<PAGE>   1

                                                                   EXHIBIT 10.15

                                                       Jefferies & Company, Inc.

         11100 Santa Monica Boulevard, 10th Floor, Los Angeles, California 90025
                                         Telephone (310) 575-5200 (800) 933-6656
                                                              Fax (310) 575-5165
CORPORATE FINANCE

                                  May 25, 2000

FREEREALTIME.COM, INC.
3333 Michelson Drive, Suite 430
Irvine, CA 92612

     Attention:           Geoff Moore, Chairman & Co-CEO
                          Brad Gunn, Co-CEO

Ladies and Gentlemen:

      1.    Retention. This letter agreement (the "Agreement") confirms that
FreeRealtime.com, Inc. (the "Company"), a Delaware corporation, has engaged
Jefferies & Company, Inc. ("Jefferies") to (i) render its written opinion to the
Board of Directors of the Company as to the fairness of the consideration to be
paid by the Company to the Company's shareholders from a financial point of view
(the "Fairness Opinion") in connection with the potential acquisition (the
"Acquisition") of Red Chip.com ("Red Chip"), and (ii) act as exclusive financial
advisor to and lead placement agent for the Company in connection with the
structuring, issuance and sale (the "Offering") of up to $20 million of equity
securities of the Company (the "Securities"). The Company and Jefferies
understand and agree that the Company may engage Roth Capital Partners as
co-placement agent (the "Co-Agent") in connection with the Offering and that
Jefferies shall have the right to approve the terms of such engagement and the
extent of the Co-Agent's participation in the Offering, which approval shall not
be unreasonably withheld. The rendering of the Fairness Opinion and the Offering
shall be referred to each individually and collectively as the "Transaction." In
connection with such engagement, Jefferies will assist the Company in (a)
identifying and contacting potential purchasers of the Securities, (b) preparing
an offering memorandum with respect to the Company and the Offering, and (c)
structuring and negotiating the financial aspects of the Offering. During the
term of the Agreement, the Company agrees that it will not, directly or
indirectly, offer any of the Securities or any similar securities for sale to,
or solicit any offer to purchase any of the same from, or otherwise contact,
approach or negotiate with respect thereto with any person or persons, other
than through Jefferies as agent. Delivery of the Fairness Opinion shall be
subject to the approval of Jefferies' Underwriting Assistance Committee and
Jefferies shall be under no obligation to update the Fairness Opinion after it
has been delivered.

      2.    Information on the Company. In connection with Jefferies' activities
hereunder, the Company will furnish Jefferies and its counsel with all material
and information regarding the business and financial condition of the Company
(all such information so furnished being the


<PAGE>   2

FREEREALTIME.COM, INC.
May 25, 2000
Page 2

"Information") and with a private placement memorandum with respect to the
Company and the Securities (such memorandum, including all exhibits or
supplements thereto, the "Offering Materials"). The Company recognizes and
confirms that Jefferies: (a) will use and rely solely on the Information,
information in the Proxy Statement prepared by the Company with respect to the
Acquisition, the Offering Materials and on information available from generally
recognized public sources in performing the services contemplated by this
Agreement without having independently verified the same; (b) is authorized as
the Company's exclusive financial advisor and sole placement agent to transmit
to any prospective purchaser of the Securities a copy or copies of the Offering
Materials, and the forms of purchase agreements and other legal documentation
necessary or advisable in connection with the transactions contemplated hereby;
(c) does not assume responsibility for the accuracy or completeness of the
Information, the Proxy Statement, the Offering Materials or such other
information; (d) will not make an appraisal of any assets or liabilities of the
Company; (e) will not perform due diligence on any potential purchasers of the
Securities; and (f) retains the right to continue to perform due diligence on
the Company during the course of the engagement.

      3.    Use of Name. The Company agrees that any reference to Jefferies in
any release, communication, or other material is subject to Jefferies' prior
written approval, which may be given or withheld in its sole discretion. If
Jefferies resigns prior to the dissemination of any such release, communication
or material, no reference shall be made therein to Jefferies, despite any prior
written approval that may have been given therefor.

      4.    Use of Advice. No statements made or advice rendered by Jefferies in
connection with the services performed by Jefferies pursuant to this Agreement
will be quoted by, nor will any such statements or advice be referred to, in any
report, document, release or other communication, whether written or oral,
prepared, issued or transmitted by, the Company or any person or corporation
controlling, controlled by or under common control with, the Company or any
director, officer, employee, agent or representative of any such person, without
the prior written authorization of Jefferies, which may be given or withheld in
its sole discretion, except to the extent required by law (in which case the
appropriate party shall so advise Jefferies in writing prior to such use and
shall consult with Jefferies with respect to the form and timing of disclosure).

      5.    Compensation. In payment for services rendered and to be rendered
hereunder by Jefferies, the Company agrees to pay to Jefferies as follows:

            (a)   A non-refundable cash fee of $100,000 upon the delivery of the
Fairness Opinion by Jefferies to the Board of Directors of the Company.

            (b)   A non-refundable cash fee of $200,000 upon the earlier to
occur of (i) the date of the first hearing with representatives of the State of
California regarding the fairness of the Acquisition, (ii) 45 days from the date
of the delivery of the Fairness Opinion to the Board of Directors of the
Company, or (iii) the consummation of a Transaction.


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FREEREALTIME.COM, INC.
May 25, 2000
Page 3

            (c)   Upon consummation of the Offering, or in the event there are
multiple closings of the sale of Securities, upon each closing, the Company
shall pay to Jefferies in cash a fee based on the aggregate gross proceeds from
such sale of Securities (the "Success Fee"). The Success Fee shall be an amount
that is equal to:

                  (i)   for each closing in which the aggregate gross proceeds
from Securities placed through Jefferies is less than $7 million, the sum of 7%
of the aggregate gross proceeds from the issuance of the Securities placed
through Jefferies in connection with such closing plus 2% of the aggregate gross
proceeds from the issuance of the Securities placed through the Co-Agent in
connection with such closing; and

                  (ii)  for each closing in which the aggregate gross proceeds
from Securities placed by Jefferies is equal to or greater than $7 million, the
greater of (A) the difference between $700,000 and the aggregate Success Fee
paid to Jefferies pursuant to Section 5(c)(i) above; or (B) the sum of 7% of the
aggregate gross proceeds from the issuance of the Securities placed by Jefferies
in connection with such closing plus 2% of the aggregate gross proceeds from the
issuance of the Securities placed by any Co-Agent in connection with such
closing.

      In addition, if the Company consummates the sale of the Securities and
undertakes within one year of the closing of the sale of the Securities (i) a
financing, Jefferies shall be given the right, but not the obligation, to act as
lead manager or co-manager for such an offering and to receive at least 40% of
the aggregate gross spread from such an offering (such gross spread in such
transactions will be mutually determined in good faith by the Company and
Jefferies and shall be based on the prevailing market for similar services); or
(ii) a merger with or into, a consolidation with, a sale of all or substantially
all of its assets to, or an acquisition of all or substantially all of the
assets of, another person or group of affiliated persons (other than the Company
or its subsidiaries) in a transaction or series of related transactions (any
such transaction, a "Sale"), then Jefferies shall be given the right, but not
the obligation, to act as a financial advisor to the Company for such
transaction or transactions. Upon receiving notice from the Company regarding
its intent to undertake such an offering or Sale, Jefferies shall promptly
indicate to the Company in writing whether it intends to exercise its right to
act as lead manager or co-manager in such offering or as a financial advisor in
such Sale. The retention and compensation of Jefferies for such subsequent
transactions shall be outlined in a separate agreement or agreements not
considered part of this Agreement.

            (d)   Upon consummation of the sale of Securities, or in the event
there are multiple closings of the sale of Securities, upon each closing of the
sale of Securities, the Company shall issue to Jefferies warrants (the
"Warrants") to purchase that number of shares of the Securities equal to:

                  (i)   for each closing in which the aggregate gross proceeds
from Securities placed by Jefferies is less than $7 million, warrants to
purchase the number of Securities equal to the sum of 7% of the number of
Securities placed through Jefferies in


<PAGE>   4


FREEREALTIME.COM, INC.
May 25, 2000
Page 4

connection with such closing plus 2% of the number of Securities placed through
the Co-Agent in connection with such closing; and

                  (ii)  for each closing in which the aggregate gross proceeds
from Securities placed by Jefferies is equal to or greater than $7 million, the
greater of (A) the difference between 200,000 and the total number of warrants
previously issued to Jefferies under Section 5(d)(i) above; or (B) the sum of 7%
of the number of securities placed through Jefferies in connection with such
closing plus 2% of the number of Securities placed through the Co-Agent in
connection with such closing.

      The Warrants shall be exercisable at any time following their issuance at
the Offering price and shall have a term of five years. The Warrants will be
evidenced by a Warrant Agreement which shall contain customary anti-dilution,
exercise and registration rights provisions and such other terms as the parties
may agree upon, and which shall be delivered by the Company to Jefferies at the
closing.

            (e)   In addition to the compensation to be paid to Jefferies as
provided in Sections 5(a), 5(b), 5(c), and 5(d) hereof, without regard to
whether any Transaction is consummated or this Agreement expires or is
terminated, the Company shall pay to, or on behalf of, Jefferies, promptly as
billed, all fees, disbursements and out-of-pocket expenses incurred by Jefferies
in connection with its services to be rendered hereunder (including, without
limitation, the fees and disbursements of Jefferies' counsel, travel and lodging
expenses, word processing charges, messenger and duplicating services, facsimile
expenses and other customary expenditures).

            (f)   Jefferies may resign at any time and the Company may terminate
Jefferies' services at any time, each by giving prior written notice to the
other. If Jefferies resigns or the Company terminates Jefferies' services for
any reason, Jefferies and its counsel shall be entitled to receive all of the
amounts due pursuant to Sections 5(a), 5(b), 5(c), 5(d) and 5(e) hereof up to
and including the effective date of such termination or resignation, as the case
may be. If, prior to the consummation of the sale of Securities, Jefferies'
services hereunder are terminated by the Company or this Agreement expires, and
the Company completes an offering similar to the Offering contemplated herein
within one year of such termination or expiration, then the Company shall pay
Jefferies concurrently with the closing of such transaction in cash the fees as
outlined in Sections 5(c) and 5(d).

            (g)   No fee paid or payable to Jefferies or any of its affiliates
shall be credited against any other fee paid or payable to Jefferies or any of
its affiliates.

            (h)   Jefferies shall have the right but not the obligation to
purchase at the closing of the sale of Securities up to $2.5 million of the
Securities at the same price and on the same terms as other investors in the
Offering.

      6.    Representations and Warranties. The Company represents and warrants
to Jefferies that (a) this Agreement has been duly authorized, executed and
delivered by the


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FREEREALTIME.COM, INC.
May 25, 2000
Page 5

Company; and, assuming the due execution by Jefferies, constitutes a legal,
valid and binding agreement of the Company, enforceable against the Company in
accordance with its terms, and (b) the Information and the Offering Materials
will not, when delivered nor at the closing of the sale of the Securities,
contain any untrue statement of a material fact or omit to state a material fact
necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading. The Company shall advise Jefferies
promptly of the occurrence of any event or any other change prior to the closing
which results in the Information or the Offering Materials containing any untrue
statement of a material fact or omitting to state any material fact necessary to
make the statements contained therein, in light of the circumstances under which
they were made, not misleading.

      7.    Indemnity; Limitation of Liability. In partial consideration of the
services to be rendered hereunder the Company shall indemnify Jefferies and
certain other Indemnified Persons (as defined in Schedule A hereto) in
accordance with Schedule A attached hereto. The Company shall not and shall
cause its affiliates and their respective directors, officers, employees,
shareholders and agents not to, initiate any action or proceeding against
Jefferies or any other Indemnified Person in connection with this engagement or
the Acquisition or Transaction unless such action or proceeding is based solely
upon the bad faith or gross negligence of Jefferies or any such Indemnified
Person. The parties hereto agree that Jefferies and the Indemnified Persons
shall not, and shall not be deemed to, owe any fiduciary duties to the Company
under this agreement or otherwise.

      8.    Conditions of Placement. It is understood that the execution of this
Agreement shall not be deemed or construed as obligating Jefferies to purchase
any of the Securities and there is no obligation on the part of Jefferies to
place the Securities or render the Fairness Opinion. Jefferies' services to be
performed hereunder are subject to certain conditions, including, among others,
(i) approval of Jefferies' Underwriting Assistance Committee, (ii) satisfactory
completion of due diligence on the Company by Jefferies, (iii) the form and
terms of the Securities being mutually acceptable to the Company, Jefferies and
prospective purchasers of the Securities, (iv) market conditions, and (v) no
adverse change in the condition of the Company.

      9.    Survival of Certain Provisions. The indemnity and contribution
agreements contained in Schedule A to this Agreement and the provisions of
Sections 2, 3, 4, 5, 6, 7, 14 and 15 of this Agreement and this Section 9 shall
remain operative and in full force and effect regardless of (a) any
investigation made by or on behalf of Jefferies, or by or on behalf of any
affiliate of Jefferies or any person controlling either, (b) completion of the
Transaction, (c) the resignation of Jefferies or any termination of Jefferies'
services or (d) any amendment, expiration or termination of this Agreement, and
shall be binding upon, and shall inure to the benefit of, any successors,
assigns, heirs and personal representatives of the Company, Jefferies, and the
Indemnified Persons.

      10.   Notices. Notice given pursuant to any of the provisions of this
Agreement shall be in writing and shall be mailed or delivered (a) if to the
Company, at the address set forth


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FREEREALTIME.COM, INC.
May 25, 2000
Page 6

above, and (b) if to Jefferies, at the offices of Jefferies at 11100 Santa
Monica Boulevard, Suite 1000, Los Angeles, California 90025, Attention: Jerry M.
Gluck, Executive Vice President and General Counsel.

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

      12.   Assignment. This Agreement may not be assigned by either party
hereto without the prior written consent of the other, to be given in the sole
discretion of the party from whom such consent is being requested. Any attempted
assignment of this Agreement made without such consent may be void, at the
option of the non-assigning party.

      13.   Third Party Beneficiaries. This Agreement has been and is made
solely for the benefit of the Company, Jefferies and the other Indemnified
Persons referred to in Schedule A hereof and their respective successors and
assigns, and no other person shall acquire or have any right under or by virtue
of this Agreement.

      14.   Construction and Choice of Law. This Agreement, together with
Schedule A attached hereto, incorporates the entire understanding of the parties
and supersedes all previous agreements relating to the subject matter hereof
should they exist. This Agreement and any issue arising out of or relating to
the parties' relationship hereunder shall be governed by, and construed in
accordance with, the laws of the State of New York, without regard to principles
of conflicts of law.

      15.   Jurisdiction and Venue. Each party hereto consents specifically to
the exclusive jurisdiction of the federal courts of the United States sitting in
the Southern District of New York, or if such federal court declines to exercise
jurisdiction over any action filed pursuant to this Agreement, the courts of the
State of New York sitting in the County of New York, and any court to which an
appeal may be taken in connection with any action filed pursuant to this
Agreement, for the purposes of all legal proceedings arising out of or relating
to this Agreement. In connection with the foregoing consent, each party
irrevocably waives, to the fullest extent permitted by law, any objection which
it may now or hereafter have to the court's exercise of personal jurisdiction
over each party to this Agreement or the laying of venue of any such proceeding
brought in such a court and any claim that any such proceeding brought in such a
court has been brought in an inconvenient forum. Each party further irrevocably
waives its right to a trial by jury and consents that service of process may be
effected in any manner permitted under the laws of the State of New York.

      16.   Heading. The section headings in this Agreement have been inserted
as a matter of convenience of reference and are not part of this Agreement.

      17.   Press Announcements. At any time after the consummation or other
public announcement of the sale of the Securities, Jefferies may place an
announcement in such


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FREEREALTIME.COM, INC.
May 25, 2000
Page 7

newspapers and publications as it may choose, stating that Jefferies has acted
as exclusive financial advisor and sole placement agent to the Company in
connection with the Transaction.

      18.   Amendment. This Agreement may not be modified or amended except in a
writing duly executed by the parties hereto.

      19.   Term. Except as provided herein, this Agreement shall run from the
date of this letter to a date of six months thereafter, unless extended by
mutual consent of the parties (the "Term").


<PAGE>   8


FREEREALTIME.COM, INC.
May 25, 2000
Page 8

      Please sign and return an original and one copy of this letter to the
undersigned to indicate your acceptance of the terms set forth herein, whereupon
this letter and your acceptance shall constitute a binding agreement between the
Company and Jefferies as of the date first above written.

                                        Sincerely,

                                        JEFFERIES & COMPANY, INC.


                                        By
                                           -----------------------------------

                                        Name:
                                              --------------------------------

                                        Title:
                                               -------------------------------

Accepted and Agreed:

FREEREALTIME.COM, INC,

By  /s/ BRAD GUNN
   -----------------------------
   Name: Brad Gunn

   Date: May 26, 2000


<PAGE>   9



                                   SCHEDULE A

                                           May 25, 2000

JEFFERIES & COMPANY, INC.
11100 Santa Monica Boulevard, 10th Floor
Los Angeles, CA 90025

Ladies and Gentlemen:

      This letter agreement is entered into pursuant to, and in order to induce
Jefferies & Company, Inc. ("Jefferies" or the "Placement Agent") to enter into,
the engagement letter, dated May 25, 2000 (as amended from time to time in
accordance with the terms thereof, the "Agreement"), between FREEREALTIME.COM,
INC. (the "Company"), a Delaware corporation, and Jefferies. Unless otherwise
noted, all capitalized terms used herein shall have the meanings set forth in
the Agreement.

      Since Jefferies will be acting on behalf of the Company in connection with
the transactions contemplated by the Agreement, and as part of the consideration
for the agreement of Jefferies to furnish its services pursuant to such
Agreement, the Company agrees to indemnify and hold harmless Jefferies and its
affiliates and their respective officers, directors, partners, counsel,
employees and agents, and any other persons controlling Jefferies or any of its
affiliates within the meaning of either Section 15 of the Securities Act of 1933
or Section 20 of the Securities Exchange Act of 1934, and the respective agents,
employees, officers, directors, partners, counsel and shareholders of such
persons (Jefferies and each such other person being referred to as an
"Indemnified Person"), to the fullest extent lawful, from and against all
claims, liabilities, losses, damages and expenses (or actions in respect
thereof), as incurred, related to or arising out of or in connection with (i)
actions taken or omitted to be taken by the Company, its affiliates, employees
or agents, (ii) actions taken or omitted to be taken by any Indemnified Person
(including acts or omissions constituting ordinary negligence) pursuant to the
terms of, or in connection with services rendered pursuant to, the Agreement or
any Transaction or proposed transaction contemplated thereby or any Indemnified
Person's role in connection therewith, provided, however, that the Company shall
not be responsible for any losses, claims, damages, liabilities or expenses of
any Indemnified Person to the extent, and only to the extent, that it is finally
judicially determined that they result solely from actions taken or omitted to
be taken by such Indemnified Person in bad faith or to be due solely to such
Indemnified Person's gross negligence, and/or (iii) any untrue statement or
alleged untrue statement of a material fact contained in any of the Information,
the Offering Materials, or in any amendment or supplement thereto, or arising
out of or based upon any omission or alleged omission of a material fact
required to be stated therein or necessary to make the statements therein not
misleading.



<PAGE>   10


JEFFERIES & COMPANY, INC.
May 25, 2000
Page 2

      The Company shall not settle or compromise or consent to the entry of any
judgment in or otherwise seek to terminate any pending or threatened action,
claim, suit or proceeding in which any Indemnified Person is or could be a party
and as to which indemnification or contribution could have been sought by such
Indemnified Person hereunder (whether or not such Indemnified Person is a party
thereto), unless such Indemnified Person has given its prior written consent or
the settlement, compromise, consent or termination includes an express
unconditional release of such Indemnified Person, satisfactory in form and
substance to such Indemnified Person, from all losses, claims, damages or
liabilities arising out of such action, claim, suit or proceeding.

      If for any reason (other than the bad faith or gross negligence of an
Indemnified Person as provided above) the foregoing indemnity is unavailable to
an Indemnified Person or insufficient to hold an Indemnified Person harmless,
then the Company, to the fullest extent permitted by law, shall contribute to
the amount paid or payable by such Indemnified Person as a result of such
claims, liabilities, losses, damages or expenses in such proportion as is
appropriate to reflect the relative benefits received by the Company on the one
hand and by Jefferies on the other, from the Transaction or proposed transaction
under the Agreement or, if allocation on that basis is not permitted under
applicable law, in such proportion as is appropriate to reflect not only the
relative benefits received by the Company on the one hand and Jefferies on the
other, but also the relative fault of the Company and Jefferies, as well as any
relevant equitable considerations. Notwithstanding the provisions hereof, the
aggregate contribution of all Indemnified Persons to all claims, liabilities,
losses, damages and expenses shall not exceed the amount of fees actually
received by Jefferies pursuant to the Agreement with respect to the Transaction.
It is hereby further agreed that the relative benefits to the Company on the one
hand and Jefferies on the other with respect to any Transaction or proposed
transaction contemplated by the Agreement shall be deemed to be in the same
proportion as (i) the total value of the Transaction bears to (ii) the fees paid
to Jefferies with respect to such Transaction. The relative fault of the Company
on the one hand and Jefferies on the other with respect to the Transaction shall
be determined by reference to, among other things, whether any untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by the Company or by Jefferies
and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.

      No Indemnified Person shall have any liability to the Company or any
officer, director, employee or affiliate thereof in connection with the services
rendered pursuant to the Agreement except for any liability for claims,
liabilities, losses or damages finally judicially determined to have resulted
solely from actions taken or omitted to be taken by such Indemnified Person in
bad faith or solely as a result of such Indemnified Person's gross negligence.

      In addition, the Company shall reimburse the Indemnified Persons for all
expenses (including, without limitation, fees and expenses of counsel) as they
are incurred in connection with investigating, preparing, defending or settling
any such action or claim, whether or not in connection with litigation in which
any Indemnified Person is a named party. If any of Jefferies' personnel appears
as witnesses, are deposed or are otherwise involved in the defense of any



<PAGE>   11


JEFFERIES & COMPANY, INC.
May 25, 2000
Page 3

action against Jefferies, the Company or the Company's officers or directors,
the Company shall pay Jefferies (i) with respect to each day that one of
Jefferies' professional personnel appears as a witness or is deposed and/or (ii)
with respect to each day that one of Jefferies' professional personnel is
involved in the preparation therefor, (a) a fee of $2,000 per day for each such
person with respect to each appearance as a witness or for a deposition and (b)
at a rate of $200 per hour with respect to each hour of preparation for any such
appearance and the Company will reimburse Jefferies for all reasonable expenses
incurred by Jefferies by reason of any of its personnel being involved in any
such action.

      The indemnity, contribution and expense reimbursement obligations set
forth herein (i) shall be in addition to any liability the Company may have to
any Indemnified Person at common law or otherwise, (ii) shall survive the
expiration of the Term, (iii) shall apply to any modification of Jefferies'
engagement and shall remain in full force and effect following the completion or
termination of the Agreement, (iv) shall remain operative and in full force and
effect regardless of any investigation made by or on behalf of Jefferies or any
other Indemnified Person and (v) shall be binding on any successor or assign of
the Company and successors or assigns to all or substantially all of the
Company's business and assets.

      Please sign and return an original and one copy of this letter to the
undersigned to indicate your acceptance of the terms set forth herein, whereupon
this letter and your acceptance shall constitute a binding agreement between the
Company and Jefferies as of the date of the Agreement.

                                   Sincerely,

                                   FREEREALTIME.COM, INC.

                                   By /s/ BRAD G. GUNN
                                      ------------------------------
                                       Brad G. Gunn

                                   Title: PRESIDENT & CO-CEO
                                          --------------------------

Accepted and Agreed:

JEFFERIES & COMPANY, INC.

By
   ------------------------------

   Name:

   Title: