SCHEDULE 13G/A

Clearwater Paper Corp

Common Stock, par value $0.0001 per share · CUSIP: 18538R103

Event date: 2025-12-31

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Southeastern Asset Management, Inc.

  Shares: 1,380,930.00 · Class: 8.6%

• Longleaf Partners Small-Cap Fund

  Shares: 1,378,835.00 · Class: 8.6%

• O. Mason Hawkins

  Shares: 0.00 · Class: 0%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.