Preliminary Proxy Statement (Form PRE 14A)

UNITED STATED

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

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

[ ] Definitive Additional Materials

[X] Soliciting Material Pursuant to sec. 240.14a-11(c) of sec. 240.14a-12

MFS UTILITIES SERIES

(Names of Registrants as Specified in their Charters)

(Name of Person(s) Filing Proxy Statement, if other than the Registrants)

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[X] No fee required

[ ] Fee computed on table below per Exchange Act Rules 14a-6(i)(4) and 0-11.

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[ ] Fee paid previously with preliminary materials.

[ ] 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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MFS Investment Management

111 Huntington Avenue

Boston, MA 02199

September 23, 2026

IMPORTANT NOTIFICATION:

MFS^® Utilities Fund

MFS^® Variable Insurance Trust - MFS^® Utilities Series

MFS^® would like to provide an update regarding the MFS Utilities Fund and MFS Variable Insurance Trust - MFS Utilities Series. On or about October 20, 2026, MFS will be mailing a proxy statement to investors seeking approval to change the classification of each Fund from "diversified" to "non-diversified."

MFS believes re-classifying the Funds as "non-diversified" is in the best interest of investors and will provide more flexibility to actively manage benchmark-relative risk among the largest names in each respective Fund and its index. MFS is advancing this proposal now given the substantial rise in the level of concentration in the market and fund over the past few years.

The mailing of the proxy materials to shareholders will commence on or about October 20, 2026. At that time, we will provide investment professionals with more details on the proxy statement to help with answering potential questions from clients. The special shareholders' meeting is expected to be held on or about December 17, 2026. No assurance can be given that shareholder approval will occur.

The investment philosophy and process of the Funds will remain the same.

We appreciate your continued confidence in MFS and welcome the opportunity to discuss these updates in further detail. For more information, please reach out to your MFS relationship manager or sales contact(s) at 1-800-343-2829. Shareholders may contact their investment professional or view the funds' updated prospectus or summary prospectus online at mfs.com.

IMPORTANT: Shareholders of MFS Utilities Fund and MFS Utilities Series should read the proxy statement when it becomes available, as it contains important information related to the solicitation process. Shareholders may access the proxy statement and any other relevant documents, free of charge, on the Securities and Exchange Commission's website or at mfs.com.

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