SCHEDULE 14A

(RULE 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934

Filed by the Registrant    x

Filed by a Party other than the Registrant    ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material Under Rule 14a-12

THE MONY GROUP INC.

(Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement if Other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

(1) Title of each class of securities to which transaction applies:

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(3) Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the filing fee is calculated and state how it was determined):

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¨ Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

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(2) Form, Schedule or Registration Statement No.:

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(4) Date Filed:

Daniel J. Mullane, President of The Advest Group, Inc. (“Advest”), a wholly-owned subsidiary of The MONY Group Inc., sent the following internal memorandum to employees of Advest on or about February 18, 2004.

Important Announcement for All Advest Employees

It has come to my attention that there are people who sold their MONY common stock who believe they are not eligible to vote in the upcoming shareholder meeting. If you held your shares as of the Record Date of January 2, 2004, you are still entitled to vote your shares and I strongly encourage you to do so. As we mentioned earlier, abstaining or choosing not to vote your shares is the same as a vote against the acquisition. We strongly believe that AXA Financial’s purchase of the MONY Group is in Advest’s best interest so please exercise your right to participate in this important process.