTEMS LOGO]


Sun Microsystems Finance

     MASTER LEASE AGREEMENT

     Master Lease # 7099534

Lessor agrees to lease to Lessee and Lessee agrees to lease from Lessor, subject
to the following terms of this Master Lease Agreement ("Master Lease") and any
Lease Schedule ("Schedule"), collectively referred to as the Lease ("Lease"),
the personal property described in any Schedule together with all attachments,
replacements, parts, substitutions, additions, upgrades, accessories, software
licenses and operating manuals (the "Product"). Each Schedule shall constitute a
separate, distinct, and independent Lease and contractual obligation of Lessee.

1.   COMMENCEMENT DATE AND TERM
The initial lease term ("Initial Term") and Lessee's rental obligations shall
begin on the Commencement Date and continue for the number of Rental Periods
specified in the Lease as set forth in Section 2 below and shall renew
automatically thereafter until terminated by either party upon not less than
ninety (90) days prior written notice. The Commencement Date with respect to
each item of Product shall be the 16th day after date of shipment to Lessee.

2.   RENT AND RENTAL PERIOD
All rental payments and any other amounts payable under a Lease are collectively
referred to as "Rent". The Rental Period shall mean the rental payment period of
either calendar months, quarters, or as otherwise specified in each Schedule.
Rent for the specified Rental Period is due and payable in advance, to the
address specified in Lessor's invoice, on the first day of each Rental Period
during the Initial Term and any extension (collectively, the "Lease Term"),
provided, however, that Rent for the period of time (if any) from the
Commencement Date to the first day of the first Rental Period shall begin to
accrue on the Commencement Date. If any Rent is not paid when due, Lessee will
pay a service fee equal to five percent (5%) of the overdue amount plus interest
at the rate of one and one half percent (1.5%) per month or the maximum legal
interest rate, whichever is less.

3.   NET LEASE, TAXES AND FEES
Each Schedule shall constitute a net lease and payment of Rent shall be absolute
and unconditional, and shall not be subject to any abatement, reduction, set
off, defense, counterclaim, interruption, deferment or recoupment for any reason
whatsoever. Lessee agrees to pay Lessor when due shipping charges, fees,
assessments and all taxes (municipal, state and federal) imposed upon a Lease or
the Product or its ownership, leasing, renting, possession or use except for
taxes based on Lessor's income.

4.   TITLE
Product shall remain personal property. Lessee shall have no right or interest
in the Product except as provided in this Master Lease and the applicable
Schedule and shall hold the Product subject and subordinate to the rights of
Lessor. Lessee agrees to execute UCC financing statements as and when requested
by Lessor and hereby appoints Lessor as its attorney-in-fact to execute such
financing statements. Lessor may file a photocopy of any Lease as a financing
statement.

Lessee will, at its expense, keep the Product free and clear from any liens or
encumbrances of any kind (except any caused by Lessor) and will indemnify and
hold Lessor harmless from and against any loss or expense caused by Lessee's
failure to do so. Lessee shall give Lessor immediate written notice of any
attachment or judicial process affecting the Product or Lessor's ownership. If
requested, Lessee will label the Product as the property of Lessor and shall
allow, subject to Lessee's reasonable security requirements, the inspection of
the Product during regular business hours.

5.   USE, MAINTENANCE AND REPAIR
Lessee, at its own expense, shall keep the Product in good repair, appearance
and condition, other than normal wear and tear and shall obtain and keep in
effect throughout the term of the Schedule a hardware and software maintenance
agreement with the manufacturer or other party acceptable to Lessor. All parts
furnished in connection with such repair and maintenance shall be manufacturer
authorized parts and shall immediately become components of the Product and the
property of Lessor. Lessee shall use the Product in compliance with
manufacturer's or supplier's suggested guidelines.

6.   DELIVERY AND RETURN OF PRODUCT
Lessee assumes the full expense of transportation, insurance and installation to
Lessee's site. Upon termination of each Schedule, Lessee will provide Lessor a
letter from the manufacturer certifying that the Product is in good operating
condition and is eligible for continued maintenance and that the operating
system is at the then current level, unless under a Sun service contract during
the Lease Term. Lessee, at its expense, shall deinstall, pack and ship the
Product to a U.S. location identified by Lessor. Lessee shall remain obligated
to pay Rent on the Product until the Product and certification are received by
Lessor.

7.   ASSIGNMENT AND RELOCATION
Lessee may sublease or assign its rights under this agreement with Lessor's
prior written consent, which consent shall not be unreasonably withheld,
subject, however, to any terms and conditions which Lessor may require. No
permitted assignment or sublease shall relieve Lessee of any of its obligations
hereunder.

Lessee acknowledges Lessor may sell and/or assign its interest or grant a
security interest in each Lease and/or the Product to an assignee ("Lessor's
Assignee"). So long as Lessee is not in default hereunder, Lessor or Lessor's
Assignee shall not interfere with Lessee's right of quiet enjoyment and use of
the Product. Upon the assignment of each Lease, Lessor's Assignee shall have any
and all discretions, rights and remedies of Lessor and all references to Lessor
shall mean Lessor's Assignee. In no event shall any assignee of Lessor be
obligated to perform any duty, covenant or condition under this Lease and Lessee
agrees it shall pay such assignee without any defense, rights of set-off or
counterclaims and shall not hold or attempt to hold such assignee liable for any
of Lessor's obligations hereunder.

Lessee, at its expense, may relocate Product (after packing it for shipment in
accordance with manufacturer's instructions) to a different address with thirty
(30) days prior written notice to Lessor. The Product shall at all times be used
solely within the United States.

8.   UPGRADES AND ADDITIONS
Lessee may affix or install any accessory, addition, upgrade, equipment or
device on the Product ("Additions") provided that such Additions (i) can be
removed without causing material damage to the Product, (ii) do not reduce the
value of the Product and (iii) are obtained from or approved by Sun
Microsystems, Inc. or an affiliate and are not subject to the interest of any
third party other than Lessor. Any other Additions may not be installed without
Lessor's prior written consent. At the end of the Lease Term, Lessee shall
remove any Additions which (i) were not leased by Lessor and (ii) are readily
removable without causing material damage or impairment of the intended
function, use, or value of the Product and restore the Product to its original
configuration. Any Additions, which are not so removable, will become the
Lessor's property (lien free).

9.   LEASE END OPTIONS
Upon written notice given at least ninety (90) days prior to expiration of the
Lease Term, and provided Lessee is not in default under any Schedule, Lessee may
(i) exercise any purchase option set forth on the Schedule, or (ii) renew the
Schedule for a minimum extension period of twelve (12) months, or (iii) return
the Product to Lessor at the expiration date of the Schedule pursuant to Section
6 above.

10.  INSURANCE, LOSS OR DAMAGE
Effective upon shipment of Product to Lessee and until Product is received by
Lessor, Lessee shall provide at its expense (i) insurance against the loss or
theft or damage to the Product for the full replacement value, and (ii)
insurance against public liability and property damage. Lessee shall provide
certificate of insurance that such coverage is in effect, upon request by
Lessor, naming Lessor as loss payee and/or additional insured as may be
required.

Lessee shall bear the entire risk of loss, theft, destruction of or damage to
any item of Product. No loss or damage shall relieve Lessee of the obligation to
pay Rent or any other obligation under the Schedule. In the event of loss or
damage, Lessee shall promptly notify Lessor and shall, at Lessor's option, (i)
place the Product in good condition and repair, or (ii) replace the Product with
lien free Product of the same model, type and configuration in which case the
relevant Schedule shall continue in full force and effect and clear title in
such Product shall automatically vest in Lessor, or (iii) pay Lessor the present
value of remaining Rent plus the buyout purchase option price provided for in
the applicable Schedule.



<PAGE>   2
11.  SELECTION, WARRANTIES AND LIMITATION OF LIABILITY
Lessee acknowledges that it has selected the Product and disclaims any reliance
upon statements made by Lessor. Lessee acknowledges and agrees that use and
possession of the Product by Lessee shall be subject to and controlled by the
terms of any manufacturer's or, if appropriate, supplier's warranty, and Lessee
agrees to look solely to the manufacturer or, if appropriate, supplier with
respect to all mechanical, service and other claims, and the right to enforce
all warranties made by said manufacturer are hereby assigned to Lessee for the
term of the Schedule.

EXCEPT AS SPECIFICALLY PROVIDED HEREIN, LESSOR HAS NOT MADE AND DOES NOT MAKE
ANY REPRESENTATIONS OR WARRANTIES, EITHER EXPRESS OR IMPLIED, AS TO ANY MATTER
WHATSOEVER, INCLUDING, WITHOUT LIMITATION, NON-INFRINGEMENT, THE DESIGN,
QUALITY, CAPACITY OR CONDITION OF THE PRODUCT, ITS MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE, IT BEING AGREED THAT AS THE LESSEE SELECTED BOTH THE
PRODUCT AND THE SUPPLIER, NO DEFECT, EITHER PATENT OR LATENT SHALL RELIEVE
LESSEE OF ITS OBLIGATION HEREUNDER. LESSEE AGREES THAT LESSOR SHALL NOT BE
LIABLE FOR SPECIFIC PERFORMANCE OR ANY LIABILITY, LOSS, DAMAGE OR EXPENSE OF ANY
KIND INCLUDING, WITHOUT LIMITATION, INDIRECT, INCIDENTAL, CONSEQUENTIAL OR
SPECIAL DAMAGES OF ANY NATURE, DAMAGES ARISING FROM THE LOSS OF USE OF PRODUCT,
LOST DATA, LOST PROFITS, OR FOR ANY CLAIM OR DEMAND.

12.  INDEMNITY
Lessee shall indemnify and hold harmless Lessor and Lessor's Assignee from and
against any and all claims, actions, suits, proceedings, liabilities, damages,
penalties, costs and expenses (including reasonable attorneys' fees), arising
out of the use, operation, possession, ownership (for strict liability in tort
only), selection, leasing, maintenance, delivery or return of any item of
Product.

13.  DEFAULT AND REMEDIES
Lessee shall be in default of any Lease if (i) Lessee fails to pay Rent within
ten (10) days of due date; (ii) Lessee fails to perform or observe or breaches
any covenant or condition of any representation or warranty in such Lease, and
such failure or breach continues unremitted for a period of ten (10) days after
written notice from Lessor; (iii) Lessee, except as expressly permitted in the
Lease, attempts to move, sell, transfer, encumber, or sublet without consent
any item of Product leased under such Lease; (iv) Lessee files or has filed
against it a petition in bankruptcy or becomes insolvent or makes an assignment
for the benefit of creditors or consents to the appointment of a trustee or
receiver or either shall be appointed for Lessee or for a substantial part of
its property without its consent, or (v) Lessee or any guarantor of Lessee is
declared legally deceased or if Lessee shall terminate its existence by merger,
consolidation, sale of substantially all of its assets or otherwise.

Upon default, Lessor may, at its option, take one or more of the following
actions; (i) declare all sums due and to become due under the Schedule
immediately due payable, (ii) require Lessee to return immediately all Product
leased under such Schedule to Lessor in accordance with Section 6 hereof, (iii)
without breach of the pease take immediate possession of and remove the Product;
(iv) sell any or all of the Product at public or private sale or otherwise
dispose of, hold, use or lease to others, or; (v) exercise any right or remedy
which may be available to Lessor under applicable law, including the right to
recover damages for the breach of the Schedule. In addition, Lessee shall be
liable for reasonable attorney's fees, other costs and expenses resulting from
any default, or the exercise of Lessor's remedies, including placing such
Product in the condition required by Section 6 hereof. Each remedy shall be
cumulative and in addition to any other remedy otherwise available to Lessor at
law or in equity. No express or implied waiver of any default shall constitute a
waiver of any of Lessor's other rights.

14.  LESSEE'S REPRESENTATIONS
Lessee represents and warrants for this Master Lease and each Schedule that the
execution, delivery and performance by Lessee have been duly authorized by all
necessary corporate action; the individual executing was duly authorized to do
so; the Master Lease and each Schedule constitute valid, binding agreements of
the Lessee enforceable in accordance with their terms; that all information
supplied by Lessee, including but not limited to the credit application and
other financial information concerning Lessee, is accurate in all material
respects as of the date provided; and if there is any material change in such
information prior to manufacturer's or, if appropriate, supplier's shipment of
Product under the Schedule, Lessee will advise Lessor of such change in writing.

15.  APPLICABLE LAW
This Master Lease and each Schedule shall in all respects be governed by and
construed in accordance with the laws of the state of California without giving
effect to the principles of conflict of laws.

16.  MISCELLANEOUS
Lessee agrees to execute and deliver to Lessor such further documents,
including, but not limited to, financing statements, assignments, and financial
reports and take such further action as Lessor may reasonably request to
protect Lessor's interest in the Product.

The performance of any act or payment by Lessor shall not be deemed a waiver of
any obligation or default on the part of Lessee. Lessor's failure to require
strict performance by Lessee of any of the provisions of the Master Lease shall
not be a waiver thereof. No rights or remedies referred to in Article 2A of the
Uniform Commercial Code will be conferred on Lessee unless expressly granted in
this Master Lease.

This Master Lease together with any Schedule constitutes the entire
understanding between the parties and supersedes any previous representations
or agreements whether verbal or written with respect to the use, possession and
lease of the Product described in that Schedule. In the event of a conflict,
the terms of the Schedule shall prevail over the Master Lease.

No amendment or change of any of the terms or conditions herein shall be
binding upon either party unless they are made in writing and are signed by an
authorized representative of each party. Each Schedule in non-cancelable for
the full term specified and each Schedule shall be binding upon, and shall
inure to the benefit of Lessor, Lessee, and their respective successors, legal
representatives and permitted assigns.

All agreements, representations and warranties contained herein shall be for
the benefit of Lessor and shall survive the execution, delivery and termination
of this Master Lease, any Schedule or related document.

Any provision of this Master Lease and/or each Schedule which is unenforceable
shall not cause any other remaining provision to be ineffective or invalid. The
captions set forth herein are for convenience only and shall not define or
limit any of the terms hereof. Any notices or demands in connection with any
Schedule shall be given in writing by regular or certified mail at the address
indicated in the Schedule, or to any other address specified.


THIS MASTER LEASE SHALL BECOME EFFECTIVE ON THE DATE
ACCEPTED BY LESSOR

LESSOR: SUN MICROSYSTEMS FINANCE
A SUN MICROSYSTEMS, INC. BUSINESS

BY:           /s/ ADAM BERMAN
-----------------------------------------
NAME:             Adam Berman
-----------------------------------------
TITLE:   Manager of Lease Originations
-----------------------------------------
DATE:              6/27/00
-----------------------------------------


LESSEE: VENTRO CORPORATION

BY:       /s/ P. MICHAEL HOULIHAN
-----------------------------------------
NAME:         P. Michael Houlihan
-----------------------------------------
TITLE:             VP Finance
-----------------------------------------
DATE:              6/22/00
-----------------------------------------





<PAGE>   3

                       ADDITIONAL TERMS FOR SMI PRODUCTS

The following additional terms and conditions shall govern the use of Sun
Microsystems, Inc. ("SMI") Products leased hereunder.

1.0 USE OF SOFTWARE

Lessee's use of any software Products ("Software") provided under this Schedule
shall be governed by the object code license accompanying such Software.

2.0 WARRANTY

Product warranties may vary depending on the specific SMI Product leased.
Applicable terms and conditions are as set out in the then current U.S. End
User Price List. Software is warranted to conform to published specifications
for a period of ninety (90) days from the date of delivery. SMI does not
warrant that: (i) operation of any Software will be uninterrupted or error
free; or (ii) functions contained in Software will operate in combinations
which may be selected for use by the licensee or meet the licensee's
requirements. These warranties extend only to Lessee as an original Lessee.

Lessee's exclusive remedy and SMI's entire liability under these warranties
will be: (i) with respect to Product, repair or at SMI's option, replacement;
and (ii) with respect to Software, use its best efforts to correct such
Software as soon as practical after licensee has notified SMI of Software's
nonconformance. If such repair, replacement or correction is not reasonably
achievable, SMI will refund the rental fee/license fee. Unless Lessee has
executed an on-site service agreement, repair or replacement will be undertaken
at a service location authorized by SMI.

All Software customization is provided "AS IS," without a warranty of any kind.

No SMI warranty shall apply to any Software that is modified without SMI's
written consent or any Product or Software which has been misused, altered,
repaired or used with equipment or software not supplied or expressly approved
by SMI.

SMI reserves the right to change these warranties at any time upon Notice and
without liability to Lessee or third parties.

EXCEPT AS SPECIFIED IN THIS AGREEMENT, ALL EXPRESS OR IMPLIED REPRESENTATIONS
AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR
A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED.

3.0 TRADEMARKS AND OTHER PROPRIETARY RIGHTS

"Trademarks" means all company names, products' names, marks, logos, designs,
trade dress and other designations or brands used by Sun Microsystems, Inc.,
its subsidiaries and affiliates ("Sun") in connection with Products, including,
Sun, Sun Microsystems, the Sun logo, SPARCstation, SPARCserver, and all Sun
product designs.

Lessee is granted no right, title, license or interest in the Trademarks.
Lessee acknowledges Sun's rights in the Trademarks and agrees that any and all
use of the Trademarks by Lessee shall inure to the sole benefit of Sun.

4.0 HIGH RISK ACTIVITIES

PRODUCTS ARE NOT FAULT-TOLERANT AND ARE NOT DESIGNED, MANUFACTURED OR INTENDED
FOR USE OR RESALE AS ON-LINE CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS
REQUIRING FAIL-SAFE PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR
FACILITIES, AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL,
DIRECT LIFE SUPPORT, OR WEAPONS SYSTEMS IN WHICH THE FAILURE OF PRODUCTS COULD
LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL
DAMAGE ("HIGH RISK ACTIVITIES"). SMI SPECIFICALLY DISCLAIMS ANY EXPRESS OR
IMPLIED WARRANTY OR FITNESS FOR HIGH RISK ACTIVITIES.

Lessee represents and warrants that it will not use, distribute or resell
Products (including Software) for High Risk Activities and that it will ensure
that its end-users or customers of Products are provided with a copy of the
notice in the previous paragraph.
<PAGE>   4
                                                                  LEASE SCHEDULE

                                             Counterpart No. 2 of 2 Counterparts


[SUN MICROSYSTEMS LOGO]

Sun Microsystems Finance

                                 LEASE SCHEDULE ("SCHEDULE") NUMBER: 7099534-001
                                                            DATED: June 19, 2000
                      TO MASTER LEASE AGREEMENT ("MASTER LEASE") NUMBER: 7099534


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
LESSEE                                                            LESSOR
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                                             <C>
Name: Ventro Corporation                                          Sun Microsystems Finance
                                                                  A Sun Microsystems, Inc. Business
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     1400 Computer Drive, Suite 200
         Mountain View, CA 94043                                  Westborough, MA 01581
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Attention: Phyllis DeVarney

-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759                                      Phone Number: 508-836-2452

-----------------------------------------------------------------------------------------------------------------------------------
Fax Number: (650) 567-7661                                        Fax Number: 508-836-2487
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
BILLING ADDRESS                                                   PAYMENT SCHEDULE
-----------------------------------------------------------------------------------------------------------------------------------
Name: Ventro Corporation                                          Lease Term 24                                   [X] Months
                                                                                                                  [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     Rent                                            [X] Month
         Mountain View, CA 94043                                  $111,383.36                        per          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Rent                                                Month
Federal ID #                                                      $                                  per              Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
LOCATION OF PRODUCT                                               END OF LEASE OPTIONS
-----------------------------------------------------------------------------------------------------------------------------------
Lessee P.O. Number                                                [X] FMV Purchase or Renewal
-----------------------------------------------------------------------------------------------------------------------------------
Location: 1500 Plymouth Street                                    [ ] $1 Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
          Mountain View, CA 94043 None with import                [ ] 10% Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Ray Taft                                               For 1$ or 10% Purchase Option, the Lease Rate is ____%
                                                                  (Required in MD, GA, TX, NH, NM)
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7430
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT DESCRIPTION: Per attached quote no. 43651-A with Enterprise Quotes US01PM14V, US01PNZF3 & US01R26AI
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
MASTER LEASE: This original executed Schedule is issued and effective as of the date set forth above. All of the terms, conditions,
representations and warranties of the Master Lease identified above are hereby incorporated herein and made a part hereof as if
they were expressly set forth in this Schedule and this Schedule constitutes a separately enforceable, complete and independent
Lease with respect to the Product described herein. By their execution and delivery of this Schedule, the parties hereby affirm all
of the terms, conditions, representations and warranties of the Master Lease.

COUNTERPARTS: This Schedule may be executed in any number of counterparts, each of which shall be sequentially numbered. No
security interest in this Lease may be created through the transfer or possession of any counterpart other than Counterpart No. 1
of this Schedule, but no transfer or possession of the Master Lease will be required to create a security interest in the Lease
evidenced by this Schedule.

The "Additional Terms for SMI Products" set forth on the next page hereof are made a part of this Schedule.

OTHER TERMS (if applicable)
-----------------------------------------------------------------------------------------------------------------------------------
AGREED AND ACCEPTED BY                                            AGREED AND ACCEPTED BY

LESSOR: SUN MICROSYSTEMS FINANCE                                  LESSEE: Ventro Corporation
A SUN MICROSYSTEMS, INC. BUSINESS

BY: /s/ ADAM BERMAN                                               BY: /s/ P. MICHAEL HOULIHAN
   ---------------------------------------------                     ---------------------------------------------
NAME: Adam Berman                                                 NAME: P. Michael Houlihan
     -------------------------------------------                       -------------------------------------------
TITLE: Manager of Lease Originations                              TITLE: VP Finance
      ------------------------------------------                        ------------------------------------------
DATE: 6/27/00                                                     DATE: 6/22/00
     -------------------------------------------                       -------------------------------------------
</TABLE>


<PAGE>   5
                                                                  LEASE SCHEDULE

                                             Counterpart No. 2 of 2 Counterparts


[SUN MICROSYSTEMS LOGO]

Sun Microsystems Finance

                                 LEASE SCHEDULE ("SCHEDULE") NUMBER: 7099534-002
                                                            DATED: June 19, 2000
                      TO MASTER LEASE AGREEMENT ("MASTER LEASE") NUMBER: 7099534


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
LESSEE                                                            LESSOR
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                                             <C>
Name: Ventro Corporation                                          Sun Microsystems Finance
                                                                  A Sun Microsystems, Inc. Business
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     1400 Computer Drive, Suite 200
         Mountain View, CA 94043                                  Westborough, MA 01581
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Attention: Phyllis DeVarney

-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759                                      Phone Number: 508-836-2452

-----------------------------------------------------------------------------------------------------------------------------------
Fax Number: (650) 567-7661                                        Fax Number: 508-836-2487
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
BILLING ADDRESS                                                   PAYMENT SCHEDULE
-----------------------------------------------------------------------------------------------------------------------------------
Name: Ventro Corporation                                          Lease Term                                      [X] Months
                                                                      24                                          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     Rent                                            [X] Month
         Mountain View, CA 94043                                  $100,734.07                        per          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Rent                                                Month
Federal ID #                                                      $                                  per              Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
LOCATION OF PRODUCT                                               END OF LEASE OPTIONS
-----------------------------------------------------------------------------------------------------------------------------------
Lessee P.O. Number                                                [X] FMV Purchase or Renewal
-----------------------------------------------------------------------------------------------------------------------------------
Location: 1500 Plymouth Street                                    [ ] $1 Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
          Mountain View, CA 94043 None with import                [ ] 10% Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Ray Taft                                               For 1$ or 10% Purchase Option, the Lease Rate is ____%
                                                                  (Required in MD, GA, TX, NH, NM)
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7430
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT DESCRIPTION: Per attached Sun Quote No43652-A & with Enterprise No. US01PM14VC-22 & US01R26AI
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
MASTER LEASE: This original executed Schedule is issued and effective as of the date set forth above. All of the terms, conditions,
representations and warranties of the Master Lease identified above are hereby incorporated herein and made a part hereof as if
they were expressly set forth in this Schedule and this Schedule constitutes a separately enforceable, complete and independent
Lease with respect to the Product described herein. By their execution and delivery of this Schedule, the parties hereby affirm all
of the terms, conditions, representations and warranties of the Master Lease.

COUNTERPARTS: This Schedule may be executed in any number of counterparts, each of which shall be sequentially numbered. No
security interest in this Lease may be created through the transfer or possession of any counterpart other than Counterpart No. 1
of this Schedule, but no transfer or possession of the Master Lease will be required to create a security interest in the Lease
evidenced by this Schedule.

The "Additional Terms for SMI Products" set forth on the next page hereof are made a part of this Schedule.

OTHER TERMS (if applicable)
-----------------------------------------------------------------------------------------------------------------------------------
AGREED AND ACCEPTED BY                                            AGREED AND ACCEPTED BY

LESSOR: SUN MICROSYSTEMS FINANCE                                  LESSEE: Ventro Corporation
A SUN MICROSYSTEMS, INC. BUSINESS

BY: /s/ ADAM BERMAN                                               BY: /s/ P. MICHAEL HOULIHAN
   ---------------------------------------------                     ---------------------------------------------
NAME: Adam Berman                                                 NAME: P. Michael Houlihan
     -------------------------------------------                       -------------------------------------------
TITLE: Manager of Lease Originations                              TITLE: VP Finance
      ------------------------------------------                        ------------------------------------------
DATE: 6/27/00                                                     DATE: 6/22/00
     -------------------------------------------                       -------------------------------------------
</TABLE>


<PAGE>   6
                                                                  LEASE SCHEDULE

                                             Counterpart No. 2 of 2 Counterparts


[SUN MICROSYSTEMS LOGO]

Sun Microsystems Finance

                                 LEASE SCHEDULE ("SCHEDULE") NUMBER: 7099534-003
                                                            DATED: June 19, 2000
                      TO MASTER LEASE AGREEMENT ("MASTER LEASE") NUMBER: 7099534


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
LESSEE                                                            LESSOR
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                                             <C>
Name: Ventro Corporation                                          Sun Microsystems Finance
                                                                  A Sun Microsystems, Inc. Business
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     1400 Computer Drive, Suite 200
         Mountain View, CA 94043                                  Westborough, MA 01581
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Attention: Phyllis DeVarney

-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759                                      Phone Number: 508-836-2452

-----------------------------------------------------------------------------------------------------------------------------------
Fax Number: (650) 567-7661                                        Fax Number: 508-836-2487
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
BILLING ADDRESS                                                   PAYMENT SCHEDULE
-----------------------------------------------------------------------------------------------------------------------------------
Name: Ventro Corporation                                          Lease Term                                      [X] Months
                                                                      24                                          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     Rent                                            [X] Month
         Mountain View, CA 94043                                  $100,734.07                        per          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Rent                                                Month
Federal ID #                                                      $                                  per              Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
LOCATION OF PRODUCT                                               END OF LEASE OPTIONS
-----------------------------------------------------------------------------------------------------------------------------------
Lessee P.O. Number                                                [X] FMV Purchase or Renewal
-----------------------------------------------------------------------------------------------------------------------------------
Location: 1500 Plymouth Street                                    [ ] $1 Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
          Mountain View, CA 94043 None with import                [ ] 10% Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Ray Taft                                               For 1$ or 10% Purchase Option, the Lease Rate is ____%
                                                                  (Required in MD, GA, TX, NH, NM)
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7430
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT DESCRIPTION: Per attached quote no 43653-A with Enterprise Quotes US01PM14V-20 & US01R26AI
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
MASTER LEASE: This original executed Schedule is issued and effective as of the date set forth above. All of the terms, conditions,
representations and warranties of the Master Lease identified above are hereby incorporated herein and made a part hereof as if
they were expressly set forth in this Schedule and this Schedule constitutes a separately enforceable, complete and independent
Lease with respect to the Product described herein. By their execution and delivery of this Schedule, the parties hereby affirm all
of the terms, conditions, representations and warranties of the Master Lease.

COUNTERPARTS: This Schedule may be executed in any number of counterparts, each of which shall be sequentially numbered. No
security interest in this Lease may be created through the transfer or possession of any counterpart other than Counterpart No. 1
of this Schedule, but no transfer or possession of the Master Lease will be required to create a security interest in the Lease
evidenced by this Schedule.

The "Additional Terms for SMI Products" set forth on the next page hereof are made a part of this Schedule.

OTHER TERMS (if applicable)
-----------------------------------------------------------------------------------------------------------------------------------
AGREED AND ACCEPTED BY                                            AGREED AND ACCEPTED BY

LESSOR: SUN MICROSYSTEMS FINANCE                                  LESSEE: Ventro Corporation
A SUN MICROSYSTEMS, INC. BUSINESS

BY: /s/ ADAM BERMAN                                               BY: /s/ P. MICHAEL HOULIHAN
   ---------------------------------------------                     ---------------------------------------------
NAME: Adam Berman                                                 NAME: P. Michael Houlihan
     -------------------------------------------                       -------------------------------------------
TITLE: Manager of Lease Originations                              TITLE: VP Finance
      ------------------------------------------                        ------------------------------------------
DATE: 6/27/00                                                     DATE: 6/22/00
     -------------------------------------------                       -------------------------------------------
</TABLE>


<PAGE>   7
                                                                  LEASE SCHEDULE

                                             Counterpart No. 2 of 2 Counterparts


[SUN MICROSYSTEMS LOGO]

Sun Microsystems Finance

                                 LEASE SCHEDULE ("SCHEDULE") NUMBER: 7099534-004
                                                            DATED: June 19, 2000
                      TO MASTER LEASE AGREEMENT ("MASTER LEASE") NUMBER: 7099534


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
LESSEE                                                            LESSOR
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                                             <C>
Name: Ventro Corporation                                          Sun Microsystems Finance
                                                                  A Sun Microsystems, Inc. Business
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     1400 Computer Drive, Suite 200
         Mountain View, CA 94043                                  Westborough, MA 01581
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Attention: Phyllis DeVarney

-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759                                      Phone Number: 508-836-2452

-----------------------------------------------------------------------------------------------------------------------------------
Fax Number: (650) 567-7661                                        Fax Number: 508-836-2487
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
BILLING ADDRESS                                                   PAYMENT SCHEDULE
-----------------------------------------------------------------------------------------------------------------------------------
Name: Ventro Corporation                                          Lease Term                                      [X] Months
                                                                    24                                            [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     Rent                                            [X] Month
         Mountain View, CA 94043                                  $100,734.07                        per          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Rent                                                Month
Federal ID #                                                      $                                  per              Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
LOCATION OF PRODUCT                                               END OF LEASE OPTIONS
-----------------------------------------------------------------------------------------------------------------------------------
Lessee P.O. Number                                                [X] FMV Purchase or Renewal
-----------------------------------------------------------------------------------------------------------------------------------
Location: 1500 Plymouth Street                                    [ ] $1 Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
          Mountain View, CA 94043 None with import                [ ] 10% Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Ray Taft                                               For 1$ or 10% Purchase Option, the Lease Rate is ____%
                                                                  (Required in MD, GA, TX, NH, NM)
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7430
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT DESCRIPTION: Per attached quote no 43656-A with Enterprise Quotes US01PM14V-30, US01PNZF3 & US01R26AI
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
MASTER LEASE: This original executed Schedule is issued and effective as of the date set forth above. All of the terms, conditions,
representations and warranties of the Master Lease identified above are hereby incorporated herein and made a part hereof as if
they were expressly set forth in this Schedule and this Schedule constitutes a separately enforceable, complete and independent
Lease with respect to the Product described herein. By their execution and delivery of this Schedule, the parties hereby affirm all
of the terms, conditions, representations and warranties of the Master Lease.

COUNTERPARTS: This Schedule may be executed in any number of counterparts, each of which shall be sequentially numbered. No
security interest in this Lease may be created through the transfer or possession of any counterpart other than Counterpart No. 1
of this Schedule, but no transfer or possession of the Master Lease will be required to create a security interest in the Lease
evidenced by this Schedule.

The "Additional Terms for SMI Products" set forth on the next page hereof are made a part of this Schedule.

OTHER TERMS (if applicable)
-----------------------------------------------------------------------------------------------------------------------------------
AGREED AND ACCEPTED BY                                            AGREED AND ACCEPTED BY

LESSOR: SUN MICROSYSTEMS FINANCE                                  LESSEE: Ventro Corporation
A SUN MICROSYSTEMS, INC. BUSINESS

BY: /s/ ADAM BERMAN                                               BY: /s/ P. MICHAEL HOULIHAN
   ---------------------------------------------                     ---------------------------------------------
NAME: Adam Berman                                                 NAME: P. Michael Houlihan
     -------------------------------------------                       -------------------------------------------
TITLE: Manager of Lease Originations                              TITLE: VP Finance
      ------------------------------------------                        ------------------------------------------
DATE: 6/27/00                                                     DATE: 6/22/00
     -------------------------------------------                       -------------------------------------------
</TABLE>


<PAGE>   8
                                                                  LEASE SCHEDULE

                                             Counterpart No. 2 of 2 Counterparts


[SUN MICROSYSTEMS LOGO]

Sun Microsystems Finance

                                 LEASE SCHEDULE ("SCHEDULE") NUMBER: 7099534-005
                                                            DATED: June 19, 2000
                      TO MASTER LEASE AGREEMENT ("MASTER LEASE") NUMBER: 7099534


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
LESSEE                                                            LESSOR
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                                             <C>
Name: Ventro Corporation                                          Sun Microsystems Finance
                                                                  A Sun Microsystems, Inc. Business
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     1400 Computer Drive, Suite 200
         Mountain View, CA 94043                                  Westborough, MA 01581
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Attention: Phyllis DeVarney

-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759                                      Phone Number: 508-836-2452

-----------------------------------------------------------------------------------------------------------------------------------
Fax Number: (650) 567-7661                                        Fax Number: 508-836-2487
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
BILLING ADDRESS                                                   PAYMENT SCHEDULE
-----------------------------------------------------------------------------------------------------------------------------------
Name: Ventro Corporation                                          Lease Term                                      [X] Months
                                                                     24                                           [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Address: 1500 Plymouth Street                                     Rent                                            [X] Month
         Mountain View, CA 94043                                  $33,948.01                         per          [ ] Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Mike Houlihan                                          Rent                                                Month
Federal ID #                                                      $                                  per              Quarters
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7759
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
LOCATION OF PRODUCT                                               END OF LEASE OPTIONS
-----------------------------------------------------------------------------------------------------------------------------------
Lessee P.O. Number                                                [X] FMV Purchase or Renewal
-----------------------------------------------------------------------------------------------------------------------------------
Location: 1500 Plymouth Street                                    [ ] $1 Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
          Mountain View, CA 94043 None with import                [ ] 10% Purchase Option
-----------------------------------------------------------------------------------------------------------------------------------
Attention: Ray Taft                                               For 1$ or 10% Purchase Option, the Lease Rate is ____%
                                                                  (Required in MD, GA, TX, NH, NM)
-----------------------------------------------------------------------------------------------------------------------------------
Phone Number: (650) 567-7430
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT DESCRIPTION: Per attached Quote no for Sun 12409 for software and services
-----------------------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------------------
MASTER LEASE: This original executed Schedule is issued and effective as of the date set forth above. All of the terms, conditions,
representations and warranties of the Master Lease identified above are hereby incorporated herein and made a part hereof as if
they were expressly set forth in this Schedule and this Schedule constitutes a separately enforceable, complete and independent
Lease with respect to the Product described herein. By their execution and delivery of this Schedule, the parties hereby affirm all
of the terms, conditions, representations and warranties of the Master Lease.

COUNTERPARTS: This Schedule may be executed in any number of counterparts, each of which shall be sequentially numbered. No
security interest in this Lease may be created through the transfer or possession of any counterpart other than Counterpart No. 1
of this Schedule, but no transfer or possession of the Master Lease will be required to create a security interest in the Lease
evidenced by this Schedule.

The "Additional Terms for SMI Products" set forth on the next page hereof are made a part of this Schedule.

OTHER TERMS (if applicable)
-----------------------------------------------------------------------------------------------------------------------------------
AGREED AND ACCEPTED BY                                            AGREED AND ACCEPTED BY

LESSOR: SUN MICROSYSTEMS FINANCE                                  LESSEE: Ventro Corporation
A SUN MICROSYSTEMS, INC. BUSINESS

BY: /s/ ADAM BERMAN                                               BY: /s/ P. MICHAEL HOULIHAN
   ---------------------------------------------                     ---------------------------------------------
NAME: Adam Berman                                                 NAME: P. Michael Houlihan
     -------------------------------------------                       -------------------------------------------
TITLE: Manager of Lease Originations                              TITLE: VP Finance
      ------------------------------------------                        ------------------------------------------
DATE: 6/27/00                                                     DATE: 6/22/00
     -------------------------------------------                       -------------------------------------------
</TABLE>


<PAGE>   9
                           LETTER OF CREDIT AGREEMENT

Re: Equipment Schedule Nos. 7099534-001, 002, 003, 004 and 005 to Master Lease
Agreement No. 7099534 between Sun Microsystems Finance, A Sun Microsystems,
Inc. Business and Ventro Corporation (collectively, the "Lease")

     THIS LETTER OF CREDIT AGREEMENT dated 6/22, 2000 (the "Letter of Credit
Agreement") is by and between Ventro Corporation, a Delaware corporation
("LESSEE"), and Sun Microsystems Finance, A Sun Microsystems, Inc. Business, a
Delaware corporation ("Sun Microsystems Finance")

                                    RECITALS

     A.   LESSEE desires Sun Microsystems Finance to purchase and/or provide
certain equipment (the "Equipment") for lease to LESSEE pursuant to the Lease.

     B.   Sun Microsystems Finance is unwilling to purchase the Equipment, or to
enter into the Lease unless and until LESSEE provides Sun Microsystems Finance
with certain additional assurances in respect of the performance of LESSEE's
obligations under the Lease.

     C.   In order to induce Sun Microsystems Finance to lease the Equipment to
LESSEE under the terms and conditions set forth in the Lease, LESSEE desires to
furnish Sun Microsystems Finance with additional assurances in the form of the
letters of credit hereinafter described.

     NOW, THEREFORE, in consideration of the above premises and the promises
herein contained and other good and valuable consideration, the receipt and
adequacy of which is acknowledged by LESSEE and Sun Microsystems Finance, it is
hereby agreed as follows:

     1.   On or before the date Sun Microsystems Finance executes the Lease, and
as a condition thereof, LESSEE, at its sole cost and expense and as security for
the performance by LESSEE of any and all of its obligations under the Lease, as
now existing or hereafter amended, this Letter of Credit Agreement, or any other
agreement between LESSEE and Sun Microsystems Finance (the Lease, this Letter of
Credit Agreement, and any such other agreement being collectively referred to as
the "Agreements"), will furnish Sun Microsystems Finance with an unconditional
and irrevocable letter of credit substantially in the form of Exhibit A attached
hereto (or in such other form as may be specified by Sun Microsystems Finance's
counsel) and in the amounts specified below (the "Initial Letter of Credit"),
naming Sun Microsystems Finance as beneficiary, which shall not have an expiry
date which is earlier than the date on which all of the obligations of LESSEE to
Sun Microsystems Finance under the Lease shall expire; provided, however, that
in order to satisfy the expiry requirement of this sentence, LESSEE may provide
Sun Microsystems Finance with one or more renewal letters of credit (each, a
"Renewal Letter of Credit") for the amounts of and consistent
<PAGE>   10
with the terms and conditions provided herein. The Initial Letter of Credit and
each Renewal Letter of Credit shall be issued for a term of not less than one
year from the date of issuance, in each case by a bank acceptable in all
respects to Sun Microsystems Finance, in Sun Microsystems Finance's sole
discretion, and shall be automatically renewed at least thirty (30) days prior
to expiration unless both parties agree in writing to the termination of this
Letter of Credit Agreement or to a reduction in the amount of any Renewal
Letter of Credit. The Initial Letter of Credit and each Renewal Letter of
Credit are together referred to as the "Letter of Credit."

If requested by Sun Microsystems Finance, the Letter of Credit shall be
accompanied by an opinion of counsel acceptable to Sun Microsystems Finance, A
Sun Microsystems, Inc. Business as to its due execution, delivery and
enforceability.

     2.   The amount of the Letter of Credit shall be Three Million Nine
Hundred Eighty Thousand Eight Hundred Sixty-four Dollars (US $3,980,864)
provided, however, that the amount of the Letter of Credit shall increase to
Five Million Six Hundred Eighty-six Thousand Nine Hundred Forty-eight Dollars
($5,686,948) (the "Increased Letter of Credit") if the sum of Lessee's "Cash"
and "Cash Equivalents," as specified in Lessee's financial statements,
decreases by more than Thirty-five Million Dollars ($35,000,000) in the
aggregate in any one fiscal quarter of Lessee. If for any reason any quarterly
financial statement of LESSEE is not publicly available for review by Sun
Microsystems Finance, then Sun Microsystems Finance may declare an immediate
event of default hereunder.

     3.   Sun Microsystems Finance shall have the right to draw on the Letter
of Credit: (a) upon LESSEE'S breach of any term or condition of any of the
Agreements; (b) upon LESSEE'S default (without regard to notice or cure
periods) under any of the Agreements; (c) if permitted to do so by any specific
provision of any of the Agreements; or (d) upon the filing of a petition by or
against LESSEE under Title 11 of the United States Code or any successor or
similar law. Sun Microsystems Finance may draw any amount not exceeding, in
total, the face amount of the Letter of Credit and may receive said monies
therefrom at Sun Microsystems Finance's sole discretion, with partial drawings
permitted in Sun Microsystems Finance's sole discretion.

     4.   Sun Microsystems Finance may elect, in its sole discretion, to hold
any monies drawn under the Letter of Credit as security for LESSEE'S
performance of its respective obligations under the Agreements or may elect to
apply some or all of said monies forthwith upon drawing same, or at any time
thereafter, to LESSEE'S obligations under the Agreements in accordance with
applicable law and the provisions of such Agreements. In the event that Sun
Microsystems Finance holds such monies as security, Sun Microsystems Finance
may commingle same with its general funds and shall have no obligation to pay
any interest thereon. Within sixty (60) days of performance by LESSEE of all of
its obligations under the Agreements, Sun Microsystems Finance shall remit to
LESSEE the balance of any monies held as security.

     5.   LESSEE shall be in default of its obligations hereunder, and such
default

<PAGE>   11
shall be deemed by Sun Microsystems Finance to be a default under the Lease, in
the event that:

     (a)  it fails to furnish the Initial Letter of Credit and each Renewal
Letter of Credit to Sun Microsystems Finance as provided herein;

     (b)  it fails to deliver to Sun Microsystems Finance not later than sixty
(60) days prior to the expiration of the Initial Letter of Credit and each
Renewal Letter of Credit, respectively, a binding commitment of a bank
acceptable to Sun Microsystems Finance, that such bank will issue a Renewal
Letter of Credit;

     (c)  it fails to deliver to Sun Microsystems Finance not later than thirty
(30) days prior to the expiration of the Initial Letter of Credit and each
Renewal Letter of Credit, respectively, the applicable Renewal Letter of
Credit; or

     (d)  it fails to furnish to Sun Microsystems Finance the Increased Letter
of Credit as provided in Section 2 above.

     6.   Sun Microsystems Finance's exercise of the rights granted to it under
this Letter of Credit Agreement, including, without limitation, the right to
present drafts and to collect same because of any breach, default or declaration
of default under the Agreements or the filing of a petition by or against LESSEE
under Title 11 of the United States Code or any successor or similar law, shall
be in addition to and not in lieu of, and Sun Microsystems Finance may pursue,
Sun Microsystems Finance's other rights and remedies provided in the Agreements
or otherwise.

Each original and renewal or replacement Letter of Credit is intended to be
additional security only and is not deemed to waive any rights which Sun
Microsystems Finance has against LESSEE or against the Equipment or under the
Agreements.

     7.   This Agreement is binding upon LESSEE and Sun Microsystems Finance,
their successors and assigns. None of the terms and conditions hereof may be
changed, modified, amended, waived or varied in any manner unless in a writing
duly signed by an authorized representative of each of the parties hereto.

     8.   All notices to be given or documents to be delivered hereunder shall
be deemed to have been duly given or delivered if received by the applicable
party at the following addresses:

     If to Sun Microsystems Finance:

                         Sun Microsystems Finance,
                         A Sun Microsystems, Inc. Business
                         1400 Computer Drive, Suite 200
                         Westborough, MA 01581
                         Attn.: Operations Counsel
<PAGE>   12

     If to LESSEE:    Ventro Corporation
                      Attn Cindy Vindasius
                      1500 Plymouth Street
                      Mountain View, CA 94043

Either LESSEE or Sun Microsystems Finance may, at any time and from time to
time, in a writing delivered to the other party, give notice of a corrected or
changed address.

     9. This Agreement shall be governed and construed in accordance with the
substantive laws, but not the choice of law rules, of the State of California.

     IN WITNESS WHEREOF, the parties have executed or caused their duly
authorized representatives to execute this Letter of Credit Agreement as of the
date first above written.

Sun Microsystems Finance,                      Ventro Corporation
a Sun Microsystems, Inc. Business



By: /s/ ADAM BERMAN                            By: /s/ P. MICHAEL HOULIHAN
   ------------------------------                 ----------------------------
       (Signature)                                       (Signature)

        Adam Berman                                    P. Michael Houlihan
---------------------------------                 ----------------------------
    (Print or Type Name)                              (Print or Type Name)

  Manager of Lease Originations                            V.P. Finance
---------------------------------                 ----------------------------
    (Print or Type Title)                             (Print or Type Title)