The sale has a cash value of 7.6bn, and will involve Koch assuming Georgia-Pacific's 4.4bn debt. Debt financing has been secured by Koch through Citigroup, which advised the company on the acquisition.

Koch Forest Products, a subsidiary of Koch, made a 28 per share cash offer for all the paper and packaging manufacturer's shares on 11 November.

Both sets of directors approved the deal, which will lead to Georgia-Pacific becoming a wholly-owned subsidiary of Koch.

The firm will continue to trade under the Georgia-Pacific name, and will operate as an independently managed company.

Georgia-Pacific is one of the world's leading producers of pulp, paper and packaging board products. It has UK operations in Bolton and Sheffield.

The firm employs 55,000 staff across the US and Europe and has annual sales of around 11.5bn.

Koch Industries is based in Kansas, and has interests in companies trading in pulp and paper, petroleum, chemicals, energy, fertilisers and securities and finance.