Exhibit 99.1 WAUSAU-MOSINEE PAPER CORPORATION REPORTS SUBSTANTIAL INCREASE IN FIRST-QUARTER EARNINGS MOSINEE, WI APRIL 26, 2004 Wausau-Mosinee Paper Corporation (NYSE:WMO) today reported first-quarter earnings of $3.5 million, or $0.07 per share, up substantially from year-ago earnings of $1.3 million, or $0.03 per share. Net sales rose 5 percent to $251.8 million, and shipments increased 2 percent to 215,000 tons. "Increased first-quarter earnings principally reflect product mix improvement and volume gains driven by successful product development efforts and our strong service platform," explained Thomas J. Howatt, president and chief executive officer. "All three of our business segments posted strong increases in operating profit despite higher fiber costs and continuing high energy prices." Specialty Paper reported its seventh consecutive quarter of year-over-year profit improvement and its highest quarterly net sales total since the second quarter of 2000. Operating profits more than doubled to $3.5 million, from $1.5 million the year before, and net sales increased 9 percent. "Specialty Paper's profit improvement was driven by new-business development, select selling price increases and strong operations," Mr. Howatt said. "Revenues from products developed within the past three years continued to exceed 40 percent during the quarter, which helped reduce shipments of lower-priced noncore products by 50 percent compared to last year." Printing & Writing reported first-quarter operating profits of $2.6 million, up substantially from $1.5 million for the same period last year. Net sales were up 2 percent as premium shipments increased 9 percent. "Margins for uncoated printing papers remain well below expectations due to three years of declining demand. We believe, however, that a combination of product breadth, benchmark service and a focus on the growth segments of the market will provide superior returns over the long term," said Mr. Howatt. Towel & Tissue's first-quarter net sales rose 4 percent, and operating profits increased 32 percent to $5.3 million, from $4.0 million in the prior year, reflecting market share gains and successful cost-reduction efforts. "Innovative product offerings, such as our recently introduced EcoSoft<trademark> Green Seal<reg-trade-mark>1 certified products, have driven growth in our target markets and improved profitability. This focus on premium products, coupled with excellent service, delivers value to our customers and helps us gain market share," Mr. Howatt added. Looking to the second quarter, Mr. Howatt said, "The benefits of an improving economy have been slow to reach most segments of the paper industry. While we continue to benefit from product development successes and select selling price increases, we expect that historically high energy prices and increasing fiber costs will mitigate a portion of the benefit. Ultimately, we expect second- quarter earnings to represent a solid improvement over the first quarter with results in the range of current analysts' estimates of $0.11 per share to $0.13 per share." Wausau-Mosinee's first-quarter conference call is scheduled for 11:00 a.m. (EDT) on Tuesday, April 27, and can be accessed through the Company's web site at www.wausaumosinee.com under "Investor Information." A replay of the webcast will be available at the same site through May 6. 1Green Seal<reg-trade-mark> is a registered trademark of Green Seal, Inc., in Washington, D.C. and is used by permission. Wausau-Mosinee Paper Corporation produces fine printing and writing papers, technical specialty papers, and "away-from-home" towel and tissue products. SAFE HARBOR UNDER THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995: The matters discussed in this news release concerning the Company's future performance or anticipated financial results are forward-looking statements and are made pursuant to the safe harbor provisions of the Securities Reform Act of 1995. Such statements involve risks and uncertainties which may cause results to differ materially from those set forth in these statements. Among other things, these risks and uncertainties include the strength of the economy and demand for paper products, increases in raw material and energy prices, manufacturing problems at Company facilities, and other risks and assumptions described in Item 1 of the Company's Form 10-K for the year ended December 31, 2003. The Company assumes no obligation to update or supplement forward- looking statements that become untrue because of subsequent events. (tables follow) WAUSAU-MOSINEE PAPER CORPORATION INTERIM REPORT - QUARTER ENDED MARCH 31, 2004 (in thousands, except share amounts) CONDENSED CONSOLIDATED STATEMENTS Three Months OF OPERATIONS (UNAUDITED) Ended March 31, 2004 2003 Net Sales $ 251,815 $ 239,826 Cost of Sales 225,117 218,947 Gross Profit 26,698 20,879 Selling & Administrative Expense 18,884 16,244 Operating Profit 7,814 4,635 Interest Expense (2,527) (2,501) Other Income/(Expense), Net 194 (14) Earnings Before Income Taxes 5,481 2,120 Provision for Income Taxes 2,029 785 Net Earnings $ 3,452 $ 1,335 Net Earnings Per Share (Basic & Diluted) $ 0.07 $ 0.03 Weighted Average Shares Outstanding (Basic) 51,617,395 51,536,891 CONDENSED CONSOLIDATED BALANCE SHEETS (NOTE 1) March 31, December 31, 2004 2003 Current Assets $267,947 $251,418 Property, Plant & Equipment, Net 555,708 565,722 Other Assets 41,034 40,960 Total Assets $864,689 $858,100 Current Liabilities $119,985 $115,004 Long-term Debt 161,964 162,174 Other Liabilities 227,880 230,606 Stockholders' Equity 354,860 350,316 Total Liabilities & Stockholders' Equity $864,689 $858,100 CONDENSED CONSOLIDATED STATEMENTS Three Months OF CASH FLOW (UNAUDITED) Ended March 31, 2004 2003 Cash Provided by Operating Activities $14,031 $14,508 Cash Used in Investing Activities: Capital Expenditures (3,937) (4,669) Acquisition of Business 0 (8,413) (3,937) (13,082) Cash Provided by (Used in) Financing Activities: Net Borrowings Under Credit Agreements 0 3,030 Payments Under Capital Lease Obligation (28) 0 Dividends Paid (4,382) (4,381) Proceeds from Stock Option Exercises 1,087 0 (3,323) (1,351) Net Increase in Cash $ 6,771 $ 75 Note 1 -Balance sheet amounts at March 31, 2004 are unaudited. The December 31, 2003 amounts are derived from audited financial statements. Note 2 -Effective March 3, 2003, the Company acquired certain assets of a laminated papers producer. The acquisition is being accounted for as a purchase business combination and, accordingly, the purchase price has been allocated using the fair values of the acquired receivables, inventory, machinery and equipment, and identifiable intangible assets. No goodwill was recorded as a result of this acquisition. Note 3- Interim Segment Information The Company's operations are classified into three principal reportable segments: the Printing & Writing Group, the Specialty Paper Group, and the Towel & Tissue Group, each providing different products. Separate management of each segment is required because each business unit is subject to different marketing, production and technology strategies. Printing & Writing produces a broad line of premium printing and writing grades at manufacturing facilities in Brokaw, Wisconsin; and Groveton, New Hampshire. Printing & Writing also includes two converting facilities that produce laminated roll wrap and related specialty finishing and packaging products, and a converting facility that converts printing and writing grades. Specialty Paper produces specialty papers at its manufacturing facilities in Rhinelander, Wisconsin; Mosinee, Wisconsin; and Jay, Maine. Towel & Tissue produces a complete line of towel and tissue products that are marketed along with soap and dispensing systems for the "away-from-home" market. Towel & Tissue operates a paper mill in Middletown, Ohio, and a converting facility in Harrodsburg, Kentucky. Sales, operating profit, and asset information by segment is as follows: (in thousands, except ton data) March 31, December 31, 2004 2003 Segment Assets (Note 1) Printing & Writing $287,628 $283,711 Specialty Paper 334,049 334,079 Towel & Tissue 162,824 165,199 Corporate & Unallocated* 80,188 75,111 $864,689 $858,100 Three Months Ended March 31, 2004 2003 Net Sales External Customers (unaudited) Printing & Writing $100,101 $ 98,377 Specialty Paper 100,931 92,458 Towel & Tissue 50,783 48,991 $251,815 $239,826 Operating Profit (unaudited) Printing & Writing $ 2,551 $ 1,486 Specialty Paper 3,451 1,512 Towel & Tissue 5,301 4,031 Total Reportable Segment Operating Profit 11,303 7,029 Corporate & Eliminations (3,489) (2,394) Interest Expense (2,527) (2,501) Other Income/(Expense), Net 194 (14) Earnings Before Income Taxes $ 5,481 $ 2,120 Depreciation, Depletion and Amortization (unaudited) Printing & Writing $ 4,176 $ 4,158 Specialty Paper 6,025 6,122 Towel & Tissue 4,496 4,582 Corporate & Unallocated 285 183 $ 14,982 $ 15,045 Tons Sold (unaudited) Printing & Writing 92,240 88,731 Specialty Paper 87,585 87,675 Towel & Tissue 35,423 34,350 215,248 210,756 <FN> * Segment assets do not include intersegment accounts receivable, cash, deferred tax assets and certain other assets which are not identifiable with the segments.