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                                                                    EXHIBIT 10.4


                          DATA BROADCASTING CORPORATION
                              3490 Clubhouse Drive
                             Jackson, Wyoming 83014



November 14, 1999

Mr. Alan J. Hirschfield
1150 Fall Creek Road
Wilson, Wyoming  83014

Dear Mr. Hirschfield:

This agreement and release (this "Letter Agreement") confirms the termination of
your status as an officer and employee of and with Data Broadcasting Corporation
(the "Company"), and each of the Company's direct and indirect subsidiaries,
such termination to be effective upon the effective time of the merger
contemplated by the Agreement and Plan of Merger, dated as of the date hereof,
among the Company, Detective Merger-Sub, Inc., Interactive Data Corporation and
Pearson Longman, Inc. (the "Termination Date"). In addition, for good and
valuable consideration, the receipt of which is hereby acknowledged, you and the
Company mutually agree as follows:

1.   Termination of Employment Agreement; Resignation as Employee and Officer.
     Your execution of this Letter Agreement hereby confirms in writing the
     termination of your status as an employee and officer of the Company and
     any and all of its subsidiaries, effective as of the Termination Date. Such
     execution further confirms that, except as otherwise provided herein, the
     employment agreement dated as of October 7, 1999 between you and the
     Company (the "Employment Agreement") is terminated effective as of the
     Termination Date, and all provisions thereof shall be null and void as of
     such date.

2.   Director Status. Although your status (if any) as Chairman or Co-Chairman
     of the Board of Directors of the Company (the "Board") will cease as of the
     Termination Date, this Letter Agreement will not affect your status as a
     member of the Board, and you may continue to serve as such until expiration
     of your term. If you are removed as a director of the Company prior to
     expiration of your term, or you are not re-elected after expiration of your
     term, any remaining payments pursuant to Section 3(a) below will be
     accelerated. Any directorships that you may hold in any subsidiary of the
     Company will terminate upon the Termination Date.

3.   Payments and Benefits. In connection with your termination and resignation,
     you shall receive the following (subject, in each case, to (i) your
     compliance with the terms of this Letter Agreement, and (ii) applicable
     statutory deductions and withholdings):

     (a)  a payment of $1,125,000, spread over the three-year period commencing
          on the Termination Date (the "Severance Period") and made in
          accordance with the Company's normal payroll practices;
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     (b)  full vesting of any unvested stock options, and the ability to
          exercise all of your outstanding options until the end of the
          Severance Period (or, if earlier, the expiration of the outside term
          of each such option); and

     (c)  continued coverage under the Company's group medical plan during the
          Severance Period on the same basis as active employees of the Company
          are covered, and for purposes of determining any period of "COBRA"
          coverage thereafter, your "qualifying event" shall be deemed to have
          occurred on the Termination Date.

4.   Cessation of all other Compensation and Benefits. From and after the
     Termination Date, and except as otherwise expressly set forth in this
     Letter Agreement, you will not receive compensation, payments or benefits
     of any kind from the Company or its subsidiaries, and you expressly
     acknowledge and agree that, except with respect to the payments and
     benefits specifically set forth in this Letter Agreement, you are not
     entitled to any compensation, payment or benefit whatsoever, including,
     without limitation, any right to payment under Section 8 or 10 of the
     Employment Agreement.

5.   Payment is in Consideration of Release and Other Continuing Obligations.
     You understand and agree that the payments provided for in Section 3 of
     this Letter Agreement are being provided to you in consideration for your
     acceptance and execution of, and in reliance upon your agreements in, this
     Letter Agreement, including but not limited to the release contained
     herein.

6.   Certain Covenants. You acknowledge and agree that Section 6
     (non-competition) and Section 7 (confidential information) of the
     Employment Agreement shall survive the termination of your employment, and
     that for purposes of Section 6 of the Employment Agreement, the restriction
     on your ability to compete will continue during the two-year period
     following the Termination Date.

7.   Non-Disparagement. You agree that you will not, directly or indirectly,
     disparage (whether in writing or orally) the Company or the Releasees (as
     defined below) in any manner whatsoever at any time.

8.   Release.

               (a) You hereby agree to accept the compensation, payments and
     benefits provided for in Section 3 hereof in full resolution and
     satisfaction of, and hereby IRREVOCABLY AND UNCONDITIONALLY RELEASE, REMISE
     AND FOREVER DISCHARGE the Company, its past, present and future direct and
     indirect parents (including Pearson plc and its affiliates), subsidiaries,
     affiliates, divisions, predecessors, successors, and assigns, and their
     respective current and former officers, directors, shareholders,
     representatives, agents and employees, in their official and individual
     capacities, jointly and individually (the "Releasees") from, any and all
     agreements, promises, liabilities, claims and demands of any kind
     whatsoever, in law or equity, whether known or unknown, suspected or
     unsuspected, fixed or contingent, apparent or concealed, which you, your
     respective heirs, executors, administrators, successors or assigns ever


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     had, now have or in the future may have, including, without limitation, any
     and all claims arising out of or relating to your employment, the
     Employment Agreement, your compensation and benefits with the Company
     and/or the termination thereof, and any and all contract, tort or fraud
     claims, claims for defamation or other personal injury, claims under any
     federal, state or municipal wage payment, discrimination or fair employment
     practices law, statute or regulation and claims for costs, expenses and
     attorneys' fees with respect thereto, arising from the beginning of the
     world through the effective date of this Letter Agreement, in each case,
     against the Company or any of the Releasees, other than any claims with
     respect to the Company's breach of this Letter Agreement. However, it is
     agreed that you do not waive your rights for coverage or indemnification
     under any directors & officers policy, or pursuant to Certificate of
     Incorporation and the the by-laws of the Company for acts or omissions
     occurring during your employment. THIS RELEASE AND WAIVER INCLUDES, WITHOUT
     LIMITATION, ANY AND ALL CLAIMS UNDER THE AGE DISCRIMINATION IN EMPLOYMENT
     ACT, 29 U.S.C. "621-634 (THE "ADEA").

               (b) By signing this Letter Agreement and by acceptance of the
     compensation, payments and benefits provided for in Section 3 above, you
     hereby WAIVE, RELEASE AND COVENANT NOT TO SUE the Company or the Releasees
     with respect to any matter relating to or arising out of any claims being
     released hereunder, and you agree that you will not (i) file, charge,
     claim, sue or cause or permit to be filed any civil action, suit or legal
     proceeding for any claims which are being released hereunder against the
     Company or the Releasees, whether in the form of a federal, state or
     municipal court lawsuit or administrative agency action, an arbitration
     proceeding or otherwise, (ii) seek reinstatement or any other monetary,
     equitable or personal relief of any kind from the Company or the Releasees,
     however that relief might be called, on the basis of any such claim, or
     (iii) accept any such relief (as described in subclause (ii) above) on the
     basis of any claims which are being released hereunder if sought by any
     person, organization or other entity other than you or acting for you or on
     your behalf. You represent and warrant as of the date hereof (i) that you
     have not filed any claim or demand for relief against the Company or
     Releasees, (ii) that there are no outstanding claims, or other claims or
     demands for relief within the meaning of this Section 8, and (iii) that
     there has been no assignment of any such claims.

9.   Consulting Services; Future Cooperation. During the Severance Period, you
     agree to make yourself available for consultation with the Company and its
     subsidiaries to provide, as requested, advice and information with respect
     to the business of the Company and its subsidiaries. You further agree that
     upon the Company's reasonable request (whether during or after the
     Severance Period), you will use reasonable efforts to assist and cooperate
     with the Company and the Releasees in connection with the defense or
     prosecution of any claim that may be made against or by the Company or the
     Releasees, or in connection with any ongoing or future investigation or
     dispute or claim of any kind involving the Company or the Releasees,
     including any proceeding before any arbitral, administrative, regulatory,
     self-regulatory, judicial, legislative, or other body or agency. You will
     not be paid any additional amounts for any consulting services that you
     render or assistance that you provide, although you will be entitled to
     reimbursement for reasonable out-of-pocket expenses.


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10.  Successors and Assigns. This Letter Agreement shall inure to the benefit of
     and shall be binding upon the parties hereto and their respective
     successors and assigns, including but not limited to (i) with respect to
     the Company, any entity with which the Company may merge or consolidate or
     to which the Company may sell substantially all of its assets, and (ii)
     with respect to you, your executors, administrators, heirs and legal
     representatives. In the event of your death during the Severance Period,
     any remaining amounts due under this Agreement shall be accelerated and
     payable to your estate.

11.  Severability; Headings. In the event that any provision of this Letter
     Agreement shall be held by a court of proper jurisdiction to be invalid,
     void or voidable or otherwise unenforceable, the balance of this Letter
     Agreement shall continue in full force and effect unless such construction
     would clearly be contrary to the intentions of the parties or would result
     in an unconscionable injustice. The headings of the sections and paragraphs
     of this Letter Agreement are for convenience of reference only and shall
     not constitute a part hereof.

12.  Miscellaneous: Choice of Law. This Letter Agreement may be executed in
     several counterparts, each or which shall be deemed to be an original but
     all of which together will constitute one and the same instrument. This
     Letter Agreement constitutes the entire agreement, and supersedes all prior
     agreements, of the parties hereto relating to the subject matter hereof,
     and there are no written or oral terms or representations made by either
     party other than those contained herein and therein. This Letter Agreement
     cannot be modified, altered or amended except by a writing signed by all
     the parties. No waiver by either party of any provision or condition of
     this Letter Agreement at any time shall be deemed a waiver of such
     provision or condition at any prior or subsequent time or of any provision
     or condition at the same or any prior or subsequent time. This Letter
     Agreement shall be governed by and construed in accordance with the
     domestic laws of the State of Delaware, without giving effect to any choice
     of law or conflict of law provision or rule (whether of the State of
     Delaware or any other jurisdiction) that would cause the application of the
     laws of any jurisdiction other than the State of Delaware.

13.  Facsimile Signatures Valid. Execution of this Letter Agreement with
     signatures transmitted via facsimile shall be considered valid.

                                     * * * *

If this Letter Agreement conforms to your understanding and is acceptable to
you, please indicate your agreement by signing and dating the enclosed copy of
this Letter Agreement where indicated and returning it to the Company. YOU
ACKNOWLEDGE AND AGREE THAT YOU HAVE BEEN PROVIDED WITH THE OPPORTUNITY TO HAVE A
PERIOD OF AT LEAST 21 DAYS IN WHICH TO REVIEW AND CONSIDER THIS LETTER
AGREEMENT, AND YOU HAVE USED SUCH REVIEW PERIOD TO THE EXTENT DESIRED BY YOU.
AFTER YOUR EXECUTION OF THIS LETTER AGREEMENT, YOU WILL THEN BE PERMITTED TO
REVOKE THIS LETTER AGREEMENT IN WRITING AT ANY TIME DURING THE PERIOD OF SEVEN
DAYS FOLLOWING THE EXECUTION THEREOF. IN THE EVENT THAT YOU EXECUTE THIS LETTER
AGREEMENT, THIS LETTER AGREEMENT WILL NOT BE EFFECTIVE OR ENFORCEABLE, AND NO
PAYMENTS WILL BE MADE HEREUNDER, UNTIL THE SEVEN-DAY REVOCATION PERIOD HAS
EXPIRED; UPON THE EXPIRATION OF SUCH SEVEN DAY PERIOD AFTER YOUR EXECUTION (AND
ASSUMING


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NO REVOCATION), THIS LETTER AGREEMENT SHALL BECOME EFFECTIVE. IN THE EVENT THAT
YOU FAIL TO EXECUTE THIS LETTER BY THE DATE SPECIFIED IN THE FIRST SENTENCE
ABOVE, OR IF YOU EXECUTE THIS LETTER AGREEMENT AND SUBSEQUENTLY ELECT TO REVOKE
THIS LETTER AGREEMENT IN WRITING PURSUANT TO THE TERMS HEREOF WITHIN SUCH SEVEN
DAY REVOCATION PERIOD, THIS LETTER AGREEMENT WILL BE OF NO FORCE OR EFFECT, AND
NO PARTY TO THIS LETTER AGREEMENT WILL HAVE ANY RIGHTS OR OBLIGATIONS HEREUNDER.

Sincerely,

Data Broadcasting Corporation


By: /s/ Mark. F. Imperiale
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   Name:  Mark F. Imperiale
   Title: President


THIS LETTER AGREEMENT IS A LEGAL DOCUMENT. YOU SHOULD CONSULT WITH AN ATTORNEY
PRIOR TO SIGNING THIS LETTER AGREEMENT.

BY SIGNING THIS LETTER AGREEMENT YOU ACKNOWLEDGE THAT YOU ARE COMPETENT, THAT
YOU HAVE BEEN PROVIDED WITH THE OPPORTUNITY TO HAVE A PERIOD OF AT LEAST 21 DAYS
IN WHICH TO REVIEW AND CONSIDER THIS LETTER AGREEMENT WITH AN ATTORNEY OF YOUR
CHOICE AND YOU HAVE USED SUCH REVIEW PERIOD TO THE EXTENT YOU DESIRED, THAT YOU
HAVE READ AND UNDERSTAND AND VOLUNTARILY ACCEPT THIS LETTER AGREEMENT AS FULLY
AND FINALLY RESOLVING, WAIVING AND RELEASING ANY AND ALL CLAIMS WHICH YOU MAY
HAVE AGAINST THE COMPANY AND RELEASEES (AS DEFINED HEREIN), INCLUDING ANY AND
ALL CLAIMS UNDER THE AGE DISCRIMINATION IN EMPLOYMENT ACT, THAT NO PROMISES OR
INDUCEMENTS HAVE BEEN MADE TO YOU EXCEPT AS SET FORTH IN THIS LETTER AGREEMENT,
AND THAT YOU HAVE SIGNED THIS LETTER AGREEMENT FREELY AND VOLUNTARILY, INTENDING
TO BE LEGALLY BOUND BY ITS TERMS. THE FOREGOING IS A SUMMARY DESCRIPTION OF THE
GENERAL IMPORT OF THIS INSTRUMENT AND DOES NOT ALTER OR AMEND THE DETAILED
PROVISIONS CONTAINED IN THE BODY HEREOF.

ACCEPTED AND AGREED:


/s/ Alan J. Hirschfield                              Date:
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Alan J. Hirschfield




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