Investor Presentaiton

L Environmental Social NorthWestern Energy 2019 ENVIRONMENTAL REPORT CODE OF CONDUCT -AND ETHICS - Environmental Report http://www.northwesternenergy.com /environment/our-environment Code of Conduct ESG Publications Governance 2020 COMMUNITY REPORT SORT-VRSTERN RAFROY http://www.northwesternenergy.com/docs/default- source/documents/corporate governance/code-of-conduct.pdf Community Works Report http://www.northwesternenergy.com/communi ty-works/community-works 2019 ANNUAL REPORT 25 25 2020 AUTHENTENENTORY PROXY STATEMENT NORTHWESTERN ENERGY Annual Report http://www.northwesternenergy.com/our- company/investor-relations/annual-reports Proxy Statement http://www.northwesternenergy.com/our- company/investor-relations/proxy-materials These five documents provide valuable insight in NorthWestern Energy's Environmental, Social and Governance (ESG) Sustainability practices. NorthWestern Energy Delivering a Bright Future

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