Clearwater Paper Corp

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

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ANNUAL MEETING OF STOCKHOLDERS

May 7, 2026

NOTICE OF ANNUAL MEETING

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LETTER FROM OUR CEO

Dear Clearwater Paper stockholders and stakeholders,In 2025 we transformed Clearwater Paper into a premier supplier of paperboard packaging products for independent converters in North America. We did this by successfully integrating the Augusta, Georgia paperboard packaging facility that we acquired from Graphic Packaging in 2024. We also successfully completed the transition of our tissue business to Sofidel America. As we made these transitions, we took actions to reduce our corporate overhead to better reflect a smaller, more streamlined business. We eliminated more than 25% of salaried roles and delivered SG&A costs at 6.5% of net sales, at the lower end of our target range of 6 to 7%.

Throughout the year our team navigated a challenging industry down cycle, driven by supply exceeding demand. With a competitor adding new capacity, industry operating rates were in the mid 80% range, below 90 to 95% that we would expect to see under normal conditions. While we believe that this is temporary, we took actions on items within our control, namely improving operational execution, reducing fixed costs, and defending our market position. We believe that this discipline will translate to sustained improvement in performance and higher margins once the industry cycle recovers.

More specifically, in addition to SG&A cost reductions, we also reduced our operational fixed costs by more than 10%. In total, we eliminated approximately 250 positions across the company and reduced our non-labor costs. These actions resulted in more than $50 million in savings during the year, helping offset some of the margin pressure that we are facing during this industry down cycle.

We continued our focus on sustainability across our pillars of Resource Stewardship, Trusted Products and Thriving People and Communities. Below are a few highlights from 2025:

•We reduced our lost time injury rate by more than 50% year over year.

•We reduced our safety risks by more than 20% through our aspects and impacts (A&I) process.

•We have integrated the Augusta facility into our greenhouse emissions reporting processes.

•We set a 10% water reduction target for the company by 2030.

•We received BPI compostable certification at our Lewiston and Cypress Bend mills that cover most of our folding carton and food service grades.

•We continued to support non-profit organizations in our operating communities through the Clearwater Paper Charitable Foundation.

While we are in a challenging business environment, we are well positioned to navigate this downturn. We have a strong balance sheet with a manageable debt load, high-quality paperboard assets in an attractive market segment and a talented team.

By intensely focusing on reducing costs, driving operational performance and defending our market share, we will position Clearwater Paper to deliver higher margins and stronger cash flows when the industry recovers to its historic levels.

Thank you for the trust that you place in all of us at Clearwater Paper.

Sincerely,

Arsen S. Kitch

President and Chief Executive Officer

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