Specialized Disclosure Report (sd)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM SD

SPECIALIZED DISCLOSURE REPORT

OTTER TAIL CORPORATION

(Exact name of registrant as specified in its charter)

Minnesota

0-53713

27-0383995

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(I.R.S. Employer

Identification No.)

215 South Cascade Street, P.O. Box 496, Fergus Falls, MN	56538-0496
(Address of principal executive offices)	(Zip Code)

George A. Koeck,

General Counsel & Corporate Secretary

(866) 410-8780

(Name and telephone number, including area code,

of the person to contact in connection with this report)

Check the appropriate box to indicate the rule pursuant to which this form is being filed, and provide the period to which the information in this form applies:

☒

Rule 13p-1 under the Securities Exchange Act (17 CFR 240.13p-1) for the reporting period from January 1 to December 31, 201 6 .

Section 1.01 and 1.02 – Conflicts Minerals Disclosure

Items 1.01 and 1.02 – Conflicts Minerals Disclosure and Report Exhibit

This Form SD and the Conflict Minerals Report, filed as Exhibit 1.01 hereto, are publicly available on our website under Investors, SEC Filings, Form SD at the website http://www.ottertail.com as well as the SEC’s EDGAR database at www.sec.gov. The content of any website referred to in this Form SD is included for general information only and is not incorporated by reference in this Form SD.

Section 2 - Exhibits

Item 2.01 Exhibits

1.01

Conflict Minerals Report for the reporting period January 1, 2016 to December 31, 2016 as required by Items 1.01 and 1.02 of this Form SD.

Signature

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, thereunto duly authorized.