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 24, 2019 (April 23, 2019)

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 23, 2019, 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, 2019. The Press Release 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 24, 2019, at 11:00 a.m. Eastern time (10:00 a.m. Central time), the Company will hold its annual meeting of stockholders at its South Dakota / Nebraska Operational Support Office, 600 Market Street West, Huron, South Dakota. 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 https://www.webcaster4.com/Webcast/Page/1050/30117.

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 24, 2019, at 3:00 p.m. Eastern time to review its financial results. During the conference call, Robert C. Rowe, president and chief executive officer, 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/1050/29072. 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 24, 2019, at (888) 203-1112 access code 3377935.

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 23, 2019
99.2*	Annual Meeting Presentation, dated April 24, 2019
99.3*	Investor Call Presentation, dated April 24, 2019
* 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 24, 2019

EX-99.1

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 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 2019 Financial Results

Company reports GAAP diluted earnings per share of $1.44 for the first quarter 2019 and declares a quarterly dividend of $0.575 per share, payable June 28, 2019.

BUTTE, MT / SIOUX FALLS, SD - April 23, 2019 - NorthWestern Corporation d/b/a NorthWestern Energy (NYSE: NWE) reported financial results for the three months ended March 31, 2019.  Net income for the period increased 24.4 percent to $72.8 million, or $1.44 per diluted share, as compared with net income of $58.5 million, or $1.18 per diluted share, for the same period in 2018. This $14.3 million increase in net income in 2019 is primarily due to higher gross margin as a result of colder winter weather and customer growth and a reduction in revenue in 2018 due to impacts of the Tax Cuts and Jobs Act (TCJA) for customer refunds. These improvements were partially offset by an increase in operating expenses.

“The winter weather we experienced in the first quarter was challenging for our customers and reminded us how important our infrastructure and service are,” said Bob Rowe, President and Chief Executive Officer. “Arctic air that settled across the plains and Pacific Northwest pushed temperatures 20 to 30 degrees below normal for weeks at a time and set several new electric and natural gas system peaks during the quarter. The blistering cold truly showcased the mettle of our crews and highlighted the importance of a robust and reliable energy system.”

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

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 2

	Three Months Ended March 31,
(in thousands, except per share amounts)	2019			2018
Revenues	$	384,220		$	341,502
Cost of sales	115,735			96,077
Gross Margin (1)	268,485			245,425
Operating, general and administrative expense	81,092			74,345
Property and other taxes	44,789			42,813
Depreciation and depletion	45,584			43,755
Total Operating Expenses	171,465			160,913
Operating income	97,020			84,512
Interest expense, net	(23,790		)	(22,970		)
Other income (expense), net	1,149			(1,129		)
Income before income taxes	74,379			60,413
Income tax expense	(1,573		)	(1,914		)
Net Income	72,806			58,499
Basic Shares Outstanding	50,381			49,416
Earnings per Share - Basic	$	1.45		$	1.18
Diluted Shares Outstanding	50,729			49,484
Earnings per Share - Diluted	$	1.44		$	1.18
Dividends Declared per Common Share	$	0.575		$	0.550
(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.

Significant Trends and Regulation

Montana General Electric Rate Case

In September 2018, we filed an electric rate case with the Montana Public Service Commission (MPSC) requesting an annual increase to electric rates of approximately $34.9 million, which represents an approximate 6.6% increase in annual base revenues. Our request is based on a return on equity of 10.65% and an overall rate of return of 7.42% (except for Colstrip Unit 4 which the MPSC previously set for the life of the facility at a 10% return on equity and an 8.25% rate of return), based on approximately $2.35 billion of electric rate base and a capital structure of approximately 51 percent debt and 49 percent equity.

We also requested that approximately $13.8 million of the rate increase be approved on an interim basis effective November 1, 2018. In March, 2019, the MPSC issued an order approving an increase in rates of approximately $10.5 million on an interim and refundable basis effective April 1, 2019. On April 5, 2019, we filed rebuttal testimony, which responded to intervenor testimony and included certain known and measurable adjustments. This testimony reflects a request for an annual increase of $30.7 million, an approximately $4.2 million reduction from our original request.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 3

A hearing is scheduled to commence on May 13, 2019. Interim rates will remain in effect on a refundable basis until the MPSC issues a final order.

We expect to file a Federal Energy Regulatory Commission (FERC) rate case for our Montana transmission assets in the second quarter of 2019. The revenue requirement associated with our Montana FERC assets is reflected in our MPSC jurisdictional rates as a credit to retail customers.

Montana Legislative Session

There are several potentially significant bills currently being considered by the Montana Legislature. In addition to many

other less substantive bills, we are monitoring potential impacts of the following:

• Legislation that would allow us to acquire up to an additional 150 MW of generation from Colstrip Unit 4 for $1 and would facilitate our placing in rates a certain amount of capital investment over the following ten years. Linked to this transaction is also a requirement to obtain a greater ownership share of the Colstrip transmission line and pay no more than the depreciated book value;

• Legislation that would remove the +/- $4.1 million “deadband” sharing provision from the PCCAM as imposed by the MPSC's January 2019 order; and

• Legislation that would prohibit the MPSC from applying a maximum contract length of 15 years to our future owned and contracted electricity supply resources as required in the MPSC's November 2017, QF order.

While the Montana legislative session is expected to end around May 1, 2019, it is premature to state how these pieces of legislation will ultimately be drafted, and how, or whether, they will be passed and / or signed into law by the Montana Governor.

Electric Supply Resource Plans

Montana - In March 2019, we issued our draft 2019 Electricity Supply Resource Procurement Plan (Montana Resource Plan). The Montana Resource Plan supports the goal of developing resources that will address the changing energy landscape in Montana to meet our customers' electric energy needs in a reliable and affordable manner. The draft is available for public comment until May 5, 2019. We expect to finalize the plan by the end of June 2019.

We are currently 630 MW short of our peak needs, which we procure in the market. We forecast that our energy portfolio will be 725 MW short by 2025 with a modest increase in customer demand. Based on our customers' future energy resource needs as identified in the Montana Resource Plan, in late 2019 we expect to solicit competitive proposals for peaking capacity available by 2022. An independent evaluator will be used to assess the proposals. We expect the process will be repeated in subsequent years to provide a resource-adequate energy and capacity portfolio by 2025.

The proposed solicitation process will allow us to consider a wide variety of resource options. These options include power purchase agreements and owned energy resources comprised of different structures, terms and technologies that are cost-effective resources. The staged approach is designed to allow for incremental steps through time with opportunities for different resource type of new technologies while also building a reliable portfolio to meet local and regional conditions and minimizing customer impacts.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 4

South Dakota - During the second quarter 2019, we anticipate issuing a request for proposals for 60 MW of flexible capacity resources to begin serving South Dakota customers by the end of 2021. Responses will be due in July 2019, with evaluation of the proposals during the second half of 2019.

Colstrip Coal Supply

Colstrip Units 3 and 4 are supplied with fuel from adjacent coal reserves under coal supply and transportation agreements with Western Energy Company (WeCo). The current contract expires at the end of 2019. WeCo filed for Chapter 11 bankruptcy protection in October 2018. An auction was held for the core assets in January 2019, including the mine adjacent to Colstrip, with no qualified bids received. As a result, in March 2019 a lenders group acquired the core assets. Immediately prior to that acquisition, WeCo assumed the existing coal supply and transportation agreements. We are working with WeCo and the joint owners to negotiate a new arrangement and at the same time exploring alternative sources for a coal supply. Any new arrangements, whether with WeCo or others, may have higher costs than the existing coal supply and transportation agreements.

Significant Earnings Drivers

Gross Margin

Consolidated gross margin for the three months ended March 31, 2019 was $268.5 million compared with $245.4 million for the same period in 2018. This $23.1 million increase was a result of a $20.2 million increase to items that have an impact on net income and $2.9 million increase to items that are offset in operating expenses, property tax expense and income tax expense with no impact to net income.

Consolidated gross margin for items impacting net income increased$20.2 million, including:

• $13.4 million increase in electric and gas retail volumes due primarily to colder winter weather and customer growth;

• $7.3 million improvement resulting from a 2018 reduction in revenue due to the impact of the TCJA one-time settlements for customer refunds; and

• $3.5 million other miscellaneous improvements.

These increases were partially offset by:

• $1.7 million decrease in Montana natural gas rates associated with the annual step down for our Montana gas production assets and the TCJA settlement;

• $1.6 million decrease from under recovery of Montana electric supply costs; and

• $0.7 million of lower demand to transmit energy across our transmission lines due to market conditions and pricing.

The change in consolidated gross margin for items that had no impact on net income represented a $2.9 million increase primarily due to the following:

• $1.7 million increase in revenues for property taxes included in trackers, offset by increased property tax expense;

• $0.8 million increase in revenues for operating costs included in trackers, offset by increased operating expense; and

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 5

• $0.4 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, 2019 were $81.1 million compared with $74.3 million for the same period in 2018. This $6.8 million increase was a result of a $3.7 million increase to items that have an impact on net income and $3.1 million increase to items that are offset in gross margin and other income (expense) with no impact to net income.

Consolidated operating, general and administrative expenses for items impacting net income increased $3.7 million, including:

• $0.9 million higher hazard tree line clearance costs;

• $0.9 million higher pension funding;

• $0.4 million higher labor expense due primarily to compensation increases;

• $0.3 million higher plant operator and maintenance at electric generation facilities; and

• $1.2 million higher other miscellaneous expenses.

The change in consolidated operating, general and administrative expenses for items that had no impact on net income increased $3.1 million primarily due to the following:    

• $3.9 million change (increase) in value of non-employee directors deferred compensation due to changes in our stock price, offset in other income;

• $1.0 million higher operating expenses included in trackers recovered through revenue; and

• $1.8 million lower expense due to the regulatory treatment of the non-service cost components of pension and postretirement benefit expense, which is offset in other income.

Property and Other Taxes

Property and other taxes were $44.8 million for the three months ended March 31, 2019, as compared with $42.8 million in the same period of 2018. This increase was primarily due to plant additions and higher 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 $45.6 million for the three months ended March 31, 2019, as compared with $43.8 million in the same period of 2018. This increase was primarily due to plant additions.

Operating Income

Consolidated operating income for the three months ended March 31, 2019 was $97.0 million as compared with $84.5 million in the same period of 2018. This increase was primarily due to higher gross margin partially offset by higher operating expenses.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 6

Interest Expense

Consolidated interest expense for the three months ended March 31, 2019 was $23.8 million, as compared with $23.0 million in the same period of 2018, due primarily to higher borrowings.

Other Income and Expense

Consolidated other income was $1.1 million for the three months ended March 31, 2019 as compared to consolidated other expense of $1.1 million during the same period of 2018. This $2.2 million improvement includes a $3.9 million increase in the value of deferred shares held in trust for non-employee directors deferred compensation, partly offset by a $1.8 million increase in other pension expense, both of which are offset in operating, general, and administrative expense with no impact to net income. Higher capitalization of Allowance for Funds Used During Construction also contributed to the increase.

Income Tax

Consolidated income tax expense for the three months ended March 31, 2019 was $1.6 million as compared with $1.9 million expense in the same period of 2018. Our effective tax rate for the three months ended March 31, 2019 was 2.1% as compared with 3.2% for the same period of 2018. We expect our 2019 effective tax rate to range between 0% - 5%.

The following table summarizes the differences between our effective tax rate and the federal statutory rate for the periods:

(in millions)	Three Months Ended March 31,
	2019					2018
Income Before Income Taxes	$	74.4				$	60.4
Income tax calculated at federal statutory rate	15.6			21.0	%	12.7			21.0	%
Permanent or flow-through adjustments:
State income, net of federal provisions	0.9			1.2	%	0.7			1.2	%
Flow-through repairs deductions	(7.9		)	(10.7	)%	(6.6		)	(10.9	)%
Production tax credits	(4.4		)	(6.0	)%	(3.9		)	(6.4	)%
Plant and depreciation of flow-through items	(1.5		)	(2.0	)%	(0.9		)	(1.6	)%
Amortization of excess deferred income tax	(1.4		)	(1.8	)%	(0.4		)	(0.6	)%
Shared-based compensation	0.2			0.3	%	0.3			0.5	%
Other, net	0.1			0.1	%	—			—	%
Subtotal	(14.0		)	(18.9	)%	(10.8		)	(17.8	)%
Income Tax Expense	$	1.6		2.1	%	$	1.9		3.2	%

Net Income

Consolidated net income for the three months ended March 31, 2019 was $72.8 million as compared with $58.5 million for the same period in 2018. This $14.3 million increase in net income in 2019 is primarily due to higher gross margin as a result of colder winter weather and customer growth and a reduction in revenue in 2018 due to impacts of the TCJA for customer refunds. These improvements were partially offset by an increase in operating expenses.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 7

Reconciliation of Primary Changes from 2018 to 2019

		Three Months Ended March 31,
	($millions, except EPS)	Pretax Income		Net (1) Income		Diluted EPS
	2018 reported	$60.4		$58.5		$1.18
Gross Margin
	Higher natural gas retail volumes	7.9		5.9		0.12
	Higher revenue due to the 2018 impacts of the TCJA settlements	7.3		5.5		0.11
	Higher electric retail volumes	5.5		4.1		0.08
	Lower Montana natural gas rates	(1.7	)	(1.3	)	(0.03	)
	Higher Montana electric supply costs	(1.6	)	(1.2	)	(0.02	)
	Lower Electric transmission	(0.7	)	(0.5	)	(0.01	)
	Other margin increases	3.5		2.6		0.05
	Subtotal: Items impacting net income	20.2		15.1		0.30
	Property taxes recovered in trackers	1.7		1.3		0.03
	Operating expenses recovered in trackers	0.8		0.6		0.01
	Production tax credits flowed-through trackers	0.4		0.3		—
	Subtotal: Items not impacting net income	2.9		2.2		0.04
	Total Gross Margin	23.1		17.3		0.34
OG&A Expense
	Higher Hazard tree expense	(0.9	)	(0.7	)	(0.01	)
	Higher pension expense	(0.9	)	(0.7	)	(0.01	)
	Higher labor expense	(0.4	)	(0.3	)	—
	Higher plant operator costs	(0.3	)	(0.2	)	—
	Other expense increases	(1.2	)	(0.9	)	(0.02	)
	Subtotal: Items impacting net income	(3.7	)	(2.8	)	(0.04	)
	Non-employee directors deferred compensation	(3.9	)	(2.9	)	(0.06	)
	Operating expenses recovered in trackers	(1.0	)	(0.7	)	(0.01	)
	Pension and other postretirement benefits	1.8		1.3		0.03
	Subtotal: Items not impacting net income	(3.1	)	(2.3	)	(0.04	)
	Total OG&A Expense	(6.8	)	(5.1	)	(0.08	)
Other items
	Higher depreciation and depletion expense	(1.8	)	(1.3	)	(0.03	)
	Higher property and other taxes	(2.0	)	(1.5	)	(0.03	)
	Higher interest expense	(0.8	)	(0.6	)	(0.01	)
	Higher other income	2.3		1.7		0.03
	Perm. & flow-through adjustments to income tax			3.8		0.07
	Impact of higher share count	—		—		(0.03	)
	Total Other items	(2.3	)	2.1		—
	Total impact of above items	14.0		14.3		0.26
	2019 reported	$74.4		$72.8		$1.44
(1) Income Tax Benefit (Expense) calculation on reconciling items assumes normal effective tax rate of 25.3%.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 8

Liquidity and Capital Resources

As of March 31, 2019, our total net liquidity was approximately $142.8 million, including $4.0 million of cash and $138.8 million of revolving credit facility availability. This compares to total net liquidity one year ago at March 31, 2018 of $206.7 million.

Dividend Declared

NorthWestern's Board of Directors declared a quarterly common stock dividend of $0.575 per share payable June 28, 2019 to common shareholders of record as of June 14, 2019.

Non-GAAP Financial Measures

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. NorthWestern has not established earnings guidance for 2019.

(in millions, except EPS)
	Three Months Ended March 31, 2019
	Pre-tax Income		Net(1) Income		Diluted EPS
2019 Reported GAAP	$74.4		$72.8		$1.44
Non-GAAP Adjustments:
Remove impact of favorable weather	(14.0	)	(10.5	)	(0.21		)
2019 Adjusted Non-GAAP	$60.4		$62.3		$1.23
	Three Months Ended March 31, 2018
	Pre-tax Income		Net(1) Income		Diluted EPS
2018 Reported GAAP	$60.4		$58.5		$	1.18
Non-GAAP Adjustments:
Remove impact of favorable weather	(4.8	)	(3.6	)	(0.07		)
2018 Adjusted Non-GAAP	$55.6		$54.9		$1.11
(1) Income tax calculation on reconciling adjustments assumes updated federal plus state statutory effective tax rate of 25.3%.

This press release includes financial information prepared in accordance with GAAP, as well as other financial measures, such as Gross Margin, Adjusted Non-GAAP Pre-Tax Income, Adjusted Non-GAAP Net Income 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 exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 9

We define Gross Margin as Revenues less Cost of Sales as presented in our Condensed Consolidated Statements of Income. Management believes that Gross Margin (revenues less cost of sales) provides a useful measure for investors and other financial statement users to analyze our financial performance in that it excludes the effect on total revenues caused by volatility in energy costs and associated regulatory mechanisms. This information is intended to enhance an investor's overall understanding of results. Under our various state regulatory mechanisms, as detailed below, our supply costs are generally collected from customers. In addition, 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, as well as to analyze how changes in loads (due to weather, economic or other conditions), rates and other factors impact our results of operations. Our Gross Margin measure may not be comparable to that of other companies' presentations or more useful than the GAAP information provided elsewhere in this report.

Management also believes the presentation of Adjusted Non-GAAP pre-tax income, net income and Diluted EPS is more representative of normal earnings than GAAP pre-tax income, net income and 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.

Company Hosting Investor Conference Call

NorthWestern will host an investor conference call and webcast on Wednesday, April 24, 2019, at 3:00 p.m. Eastern time to review its financial results for the quarter ending March 31, 2019.

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 https://www.webcaster4.com/Webcast/Page/1050/30117. 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.

Notice of Annual Stockholders Meeting

NorthWestern will also hold its annual stockholders meeting on Wednesday, April 24, 2019, at 11:00 a.m. Eastern Time (10:00 a.m. Central Time) at the Operational Support Office, 600 Market Street West, Huron, SD 57350.

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 https://www.webcaster4.com/Webcast/Page/1050/30126. 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 726,400 customers in Montana, South Dakota and Nebraska. We have generated and distributed electricity in South Dakota and distributed natural gas in South Dakota and Nebraska since 1923 and have generated and distributed electricity and distributed natural gas in Montana since 2002. More information on NorthWestern Energy is available on the company's Web site at www.northwesternenergy.com.

NorthWestern Reports First Quarter 2019 Financial Results

April 23, 2019

Page 10

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 Earnings". 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 2018 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                    Jo Dee Black (866) 622-8081

travis.meyer@northwestern.com                jodee.black@northwestern.com

EX-99.2

NorthWestern Energy Annual Meeting of Stockholders - April 24, 2019

Forward Looking Statements Forward Looking Statements O’Dell Creek - Madison River Valley - Montana 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. Company Information NorthWestern Corporation Corporate Office Investor Relations Officer dba: NorthWestern Energy 3010 West 69th Street Travis Meyer Ticker: NWE Sioux Falls, SD 57108 605-978-2967 Trading on the NYSE (605) 978-2900 travis.meyer@northwestern.com www.northwesternenergy.com 2

About NorthWestern South Dakota Operations Electric 63,800 customers 3,572 miles – transmission & distribution lines 440 MW nameplate owned power generation Natural Gas 46,900 customers 1,697 miles of transmission and distribution pipeline Montana Operations Electric 374,000 customers 24,767 miles – transmission & distribution lines 871 MW maximum capacity owned power generation Natural Gas 199,200 customers 6,881 miles of transmission and distribution pipeline Nebraska Operations 17.75 Bcf of gas storage capacity Natural Gas Own 51.7 Bcf of proven natural gas reserves 42,500 customers 795 miles of distribution pipeline 3 Data as of 12/31/2018

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

A Diversified Electric and Gas Utility (1) (1) September 2018 Montana electric rate review, filed with rate base of $2.34 billion, calculated with 13-month average and known and measurable adjustments. NorthWestern’s ‘80/20’ rules: Approximately 80% Electric, 80% Residential and 80% Montana. Over $3.6 billion of rate base investment to serve our customers 5 Data as of 12/31/2018. (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure. See appendix for additional disclosure.

Highly Carbon-Free Supply Portfolio Based upon 2018 MWH’s of owned and long-term contracted resources. Approximately 55% 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 6 portfolio was delivered to our customers.

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

Solid Economic Indicators 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, 2016/2017 EEI Statistical Yearbook – Table 7.2 and EIA.gov Black Eagle Power House • Customer growth rates historically exceed National Averages. 8 • Unemployment rates in all three of our states are below or in-line with National Average.

A History of Growth $3.30-$3.50 $3.10 - $3.30 $2.60$3.20 - $2.75-$3.40 2009-2018 CAGR’s: GAAP EPS: 7.6% - Non-GAAP EPS: 5.9% - Dividend: 5.7% 9 See appendix for “Non-GAAP Financial Measures”

Earnings Growth $3.30$3.30-$3.45-$3.50 $3.10 - $3.30 $2.60$3.20 - $2.75-$3.40 Non-GAAP Adjusted EPS Growth averaged 6.3% from 2013-2018 We are not providing 2019 EPS guidance at this time due to the pending Montana rate case. However, 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. 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 See appendix for additionalcould disclosures allow us regardingto achieve “Non the-GAAP higher Financial-end Measures of our” range over the long term. 10 See “Non-GAAP Financial Measures” slide in appendix for “Non-GAAP “Adjusted EPS”.

Track Record of Delivering Results * Peer Group: ALE, AVA, BKH, EE, IDA, MGEE, NWN, OGE, OTTR, PNM, POR & SR Return on Equity on GAAP Earnings within 9.5% - 11.0% band over the last 8 years with average of 10.3%. Total Shareholder Return is better than our 12 peer average for the 10 year period but lags in the 1, 3 & 5 year periods, due in part to some unfavorable regulatory decisions in Montana. 11 See appendix for “Non-GAAP Financial Measures”

Recent Shareholder Return 2018 TSR: NWE TSR: 3.47% Peer TSR: 6.29% Rank: 10th of 12 peers 1st Quarter: NWE TSR: 19.43% Peer TSR: 10.58% Rank: 1st of 12 peers We reached an all- time high closing stock price of $71.30 on March 26th and an all-time high intra-day trading price of $71.77 also on March 26th. • 12 member peer group: ALE (ALLETE), AVA (Avista), BKH (Black Hills Corp), EE (El Paso Electric), IDA (IDACORP), MGEE (MGE Energy), NWN (Northwest Natural Gas),OGE (OGE Energy), OTTR (Otter Tail Power), PNM (PNM Resources), POR (Portland 12 General Electric), and SR (Spire)

Investment for Our Customers’ Benefit 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. 2008-2018 CAGRs Estimated Rate Base: 12.2% GAAP Diluted EPS: 8.3% 2008-2018 CAGRs NWE typical electric bill: 1.9% NWE typical natural gas bill: (5.4%) 13 2008-2018 CAGRs US average electric bill: 1.9%* US average natural gas bill: (2.7%)**

Balance Sheet Strength and Liquidity Investment grade credit ratings, liquidity generally in excess of $100 million target, and debt to cap moving lower within our targeted 50%-55% range. 14

Credit Ratings While great strides have been made since emergence from bankruptcy in 2004, regulatory concerns in Montana have put pressure on credit ratings over the last few years. On February 5, 2018, Fitch placed us on Negative Outlook. On May 18, 2018, Moody’s downgraded our senior secured 15 and unsecured credit ratings.

Strong Cash Flows While maintenance capex and total dividend payments have continued to grow since 2011 (11.9% and 11.2% CAGR respectively), Cash Flow from Operations (CFO) has, on average, exceeded maintenance capex and dividend payments by approximately $7 million per year. Note: 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. We expect NOLs to be available into 2020 with alternative minimum tax credits and production tax credits to be available into 2022 to reduce cash taxes. Additionally, we anticipate our effective tax rate to reach 10% by 2023. 16 (See appendix for “Non-GAAP Financial Measures” relating to free cash flow and disclaimer on NOLs)

Capital Spending Forecast $1.6 billion of total capital investment over five years. Increased investment in first three years (relative to last two years) is primarily a result of advanced metering infrastructure (AMI) project. We anticipate funding the expenditures with a combination of cash flows (aided by NOLs available into 2020) and long-term debt issuances. Significant capital investments that are not in the above projections or further negative regulatory actions could necessitate additional equity funding. Capital projections above do not include investment necessary to address capacity issues as identified in the South Dakota and pending* Montana Electricity Supply Resource Procurement Plans. 17 *Draft plan was released in March 2019.

Recent Significant Achievements 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. Best electric reliability scores • Low SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index) in 2018. Especially significant considering our rugged service territories. Corporate Governance Finalist • In 2018 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 our board of directors by 2020 Women on Boards. Three of the company’s eight independent directors are female. Investor Relations Program Recognition • Recognized, in 2018, by Institutional Investor as a top midcap utility and energy company based on access to senior management, well-informed and empowered IR team, appropriate and timely disclosures and constructive earnings calls. Environmental, Social and Governance Reporting • Published EEI’s ESG / Sustainability reporting template in December 2018. This quantitative information supplements our biennial Stewardship Report that highlights our commitment to Echo Lake Nordic Trail the stewardship of natural resources and our sustainable business practices. Acquired Two Dot Wind Farm 18 • June 2018 acquired 9.7 MW wind project, near Geyser, Montana, for $18.5 million.

Looking Forward Regulatory • MPSC to review Montana general electric rate review, filed in September 2018. $3.30$3.30-$3.45-$3.50 $3.10 - $3.30 • We expect to file an associated FERC rate case for $2.60$3.20 - $2.75-$3.40 our Montana transmission assets in the second quarter 2019. Continue to Invest in our T&D infrastructure • Comprehensive infrastructure capital investment program to ensure safety, capacity and reliability. • Natural gas pipeline investment (SAFE PIPES Act, Integrity Verification Process and Pipeline & Hazardous Materials Safety Administration proposed regulations). • Grid modernization, advanced distribution management system and advanced metering infrastructure investment Plans to join Western Energy Imbalance Market (EIM) • Real-time energy market could mean lower cost of energy for Montana customers, more efficient use of renewables and greater power grid reliability. Cost Control Efforts • Continue to monitor costs, including labor, benefits and property tax valuations to mitigate increases. Advance Electricity Resource Planning efforts in South Dakota and Montana 19

Exemplary Board of Directors (left to right) Stephan Adik – Chairman of the Board - Independent Director since November 1, 2004 Anthony Clark – Independent Director since December 6, 2016 – Governance & Innovation and Human Resources Committees Dana Dykhouse – Independent Director since January 30, 2009 – Human Resources (Chair) and Audit Committees Jan Horsfall – Independent Director since April 23, 2015 – Audit and Governance & Innovation Committees Britt Ide – Independent Director since April 27, 2017 – Governance & Innovation and Audit Committees Julia Johnson – Independent Director since November 1, 2004 – Governance & Innovation (Chair) and Human Resources Committees Robert Rowe - CEO & President – Director since August 13, 2008 Linda Sullivan – Independent Director since April 27, 2017 – Audit (Chair) and Human Resources Committees 20

Experienced Executive Team (left to right) Robert Rowe - President & CEO – current position since 2008 Brian Bird – CFO – current position since 2003 Michael Cashell – VP Transmission – current position since 2011 Heather Grahame – General Counsel and VP Regulatory and Federal Government Affairs – current position since 2010 John Hines – VP Supply – current position since 2011 Crystal Lail – VP & Controller – current position since 2015 Curtis Pohl – VP Distribution – current position since 2003 Bobbi Schroeppel – VP Customer Care, Communications & Human Resources – current position since 2002 21

Strong Corporate Governance Environmental, Social & Governance Report Published EEI’s ESG / Sustainability reporting template in December 2018. This quantitative information supplements our biennial Stewardship Report that highlights our commitment of the stewardship of natural resources and our sustainable business practices. 20 / 20 – Women on Boards Recognized for gender diversity on its board of directors by 2020 Women on Boards. Three of the company’s eight independent directors are female. Cogent Reports NorthWestern Energy was named “Utility Customer Champion” as one of the Most Trusted Brands, in 2014 and 2015, published by Cogent Reports, which surveyed customers from 125 utilities to develop brand-trust scores for combined electric and natural gas utilities. Corporate Governance Award Winner NorthWestern Corporation’s 2014 proxy statement won two governance awards – Exemplary Compensation Discussion and Analysis from NYSE Governance Services and Best Proxy Statement (Small to Mid-Cap) by Corporation Secretary magazine. NorthWestern was recognized as a finalist by Corporate Secretary magazine in the same category in 2012, 2013, 2016, 2017 & 2018. Best Investor Relations Program Recognized in 2018, by Institutional Investor as a top midcap utility and energy company based on access to senior management, well-informed and empowered IR team, appropriate and timely disclosures and constructive earnings calls. NYSE Ethics In 2013, NorthWestern Energy earned an “A” from New York Stock Exchange’s Corpedia, for its Code of Conduct and Ethics, putting it in the top 2 percent of all 22 energy and utility companies reviewed.

Strong Corporate Governance Forbes America’s Most Trustworthy Companies “America’s Most Trustworthy Companies,” which identifies the most transparent and trustworthy businesses that trade on the American exchanges. The quantitative and qualitative data analysis looks beyond the raw data on companies’ financial statements to assess the true quality of corporate accounting and management practices. Each year Forbes recognizes 100 companies out of over 8,0000 for this foremost honor. NWE was on of only three utilities to be distinguished with this honor, by Forbes, in 2013. Sioux Empire United Way Business of the Year In February 2017, NorthWestern Energy won Business of the Year, in the 0-100 employee category, from the Sioux Empire United Way (Sioux Falls, SD). Our approximate 40 employees in the Sioux Falls office had the second best giving per employee and also had 100 percent participation in giving for 2016. Community Works Community Works encompasses NorthWestern Energy’s tradition of funding community activities, charitable efforts and economic development within its service territory. NorthWestern Energy’s Community Works programs currently provide more than $2 million annually in funds for community sponsorships, charitable contributions and economic development organizations in Montana, South Dakota and Nebraska. South Dakota National Guard Pro Patria Award The South Dakota National Guard and the Employer Support of the Guard and Reserve (ESGR) recognized NorthWestern in early 2014 with its Pro-Patria award for “exceptional support of national defense through leadership practices and personnel policies” in support of employees who serve in the National Guard and Reserves. The award is given to one company annually. Worksite Health In May 2014, NorthWestern Corporation was recognized, by the Montana Worksite Heath Promotion Coalition, for excellence in promoting worksite health and earned the Gold Award, for our wellness program “Energize Your Life”. Glass Lewis NorthWestern Energy was recognized by Glass Lewis, a leading investment research and global proxy advisory firm, as one of the top 42 companies in the US for its 2011 “Say on Pay” proposal, which recognizes companies with clear disclosure and conservative policy with regards to compensation. 23

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

25

NorthWestern Energy Profile (1) Rate base reflects amounts on which we are authorized to earn a return. (2) Rate base amounts are estimates as of December 31, 2018 (3) The revenue requirement associated with the FERC regulated portion of Montana electric transmission and DGGS are included as revenue credits to our MPSC jurisdictional customers. Therefore, we do not separately reflect FERC authorized rate base or authorized returns. (4) For those items marked as “n/a” the respective settlement and/or order was not specific as to these terms. Note: Data as reported in our 2018 10-K September 2018 Montana electric rate review, filed with rate base of $2.34 billion, calculated with 13th month average and known and measurable adjustments. 26

Non-GAAP Financial Measures 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 27 measures.

Non-GAAP Financial Measures 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. 28

Non-GAAP Financial Measures 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 29 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

Two Dot Wind Farm – Montana 2019 First Quarter Earnings Webcast April 24, 2019

Presenting Today 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 Bob Rowe, statements often address our expected future business President & CEO 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 of this document 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 Brian Bird, assumptions, actual results may differ materially. The Vice President & CFO 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. 2

Recent Highlights • Net income for the first quarter of 2019 increased $14.3 million, or 24.4%, as compared to the same period in 2018. This increase was primarily due to higher gross margin as a result of colder winter weather and customer growth and a reduction in revenue in 2018 due to impacts of the Tax Cuts and Jobs Act, partly offset by higher operating expenses. • Diluted earnings per share increased $0.26, or 22.0%, as compared to the same period in 2018. o After adjusting for favorable weather in both periods, Non-GAAP* adjusted earnings per share increased $0.12, or 10.8%, as compared to the same period in 2018. • On April 15, 2019 we issued a request for proposals for 60 MW of flexible capacity resources to begin serving South Dakota customers by the end of 2021. Responses are due in July 2019, with evaluation of the proposals during the second half of 2019. • The Board of Directors declared a quarterly dividend of $0.575 per share payable June 28th to shareholders of record as of June 14th, 2019. 3 * See slides 12 & 24 for additional information and Non-GAAP disclosures.

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

Gross Margin (First Quarter) (dollars in millions) Three Months Ended March 31, 2019 2018 Variance Electric $ 196.0 $ 181.0 $ 15.0 8.3% Natural Gas 72.5 64.4 8.1 12.6% Total Gross Margin (1) $ 268.5 $ 245.4 $ 23.1 9.4% Increase in gross margin due to the following factors: $ 7.9 Natural gas retail volumes 7.3 Tax Cuts and Jobs Act impact 5.5 Electric retail volumes (1.7) Montana natural gas rates (1.6) Montana electric supply costs (0.7) Electric transmission 3.5 Other miscellaneous increases $ 20.2 Change in Gross Margin Impacting Net Income $ 1.7 Property taxes recovered in trackers 0.8 Operating expenses recovered in trackers 0.4 Production tax credits flowed-through trackers $ 2.9 Change in Gross Margin Offset Within Net Income $ 23.1 Increase in Gross Margin 5 (1) Gross Margin, defined as revenues less cost of sales, is a non-GAAP Measure See appendix for additional disclosure.

Weather (First Quarter) Extremely cold February and March contributed approximately $14.0M pretax gross margin benefit as compared to normal and $9.2M pretax benefit as compared to first quarter 2018. 6

Operating Expenses (First Quarter) (dollars in millions) Three Months Ended March 31, 2019 2017 Variance Operating, general & admin. $ 81.1 $ 74.3 $ 6.8 9.2% Property and other taxes 44.8 42.8 2.0 4.7% Depreciation and depletion 45.6 43.8 1.8 4.1% Operating Expenses $ 171.5 $ 160.9 $ 10.6 6.6% Increase in Operating, general & administrative expense due to the following factors: $ 0.9 Hazard trees 0.9 Pension expense 0.4 Labor expense 0.3 Plant operator costs 1.2 Other miscellaneous increases $ 3.7 Change in OG&A Items Impacting Net Income $ 3.9 Non-employee directors deferred compensation 1.0 Operating expenses recovered in trackers (1.8) Pension and other postretirement benefits $ 3.1 Change in OG&A Items Offset Within Net Income $ 6.8 Increase in Operating, General & Administrative Expenses $2.0 million increase in property and other taxes due primarily to plant additions and higher annual estimated property valuations in Montana. $1.8 million increase in depreciation and depletion expense primarily due to plant additions. 7

Operating to Net Income (First Quarter) (dollars in millions) Three Months Ended March 31, 2019 2018 Variance Operating Income $ 97.0 $ 84.5 $ 12.5 14.8% Interest Expense (23.8) (23.0) (0.8) (3.5%) Other Income / (Expense) 1.1 (1.1) 2.2 200.0% Income Before Taxes 74.4 60.4 14.0 23.2% Income Tax Expense (1.6) (1.9) 0.3 15.8% Net Income $ 72.8 $ 58.5 $ 14.3 24.4% $0.8 million increase in interest expenses was primarily due to higher borrowings. $2.2 million improvement in other income. This includes a $3.9 million increase in the value of deferred shares held in trust for non-employee directors deferred compensation, partly offset by $1.8 million increase in other pension expense, both of which are offset in OG&A expenses with no impact to net income. Higher capitalization of AFUDC also contributed to the increase. $0.3 million decrease in income tax expense due to a higher flow through adjustments to income taxes partly offset by higher pretax income. 8

Income Tax Reconciliation (First Quarter) 9

Balance Sheet Improvement in debt to capitalization ratio; which is now closer to bottom end of 50%-55% targeted range. Debt to Total Capitalization was 52.0% at March 31, 2018 10

Cash Flow Cash from operating activities decreased by $61.6 million primarily due to an increase in market purchases of supply resulting in an under collection of supply costs from customers in the current period, credits to Montana customers during the current period related to TCJA, and the receipt of insurance proceeds during the three months ended March 31, 2018. 11

Adjusted Non-GAAP Earnings (First Quarter) 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) As a result of the adoption of Accounting Standard Update 2017-07 in March 2018, pension and other employee benefit expense is now disaggregated on the GAAP income statement with portions now recorded in both OG&A expense and Other (Expense) Income lines. To facilitate better understanding of trends in year-over-year comparisons, the non-GAAP adjustment above re-aggregates the expense in OG&A - 12 as it was historically presented prior to the ASU 2017-07 (with no impact to net income or earnings per share).

Looking Forward Regulatory • MPSC to review Montana general electric rate review, filed in September 2018. $3.30$3.30-$3.45-$3.50 $3.10 - $3.30 • We expect to file an associated FERC rate case for $2.60$3.20 - $2.75-$3.40 our Montana transmission assets in the second quarter 2019. Continue to Invest in our T&D infrastructure • Comprehensive infrastructure capital investment program to ensure safety, capacity and reliability. • Natural gas pipeline investment (SAFE PIPES Act, Integrity Verification Process and Pipeline & Hazardous Materials Safety Administration proposed regulations). • Grid modernization, advanced distribution management system and advanced metering infrastructure investment Plans to join Western Energy Imbalance Market (EIM) • Real-time energy market could mean lower cost of energy for Montana customers, more efficient use of renewables and greater power grid reliability. Cost Control Efforts • Continue to monitor costs, including labor, benefits and property tax valuations to mitigate increases. Advance Electricity Resource Planning efforts in South Dakota and Montana 13

Montana Electric Rate Case Background • First general electric rate case in Montana since 2009. The filing also requests: • While we have efficiently managed operating and administrative costs, • Approval to capitalize Demand increased Montana property taxes and significant investment in the Side Management Costs system have compelled the request for rate relief. • Establish a new baseline for PCCAM costs September 2018 Filing (Docket D2018.2.12) • Place Two Dot Wind in rate base • Filed based on 2017 test year and $2.34 billion of rate base. • Approval of new net metering • Requested $34.9 million annual increase to electric rates customer class and rate for new residential private generation (~7.4% increase to the typical residential bill). • On April 5, 2019, we filed rebuttal testimony that updated and lowered our requested increase to $30.7 million. This update responded to intervenor testimony and included certain known and measurable adjustments. • Request includes a10.65% return on equity, 4.26% cost of debt, 49.4% equity & 7.42% return on rate base1 • In March 2019, the MPSC issued an order approving an increase in rates of approximately $10.5 million on an interim and refundable basis effective April 1, 2019. Update • Feb. 12: Intervenor testimony file with the consumer advocate recommending a $17.3 million rate decrease. • Feb. 28: 4-0 vote at MPSC work session to request additional testimony on 5 issues ($500k of unexplained generation expense, disposition of excess accumulated deferred income tax liability, hazard tree and wildfire liability mitigation, recently constructed Montana corporate office building, and street lighting tariffs). Next Steps • May 3: Final day for NWE and intervenors to respond to discovery. • May 13: Hearing commences and continues day-to-day as necessary. 14 1. Except for Colstrip Unit 4 which has an lifetime ROR of 8.25% per D2008.6.69 (Order No. 6925f)

Relevant Legislation There are several potentially significant bills currently being considered by the Montana Legislature. In addition to many other less substantive bills, we are monitoring potential impacts of the following: • Legislation that would allow us to acquire up to an additional 150 MW of generation from Colstrip Unit 4 for $1 and would facilitate our placing in rates a certain amount of capital investment over the following ten years. Linked to this transaction is also a requirement to obtain a greater ownership share of the Colstrip transmission line and pay no more than the depreciated book value; • Legislation that would remove the +/- $4.1 million “deadband” sharing provision from the PCCAM as imposed by the MPSC's January 2019 order; and • Legislation that would prohibit the MPSC from applying a maximum contract length of 15 years to our future owned and contracted electricity supply resources as required in the MPSC's November 2017, Qualifying Facilities order. While the Montana legislative session is expected to end around May 1, 2019, it is premature to state how these pieces of legislation will ultimately be drafted, and how, or whether, they will be passed and / or signed into law by the Montana Governor. 15

NWE Energy Supply Resource Plans South Dakota Electricity Supply Resource Plan Ryan Dam Upgrade • Published fall of 2018, the plan focuses on modernization of our fleet to improve reliability and flexibility, maintain compliance in Southwest Power Pool, and lowering operating costs. The plan identifies 90MWs of existing generation that should be retired and replaced over the next 10 years. • On April 15, 2019, we issued a request for proposals for 60 MW of flexible capacity resources to begin serving South Dakota customers by the end of 2021. Responses are due in July 2019, with evaluation of the proposals during the second half of 2019. Montana Electricity Supply Resource Plan • Draft plan was filed in early March 2019 and expected to be finalized by the end of June 2019 after a 60 day public comment period. • The plan supports the goal of developing resources that will address the changing energy landscape in Montana to meet our customers’ electric energy needs in a reliable and affordable manner. • We are currently 630 MW short of our peak needs, which we procure in the market. We forecast that our energy portfolio will be 725 MW short by 2025 with a modest increase in customer demand. • Planned regional retirements of 3,500 MW of coal-fired generation are forecasted by the Northwest Power and Conservation Council causing regional energy shortages as early as 2021. • We expect to solicit competitive all-source proposals in late 2019 for peaking capacity available by 2022. • We expect the process will be repeated in subsequent years to provide a resource-adequate energy and capacity portfolio by 2025. The all-source capacity additions discussed above are subject to a competitive solicitation process administered by independent evaluators. As a result, we have not included the necessary capital investment in our current five year capital forecast. These additions could increase our capital spending in excess of $200 million over the next five years. 16

Capital Investment Forecast $1.6 billion of total capital investment over five years. Increased investment in first three years (relative to last two years) is primarily a result of advanced metering infrastructure (AMI) project. We anticipate funding the expenditures with a combination of cash flows (aided by NOLs available into 2020) and long-term debt issuances. Significant capital investments that are not in the above projections or further negative regulatory actions could necessitate additional equity funding. Capital projections above do not include investment necessary to address capacity issues as identified in the South Dakota and pending* Montana Electricity Supply Resource Procurement Plans. *Draft plan was released early March 2019. 17

Conclusion Best Attractive Pure Strong Solid Utility Practices Future Electric & Earnings & Foundation Corporate Growth Gas Utility Cash Flows Governance Prospects 18

Appendix 19

Montana Electric Tracker Update The MPSC issued a final order in January 2019 approving a Power Cost & Credit Adjustment Mechanism (PCCAM) with the following provisions: • A baseline of power supply costs; • Symmetrical deadband of +/- $4.1 million from the established baseline. Supply cost variances above or below the deadband are shared 90/10 with customers/shareholders, respectively; and • Retroactive implementation to the effective date of the new legislation (July 1, 2017). Our 2019 results include a net reduction in the recovery of supply costs from customers of approximately $1.6 million in the Consolidated Statements of Income. • For the 2017/2018 period, actual costs were below base revenues by approx. $3.4 million, resulting in no refund to customers. • For the 2018/2019 period, actual costs were above base revenues by approx. $27.6 million, resulting in a regulatory asset for collection from customers of approx. $21.2 million and a $6.5 million reduction in recovery of supply costs for the first nine months of the twelve month tracker period. 20

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

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

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

Appendix Non-GAAP Financial Measures 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 24 measures.

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