Exhibit 4.1


 


FOURTH AMENDMENT TO THIRD AMENDED AND RESTATED
CREDIT AGREEMENT


 


THIS FOURTH AMENDMENT
(this “Amendment”), dated as of October 31, 2016, amends and modifies that certain Third Amended and Restated Credit
Agreement, dated as of October 29, 2012 (as amended by the First Amendment thereto dated October 29, 2013, the Second Amendment
thereto dated November 3, 2014 and the Third Amendment thereto dated October 29, 2015, the “Credit Agreement”), among
Otter Tail Corporation (the “Borrower”), U.S. BANK NATIONAL ASSOCIATION,
as Administrative Agent (in such capacity, the “Agent”), and the Lenders, as defined therein. Terms not otherwise expressly
defined herein shall have the meanings set forth in the Credit Agreement.


 


FOR VALUE RECEIVED,
the Borrower, the Lenders and the Agent agree that the Credit Agreement is amended as follows.


 


ARTICLE I - AMENDMENTS


 


1.1         The
definition of “Termination Date” appearing in Section 1.1 of the Credit Agreement is hereby amended to replace the
date “October 29, 2020” with the date “October 29, 2021”.


 


1.2         Section
1.1 of the Credit Agreement is hereby amended to insert the following definitions alphabetically therein:


 


“Bail-In
Action” means the exercise of any Write-Down and Conversion Powers by the applicable EEA Resolution Authority in respect
of any liability of an EEA Financial Institution.


 


“Bail-In
Legislation” means, with respect to any EEA Member Country implementing Article 55 of Directive 2014/59/EU of the European
Parliament and of the Council of the European Union, the implementing law for such EEA Member Country from time to time which is
described in the EU Bail-In Legislation Schedule.


 


“EEA
Financial Institution” means (a) any institution established in any EEA Member Country which is subject to the supervision
of an EEA Resolution Authority, (b) any entity established in an EEA Member Country which is a parent of an institution described
in clause (a) of this definition, or (c) any institution established in an EEA Member Country which is a subsidiary of an institution
described in clauses (a) or (b) of this definition and is subject to consolidated supervision with its parent.


 


“EEA
Member Country” means any of the member states of the European Union, Iceland, Liechtenstein, and Norway.


 


“EEA
Resolution Authority” means any public administrative authority or any Person entrusted with public administrative authority
of any EEA Member Country (including any delegee) having responsibility for the resolution of any EEA Financial Institution.


 




     


     

    

 


“EU
Bail-In Legislation Schedule” means the EU Bail-In Legislation Schedule published by the Loan Market Association (or
any successor Person), as in effect from time to time.


 


“Write-Down
and Conversion Powers” means, with respect to any EEA Resolution Authority, the write-down and conversion powers of such
EEA Resolution Authority from time to time under the Bail-In Legislation for the applicable EEA Member Country, which write-down
and conversion powers are described in the EU Bail-In Legislation Schedule.


 


1.3         The
definition of “Defaulting Bank” appearing in Section 1.1 of the Credit Agreement is hereby amended to delete the word
“or” now appearing in clause (e) therein and substitute a comma “,” therefor and insert immediately after
the phrase “an instrumentality thereof” the following: “or (iii) has or whose parent company has become the subject
of a Bail-In Action”.


 


1.4         Article
XII of the Credit Agreement is hereby amended to insert the following new Section 12.18 at the end thereof:


 


Section 12.18   Acknowledgement
and Consent to Bail-In of EEA Financial Institutions. Notwithstanding anything to the contrary in any Loan Document or in any
other agreement, arrangement or understanding among any such parties, each party hereto acknowledges that any liability of any
EEA Financial Institution arising under any Loan Document may be subject to the Write-Down and Conversion Powers of an EEA Resolution
Authority and agrees and consents to, and acknowledges and agrees to be bound by:


 


(a)         the
application of any Write-Down and Conversion Powers by an EEA Resolution Authority to any such liabilities arising hereunder which
may be payable to it by any party hereto that is an EEA Financial Institution; and


 


(b)         the
effects of any Bail-In Action on any such liability, including, if applicable:


 


(i)          a
reduction in full or in part or cancellation of any such liability;


 


(ii)         a
conversion of all, or a portion of, such liability into shares or other instruments of ownership in such EEA Financial Institution,
its parent entity, or a bridge institution that may be issued to it or otherwise conferred on it, and that such shares or other
instruments of ownership will be accepted by it in lieu of any rights with respect to any such liability under this Agreement or
any other Loan Document; or


 


(iii)        the
variation of the terms of such liability in connection with the exercise of the Write-Down and Conversion Powers of any EEA Resolution
Authority.


 




    	2



     

    

 


1.5         Article
VII of the Credit Agreement is hereby amended to insert the following new Section 7.19 at the end thereof:


 


Section 7.19: EEA
Financial Institutions. Neither the Borrower nor any Subsidiary is an EEA Financial Institution.


 


1.6         Section
2.11(g) of the Credit Agreement is hereby amended to restate the second sentence therein in its entirety as follows:


 


“Subject
to Section 12.18, nothing contained in the foregoing shall be deemed to constitute a waiver by the Borrower of any of its rights
or remedies (whether in equity or law) against any Bank which fails to fund any of its Loans hereunder at the time or in the amount
required to be funded under the terms of this Agreement.”


 


1.7         Schedule
1.1(a) (Commitments and Percentages), Schedule 1.1(b) (Material Subsidiaries), Schedule 1.1(c) (Departing Bank Schedule), Schedule
7.6 (Litigation and Contingent Liabilities), Schedule 7.15 (Subsidiaries), Schedule 7.16 (Partnerships/Joint Ventures), Schedule
9.4 (Exceptions to Ownership of Material Subsidiaries), Schedule 9.7 (Investments), Schedule 9.8 (Existing Liens) and Schedule
9.10 (Certain Transactions with Related Parties), are hereby amended in their entirety to be in the forms of Schedule 1.1(a), Schedule
1.1(b), Schedule 1.1(c), Schedule 7.6, Schedule 7.15, Schedule 7.16, Schedule 9.4, Schedule 9.7, Schedule 9.8 and Schedule 9.10
attached hereto and made a part hereof.


 


ARTICLE II - REPRESENTATIONS AND WARRANTIES


 


To induce the Agent
and the Lenders to enter into this Amendment and to make and maintain the Loans under the Credit Agreement as amended hereby, the
Borrower hereby warrants and represents to the Agent and the Lenders that it is duly authorized to execute and deliver this Amendment,
and to perform its obligations under the Credit Agreement as amended hereby, and that this Amendment constitutes the legal, valid
and binding agreement of the Borrower, enforceable in accordance with its terms, subject to limitations as to enforceability which
might result from bankruptcy, insolvency, moratorium and other similar laws affecting creditors’ rights generally and subject
to limitations on the availability of equitable remedies.


 


ARTICLE III - CONDITIONS PRECEDENT


 


This Amendment shall
become effective on the date first set forth above, provided, however, that the effectiveness of this Amendment is subject to the
satisfaction of each of the following conditions precedent:


 


3.1         Warranties. Before and
after giving effect to this Amendment, the representations and warranties in the Credit Agreement shall be true and correct as
though made on the date hereof with respect to representations and warranties containing qualifications as to materiality, and
true and correct as though made on the date hereof in all material respects with respect to representations and warranties without
qualifications as to materiality, except for changes that are permitted by the terms of the Credit Agreement. The execution by
the Borrower of this Amendment shall be deemed a representation that the Borrower has complied with the foregoing condition.


 




    	3



     

    

 


3.2         Defaults.    Before and after giving effect to this Amendment, no Default and no Event of Default shall have occurred and be continuing under
the Credit Agreement. The execution by the Borrower of this Amendment shall be deemed a representation that the Borrower has complied
with the foregoing condition.


 


3.3         Documents.    The Borrower, the Agent and the Lenders shall have executed and delivered this Amendment.


 


3.4         Fees.    The Agent shall have received all fees and other amounts due and payable on or prior to the date hereof, including, without limitation,
(i) all fees set forth in that certain Fee Letter by and between the Borrower and the Agent dated as of October 31, 2016 and (ii)
to the extent invoiced reasonably in advance, reimbursement or payment of all out-of-pocket expenses required to be reimbursed
or paid by the Borrower under the Credit Agreement.


 


3.5         Reduction
of Commitment.    The Agent shall have received irrevocable notice pursuant
to Section 4.3 that the Borrower has elected to reduce the Commitment, effective as of the date of this Amendment to an aggregate
amount not greater than $130,000,000.


 


ARTICLE IV - GENERAL


 


4.1         Expenses.    The Borrower agrees to reimburse the Agent upon demand for all reasonable expenses (including reasonable attorneys' fees and legal
expenses) incurred by the Agent in the preparation, negotiation and execution of this Amendment and any other document required
to be furnished herewith.


 


4.2         Counterparts.    This Amendment may be executed in as many counterparts as may be deemed necessary or convenient, and by the different parties hereto
on separate counterparts, each of which, when so executed, shall be deemed an original but all such counterparts shall constitute
but one and the same instrument.


 


4.3         Severability.    Any provision of this Amendment which is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the remaining portions hereof or affecting the validity
or enforceability of such provisions in any other jurisdiction.


 


4.4         Governing
Law.    This Amendment shall be a contract made under the laws of the State of Minnesota, which laws shall govern all the rights
and duties hereunder.


 




    	4



     

    

 


4.5         Successors;
Enforceability. This Amendment shall be binding upon the Borrower, the Agent and the Lenders and their respective successors
and assigns, and shall inure to the benefit of the Borrower, the Agent and the Lenders and the successors and assigns of the Agent
and the Lenders. Except as hereby amended, the Credit Agreement shall remain in full force and effect and is hereby ratified and
confirmed in all respects.


 


[Signature Pages Follow]


 




    	5



     

    

 


IN WITNESS WHEREOF, the parties hereto have
caused this Amendment to be executed by their respective officers thereunto duly authorized as of the date first written above.


 


	 	OTTER TAIL CORPORATION
	 	 
	 	By:	/s/ Kevin Moug
	 	 	 
	 	Title:	Chief Financial Officer


 


	 	4334 18th Avenue South
	 	Suite 200
	 	Fargo, North Dakota 58103
	 	Attention:	Mr. Kevin G. Moug,
	 	 	Chief Financial Officer
	 	Telephone:  (701) 451-3562
	 	Fax:  (701) 232-4108


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


	 	U.S. BANK NATIONAL ASSOCIATION,
	 	as Agent and a Bank
	 	 
	 	By:	/s/ Jacquelyn Ness
	 	 	 
	 	Title:	Vice President
	 	 
	 	505 Second Avenue North
	 	Mail Code EP-ND-0630
	 	Fargo, ND 58102
	 	Attention:  Jacquelyn Ness, Vice President
	 	Telephone:  (701) 280-3655
	 	Fax:  (701) 280-3580


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


	 	BANK OF AMERICA, N.A., as Co-Syndication Agent and as a Bank
	 	 
	 	By:	/s/ Casey Klepsch
	 	 	 
	 	Title:	Assistant Vice President
	 	 
	 	IL4-135-04-13
	 	135 South LaSalle Street
	 	Chicago, IL  60603
	 	Attention: Casey Klepsch
	 	Telephone:  (312) 904-7465
	 	Fax:   (312) 992-9981


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


	 	JPMORGAN CHASE BANK, N.A., as Co-Syndication Agent and as a Bank
	 	 	 
	 	By:	/s/ Justin Martin
	 	 	 
	 	Title:	Authorized Officer
	 	 
	 	10 South Dearborn, 9th Floor, IL1-0090
	 	Chicago, IL  60603
	 	Attention:  Justin Martin
	 	Telephone:  (312) 732-4441
	 	Fax:  (312) 732-1762


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


	 	KEYBANK NATIONAL ASSOCIATION, as Documentation Agent and as a Bank
	 	 	 
	 	By:	/s/ Keven D. Smith
	 	 	 
	 	Title:	Senior Vice President
	 	 
	 	127 Public Square
	 	Mail Code: OH-01-27-1125
	 	Cleveland, OH 44114
	 	Attention: Keven D. Smith
	 	Telephone: (206) 343-6966
	 	Fax: (216) 689-4981


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


	 	BANK OF THE WEST, a California Banking Corporation, as a Bank
	 	 	 
	 	By:	/s/ David Wang
	 	 	 
	 	Title:	Director
	 	 
	 	250 Marquette Ave., Suite 575
	 	Minneapolis, MN  55401
	 	Attention:  David Wang
	 	Telephone:  (612) 339-1403
	 	Fax:  (612) 339-6362


 


(Signature Page to Fourth Amendment to
Otter Tail Corporation Credit Agreement)


 




     


     

    

 


Schedule 1.1(a)


 


Commitments and Percentages


 


	Bank:	 	Initial Commitment:	 	 	Percentage:	 
	 	 	 	 	 	 	 
	U.S. Bank National Association	 	$	39,000,000	 	 	 	30	%
	 	 	 	 	 	 	 	 	 
	JPMorgan Chase Bank, N.A.	 	$	26,000,000	 	 	 	20	%
	 	 	 	 	 	 	 	 	 
	Bank of America, N.A.	 	$	26,000,000	 	 	 	20	%
	 	 	 	 	 	 	 	 	 
	KeyBank National Association	 	$	23,833,333	 	 	 	18.33333307692	%
	 	 	 	 	 	 	 	 	 
	Bank of the West	 	$	15,166,667	 	 	 	11.666666923077	%
	 	 	 	 	 	 	 	 	 
	Total:	 	$	130,000,000	 	 	 	100	%



 




     


     

    

 


Schedule 1.1(b)


 


Material Subsidiaries

(as of the date of the Fourth Amended and Restated Credit Agreement)


 


	 	BTD Manufacturing, Inc.	 
	 	Northern Pipe Products, Inc.	 
	 	Varistar Corporation	 
	 	Vinyltech Corporation	 


 




     


     

    

 


Schedule 1.1(c)


 


Departing Bank Schedule


 


None.


 




     


     

    

 


Schedule 7.6


 


Litigation (Section 7.6)

Contingent Liabilities (Section 7.6)


 


Ameren Services Company, etal v. FERC DC Circuit Case No. 07-1141. 
The case is an appeal from FERC challenging its treatment of MISO Revenue Sufficiency Guarantee (“RSG”) charges for
entities participating in the MISO wholesale energy market since the market’s start on April 1, 2005.  Otter Tail Power
was a participant in the market and could be adversely affected by certain outcomes.


 


Contingent Liabilities


Based on a potential reduction by the FERC in the ROE component
of the MISO Tariff, OTP has recorded a $2.4 million liability on its balance sheet as of September 30, 2016, representing OTP’s
best estimate of a refund obligation that would arise, net of amounts that would be subject to recovery under state jurisdictional
TCR riders, if FERC orders a reduction in ROE component of the MISO Tariff.


 


In 2014, the Environmental Protection Agency (EPA) published
proposed standards of performance for CO2 emissions from new fossil fuel-fired power plants, proposed CO2 emission guidelines for
existing fossil fuel-fired power plants and proposed CO2 standards of performance for CO2 emissions from reconstructed and modified
fossil fuel-fired power plants under section 111 of the Clean Air Act. The EPA published final rules for each of these proposals
on October 23, 2015. All of these rules have been challenged on legal grounds and are currently pending in the D.C. Circuit. On
February 9, 2016 the U.S. Supreme Court granted a stay of the CO2 emission guidelines for existing fossil fuel-fired power plants,
pending disposition of petitions for review in the D.C. Circuit and disposition of a petition for a writ of certiorari seeking
review by the U.S. Supreme Court, if such a writ is sought. Oral argument before all the judges of the D.C. Circuit (en banc review)
is scheduled for September 2016. Uncertainty regarding the status of the rules will likely continue for some time. OTP is actively
engaged with the stakeholder processes in each of its states that have continued to move forward with planning efforts during the
stay.


 




     


     

    

 


Schedule 7.15


 


Subsidiaries (Section 7.15)


Subsidiaries of Otter Tail Corporation


 


	Company	State of

Organization	Number and Class of Shares Issued

and Owned by Otter Tail

Corporation or its Subsidiaries	Footnote

Ref.
	AEV, Inc.	Minnesota	100 Shares Common	(1)
	ASI, Inc.	Minnesota	100 Shares Common	(3)
	BTD Manufacturing, Inc. 	Minnesota	200 Shares Common	(1)
	IMD, Inc.	North Dakota	980 Shares Common	(1)
	Miller Welding & Iron Works, Inc.	Minnesota	1,000 Shares Common	(5)
	Northern Pipe Products, Inc.	North Dakota	10,000 Shares Common	(1)
	Otter Tail Assurance Limited	Cayman Islands	50,000 Shares Common	(4)
	Otter Tail Energy Services Company, Inc.	Minnesota	1,000 Shares Common	(4)
	Otter Tail Power Company	Minnesota	100 Shares Common	(4)
	Sheridan Ridge II, LLC	Minnesota	1,000 Membership Units	(2)
	Shrco, Inc.	Minnesota	100 Shares Common	(1)
	T.O. Plastics, Inc. 	Minnesota	100 Shares Common	(1)
	Varistar Corporation	Minnesota	100 Shares Common	(4)
	Vinyltech Corporation 	Arizona	100 Shares Common	(1)


 


	
        (1)  Subsidiary
        of Varistar Corporation

        (2)  Subsidiary
        of Otter Tail Energy Services Company, Inc.

        (3)  Subsidiary
        of Shrco, Inc.
	
        (4)  Subsidiary
        of Otter Tail Corporation

        (5)  Subsidiary
        of BTD Manufacturing, Inc.

         



 




     


     

    

 


Schedule 7.16


Partnerships and Joint Ventures

as of June 30, 2016


 


	Partnership Name	 	Type of
 Partnership
 Interest	 	Ownership
 Percentage	 	 	Book value of
 Investment
 June 30, 2016	 
	Boston Financial Institutional Tax Credit VIII Fund	 	Limited	 	 	3.4	 	 	$	0	 
	Walnut Properties Limited – Summit Group	 	Limited	 	 	15.7	 	 	$	0	 
	WNC Institutional Tax Credit Fund II	 	Limited	 	 	13.3332	 	 	$	0	 
	Grace Village Limited Partnership	 	Limited	 	 	89.0	 	 	$	0	 
	The Homestead Limited Partnership	 	Limited	 	 	89.0	 	 	$	0	 
	Lincoln Square of Alexandria Limited Partnership	 	Limited	 	 	89.0	 	 	$	0	 
	Total	 	 	 	 	 	 	 	$	0	 



 


In the ordinary course of business, Otter
Tail Power Company has entered into contractual arrangements with other regional utilities providing for ownership interests (both
as tenants-in-common and discretely) in transmission and generation assets.


 


No Subsidiary Guarantor has any partnership or joint venture
interest.


 




     


     

    

 


Schedule 9.4


 


Exceptions to Ownership of Material Subsidiaries
(Section 9.4)


 


None.


 




     


     

    

 


Schedule 9.7


 


Investments (Section 9.7)


 


	 	 	As of 
 September 30, 2016	 
	Investment in Loan Pools (OTP)	 	$	68,000	 
	Investments – Bank of Butterfield (OTAL)	 	 	9,189,548	 
	CoBank (St Paul Bank for Coop’s)  (VSC)	 	 	73,012	 
	Relocation Loans to Employees (OTP)	 	 	50,000	 
	Trusts Associated with Large Transmission Projects	 	 	5,236,522	 
	Other Miscellaneous (OTP)	 	 	10,110	 
	 	 	 	 	 
	Total Investments of Otter Tail Corporation and Subsidiaries	 	$	14,627,192	 



 




     


     

    

 


Schedule 9.8


 


Existing Liens (Section 9.8)


 


None.


 




     


     

    

 


Schedule 9.10


 


Certain Transactions with Related Parties
(Section 9.10)


 


None.