UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

August 10, 2020
Date of Report (Date of Earliest Event Reported)

Central Index Key Number of the issuing entity:  0001716187
Wells Fargo Commercial Mortgage Trust 2017-C40
(Exact name of issuing entity)

Central Index Key Number of the registrant:  0000850779
Wells Fargo Commercial Mortgage Securities, Inc.
(Exact name of registrant as specified in its charter)

c/o Wells Fargo Bank, National Association
9062 Old Annapolis Road
Columbia, MD 21045
(Address of principal executive offices of the issuing entity)

(212) 214-5600
Registrant's Telephone number, including area code

Former name or former address, if changed since last report:  Not Applicable

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐  Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐  Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act(17 CFR 240.14d-2(b))

☐  Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act(17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

☐  Emerging growth company

☐  If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised Financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

The Certificate Administrator made distributions to the Certificateholders on the July 17, 2020 Distribution Date where Class A-1 was paid $476,709.17 and the RR Interest was paid $25,089.96 in principal. The Certificate Administrator was notified of a revision to the July distribution and subsequently paid additional principal to Class A-1 in the amount of $1,244,337.45 and to the RR Interest in the amount of $65,425.18. On August 12, 2020, the Certificate Administrator was notified of an overpayment to Class A-1 and the RR Interest based on the first set of revised data, and recovered $635,516.36 from Class A-1 and $33,448.22 from the RR Interest. In total, Class A-1 received $1,085,530.33 in principal and the RR Interest received $57,133.18 in principal for the July distribution.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Wells Fargo Commercial Mortgage Securities, Inc.
(Depositor)