8-K

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

Date of Report (Date of earliest event reported): April 25, 2018 (April 25, 2018)

NorthWestern Corporation

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation)		1-10499 (Commission File Number)	46-0172280 (IRS Employer Identification No.)
3010 W. 69th Street Sioux Falls, South Dakota (Address of principal executive offices)			57108 (Zip Code)
	(605) 978-2900 (Registrant's telephone number, including area code)

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 (see General Instruction A.2. below):

[ ] 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))

Indicate by check mark whether the registrant is an emerging growth company as defined in 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.

[ ]

Item 2.02 Results of Operations and Financial Condition

On April 24, 2018, NorthWestern Corporation d/b/a NorthWestern Energy (NYSE: NWE) (the “Company”) issued a press release (the “Press Release”) discussing financial results for the quarter ended March 31, 2018, and reaffirmed its 2018 adjusted non-GAAP earnings guidance range of $3.35 – $3.50 per diluted share. Assumptions concerning the earnings guidance for 2018 can be found in the Press Release, which is furnished as Exhibit 99.1 hereto and is incorporated herein by reference.

The information in this Current Report on Form 8-K provided under Item 2.02 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information provided under Item 2.02 in this Current Report shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.

Item 7.01 Regulation FD Disclosure.

Annual Meeting Presentation. On April 25, 2018, at 12:00 p.m. Eastern time (10:00 a.m. Mountain time), the Company will hold its annual meeting of stockholders at its Montana Operations Support Office, 11 East Park Street, Butte, Montana 59701. During the annual meeting, Robert C. Rowe, president and chief executive officer of the Company will make a presentation (the "Annual Meeting Presentation") to stockholders and other attendees that will discuss the Company's operations.

A live webcast of the annual meeting can be accessed from the Company’s website at www.northwesternenergy.com under the “Our Company / Investor Relations / Presentations and Webcasts” heading or by visiting www.webcaster4.com/Webcast/Page/1050/25301.

Investor Call Presentation. Also as previously announced and as stated in the Press Release, the Company will host an investor conference call and webcast on April 25, 2018, at 3:30 p.m. Eastern time to review its financial results. During the conference call, Mr. Rowe and Brian B. Bird, vice president and chief financial officer of the Company, will make a slide presentation (the "Investor Call Presentation") concerning the Company's financial results.

A live webcast of the investor conference call can be accessed from the Company’s website at www.northwesternenergy.com under the "Our Company / Investor Relations / Presentations and Webcasts" heading or by visiting www.webcaster4.com/Webcast/Page/1050/25281. To listen and view the slideshow presentation, please go to the site at least 10 minutes in advance of the call to register. An archived webcast will be available shortly after the call and will be available for one year. A telephonic replay of the call will be available for one month, beginning at 6:00 p.m. Eastern time on April 25, 2018, at (800) 485-8312 access code 4517992.

Copies of the Annual Meeting Presentation and Investor Call Presentation are being furnished pursuant to Regulation FD as Exhibits 99.2 and 99.3, respectively, to this Current Report on Form 8-K and are incorporated herein by reference. The information in the presentations shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section. Furthermore, the presentations shall not be deemed to be incorporated by reference into the Company's filings under the Securities Act of 1933, as amended, or under the Securities Exchange Act of 1934, as amended, except as set forth with respect thereto in any such filing.

Item 9.01 Financial Statements and Exhibits.

Exhibit No.	Description of Document
99.1*	Press Release dated April 24, 2018
99.2*	Annual Meeting Presentation, dated April 25, 2018
99.3*	Investor Call Presentation, dated April 25, 2018
* filed herewith

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.

	NorthWestern Corporation
By:	/s/ Timothy P. Olson
	Timothy P. Olson
	Corporate Secretary

Date: April 25, 2018

EX-99.1

NorthWestern Corporation d/b/a NorthWestern Energy 3010 W. 69^th Street Sioux Falls, SD 57108 www.northwesternenergy.com

FOR IMMEDIATE RELEASE

NorthWestern Reports First Quarter 2018 Financial Results

Company reports GAAP diluted earnings per share of $1.18 for the first quarter 2018;

Declares a quarterly dividend of $0.55 per share payable June 29, 2018: and

Reaffirms full year 2018 guidance.

SIOUX FALLS, S.D. - April 24, 2018 - NorthWestern Corporation d/b/a NorthWestern Energy (NYSE: NWE) reported financial results for the quarter ended March 31, 2018.  Net income for the period increased 3.4% to $58.5 million, or $1.18 per diluted share, as compared with net income of $56.6 million, or $1.17 per diluted share, for the same period in 2017. This $1.9 million increase in net income in 2018 is primarily due to colder winter weather, higher Montana natural gas rates and increased demand for transmission on our system and lower operating, general and administrative expense in 2018.

Additional information regarding this release can be found in the earnings presentation found at www.northwesternenergy.com/our-company/investor-relations/presentations-and-webcasts.

“Colder weather and cost controls during our first quarter of 2018 were partially offset by higher property tax and depreciation expense.  We also spent a considerable amount of time, along with the rest of the industry, supporting the implementation of the new federal income tax law,” said Bob Rowe, President and Chief Executive Officer. “NorthWestern has submitted proposals to its regulators that ensures the new tax law provides an opportunity to pass benefits on to customers, through lower utility bills, and allow us make important incremental expenditures on our system to continue to improve safety and reliability.”

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 2

	Three Months Ended March 31,
(in thousands, except per share amounts)	2018			2017 (2)
Revenues	$	341,502		$	367,312
Cost of Sales	96,077			119,817
Gross Margin (1)	245,425			247,495
Operating, general and administrative expense	74,345			78,334
Property and other taxes	42,813			39,928
Depreciation and depletion	43,755			41,461
Total Operating Expenses	160,913			159,723
Operating Income	84,512			87,772
Interest Expense, net	(22,970		)	(23,400		)
Other Income	(1,129		)	(1,128		)
Income Before Income Taxes	60,413			63,244
Income Tax Expense	(1,914		)	(6,677		)
Net Income	58,499			56,567
Basic: Average Shares Outstanding	49,416			48,386
Earnings per Share - Basic	$	1.18		$	1.17
Diluted: Average Shares Outstanding	49,484			48,503
Earnings per Share - Diluted	$	1.18		$	1.17
Dividends Declared per Common Share	$	0.55		$	0.525
(1) Gross Margin, defined as Revenues less Cost of Sales, is a non-GAAP financial measure.       See "Non-GAAP Financial Measures" section below for more information.
(2) We adopted ASU 2017-07 on January 1, 2018. As a result, we recorded the nonservice cost component of net periodic benefit cost within other expense, net. We adopted this standard retrospectively and $2.6 million was reclassified from operating, general and administrative expenses to other expense, net for the three months ended March 31, 2017, to conform to current period presentation.

Significant Earnings Drivers

Gross Margin

Consolidated gross margin for the three months ended March 31, 2018 was $245.4 million compared with $247.5 million for the same period in 2017. This $2.1 million decrease was a result of a $4.1 million increase to items that have an impact on net income and $6.2 million decrease to items that are offset in operating expenses and income tax expense with no impact to net income.

Consolidated gross margin for items impacting net income increased $4.1 million, including:

• $1.9 million increase in our Montana gas rates effective September 1, 2017;

• $1.5 million increase in electric and natural gas retail volumes due primarily to colder winter weather and customer growth; and

• $1.5 million increase due to higher demand to transmit energy across our transmission lines due to market conditions and pricing; partially offset by an

• $0.8 million decrease in other miscellaneous margin items.

The change in consolidated gross margin for items that had no impact on net income represented a $6.2 million decrease primarily due to the following:

• $7.3 million decrease due to the deferral of revenue as a result of the Tax Cuts and Job Act (TCJA), offset by a decrease in income tax expense;

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 3

• $0.6 million increase in revenues for property taxes included in trackers, offset by increased property tax expense; and

• $0.5 million increase in revenue due to the decrease in production tax credit benefits passed through to customers in our tracker mechanisms, which are offset by increased income tax expense.

Operating, General and Administrative Expenses

Consolidated operating, general and administrative expenses for the three months ended March 31, 2018 were $74.3 million compared with $78.3 million for the same period in 2017. The $4.0 million decrease was primarily due to:

• $2.3 million decrease due to the change in value of non-employee directors deferred compensation due to changes in our stock price (offset by changes in other income with no impact on net income);

• $1.5 million lower maintenance costs at our Dave Gates Generating Station and Colstrip Unit 4 facilities;

• $1.3 million decreased labor costs due primarily to more time being spent by employees on capital projects rather than maintenance projects (which are expensed);

• $0.9 million lower Distribution System Infrastructure Project related expenses, which concluded at the end of 2017: and

• $0.9 million other miscellaneous decreases.

These decreases were partially offset by a $2.9 million increase in employee benefit expense associated with the regulatory treatment of pension expense, which is primarily offset in other expense below.

Property and Other Taxes

Property and other taxes were $42.8 million for the three months ended March 31, 2018, as compared with $39.9 million in the same period of 2017. This increase was primarily due to plant additions and higher annual estimated property valuations in Montana. We estimate property taxes throughout each year, and update based on valuation reports received from the Montana Department of Revenue. Under Montana law, we are allowed to track the increases in the actual level of state and local taxes and fees and adjust our rates to recover the increase between rate cases less the amount allocated to FERC-jurisdictional customers and net of the associated income tax benefit.

Depreciation and Depletion Expense

Depreciation and depletion expense was $43.8 million for the three months ended March 31, 2018, as compared with $41.5 million in the same period of 2017. This increase was primarily due to plant additions.

Operating Income

Consolidated operating income for the three months ended March 31, 2018 was $84.5 million as compared with $87.8 million in the same period of 2017. This decrease was primarily due to the decrease in gross margin (resulting from the $7.3 million TCJA deferral which is largely offset by reduced income tax expense) and increase in property taxes and depreciation and depletion expense, as discussed above.

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 4

Interest Expense

Consolidated interest expense for the three months ended March 31, 2018 was $23.0 million, as compared with $23.4 million in the same period of 2017. This decrease was primarily due to the refinancing of debt in 2017, partly offset by rising interest rates.

Other Expense

Consolidated other expense, net remained flat at $1.1 million for the three months ended March 31, 2018 as compared with the same period of 2017. This includes a decrease in other pension expense, offset by an increase in expense associated with the change in the value of deferred shares held in trust for non-employee directors deferred compensation, both

of which are offset in operating, general, and administrative expenses with no impact to net income.

Income Tax

Consolidated income tax expense for the three months ended March 31, 2018 was $1.9 million as compared with $6.7 million in the same period of 2017. Our effective tax rate for the three months ended March 31, 2018 was 3.2% as compared with 10.6% for the same period of 2017. We expect our 2018 effective tax rate to range between 0% - 5%.

The following table summarizes the differences between our effective tax rate and the federal statutory rate (in millions):

(in millions)	Three Months Ended March 31,
	2018					2017
Income Before Income Taxes	$	60.4				$	63.2
Income tax calculated at federal statutory rate	12.7			21.0	%	22.1			35.0	%
Permanent or flow-through adjustments:
State income, net of federal provisions	0.7			1.2	%	(0.8		)	(1.3	)%
Flow-through repairs deductions	(6.6		)	(10.9	)%	(8.8		)	(13.9	)%
Production tax credits	(3.9		)	(6.4	)%	(3.8		)	(6.1	)%
Plant and depreciation of flow-through items	(0.9		)	(1.6	)%	(1.4		)	(2.3	)%
Shared-based compensation	0.3			0.5	%	(0.4		)	(0.6	)%
Other, net	(0.4		)	(0.6	)%	(0.2		)	(0.2	)%
Subtotal	(10.8		)	(17.8	)%	(15.4		)	(24.4	)%
Income Tax Expense	$	1.9		3.2	%	$	6.7		10.6	%

We compute income tax expense for each quarter based on the estimated annual effective tax rate for the year, adjusted for certain discrete items. Our effective tax rate typically differs from the federal statutory tax rate primarily due to the regulatory impact of flowing through federal and state tax benefits of repairs deductions, state tax benefit of accelerated tax depreciation deductions (including bonus depreciation when applicable) and production tax credits.

Net Income

Consolidated net income for the three months ended March 31, 2018 was $58.5 million as compared with $56.6 million for the same period in 2017. This increase is primarily due higher

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 5

Montana natural gas rates, colder winter weather, increased demand for electric transmission, and lower operating, general and administrative expense in 2018.

Reconciliation of Primary Changes from 2017 to 2018

		Three Months Ended March 31,
	($millions, except EPS)	Pre-tax Income		Net (1) Income		Diluted EPS
	2017 reported	$63.2		$56.6		$1.17
Gross Margin
	Montana natural gas and production rates	1.9		1.4		0.03
	Electric transmission	1.5		1.1		0.02
	Electric retail volumes	1.1		0.8		0.02
	Natural gas retail volumes	0.4		0.3		—
	Other	(0.8	)	(0.6	)	(0.01	)
	Subtotal: Margin Items Impacting Net Income	4.1		3.0		0.06
	Tax Cuts and Job Acts deferral (subject to refund)	(7.3	)	(5.5	)	(0.11	)
	Property and other taxes	0.6		0.4		0.01
	Production tax credits flowed-through trackers	0.5		0.4		0.01
	Subtotal: Margin Items Not Impacting Net Income (2)	(6.2	)	(4.7	)	(0.09	)
	Total Gross Margin	(2.1	)	(1.7	)	(0.03	)
OG&A Expense
	Non-employee director deferred compensation	2.3		1.7		0.03
	Maintenance costs	1.5		1.1		0.02
	Labor	1.3		1.0		0.02
	Distribution System Infrastructure Project expenses	0.9		0.7		0.01
	Employee benefits	(2.9	)	(2.2	)	(0.04	)
	Other	0.9		0.7		0.01
	Total OG&A Expense	4.0		3.0		0.05
Other items
	Depreciation and depletion expense	(2.3	)	(1.7	)	(0.03	)
	Property and other taxes	(2.9	)	(2.2	)	(0.04	)
	Interest expense	0.4		0.3		—
	Permanent and flow-through adjustments to income tax			4.2		0.08
	Impact of higher share count	—		—		(0.02	)
	Total Other items	(4.8	)	0.6		(0.01	)
	Total impact of above items	(2.8	)	1.9		0.01
	2018 reported	$60.4		$58.5		$1.18
(1) Income Tax calculation on reconciling items assumes federal plus state statutory effective tax rate of 25.3% (38.5% prior to TCJA).
(2) These items are offset in property tax and income tax expense and have no impact to net income.

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 6

Liquidity and Capital Resources

As of March 31, 2018, our total net liquidity was approximately $206.7 million, including $4.7 million of cash and $202.0 million of revolving credit facility availability. This compares to total net liquidity one year ago at March 31, 2017 of $183.5 million.

In September 2017, we entered into an equity distribution in which we may offer and sell shares of our common stock from time to time, having an aggregate gross sales price of up to $100 million. During 2017, we received net proceeds of approximately $54 million from the sale of our common stock. There were no issuances during the first quarter of 2018. We expect to issue the remaining $46 million of shares under the agreement during 2018.

Dividend Declared

NorthWestern's Board of Directors declared a quarterly common stock dividend of $0.55 per share, payable June 29, 2018 to common shareholders of record as of June 15, 2018.

Significant Items Not Contemplated in Guidance

A reconciliation of items not factored into our 2018 and final 2017 adjusted non-GAAP earnings guidance of $3.35 - $3.50 and $3.30 - $3.45 per diluted share, respectively, are summarized below. The amount below represents a non-GAAP measure that may provide users of this data with additional meaningful information regarding the impact of certain items on our expected earnings. More information on this measure can be found in the "Non-GAAP Financial Measures" section below.

(in millions, except EPS)							Estimated to Meet Guidance
Three Months Ended March 31, 2018							EPS Q2-Q4 2018					EPS Full Year 2018
	Pre-tax Income		Net(1) Income		Diluted EPS		Low		-		High	Low		-		High
2018 Reported GAAP	$60.4		$58.5		$1.18
Non-GAAP Adjustments:
Remove favorable weather	(4.8	)	(3.6	)	(0.07	)
2018 Adjusted Non-GAAP	$55.6		$54.9		$1.11		$2.24		-		$2.39	$3.35		-		$3.50
(in millions, except EPS)							Actual
Three Months Ended March 31, 2017							EPS Q2-Q4 2017					EPS Full Year 2017
	Pre-tax Income		Net(2) Income		Diluted EPS		Pre-tax Income		Net(2) Income		Diluted EPS	Pre-tax Income		Net(2) Income		Diluted EPS
2017 Reported GAAP	$63.2		$56.6		$1.17		$112.9		$106.1		$2.17	$176.1		$162.7		$3.34
Non-GAAP Adjustments:
Remove favorable weather	(3.2	)	(2.0	)	(0.04	)	(0.2	)	(0.1	)	—	(3.4	)	(2.1	)	(0.04	)
2017 Adjusted Non-GAAP	$60.0		$54.6		$1.13		$112.7		$106.0		$2.17	$172.7		$160.6		$3.30
(1) Income tax calculation on reconciling adjustments assumes updated federal plus state statutory effective tax rate of 25.3%.
(2) Income tax calculation on reconciling adjustments assumes previous federal plus state statutory effective tax rate of 38.5%.

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 7

2018 Earnings Guidance Reaffirmed

NorthWestern reaffirms its 2018 adjusted non-GAAP earnings guidance range of $3.35 - $3.50 per diluted share based upon, but not limited to, the following major assumptions and expectations:

• Normal weather in our electric and natural gas service territories;

• Equitable regulatory treatment in the process of passing Tax Cuts and Jobs Act benefits on to customers;

• Recovery of Montana energy supply costs as proposed in our pending Power Cost & Credit Adjustment Mechanism (PCCAM);

• A consolidated income tax rate of approximately 0% to 5% of pre-tax income; and

• Issuance of the remaining $46 million of equity under our current distribution agreement resulting in diluted average shares outstanding ranging between approximately 50.0 million to 50.2 million

Company Hosting Investor Conference Call

NorthWestern will host an investor conference call and webcast tomorrow, April 25, 2018, at 3:30 p.m. Eastern time to review its financial results for the quarter ending March 31, 2018. The conference call will be webcast live on the Internet at www.northwesternenergy.com under the “Our Company / Investor Relations / Presentations and Webcasts” heading or by visiting www.webcaster4.com/Webcast/Page/1050/25281. To participate, please go to the site at least 10 minutes in advance of the webcast to register. An archived webcast will be available shortly after the call and remain active for one year.

A telephonic replay of the call will be available for one month, beginning at 6:00 p.m. Eastern time on April 25, 2018, at (800) 485-8312 access code 4517992.

Notice of Annual Stockholders Meeting

NorthWestern will also hold its annual stockholders meeting on Wednesday, April 25, 2018, at 12:00 p.m. Eastern Time (10:00 a.m. Mountain Time) at the Montana Operations Support Office, 11 East Park Street, Butte, Montana 59701.

The annual stockholders meeting will be webcast live on the Internet at www.northwesternenergy.com under the “Our Company / Investor Relations / Presentations and Webcasts” heading or by visiting www.webcaster4.com/Webcast/Page/1050/25301. To participate, please go to the site at least 10 minutes in advance of the call to register.

About NorthWestern Energy

NorthWestern Corporation, doing business as NorthWestern Energy, provides electricity and / or natural gas to approximately 718,300 customers in Montana, South Dakota and Nebraska. More information on NorthWestern Energy is available on the company's Web site at www.northwesternenergy.com.

Non-GAAP Financial Measures

This press release includes financial information prepared in accordance with GAAP, as well as other financial measures, such as Gross Margin and Adjusted Non-GAAP Diluted EPS, that are considered “non-GAAP financial measures.”Generally, a non-GAAP financial measure is a numerical measure of a company's financial performance, financial position or cash flows that

NorthWestern Reports First Quarter 2018 Financial Results

April 24, 2018

Page 8

exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP. Gross Margin (Revenues less Cost of Sales) is a non-GAAP financial measure due to the exclusion of depreciation and depletion from the measure. Gross Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs. Adjusted Non-GAAP Diluted EPS is another non-GAAP measure. The Company believes the presentation of Adjusted Non-GAAP Diluted EPS is more representative of our normal earnings than the GAAP EPS due to the exclusion (or inclusion) of certain impacts that are not reflective of ongoing earnings.

The presentation of these non-GAAP measures is intended to supplement investors' understanding of our financial performance and not to replace other GAAP measures as an indicator of actual operating performance.Our measures may not be comparable to other companies' similarly titled measures.

Special Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, without limitation, the information under "Significant Items Not Contemplated in Guidance" and “2018 Earnings Guidance Reaffirmed”.  Forward-looking statements often address our expected future business and financial performance, and often contain words such as “expects,” “anticipates,” “intends,” “plans,”“believes,”“seeks,” or “will.”  These statements are based upon our current expectations and speak only as of the date hereof. Our actual future business and financial performance may differ materially and adversely from those expressed in any forward-looking statements as a result of various factors and uncertainties, including, but not limited to:

• adverse determinations by regulators, as well as potential adverse federal, state, or local legislation or regulation, including costs of compliance with existing and future environmental requirements, could have a material effect on our liquidity, results of operations and financial condition;

• changes in availability of trade credit, creditworthiness of counterparties, usage, commodity prices, fuel supply costs or availability due to higher demand, shortages, weather conditions, transportation problems or other developments, may reduce revenues or may increase operating costs, each of which could adversely affect our liquidity and results of operations;

• unscheduled generation outages or forced reductions in output, maintenance or repairs, which may reduce revenues and increase cost of sales or may require additional capital expenditures or other increased operating costs; and

• adverse changes in general economic and competitive conditions in the U.S. financial markets and in our service territories.

Our 2017 Annual Report on Form10-K, Quarterly Reports on Form10-Q, reports on Form8-K and other Securities and Exchange Commission filings discuss some of the important risk factors that may affect our business, results of operations and financial condition.We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Relations Contact:                    Media Contact:

Travis Meyer (605) 978-2967                    Butch Larcombe (866) 622-8081

travis.meyer@northwestern.com                butch.larcombe@northwestern.com

EX-99.2

NorthWestern Energy Annual Meeting of Stockholders - April 25, 2018 Dr. E. Linn Draper Jr. addressing NWE employees in April 2017

2 Forward Looking Statements Forward Looking Statements During the course of this presentation, there will be forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements often address our expected future business and financial performance, and often contain words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” or “will.” The information in this presentation is based upon our current expectations as of the date hereof unless otherwise noted. Our actual future business and financial performance may differ materially and adversely from our expectations expressed in any forward-looking statements. We undertake no obligation to revise or publicly update our forward-looking statements or this presentation for any reason. Although our expectations and beliefs are based on reasonable assumptions, actual results may differ materially. The factors that may affect our results are listed in certain of our press releases and disclosed in the Company’s most recent Form 10-K and 10-Q along with other public filings with the SEC. NorthWestern Corporation dba: NorthWestern Energy Ticker: NWE Trading on the NYSE www.northwesternenergy.com Corporate Office 3010 West 69th Street Sioux Falls, SD 57108 (605) 978-2900 Investor Relations Officer Travis Meyer 605-978-2967 travis.meyer@northwestern.com Company Information

About NorthWestern 3 Montana Operations Electric 369,100 customers 24,495 miles – transmission & distribution lines 809 MW nameplate owned power generation Natural Gas 196,700 customers 7,287 miles of transmission and distribution pipeline 17.75 Bcf of gas storage capacity Own 55.9 Bcf of proven natural gas reserves Nebraska Operations Natural Gas 42,400 customers 790 miles of distribution pipeline South Dakota Operations Electric 63,600 customers 3,560 miles – transmission & distribution lines 440 MW nameplate owned power generation Natural Gas 46,500 customers 1,681 miles of transmission and distribution pipeline Data as of 12/31/2017

NWE - An Investment for the Long Term 4 • 100% regulated electric & natural gas utility business with over 100 years of operating history • Solid economic indicators in service territory • Diverse electric supply portfolio ~56% hydro & wind Black Eagle damPure Electric & Gas Utility Solid Utility Foundation Strong Earnings & Cash Flow Attractive Future Growth Prospects Financial Goals & Metrics Best Practices Corporate Governance • Residential electric & gas rates below national average • Solid system reliability (EEI 2nd quartile) • Solid JD Power Overall Customer Satisfaction scores • Low leaks per 100 miles of pipe (AGA 1st quartile) • Disciplined maintenance capital investment program to ensure safety and reliability • Significant investment in renewable resources (hydro & wind) will provide long-term energy supply pricing stability for the benefit of customers for many years to come • Further opportunity for energy supply investment to meet significant capacity shortfalls • Consistent track record of earnings & dividend growth • Strong cash flows aided by net operating loss carry- forwards anticipated to be available into 2020 • Strong balance sheet & investment grade credit ratings • Debt to total capitalization ratio of 50%-55% with liquidity of $100 million or greater • Targeted 6%-9% long-term total shareholder return (eps growth plus dividend yield) • Targeted dividend payout ratio of 60%-70%

A Diversified Electric and Gas Utility 5 NorthWestern’s ‘80/20’ rules: Approximately 80% Electric, 80% Residential and 80% Montana. Over $3.5 billion of rate base investment to serve our customers Data as of 12/31/2017. (1) (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure. (1)

6 Highly Carbon-Free Supply Portfolio Based upon 2017 MWH’s of owned and long-term contracted resources. Approximately 56% of our total company owned and contracted supply is carbon-free. NorthWestern does not own all the renewable energy certificates (RECs) generated by contracted wind, and periodically sells its own RECs with proceeds benefiting retail customers. Accordingly, we cannot represent that 100% of carbon-free energy in the portfolio was delivered to our customers.

Strong Utility Foundation 7  Solid and improving JD Power Overall Customer Satisfaction Scores  Residential electric and natural gas rates below national average  Solid electric system reliability and low gas leaks per mile

Solid Economic Indicators 8 • Customer growth rates historically exceed National Averages. • Unemployment rates in all three of our states are below or in-line with National Average. Source: NorthWestern customer growth - 2008-2016 Forms 10-K Unemployment Rate: US Department of Labor via SNL Database 2/21/17 Electric: EEI Statistical Yearbook (published December 2015, table 7.2) Natural Gas: EIA.gov (Data table "Number of Natural Gas Consumers") Source: Company 10K’s, 2015/2016 EEI Statistical Yearbook – Table 7.2 and EIA.gov Black Eagle Power House

A History of Growth 9 2008-2017 CAGR’s: GAAP EPS: 7.3% - Non-GAAP EPS: 6.8% - Dividend: 5.3% See appendix for “Non-GAAP Financial Measures” $2.60 - $2.75 $3.10 - $3.30 $3. 0-$3.40 $3.30-$3.50

Track Record of Delivering Results 10 Return on equity within 9.3% - 11.0% band over the last 6 years. See appendix for “Non-GAAP Financial Measures” Total Shareholder Return is better than our 13 peer average for the 10 year period but lags in the 1, 3 & 5 year periods, due primarily to concerns over Montana regulatory decisions. * Peer Group: ALE, AVA, BKH, EE, GXP, IDA, MGEE, OGE, OTTR, PNM, POR, VVC, WR

Investment for Our Customers’ Benefit 11 Over the past 8 years we have been reintegrating our Montana energy supply portfolio and making additional investments across our entire service territory to enhance system safety, reliability and capacity. We have made these enhancements with minimal impact to customers’ bills while maintaining bills lower than the US average. As a result we have also been able to deliver solid earnings growth for our investors. 2008-2017 CAGRs Estimated Rate Base: 13.3% GAAP Diluted EPS: 7.3% 2008-2017 CAGRs NWE typical electric bill: 2.1% NWE typical natural gas bill: (6.1%) 2008-2016 CAGRs US average electric bill: 1.7%* US average natural gas bill: (4.0%)**

Balance Sheet Strength and Liquidity 12 Investment grade credit ratings, liquidity generally in excess of $100 million target, and debt to cap moving lower within our targeted 50%-55% range.

Credit Ratings 13 Moody’s downgraded our senior secured and unsecured credit rating on March 10, 2017 and has placed us on a Negative Outlook. Moody’s is now in line with Fitch and still above S&P on a secured basis. On February 5, 2018, Fitch also placed us on Negative Outlook. Electric and natural gas utilities average S&P rating Electric and natural gas utilities average Moody’s rating Moody’s: A2 Fitch: A S&P: A-

While maintenance capex and total dividend payments have continued to grow since 2011 (12.9% and 13.0% CAGR respectively), Cash Flow from Operations (CFO) has, on average, exceeded maintenance capex and dividend payments by approximately $24 million per year. 2016 CFO is less than 2015 largely due to $30.8M refund to customers related to FERC/DGGS ruling and $7.2M refund to customers for difference in SD Electric interim & final rates. With the addition of production tax credits from the Beethoven Wind project and continued flow-through tax benefits, we anticipate our effective tax rate approaching 10% by 2022. Additionally, we expect NOLs to be available into 2020, and Alternative Minimum Tax credits / Production Tax Credits to be available into 2022 to reduce cash taxes. (See appendix for “Non-GAAP Financial Measures” relating to free cash flow and disclaimer on NOL’s) Strong Cash Flows 14

Exemplary Board of Directors 15 Board of Directors (left to right) Linda G. Sullivan – Independent Director since April 27, 2017 – Audit Committee Dana J. Dykhouse – Independent Director since January 30, 2009 – Human Resources (chair) and Audit Committees Britt E. Ide – Independent Director since April 27, 2017 – Governance & Innovation Committee Jan R. Horsfall – Independent Director since April 23, 2015 – Audit and Governance & Innovation Committees Anthony T. Clark – Independent Director since December 6, 2016 – Governance & Innovation Committee Robert C. Rowe - CEO & President – Director since August 13, 2008 Dr. E. Linn Draper Jr. -Chairman of the Board – Independent Director since November 1, 2004. Retiring April 2018 Julia L. Johnson – Independent Director since November 1, 2004 – Governance & Innovation (chair) and Human Resources Committees Stephan P. Adik – Independent Director since November 1, 2004 – Audit (chair) and Human Resources Committees

Experienced Executive Team 16 Executive Management Team (left to right) Crystal D. Lail – VP & Controller – current position since 2015 Curtis T. Pohl – VP Distribution – current position since 2003 Bobbi L. Schroeppel – VP Customer Care, Communications & Human Resources – current position since 2002 Brian B. Bird – VP & CFO – current position since 2003 Heather H. Grahame – VP & General Counsel – current position since 2010 Robert C. Rowe - President & CEO – current position since 2008 John D. Hines – VP Supply – current position since 2011 Michael R. Cashell – VP Transmission – current position since 2011

Strong Corporate Governance 17

Strong Corporate Governance 18

2018 Earnings Guidance 19 $2.60 - $2.75 $3.10 - $3.30 $3. 0-$3.40 $3.30-$3.50 See appendix for additional disclosures regarding “Non-GAAP Financial Measures” $3.30-$3.45 NorthWestern’s 2018 earnings guidance range of $3.35 - $3.50 per diluted share is based upon, but not limited to, the following major assumptions and expectations: • Normal weather in our electric and natural gas service territories; • Equitable regulatory treatment in the process of passing Tax Cuts and Jobs Act benefits on to customers; • Recovery of Montana energy supply costs as proposed in our pending Power Cost & Credit Adjustment Mechanism (PCCAM); • A consolidated income tax rate of approximately 0% to 5% of pre-tax income; and • Issuance of the remaining $46 million of equity under our current distribution agreement resulting in diluted average shares outstanding ranging between approximately 50.0 million to 50.2 million. Continued investment in our system to serve our customers and communities is expected to provide a targeted long term 6-9% total return to our investors through a combination of earnings growth and dividend yield. However, negative outcomes in upcoming regulatory proceedings may result in near-term returns below our 6-9% targeted range. Generation investment to reduce or eliminate our capacity shortfall could allow us to achieve the higher-end of our range over the long term. See “Non-GAAP Financial Measures” slide in appendix for “Non-GAAP “Adjusted EPS”.

Recent Significant Achievements 20 Echo Lake Nordic Trail Strong year for safety at NorthWestern • Continue to be a top performer among Edison Electric Institute member companies. Record best customer satisfaction scores with JD Power & Associates • Once again received our best JD Powers overall satisfaction survey score in 2017. Corporate Governance Finalist • In 2017 NorthWestern’s proxy statement was again recognized as a finalist for “Best Proxy Statement (Small to Mid Cap)” by Corporate Secretary Magazine. We won the award in 2014. Board Diversity Recognition • Recognized for gender diversity on its board of directors by 2020 Women on Boards. Three of the company’s eight independent directors are female. Second Annual Environmental Report • Published in December 2017, this report highlights our commitment to the stewardship of natural resources and our sustainable business practices.

Looking Forward 21 Echo Lake Nordic Trail Much of our focus in the next year will be on the electric rate case in Montana and controlling our costs to benefit all stakeholders while continuing to invest in our core business to provide safe and reliable energy for our all of our customers. Black Eagle Power House Regulatory • Regulatory treatment of tax reform - determine best way to provide long-term benefit to customers and system while keeping investors ‘whole’. • Working toward successful implementation of new Power Cost and Credit Adjustment Mechanism • Anticipate filing an electric rate case by September 2018 (based on a 2017 test year). Continue to Invest in our T&D infrastructure • Transition from DSIP/TSIP to overall infrastructure capital investment plan • Natural gas pipeline investment (Integrity Verification Process and PHMSA1 Requirements) • Grid modernization, advanced distribution management system and advanced metering infrastructure investment Update Electricity Resource Procurement Plans in Montana & South Dakota • Montana: Least cost / lowest risk approach to address intermittent capacity and reserve margin needs • South Dakota: Generation fleet assessment to evaluate economic retirement / replacement opportunities Natural Gas Reserve Acquisition Opportunities • Acquisitions at a price that benefits both customers and shareholders Cost Control Efforts • Continue to monitor costs, including labor, benefits and property tax valuations to mitigate increases 1. Pipeline & Hazardous Materials Safety Administration (PHMSA)

Capital Spending Forecast 22 2018 Significant Updates Out: Approximately $123 million of previously included investment in capacity generation has been removed pending update of Integrated Resource Plans in both Montana and South Dakota (expected to be completed by year-end 2018). In: Approximately $126 million of incremental investment related to grid modernization and automated meter infrastructure for Montana. South Dakota and Nebraska AMI investment spend was previously included ($28M). The current estimated cumulative 5 year capital spending is $1.596 billion. We anticipate funding the expenditures with a combination of cash flows (aided by NOLs available into 2020), the remainder of our current equity distribution program and long-term debt issuances. Significant capital investments, that are not in the above projections, or further negative regulatory actions could necessitate additional equity issuances.

"Linn has been a tremendous Board member. His distinguished career, experience, and stature within the utility industry is unmatched and will be difficult to replace. As Chair, his leadership beginning with our emergence from bankruptcy in 2004 and continuing today has been a significant factor in our success. We will miss his presence. I look forward to his friendship and advice for many years to come. Personally, I have been privileged to have one of the wisest and most decent leaders in this or any industry as a mentor and friend. We are fortunate to have another experienced industry leader, Steve Adik, take over the reins as Board chair. Steve has been an outstanding Audit Committee Chair, and has been active in all aspects of the Board’s duties. He’s respected in the industry and by our employees. Like our entire Board, Steve is committed to our customers and to our employees as well as to our shareholders.” Bob Rowe, President & CEO Farewell and Thank You Dr. E. Linn Draper Jr. 23

Conclusion 24 Best Practices Corporate Governance Pure Electric & Gas Utility Solid Utility Foundation Strong Earnings & Cash Flows Attractive Future Growth Prospects

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NorthWestern Energy Profile 26

Non-GAAP Financial Measures 27 These materials include financial information prepared in accordance with GAAP, as well as other financial measures, such as Gross Margin and Adjusted Diluted EPS, that are considered “non-GAAP financial measures.” Generally, a non-GAAP financial measure is a numerical measure of a company's financial performance, financial position or cash flows that exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP. Gross Margin (Revenues less Cost of Sales) is a non-GAAP financial measure due to the exclusion of depreciation from the measure. Gross Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs. Adjusted Diluted EPS is another non-GAAP measure. The Company believes the presentation of Adjusted Diluted EPS is more representative of our normal earnings than the GAAP EPS due to the exclusion (or inclusion) of certain impacts that are not reflective of ongoing earnings. The presentation of these non-GAAP measures is intended to supplement investors' understanding of our financial performance and not to replace other GAAP measures as an indicator of actual operating performance. Our measures may not be comparable to other companies' similarly titled measures.

Non-GAAP Financial Measures 28 Disclaimer on Net Operating Net Operating Losses (NOL’s): The expected tax rate and the expected availability of NOLs are subject to significant business, economic, regulatory and competitive uncertainties and contingencies, many of which are beyond the control of the Company and its management, and are based upon assumptions with respect to future decisions, which are subject to change. Actual results will vary and those variations may be material. For discussion of some of the important factors that could cause these variations, please consult the “Risk Factors” section of our most recent 10-K filed with the SEC.

Non-GAAP Financial Measures 29 The data presented in this presentation includes financial information prepared in accordance with GAAP, as well as other Non- GAAP financial measures such as Gross Margin (Revenues less Cost of Sales), Free Cash Flows (Cash flows from operations less maintenance capex and dividends) and Net Debt (Total debt less capital leases), that are considered “Non-GAAP financial measures.” Generally, a Non-GAAP financial measure is a numerical measure of a company’s financial performance, financial position or cash flows that exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP. The presentation of Gross Margin, Free Cash Flows and Net Debt is intended to supplement investors’ understanding of our operating performance. Gross Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs. Net Debt is used by our company to determine whether we are properly levered to our Total Capitalization (Net Debt plus Equity). Our Gross Margin, Free Cash Flows and Net Debt measures may not be comparable to other companies’ similarly labeled measures. Furthermore, these measures are not intended to replace measures as determined in accordance with GAAP as an indicator of operating performance.

EX-99.3

2018 First Quarter Earnings Webcast April 25, 2018 Black Eagle Dam

Presenting Today 2 Bob Rowe, President & CEO Brian Bird, Vice President & CFO Forward Looking Statements During the course of this presentation, there will be forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements often address our expected future business and financial performance, and often contain words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” or “will.” The information in this presentation is based upon our current expectations as of the date hereof unless otherwise noted. Our actual future business and financial performance may differ materially and adversely from our expectations expressed in any forward-looking statements. We undertake no obligation to revise or publicly update our forward-looking statements or this presentation for any reason. Although our expectations and beliefs are based on reasonable assumptions, actual results may differ materially. The factors that may affect our results are listed in certain of our press releases and disclosed in the Company’s 10-K and 10-Q along with other public filings with the SEC.

• First quarter operating income decreased $3.3 million as compared to the same period in 2017. However, if adjusted to remove the $7.3 million revenue deferral recorded during the quarter related to the Tax Cuts and Jobs Act, operating income would have increased by $4.0 million, or 4.6%. • Net income for the quarter was up $1.9 million, or 3.4%, as compared to the same period in 2017 primarily due to colder winter weather, an increase in Montana natural gas rates, increased demand for transmission and lower operating, general and administrative expense. • As a result of increased average share count, diluted earnings per share increased by a lesser 0.9%, to $1.18 as compared to $1.17 during the same period in 2017. • Adjusted non-GAAP* earnings per share were $1.11 as compared to $1.13 during the same period in 2017. • The Board declared a quarterly dividend of $0.55 per share payable June 29th to shareholders of record as of June 15th, 2018. First Quarter Highlights 3 * See slides 13 & 24 for additional information and Non-GAAP disclosures.

Summary Financial Results (First Quarter) 4 (1) (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure.

5 Gross Margin (First Quarter) (dollars in millions) Three Months Ended March 31, 2018 2017 Variance(1) Operating Revenues $ 341.5 $ 367.3 ($ 25.8) (7.0%) Cost of Sales 96.1 119.8 (23.7) (19.8%) Gross Margin $ 245.4 $ 247.5 ($ 2.1) (0.8%) Decrease in gross margin due to the following factors: $ 1.9 Montana natural gas and production rates 1.5 Electric transmission 1.1 Electric retail volumes 0.4 Natural gas retail volumes (0.8) Other $ 4.1 Change in Gross Margin Impacting Net Income $ (7.3) Deferral of revenue due to change in income tax law 0.6 Property taxes recovered in trackers 0.5 Production tax credits flowed-through trackers $ (6.2) Change in Gross Margin Offset Within Net Income $ (2.1) Decrease in Consolidated Gross Margin Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure. (1) During the first quarter of 2018, we revised our presentation of revenues associated with being a market participant in the Southwest Power Pool to net them with the associated cost of sales. These revenues were previously recorded gross in electric revenues in the Condensed Consolidated Statement of Income. This results in a decrease in electric revenue and a corresponding decrease in cost of sales. There was no impact to operating or net income. We assessed the materiality of this change in presentation, taking into account quantitative and qualitative factors, and determined it to be immaterial. We applied the change in presentation prospectively only.

Weather (First Quarter) 6 Mean Temperature from Normal We estimate favorable weather in Q1 2018 contributed approximately $4.8M pretax benefit as compared to normal and $1.6M pretax benefit as compared to Q1 2017.

Operating Expenses (First Quarter) 7 Increase in operating expenses due mainly to the following factors: $4.0 million decrease in OG&A $ (2.3) Non-employee directors deferred compensation $ (1.5) Maintenance costs $ (1.3) Labor $ (0.9) Distribution System Infrastructure Project expenses $ 2.9 Employee benefits $ (0.9) Other $2.9 million increase in property and other taxes due primarily to plant additions and higher estimated property valuations in Montana. $2.3 million increase in depreciation and depletion expense primarily due to plant additions. (dollars in millions) Three Months Ended March 31, 2018 2017 Variance Operating, general & admin. $ 74.3 $ 78.3 $ (4.0) (5.1%) Property and other taxes 42.8 39.9 2.9 7.3% Depreciation and depletion 43.8 41.5 2.3 5.5% Operating Expenses $ 160.9 $ 159.7 $ 1.2 0.8%

Operating to Net Income (First Quarter) 8 $0.4 million decrease in interest expenses was primarily due to debt refinancing of debt in 2017, partly offset by rising interest rates. No change in other expense. A decrease in other pension expense, offset by a increase in expense associated with the change in the value of deferred shares held in trust for non-employee directors deferred compensation, both of which are offset in operating, general, and administrative expenses with no impact to net income. $4.7 million decrease in income tax expense due primarily to a lower statutory federal tax rate of 21.0% compared to 35.0% in 2017 and lower pretax income, partially offset by lower flow-through repairs deductions. (dollars in millions) Three Months Ended March 31, 2018 2017 Variance Operating Income $ 84.5 $ 87.8 $ (3.3) (3.8%) Interest Expense (23.0) (23.4) 0.4 1.7% Other Expense (1.1) (1.1) 0.0 0.0% Income Before Taxes 60.4 63.2 (2.8) (4.4%) Income Tax Expense (1.9) (6.6) 4.7 71.2% Net Income $ 58.5 $ 56.6 $ 1.9 3.4%

Pre-Tax Earnings Bridge (First Quarter ‘18 vs ’17) 9 Pre-Tax income decreased by $2.8 million in the 1st quarter 2018 vs the same period in 2017. This was primarily due to the decrease in gross margin resulting from the $7.3 million TCJA deferral (which is largely offset by reduced income tax expense but not shown in the pretax bridge above).

Income Tax Reconciliation 10

Balance Sheet 11 NorthWestern’s Ratio of debt to total capitalization decreased from 53.7% at 12/31/17 to 52.0% at 3/31/18.

Cash Flow 12 Cash from operating activities improved by $15.8 million primarily due to the receipt of insurance proceeds and improved collections of supply costs in 2018. During 2017, we received net proceeds of approximately $54 million from the sale our common stock. There were no issuances during the first quarter of 2018. We expect to issue the remaining $46 million under the $100 million equity distribution agreement during 2018.

Adjusted Non-GAAP Earnings (First Quarter) 13 The adjusted non-GAAP measures presented in the table above are being shown to reflect significant items that were not contemplated in our original guidance, however they should not be considered a substitute for financial results and measures determined or calculated in accordance with GAAP. (1) During the first quarter of 2018, we revised our presentation of revenues associated with being a market participant in the Southwest Power Pool to net them with the associated cost of sales. These revenues were previously recorded gross in electric revenues in the Condensed Consolidated Statement of Income. This results in a decrease in electric revenue and a corresponding decrease in cost of sales. There was no impact to operating or net income. We assessed the materiality of this change in presentation, taking into account quantitative and qualitative factors, and determined it to be immaterial. We applied the change in presentation prospectively only. (2) We adopted ASU 2017-07 on January 1, 2018. As a result, we recorded the non-service cost component of net periodic benefit cost within other expense, net. We adopted this standard retrospectively and $2.6 million was reclassified from operating, general and administrative expenses to other expense, net for the three months ended March 31, 2017, to conform to current period presentation.

2018 Earnings Guidance 14 $2.60 - $2.75 $3.10 - $3.30 $3. 0-$3.40 $3.30-$3.50 See appendix for additional disclosures regarding “Non-GAAP Financial Measures” $3.30-$3.45 NorthWestern’s 2018 earnings guidance range of $3.35 - $3.50 per diluted share is based upon, but not limited to, the following major assumptions and expectations: • Normal weather in our electric and natural gas service territories; • Equitable regulatory treatment in the process of passing Tax Cuts and Jobs Act benefits on to customers; • Recovery of Montana energy supply costs as proposed in our pending Power Cost & Credit Adjustment Mechanism (PCCAM); • A consolidated income tax rate of approximately 0% to 5% of pre-tax income; and • Issuance of the remaining $46 million of equity under our current distribution agreement resulting in diluted average shares outstanding ranging between approximately 50.0 million to 50.2 million. Continued investment in our system to serve our customers and communities is expected to provide a targeted long term 6-9% total return to our investors through a combination of earnings growth and dividend yield. However, negative outcomes in upcoming regulatory proceedings may result in near-term returns below our 6-9% targeted range. Generation investment to reduce or eliminate our capacity shortfall could allow us to achieve the higher-end of our range over the long term. See “Non-GAAP Financial Measures” slide in appendix for “Non-GAAP “Adjusted EPS”.

Looking Forward 15 $2.60 - $2.75 $3.10 - $3.30 $3. 0-$3.40 $3.30-$3.50 See appendix for additional disclosures regarding “Non-GAAP Financial Measures” $3.30-$3.45 Regulatory • Regulatory treatment of tax reform - determine best way to provide long-term benefit to customers and system while keeping investors ‘whole’. • Working toward successful implementation of new Power Cost and Credit Adjustment Mechanism • Anticipate filing an electric rate case by September 2018 (based on a 2017 test year). Continue to Invest in our T&D infrastructure • Transition from DSIP/TSIP to overall infrastructure capital investment plan • Natural gas pipeline investment (Integrity Verification Process and PHMSA1 Requirements) • Grid modernization, advanced distribution management system and advanced metering infrastructure investment Update Electricity Resource Procurement Plans in Montana & South Dakota • Montana: Least cost / lowest risk approach to address intermittent capacity and reserve margin needs • South Dakota: Generation fleet assessment to evaluate economic retirement / replacement opportunities Natural Gas Reserve Acquisition Opportunities • Acquisitions at a price that benefits both customers and shareholders Cost Control Efforts • Continue to monitor costs, including labor, benefits and property tax valuations to mitigate increases 1. Pipeline & Hazardous Materials Safety Administration (PHMSA) Much of our focus in the next year will be on the electric rate case in Montana and controlling our costs to benefit all stakeholders while continuing to invest in our core business to provide safe and reliable energy for our all of our customers. Black Eagle Power House

Regulatory & Legal Update 16 Montana Property Tax Tracker Filing • On January 29th the MPSC issued an order in our 2017 property tax tracker filing by further reducing our recovery of Montana property taxes by a total of $3.5 million impacting both 2017 and 2018 (approximately $1.75 million each year). This change was a result of applying an alternate allocation methodology that lowers the property tax allocation to our electric retail customers (with a higher allocation to FERC customers for which we do not have a tracking mechanism). • On February 8th we filed a motion for reconsideration with the MPSC. • An April 5th hearing granted our motion to only apply the alternate methodology on a prospective basis. Power Cost and Credit Adjustment Mechanism (PCCAM) • In April 2017, the Montana legislature passed House Bill 193, amending the statute that provided for mandatory recovery of our prudently incurred electric supply costs. The revised statute gives the MPSC additional discretion. The MPSC initiated a process to develop a replacement mechanism. In July 2017 we filed a proposed electric PCCAM that was in line with commissioner testimony provided to the legislature in support of HB193. In December 2017 the MPSC issued a Notice of Additional Issues stating that the range of options proposed in the parties’ testimony was not sufficient and directed parties to consider alternatives incorporating risk-sharing features. • On February 7th we filed testimony and addressed the MPSC’s additional issues. Intervenor additional issues testimony was filed March 23rd with rebuttal testimony due by April 30th. • A hearing is scheduled to begin May 31, 2018. • The MPSC decision may apply to variable costs on a retroactive basis to July 1, 2017 (the effective date of HB193). FERC / Dave Gates Generation Station (DGGS) • We received an order from FERC in April 2014 regarding DGGS cost allocation between retail & wholesale customers. • FERC denied our request for rehearing in May 2016 and required us to make refunds in June 2016 totaling $30.8 million. • In March 2018 we received an opinion from a three judge panel (US Circuit Court of Appeals) denying our petition for review. Colstrip Unit 4 - Disallowance of Replacement Power Costs • In May 2016, the MPSC issued a final order disallowing recovery of certain costs related to a 2013 outage at Colstrip. • In September 2016 we appealed the order to the Montana District Court arguing the decision was arbitrary and capricious and violated Montana law. We expect a decision on this appeal within the next 9 months.

Estimated Impacts of the Tax Cuts & Jobs Act 17 We currently believe our debt coverage ratios will be adequate to maintain existing credit ratings. However, further negative regulatory actions will likely lead to credit downgrades and could necessitate additional equity issuances. • Dockets have been initiated in each of our jurisdictions to address the impact from the change in tax law and to provide any benefits to customers effective January 1st. We have made filings in Montana, South Dakota and Nebraska and do not expect the required FERC filing to be significant. • Based on our proposed “Current Year” methodology calculation, as of March 31st we have deferred $7.3 million of revenue associated with the change in law into a regulatory liability account (estimated to be $15-20 million for the full year 2018). The revenue deferral is anticipated to be offset by a similar reduction to income tax expense and have minimal impact on net income. • We also provided a calculation based upon a “Restated Historic” calculation methodology. If commissions elect this methodology, it would result in customer givebacks that exceed the tax benefits we expect to receive in 2018 and would result in approximately $8-12 million of additional pretax earnings and cash flow impact. • Utilization of the deferred revenue (regulatory liability) will be determined in the pending dockets. Procedural schedules have not yet been established. • As a result of tax reform, we have updated our effective tax rate assumption included in 2018 guidance to 0% - 5% (prev. 8% - 12%). NOLs are now anticipated to be available into 2020 (prev. 2021). We also reduced our deferred tax liability by $321 million as of December 31, 2017. This reduction was offset in regulatory assets and liabilities. The illustration above is based on consolidated company estimates. Actual impact will ultimately be subject to regulatory approval. The $15-$20 million range shown includes $2-$4 million of annual amortization of excess deferred taxes subject to the average rate assumption method (ARAM).

Capital Spending Forecast 18 2018 Significant Updates Out: Approximately $123 million of previously included investment in capacity generation has been removed pending update of Integrated Resource Plans in both Montana and South Dakota (expected to be completed by year-end 2018). In: Approximately $126 million of incremental investment related to grid modernization and automated meter infrastructure for Montana. South Dakota and Nebraska AMI investment spend was previously included ($28M). The current estimated cumulative 5 year capital spending is $1.596 billion. We anticipate funding the expenditures with a combination of cash flows (aided by NOLs available into 2020), the remainder of our current equity distribution program and long-term debt issuances. Significant capital investments, that are not in the above projections, or further negative regulatory actions could necessitate additional equity issuances.

Conclusion 19 Best Practices Corporate Governance Pure Electric & Gas Utility Solid Utility Foundation Strong Earnings & Cash Flows Attractive Future Growth Prospects

20 Appendix

21 Segment Results (First Quarter)Appendix (1) (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure. (1)

22 Electric Segment (First Quarter)Appendix (1) (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure.

23 Natural Gas Segment (First Quarter)Appendix (1) (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure.

These materials include financial information prepared in accordance with GAAP, as well as other financial measures, such as Gross Margin and Adjusted Diluted EPS, that are considered “non-GAAP financial measures.” Generally, a non-GAAP financial measure is a numerical measure of a company's financial performance, financial position or cash flows that exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP. Gross Margin (Revenues less Cost of Sales) is a non-GAAP financial measure due to the exclusion of depreciation from the measure. Gross Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs. Adjusted Diluted EPS is another non-GAAP measure. The Company believes the presentation of Adjusted Diluted EPS is more representative of our normal earnings than the GAAP EPS due to the exclusion (or inclusion) of certain impacts that are not reflective of ongoing earnings. The presentation of these non-GAAP measures is intended to supplement investors' understanding of our financial performance and not to replace other GAAP measures as an indicator of actual operating performance. Our measures may not be comparable to other companies' similarly titled measures. Non-GAAP Financial Measures 24 Appendix

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