Wdesk | Exhibit






INSTRUMENT OF AMENDMENT TO THE
MDU RESOURCES GROUP, INC.
401(k) RETIREMENT PLAN




The MDU Resources Group, Inc. 401(k) Retirement Plan (as amended and restated January 1, 2017) (the “K‐Plan”), is hereby amended effective as of May 24, 2018, as follows:


 
		
	1.
	By replacing the table in Section D-1-2 Eligibility to Share in the Profit Sharing Feature of Supplement D-1, Provisions Relating to the Profit Sharing Feature for Certain Participating Affiliates, in its entirety, with the following:




	
		
	Participating Affiliate
	Current Effective Date
(Original Effective Date)2

	Ames Sand & Gravel, Inc.
	January 1, 2016
(July 16, 2007)

	Anchorage Sand & Gravel Company, Inc. (excluding President)
	January 1, 1999

	Baldwin Contracting Company, Inc.
	January 1, 1999

	Capital Electric Line Builders, Inc.7
	January 1, 2014

	Cascade Natural Gas Corporation1
	January 1, 2017
 (July 2, 2007)

	Concrete, Inc.
	January 1, 2001

	Connolly-Pacific Co.
	January 1, 2007

	DSS Company
	January 1, 2004
(July 8, 1999)

	E.S.I., Inc.
	January 1, 2008
(January 1, 2003)

	Fairbanks Materials, Inc.
	May 1, 2008

	Granite City Ready Mix, Inc.
	June 1, 2002

	Great Plains Natural Gas Co.1
	January 1, 2017
(January 1, 2008)






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	Participating Affiliate
	Current Effective Date
(Original Effective Date)2

	Hawaiian Cement (non-union employees hired after December 31, 2005)
	January 1, 2009

	Intermountain Gas Company1
	January 1, 2017
(January 1, 2011)

	JTL Group, Inc.5/6
	January 1, 2015
(January 1, 2014)

	Jebro Incorporated
	November 1, 2005

	Kent’s Oil Service4
	January 1, 2007

	Knife River – North Dakota Division, a Division of Knife River Corporation – North Central
	January 1, 2016
(January 1, 2007)

	Knife River Corporation – Mountain West
	May 1, 2018
(January 1, 2015)

	Knife River Corporation – North Central
	January 1, 2016
(January 1, 2007)

	Knife River Corporation – Northwest (the Central Oregon Division, f/k/a HTS)
	May 1, 2010
(January 1, 1999)

	Knife River Corporation – Northwest (the Southern Oregon Division)
	

January 1, 2012



	Knife River Corporation – Northwest (the Western Oregon Division)
	

January 1, 2012



	Knife River Corporation - South
(f/k/a Young Contractors, Inc.)
	January 1, 2008
(January 1, 2007)

	Knife River Midwest, LLC
	January 1, 2016
(April 1, 2004)

	LTM, Incorporated
	January 1, 2003

	MDU Resources Group, Inc.1
	January 1, 2017

	Montana-Dakota Utilities Co. 
(non-union employees)1
	January 1, 2017
(January 1, 2008)






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	Participating Affiliate
	Current Effective Date
(Original Effective Date)2

	Montana-Dakota Utilities Co.
(union employees)
	January 1, 2008

	Northstar Materials, Inc.
	January 1, 2016
(January 1, 2003)

	OEG, Inc.3
	March 7, 2011

	Wagner Industrial Electric, Inc.
	

January 1, 2008



	Wagner Smith Equipment Co.
	January 1, 2008
(July 1, 2000)

	WBI Energy, Inc.1
	January 1, 2017
(May 1, 2012)

	

WBI Energy Midstream, LLC1
	January 1, 2017
 (January 1, 2001)

	WBI Energy Transmission, Inc.1
	January 1, 2017
 (January 1, 2009)

	WHC, Ltd.
	September 1, 2001






 1/Eligible employees only include those in salary grade levels 29-38.
2/In the event a Participating Affiliate adopts a Profit Sharing Feature on a date other than January 1, effective as of the date of participation in the Plan, the amount of any such contribution allocated to a Supplement D‐1 Participant shall be based upon Compensation, received while in the employ of the Participating Affiliate after the date of acquisition by the Company or any Affiliate. 
3/Requirement to be an Active Employee on the last day of the Plan Year does not apply.
4/The following participant of Kent’s Oil Service is granted vesting service for prior years of service with Spirit Road Oils: Jose Padilla.
5/Eligible JTL Casper hourly employees (both union and nonunion), including those employees who participate in the Operating Engineers Local No. 800 & The Wyoming Contractors’ Association, Inc. Pension Trust Fund for Wyoming (JTL MEP employees.)
6/Eligible salaried employees of JTL hired after December 31, 2014 or any other JTL employee who transfers to a salaried position after December 31, 2014.
7/Eligible employees participating in a management incentive compensation plan are not eligible for a Profit Sharing Contribution.












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	2.
	By replacing the table in Section D-2-2 Eligibility to Share in the Retirement Contribution of Supplement D-2, Provisions Relating to the Retirement Contribution Feature for Certain Participating Affiliates, in its entirety, with the following:






	
			
	Participating Affiliate
	Current Effective Date (Original Effective Date)
	Retirement Contribution Amount - Percentage of Compensation

	Cascade Natural Gas Corporation (non-bargaining)
	January 1, 2011
(July 2, 2007)
	5%

	Cascade Natural Gas Corporation (Field Operations Bargaining Unit employees hired on or after 1/1/2007)
	May 1, 2015
(July 2, 2007)
	5%

	Great Plains Natural Gas Co.
	January 1, 2003
	5%

	Intermountain Gas Company
	January 1, 2011
(October 12, 2008)
	5%

	OEG, Inc.
	May 24, 2018
March 7, 2011
	6%

	Rocky Mountain Contractors, Inc.
(non-bargaining)
	January 1, 2005
	5%

	WBI Energy Midstream, LLC1
	July 1, 2012
(January 1, 2001)
	5%






1The following participants of WBI Energy Midstream, LLC are excluded:, Grady Breipohl, Jon Forbes, Richard Guderjahn, Steven Haag, Raymond Harms, Wade Hasler, Douglas Henry, Pamela Lynn, Todd Mandeville, Marlin Mogan, and Dale Sudbrack due to participation in the appropriate pension plan replacement contribution.




		
	3.
	By replacing the following paragraph for On Electric Group, Inc. on Schedule A to the K-Plan, in its entirety, with the following:




OEG, Inc. (“OEG”) shall make a matching contribution equal to one hundred percent (100%) of each OEG employee’s participating savings contribution, up to the maximum savings contribution of two percent (2%) of compensation for each pay period. Prior to March 7, 2011, OEG did not make matching contributions for OEG employees.


Effective March 7, 2011 and as amended May 24, 2018.














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IN WITNESS WHEREOF, MDU Resources Group, Inc., as Sponsoring Employer of the K-Plan, has caused this amendment to be duly executed by a member of the MDU Resources Group, Inc. Employee Benefits Committee on this 6th  day of September, 2018.




MDU RESOURCES GROUP, INC.
   EMPLOYEE BENEFITS COMMITTEE






By:  /s/ Jason L. Vollmer  
     Jason L. Vollmer, Chairman


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