Drinker Biddle & Reath LLP

191 North Wacker Drive

Suite 3700

Chicago, IL 60606-1698

312-569-1000 (Phone)

312-569-3000 (Facsimile)

www.drinkerbiddle.com

VIA EDGAR TRANSMISSION

October 10, 2012

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Re: FlexShares Trust (the “Trust”)

Securities Act File No. 333-173967

Investment Company Act File No. 811-22555

Ladies and Gentlemen:

On behalf of the Trust, I hereby transmit for filing pursuant to Rule 497 under the Securities Act of 1933, as amended (the “1933 Act”), exhibits containing risk/return summary information in the eXtensible Business Reporting Language (XBRL) format that mirrors the risk/return summary information contained in the Prospectus dated September 21, 2012 for the FlexShares^® Morningstar Developed Markets ex-US Factor Tilt Index Fund, a series of the Trust, as filed pursuant to Rule 497 under the 1933 Act on September 25, 2012 (0001193125-12-403496).

Questions and comments may be directed to the undersigned at (312) 569-1167.

Very truly yours,

/s/ Veena K. Jain

Veena K. Jain

Enclosures

cc: Peter K. Ewing

Craig Carberry, Esq.