MARB First Trust Merger Arbitrage ETF

CHAPMAN AND CUTLER LLP 111 WEST MONROE STREET
CHICAGO, ILLINOIS 60603

April 3, 2020

Securities and Exchange Commission
100 F Street, N.E.
Washington, DC 20549

Ladies and Gentlemen:

On behalf of First Trust Exchange-Traded Fund III (the "Registrant"), we are transmitting for electronic filing pursuant to Rule 497(e) under the Securities Act of 1933, as amended, the exhibits containing interactive data format risk/return summary information that mirrors the risk/return summary information in the supplement to the Prospectus for the Registrant filed pursuant to Rule 497(e) on April 1, 2020. The Registration Statement relates to First Trust RiverFront Dynamic Asia Pacific ETF, First Trust RiverFront Dynamic Developed International ETF, First Trust RiverFront Dynamic Emerging Markets ETF and First Trust RiverFront Dynamic Europe ETF, each a series of the Registrant.

If you have any questions or comments, please telephone the undersigned at
(312) 845-3484.

Very truly yours,

CHAPMAN AND CUTLER LLP

By: /s/ Morrison C. Warren
    ------------------------------
        Morrison C. Warren

Enclosure

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