Georgia-Pacific Corp., a paper products company that also supplies products to the flooring industry, has agreed to be acquired by Koch Industries for about $21 billion. Koch, based in Wichita, manufactures flooring fibers, pulp and paper, and operates a range of business including refineries and pipelines.

When finalized, the deal stands to create the nation's biggest private company. It will also give Georgia-Pacific a greater level of vertical integration and a steady source of raw material.

The proposed acquisition comes less than two years after Koch acquired Invista, the nylon fibers business that makes Lycra and Stainmaster, from DuPont. In addition to building materials, Georgia-Pacific's consumer brands include Dixie paper cups and Quilted Northern bath tissue.