EXHIBIT 4.1

#### AMENDMENT TO THE SERIES E PREFERRED STOCK PURCHASE AGREEMENT

This Amendment to the Series E Preferred Stock Purchase Agreement (the
"Amendment") is entered into as of August 16, 2001, by and among OptiMark
Holdings, Inc., a Delaware corporation (the "Company"), and each of the
entities, severally and not jointly, whose names are set forth on the signature
pages hereto.

WHEREAS, the Company and each of the entities
(which entities are hereinafter
collectively referred to as "Initial Purchasers"), severally and not jointly,
whose names are set forth on the Schedule of Initial Purchasers attached as
Annex A to this Amendment have entered into a Series E Preferred Stock Purchase
Agreement, dated as of June 29, 2001 (the "Purchase Agreement"). Defined terms
used herein but not defined herein shall have the meanings ascribed to them in
the Purchase Agreement; and

WHEREAS, the Company has requested that the Initial Purchasers agree to amend
the Purchase Agreement and the Initial Purchasers, being the holders of at least
a majority of the Shares as of the date hereof, have agreed to accommodate such
request.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties, intending to be legally bound,
hereby agree as follows:

1.     Amendment of
Section 5.4.  Section 5.4 of the Purchase Agreement is hereby amended by adding
after the last sentence of Section 5.4 the following:

| | In
the event SOFTBANK exercises its right to have the Compensation Committee
Requirement satisfied pursuant to the immediately preceding sentence and
SOFTBANK fails to give the Company notice of such exercise no later than seven
days prior to any Closing Date, SOFTBANK shall waive the Companys
obligations pursuant to Section 6.2(k) with respect to such Closing Date.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

2.     Amendment of Exhibit
A.  Exhibit A of the Purchase Agreement is hereby deleted and
replaced in its entirety by the following:

### Exhibit A

|Closing Date | Purchaser | Purchase Price |  | PreferredShares
Issued
|------------ | --------- | -------------- |  | ----------------------

|June 29, 2001 | Softbank Capital Partners LP      | $3,024,879  |  | 201,658
|------------- | --------------------------------- | ----------- |  | -------
|              | Softbank Capital LP               | $2,972,910  |  | 198,194
|              | Softbank Capital Advisors Fund LP | $52,211     |  | 3,480  
|              |                                   |             |  |        
|              |                                   | $6,050,000* |  | 403,332

*On the First Closing Date, $4,069,064.41 will be paid by SOFTBANK pursuant to
the cancellation of six promissory notes issued by the Company to SOFTBANK.
$4,000,000 of such amount is the aggregate principal amount of the notes and the
balance is interest due as of such date. In addition, SOFTBANK will
withhold $154,140.05 from the $6,050,000 due at the First Closing for payment of fees of its counsel.

|July 13, 2001            | Softbank Capital Partners LP      | $549,978    |  | 36,665   
|------------------------ | --------------------------------- | ----------- |  | ---------
|                         | Softbank Capital LP               | $540,529    |  | 36,035   
|                         | Softbank Capital Advisors Fund LP | $9,493      |  | 633      
|                         |                                   |             |  |          
|                         |                                   | $1,100,000  |  | 73,333   
|                         |                                   |             |  |          
|August 13, 2001          | Softbank Capital Partners LP      | $651,759.65 |  | 43,451   
|                         | Softbank Capital LP               | $640,561.96 |  | 42,704   
|                         | Softbank Capital Advisors Fund LP | $11,249.82  |  | 750      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,325,000  |  | 88,333   
|                         |                                   |             |  |          
|September 14, 2001       | Softbank Capital Partners LP      | $680,758.49 |  | 45,384   
|                         | Softbank Capital LP               | $669,062.58 |  | 44,604   
|                         | Softbank Capital Advisors Fund LP | $11,750.36  |  | 784      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,383,000  |  | 92,200   
|                         |                                   |             |  |          
|October 11, 2001         | Softbank Capital Partners LP      | $614,261.15 |  | 40,951   
|                         | Softbank Capital LP               | $603,707.71 |  | 40,247   
|                         | Softbank Capital Advisors Fund LP | $10,602.57  |  | 707      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,250,000  |  | 83,333   
|                         |                                   |             |  |          
|November 13, 2001        | Softbank Capital Partners LP      | $539,264.15 |  | 35,951   
|                         | Softbank Capital LP               | $529,999.21 |  | 35,333   
|                         | Softbank Capital Advisors Fund LP | $9,308.07   |  | 621      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,100,000  |  | 73,333   
|                         |                                   |             |  |          
|December 13, 2001        | Softbank Capital Partners LP      | $539,264.15 |  | 35,951   
|                         | Softbank Capital LP               | $529,999.21 |  | 35,333   
|                         | Softbank Capital Advisors Fund LP | $9,308.07   |  | 621      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,100,000  |  | 73,333   
|                         |                                   |             |  |          
|January 14, 2002         | Softbank Capital Partners LP      | $539,264.15 |  | 35,951   
|                         | Softbank Capital LP               | $529,999.21 |  | 35,333   
|                         | Softbank Capital Advisors Fund LP | $9,308.07   |  | 621      
|                         | Big Island LLC                    | $21,428.57  |  | 1,428    
|                         |                                   |             |  |          
|                         |                                   | $1,100,000  |  | 73,333   
|                         |                                   |             |  |          
|February 13, 2002        | Softbank Capital Partners LP      | $285,274.31 |  | 19,018   
|                         | Softbank Capital LP               | $280,373.09 |  | 18,693   
|                         | Softbank Capital Advisors Fund LP | $4,924.03   |  | 327      
|                         | Big Island LLC                    | $21,428.57  |  | 1,432    
|                         |                                   |             |  |          
|                         |                                   | $592,000    |  | 39,470   
|                         |                                   |             |  |          
|                         |                                   |             |  |          
|                         |                                   |             |  |          
|Total After All Closings |                                   | $15,000,000 |  | 1,000,000

2

3.     Amendment of Exhibit
E-2.  Exhibit E-2 of the Purchase Agreement is hereby deleted and
replaced in its entirety by the following:

#### Exhibit E-2

#### Employees
Subject to the Non-CompetitionAgreement on
or Before July 13, 2001

Gary Meshell
Trevor Price

#### Employees
Subject to the Non-CompetitionAgreement on
or Before August 13, 2001

Robert Warshaw

4.     No Other Amendments; Purchase Agreement
Remains in Effect.  Except as expressly amended by this Amendment,
the Purchase Agreement shall remain in full force and effect in the form in
which it existed immediately prior to the execution and delivery of this
Amendment.

5.     Fees and Expenses.  Each party
shall bear its own fees and expenses incurred in connection with the
negotiation, preparation, execution and delivery of this Amendment.

6.     Modification and Waiver.  No
amendment or modification of the terms or provisions of this Amendment shall be
binding unless the same shall be in writing and duly executed by the parties
hereto. No waiver of any of the provisions of this Amendment shall be deemed to
or shall constitute a waiver of any other provisions hereof. No delay on the
part of any party in exercising any right, power or privilege hereunder shall
operate as a waiver thereof.

7.     No Implied Rights. Nothing herein,
express or implied, is intended to or shall be construed to confer upon or give
to any person, firm, corporation or legal entity, other than the parties hereto
and their affiliates, any interest, rights, remedies or other benefits with
respect to or in connection with any agreement or provision contained herein or
contemplated hereby.

8.     Entire Agreement.  This
Amendment and the Purchase Agreement set forth the entire understanding of the
parties with respect to the subject matter hereof and thereof. Any previous
understandings between the parties regarding the subject matter hereof and
thereof are merged into and superseded by this Amendment and the Purchase
Agreement.

9.     Counterparts.  This Amendment
may be executed in one or more counterparts, each of which shall be deemed to be
an original, but all of which shall constitute one and the same instrument.

10.     Governing Law.  This Amendment
shall be governed by and construed in accordance with the laws of the State of
New York.

3

IN WITNESS WHEREOF, the parties hereto have executed this Amendment to the Purchase
Agreement as of the date set forth in the first paragraph hereof.

| | OPTIMARK HOLDINGS, INC.
| | -----------------------

| | By: | /s/ Robert J Warshaw              | 
| | --- | --------------------------------- | 
| |     |                                   | 
| |     | Name: Robert J Warshaw
Title: CEO | 

| | SOFTBANK CAPITAL PARTNERS LP
| | ----------------------------

| | By: | SOFTBANK Capital Partners LLCIts General Partner | 
| | --- | ------------------------------------------------ | 

| | By: | /s/ Steven J. Murray                        | 
| | --- | ------------------------------------------- | 
| |     |                                             | 
| |     | Name: Steven J. Murray
Title: Admin. Member | 

| | Address:1188 Centre Street
Newton Center, Massachusetts  02459
Attention:  Ron Fisher
Facsimile No.:  (617) 928-9301
| | --------------------------------------------------------------------------------------------------------------------

4

| | SOFTBANK CAPITAL LP
| | -------------------

| | By: | SOFTBANK Capital Partners LLCIts General Partner | 
| | --- | ------------------------------------------------ | 

| | By: | /s/ Steven J. Murray                        | 
| | --- | ------------------------------------------- | 
| |     |                                             | 
| |     | Name: Steven J. Murray
Title: Admin. Member | 

| | Address:1188 Centre Street
Newton Center, Massachusetts  02459
Attention:  Ron Fisher
Facsimile No.:  (617) 928-9301
| | --------------------------------------------------------------------------------------------------------------------

| | SOFTBANK CAPITAL ADVISORS FUND LP
| | ---------------------------------

| | By: | SOFTBANK Capital Partners LLCIts General Partner | 
| | --- | ------------------------------------------------ | 

| | By: | /s/ Steven J. Murray                        | 
| | --- | ------------------------------------------- | 
| |     |                                             | 
| |     | Name: Steven J. Murray
Title: Admin. Member | 

| | Address:1188 Centre Street
Newton Center, Massachusetts  02459
Attention:  Ron Fisher
Facsimile No.:  (617) 928-9301
| | --------------------------------------------------------------------------------------------------------------------

Acknowledged and AgreedBIG ISLAND LLC

|By: |                                      | 
|--- | ------------------------------------ | 
|    |                                      | 
|By: | /s/ David R. Duncan                  | 
|    |                                      | 
|    | Name: David R. Duncan
Title: Manager | 

|Address:1777 South Harrison Street
Penthouse One
Denver, Colorado  80210
Attention:  David R. Duncan
Facsimile No.:  (303) 757-0252 | 
|----------------------------------------------------------------------------------------------------------------------------------- | 

5

Annex A

##### Schedule of Initial Purchasers

Softbank Capital Partners LP
Softbank Capital LP
Softbank Capital Advisors Fund LP