Financial Data and Key Metrics Changes - Clearwater Paper reported net sales of $453 million for Q4 2020, representing a growth of approximately 4% year-over-year, and adjusted EBITDA of $72 million, which is a 38% increase compared to the same quarter last year [4][16] - Diluted net income per share for Q4 was $1.34, with full year diluted net income per share at $4.61, both showing significant increases over prior periods [16] Business Line Data and Key Metrics Changes - The tissue business experienced higher sales and production volumes year-over-year, shipping 13.9 million cases in Q4 2020, up 5.3% compared to Q4 2019, but down 4.2% from Q3 2020 [11][24] - The paperboard business also performed strongly, with robust backlogs leading to a price increase announcement of $50 per ton across the SBS portfolio effective February 2 [5][14] Market Data and Key Metrics Changes - The U.S. tissue market traditionally consists of two-thirds at-home and one-third away-from-home consumption, with a shift towards at-home consumption due to COVID-19 [9] - The company anticipates a potential shift back to away-from-home consumption as vaccination rates increase, which may negatively impact the at-home market [9] Company Strategy and Development Direction - Clearwater Paper is focused on debt reduction and operational improvements, having reduced net debt by $200 million in 2020 and targeting a net debt to adjusted EBITDA ratio of 2.5x [31][36] - The company is exploring both internal investments to improve competitiveness and external opportunities that provide synergies [37] Management's Comments on Operating Environment and Future Outlook - Management noted that the first quarter of 2021 is expected to see lower tissue shipments compared to both the prior year and the previous quarter, with January shipments at 4.6 million cases and February trending below 4 million cases [26][47] - The company expects inflationary pressures of $40 million to $50 million for the year, primarily driven by pulp costs, with a modest impact expected in Q1 [39][53] Other Important Information - A one-time discretionary bonus of $1,000 was paid to over 2,800 employees in November 2020 as recognition for their efforts during the pandemic [7][42] - The company experienced a weather-related outage that could impact Q1 results by approximately $6 million to $8 million [14][27] Q&A Session Summary Question: Impact of higher pulp costs in Q1 and throughout the year - Management indicated that pulp prices have increased over $100 a ton, with modest impacts expected in Q1 but more significant effects anticipated in Q2 through Q4 [39] Question: Implementation of price increases in the paperboard market - The implementation of the announced price increase is expected to take a couple of quarters, with a mix of spot and contract-based pricing [41] Question: Details on the one-time bonus distribution - The $2.8 million bonus was aimed at most employees, with accruals made in Q3 [42][43] Question: Updates on multi-employer pension programs - Proposed legislation could provide substantial financial relief for multi-employer pension plans, which would positively impact Clearwater [44] Question: Tissue production and shipment expectations - January shipments were 4.6 million cases, with February trending below 4 million cases, and expectations for a high single to low double-digit decline in tissue volumes for the full year [47][49] Question: Guidance on inflation and its components - Inflation is expected to be driven by pulp, freight, and energy costs, with most impacts anticipated in Q2 through Q4 [53][54] Question: Clarification on capital allocation strategies - The focus remains on debt reduction, with potential for small to medium-sized internal projects and external opportunities being explored [69]

`UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 or ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-34146 | --- | --- | |----------------------------------------------------------------------------|--------------------------------- ...

[PART I. FINANCIAL INFORMATION](index=4&type=section&id=PART%20I.%20FINANCIAL%20INFORMATION) This section presents the unaudited consolidated financial statements and management's discussion and analysis for the company [ITEM 1. Consolidated Financial Statements](index=4&type=section&id=ITEM%201.%20Consolidated%20Financial%20Statements) This section presents Clearwater Paper Corporation's unaudited consolidated financial statements, including balance sheets, income statements, cash flows, and detailed notes [Consolidated Balance Sheets](index=4&type=section&id=Consolidated%20Balance%20Sheets) The Consolidated Balance Sheet shows a decrease in total assets to **$1,826.9 million** from **$1,877.7 million** at year-end 2019, primarily due to lower property, plant, and equipment, while total liabilities decreased to **$1,330.8 million** and total stockholders' equity increased to **$496.2 million** Consolidated Balance Sheet Highlights (in millions) | Account | Sep 30, 2020 | Dec 31, 2019 | | :--- | :--- | :--- | | **Total Assets** | **$1,826.9** | **$1,877.7** | | Total Current Assets | $492.0 | $465.8 | | Property, plant and equipment, net | $1,200.9 | $1,257.7 | | **Total Liabilities** | **$1,330.8** | **$1,445.7** | | Long-term debt | $785.5 | $884.5 | | **Total Stockholders' Equity** | **$496.2** | **$432.0** | [Consolidated Statements of Operations](index=5&type=section&id=Consolidated%20Statements%20of%20Operations) The company reported a significant turnaround in profitability, with net income of **$21.4 million** in Q3 2020 and **$54.5 million** for the nine months ended September 30, 2020, driven by increased net sales Key Operating Results (in millions, except per-share data) | Metric | Q3 2020 | Q3 2019 | 9 Months 2020 | 9 Months 2019 | | :--- | :--- | :--- | :--- | :--- | | Net Sales | $457.4 | $445.2 | $1,415.8 | $1,326.0 | | Income (loss) from operations | $49.2 | $(2.4) | $116.2 | $27.2 | | Net income (loss) | $21.4 | $(11.0) | $54.5 | $(7.6) | | Diluted EPS | $1.28 | $(0.66) | $3.27 | $(0.46) | [Consolidated Statements of Cash Flows](index=7&type=section&id=Consolidated%20Statements%20of%20Cash%20Flows) Net cash provided by operating activities significantly improved to **$176.1 million** for the nine months ended September 30, 2020, while cash used in investing activities decreased due to the completion of the Shelby expansion, and financing activities primarily focused on debt repayments Cash Flow Summary for Nine Months Ended Sep 30 (in millions) | Cash Flow Activity | 2020 | 2019 | | :--- | :--- | :--- | | Net cash from Operating Activities | $176.1 | $(16.2) | | Net cash used in Investing Activities | $(27.5) | $(125.8) | | Net cash (used in) from Financing Activities | $(122.5) | $127.4 | | **Increase (decrease) in cash** | **$26.1** | **$(14.7)** | [Notes to Consolidated Financial Statements](index=10&type=section&id=Notes%20to%20Consolidated%20Financial%20Statements) The notes provide detailed information supporting the financial statements, covering accounting standards, fair value, debt, leases, and segment performance, including the issuance of new senior notes and changes in the effective income tax rate - The company issued **$275 million** of 4.75% senior notes due 2028 and used the proceeds to redeem its 4.50% notes due 2023, resulting in a **$3.2 million** loss on early debt extinguishment[37](index=37&type=chunk)[42](index=42&type=chunk) - The effective income tax rate for the first nine months of 2020 was **21%**, down from **38%** in the same period of 2019, benefiting from a **$7.0 million** provision from the CARES Act[44](index=44&type=chunk) Segment Net Sales and Operating Income (in millions) | Segment | Q3 2020 Sales | Q3 2019 Sales | Q3 2020 Op. Income | Q3 2019 Op. Income | | :--- | :--- | :--- | :--- | :--- | | Consumer Products | $248.3 | $228.5 | $31.3 | $(4.4) | | Paperboard | $209.1 | $216.6 | $32.8 | $17.1 | [ITEM 2. Management's Discussion and Analysis of Financial Condition and Results of Operations](index=19&type=section&id=ITEM%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses the financial impact of the COVID-19 pandemic, segment operating results, and the company's liquidity and capital resources - The COVID-19 pandemic led to a significant increase in demand for 'at home' tissue products in the first nine months of 2020, while paperboard demand saw increases in food packaging but decreases in food service[62](index=62&type=chunk) Financial Performance Summary (in millions) | Metric | Q3 2020 | Q3 2019 | 9 Months 2020 | 9 Months 2019 | | :--- | :--- | :--- | :--- | :--- | | Net Sales | $457.4 | $445.2 | $1,415.8 | $1,326.0 | | Net Income (Loss) | $21.4 | $(11.0) | $54.5 | $(7.6) | | Adjusted EBITDA | $77.2 | $31.5 | $211.6 | $115.6 | [Our Operating Results](index=22&type=section&id=Our%20Operating%20Results) The Consumer Products segment experienced an **8.7%** sales increase and significant operating income growth due to COVID-19-driven retail tissue demand, while the Paperboard segment's sales decreased but operating income grew **92.1%** due to lower input costs Consumer Products Segment Performance (Q3 2020 vs Q3 2019) | Metric | Q3 2020 | Q3 2019 | % Change | | :--- | :--- | :--- | :--- | | Sales | $248.3M | $228.5M | +8.7% | | Operating Income (Loss) | $31.3M | $(4.4)M | n.m. | | Adjusted EBITDA | $48.3M | $14.6M | +230.8% | | Retail Shipments (tons) | 86,292 | 79,526 | +8.5% | Paperboard Segment Performance (Q3 2020 vs Q3 2019) | Metric | Q3 2020 | Q3 2019 | % Change | | :--- | :--- | :--- | :--- | | Sales | $209.1M | $216.6M | -3.5% | | Operating Income | $32.8M | $17.1M | +92.1% | | Adjusted EBITDA | $42.0M | $28.3M | +48.6% | | Shipments (tons) | 211,820 | 214,537 | -1.3% | [Liquidity and Capital Resources](index=24&type=section&id=Liquidity%20and%20Capital%20Resources) The company's liquidity significantly improved with **$176.1 million** in operating cash flow for the first nine months of 2020, enabling substantial debt repayments and a sharp decrease in capital expenditures - Net cash from operating activities increased to **$176.1 million** in the first nine months of 2020 from a use of **$16.2 million** in 2019, driven by higher net income and lower inventories[82](index=82&type=chunk) - Cash used for investing activities fell to **$27.5 million** from **$125.8 million** year-over-year, primarily due to the completion of the Shelby expansion in late 2019[83](index=83&type=chunk) - Improved operating results and lower capital spending allowed for significant debt repayments, resulting in a net cash use of **$122.5 million** in financing activities for the first nine months of 2020[84](index=84&type=chunk) [ITEM 3. Quantitative and Qualitative Disclosures About Market Risk](index=25&type=section&id=ITEM%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk exposure is to interest rate fluctuations on its variable-rate debt, specifically the Term Loan and ABL Credit Agreements, with **$199.3 million** in borrowings subject to this risk as of September 30, 2020 - A one percentage point change in interest rates would have an approximate **$2.0 million** annual effect on interest expense, based on the **$199.3 million** of variable-rate debt outstanding at the end of Q3 2020[87](index=87&type=chunk) [ITEM 4. Controls and Procedures](index=26&type=section&id=ITEM%204.%20Controls%20and%20Procedures) Management, including the CEO and CFO, evaluated the company's disclosure controls and procedures and concluded they were effective as of September 30, 2020, with no material changes to internal control over financial reporting during the third quarter - The CEO and CFO concluded that the company's disclosure controls and procedures are effective in ensuring that material information is recorded, processed, and reported in a timely manner[89](index=89&type=chunk) - No changes occurred during the third quarter of 2020 that materially affected, or are likely to materially affect, the company's internal control over financial reporting[90](index=90&type=chunk) [PART II. OTHER INFORMATION](index=27&type=section&id=PART%20II.%20OTHER%20INFORMATION) This section covers legal proceedings, key risk factors, and a list of exhibits filed with the report [ITEM 1. Legal Proceedings](index=27&type=section&id=ITEM%201.%20Legal%20Proceedings) The company may be involved in various claims and litigation arising from its business operations, but management believes the outcomes will not have a material adverse effect on its financial condition - The company does not expect any ongoing legal proceedings to have a material adverse effect on its financial condition[92](index=92&type=chunk) [ITEM 1A. Risk Factors](index=27&type=section&id=ITEM%201A.%20Risk%20Factors) The COVID-19 pandemic is identified as a significant risk factor, potentially impacting operations, supply chains, demand, and financial markets despite short-term tissue demand increases - The primary risk factor discussed is the COVID-19 pandemic, which could materially and adversely affect the business through various channels despite the initial surge in tissue demand[93](index=93&type=chunk) - Specific pandemic-related risks include: facility closures, supply chain disruptions (e.g., eucalyptus pulp from Brazil), decreased paperboard demand in a recession, interruptions to distribution, and volatility in pension plan assets[93](index=93&type=chunk) - The company notes that the initial stocking up of tissue products by consumers will likely lead to a future drop in purchasing as the pandemic subsides, with demand expected to normalize[93](index=93&type=chunk) [ITEM 6. Exhibits](index=30&type=section&id=ITEM%206.%20Exhibits) This section lists the exhibits filed with the Form 10-Q, including the indenture for the 2028 Senior Notes, an amendment to the ABL Credit Agreement, CEO/CFO certifications, and XBRL data files

[PART I. FINANCIAL INFORMATION](index=4&type=section&id=PART%20I.%20FINANCIAL%20INFORMATION) [Consolidated Financial Statements](index=4&type=section&id=ITEM%201.%20Consolidated%20Financial%20Statements) This section presents Clearwater Paper Corporation's unaudited consolidated financial statements, highlighting increased net income and operating cash flow [Consolidated Balance Sheets](index=4&type=section&id=Consolidated%20Balance%20Sheets) Total assets slightly decreased to **$1,841.5 million**, while liabilities reduced and stockholders' equity increased to **$470.8 million** Consolidated Balance Sheet Highlights (in millions) | Account | June 30, 2020 | December 31, 2019 | | :--- | :--- | :--- | | **Total Assets** | **$1,841.5** | **$1,877.7** | | Cash and cash equivalents | $48.2 | $20.0 | | Inventories | $235.3 | $281.4 | | Property, plant and equipment, net | $1,219.7 | $1,257.7 | | **Total Liabilities** | **$1,370.7** | **$1,445.7** | | Long-term debt | $827.9 | $884.5 | | **Total Stockholders' Equity** | **$470.8** | **$432.0** | [Consolidated Statements of Operations](index=5&type=section&id=Consolidated%20Statements%20of%20Operations) Net sales increased to **$480.5 million** for Q2 2020, with net income significantly improving to **$22.8 million** from a prior-year loss Statement of Operations Highlights (in millions, except per-share data) | Metric | Three Months Ended June 30, 2020 | Three Months Ended June 30, 2019 | Six Months Ended June 30, 2020 | Six Months Ended June 30, 2019 | | :--- | :--- | :--- | :--- | :--- | | Net sales | $480.5 | $452.0 | $958.4 | $880.8 | | Income from operations | $48.1 | $15.3 | $67.0 | $29.7 | | Net income (loss) | $22.8 | $(0.4) | $33.1 | $3.4 | | Diluted EPS | $1.36 | $(0.03) | $1.99 | $0.21 | [Consolidated Statements of Cash Flows](index=7&type=section&id=Consolidated%20Statements%20of%20Cash%20Flows) Operating cash flow significantly increased to **$121.1 million**, with reduced investing outflows and net cash used in financing for debt repayment Cash Flow Summary for Six Months Ended June 30 (in millions) | Activity | 2020 | 2019 | | :--- | :--- | :--- | | Net cash provided by operating activities | $121.1 | $14.7 | | Net cash used in investing activities | $(17.8) | $(108.4) | | Net cash provided by (used in) financing activities | $(76.5) | $113.0 | [Notes to Consolidated Financial Statements](index=11&type=section&id=Notes%20to%20Consolidated%20Financial%20Statements) Notes detail financial statements, including debt structure, tax calculations, and segment performance, highlighting a **$60 million** debt prepayment and **11%** effective tax rate - The company made a voluntary prepayment of **$60 million** on its Term Loan during the second quarter of 2020[39](index=39&type=chunk) - The effective income tax rate for the first six months of 2020 was **11%**, significantly lower than **54%** in 2019, primarily due to tax credits and a **$7.1 million** CARES Act benefit[43](index=43&type=chunk) Segment Operating Income (in millions) | Segment | Six Months Ended June 30, 2020 | Six Months Ended June 30, 2019 | | :--- | :--- | :--- | | Consumer Products | $50.9 | $(3.9) | | Paperboard | $58.7 | $63.0 | [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=19&type=section&id=ITEM%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses COVID-19's impact, boosting Consumer Products sales and profitability, while Paperboard sales declined, and the company improved liquidity - The company experienced a significant increase in demand for 'at home' tissue products in H1 2020 due to COVID-19, while paperboard demand was mixed[59](index=59&type=chunk) Key Financial Metrics Comparison (in millions) | Metric | Q2 2020 | Q2 2019 | H1 2020 | H1 2019 | | :--- | :--- | :--- | :--- | :--- | | Net Sales | $480.5 | $452.0 | $958.4 | $880.8 | | Net Income (Loss) | $22.8 | $(0.4) | $33.1 | $3.4 | | Adjusted EBITDA | $79.0 | $44.3 | $134.3 | $84.1 | [Operating Results by Segment](index=22&type=section&id=Our%20Operating%20Results) Consumer Products sales increased **22.6%** due to COVID-19 demand, boosting operating income, while Paperboard sales decreased **9.8%** Consumer Products Segment Performance - Q2 2020 vs Q2 2019 (in millions) | Metric | Q2 2020 | Q2 2019 | % Change | | :--- | :--- | :--- | :--- | | Sales | $275.1M | $224.3M | +22.6% | | Operating Income (Loss) | $36.6M | $(5.1)M | n.m. | | Adjusted EBITDA | $53.7M | $12.3M | +337.8% | | Retail Shipments (tons) | 95,432 | 76,175 | +25.3% | Paperboard Segment Performance - Q2 2020 vs Q2 2019 (in millions) | Metric | Q2 2020 | Q2 2019 | % Change | | :--- | :--- | :--- | :--- | | Sales | $205.4M | $227.7M | -9.8% | | Operating Income | $32.2M | $33.6M | -4.2% | | Adjusted EBITDA | $41.4M | $43.1M | -3.8% | | Shipments (tons) | 207,410 | 225,188 | -7.9% | [Liquidity and Capital Resources](index=24&type=section&id=Liquidity%20and%20Capital%20Resources) Liquidity significantly improved in H1 2020, with operating cash flow increasing to **$121.1 million**, enabling a **$60 million** debt prepayment and covenant compliance - Net cash from operating activities increased to **$121.1 million** for H1 2020, compared to **$14.7 million** in H1 2019, due to higher net income and lower inventories[79](index=79&type=chunk) - Capital expenditures are expected to be approximately **$45 million to $50 million** for full year 2020, a significant decrease from the prior year[80](index=80&type=chunk) - The company was in compliance with all debt covenants as of June 30, 2020, with a first lien secured leverage ratio of **0.97x**, below the **2.00x** threshold[39](index=39&type=chunk)[82](index=82&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=25&type=section&id=ITEM%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk is interest rate fluctuations on its **$239.3 million** variable-rate debt, with a **1%** change impacting interest expense by **$2.4 million** annually - The company is exposed to interest rate risk on **$239.3 million** of variable-rate debt outstanding as of June 30, 2020[84](index=84&type=chunk) - A one percentage point change in interest rates would have an approximate **$2.4 million** annual impact on interest expense[84](index=84&type=chunk) [Controls and Procedures](index=26&type=section&id=ITEM%204.%20Controls%20and%20Procedures) CEO and CFO concluded disclosure controls and procedures were effective as of June 30, 2020, with no material changes to internal controls - The CEO and CFO concluded that the company's disclosure controls and procedures were effective as of June 30, 2020[86](index=86&type=chunk) - No material changes to the company's internal control over financial reporting occurred during the second quarter of 2020[87](index=87&type=chunk) [PART II. OTHER INFORMATION](index=27&type=section&id=PART%20II.%20OTHER%20INFORMATION) [Legal Proceedings](index=27&type=section&id=ITEM%201.%20Legal%20Proceedings) Management does not expect ongoing legal proceedings to have a material adverse effect on the company's financial condition - The company does not expect any ongoing legal proceedings to have a material adverse effect on its financial condition[89](index=89&type=chunk) [Risk Factors](index=27&type=section&id=ITEM%201A.%20Risk%20Factors) The COVID-19 pandemic is a significant risk, potentially causing facility closures, supply chain disruptions, and demand volatility, with its full impact highly uncertain - The COVID-19 pandemic is identified as a significant risk factor with a highly uncertain and difficult-to-predict impact on the business[90](index=90&type=chunk)[92](index=92&type=chunk) - Specific risks heightened by the pandemic include facility closures, supply chain disruptions, volatility in consumer demand, and potential inability to collect on accounts receivable[90](index=90&type=chunk) - The initial surge in tissue product demand due to consumer stocking will likely lead to a drop in purchasing as the pandemic subsides, with demand expected to normalize[90](index=90&type=chunk) [Exhibits](index=30&type=section&id=ITEM%206.%20Exhibits) This section lists exhibits filed with Form 10-Q, including amendments to stock and compensation plans, and CEO/CFO certifications - Filed exhibits include amendments to the 2017 Stock Incentive Plan and other compensation plans, as well as required CEO and CFO certifications[96](index=96&type=chunk)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-Q (Mark One) Title of each class Trading Symbol(s) Name of each exchange on which registered ý Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended March 31, 2020 or ¨ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to Commission File Number: 001-34146 CLEARWATER PAPER CORPORATION (Exact name ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Delaware 20-3594554 (State or other jurisdiction of incorporation or organization) (IRS Employer Identification No.) 601 W. Riverside Avenue, Suite 1100 Spokane ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-Q (Mark One) ý Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended September 30, 2019 or ¨ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 | --- | --- | |-------------------------------------------------------------------------------|------------------------------------------| | For the transition period from | to | | Comm ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-Q (Mark One) ý Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended June 30, 2019 or ¨ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 | --- | --- | |-------------------------------------------------------------------------------|------------------------------------------| | For the transition period from | to | | Commissio ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-Q (Mark One) ý Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended March 31, 2019 or ¨ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 | --- | --- | |-------------------------------------------------------------------------------|------------------------------------------| | For the transition period from | to | | Commissi ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 Form 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-34146 CLEARWATER PAPER CORPORATION (Exact name of registrant as specified in its charter) Delaware 20-3594554 (State or other jurisd ...