Dow Chemical Co. and DuPont Co., two historic giants of U.S. industry, will join in an all-stock merger of equals that's the first step in a plan to create three new highly focused businesses.

The deal, the largest ever in the chemicals industry, will create a $130 billion company that combines products from both Dow and DuPont in the areas of agriculture, commodities chemicals and specialty chemicals to create the new businesses. The agreement, percolating since at least February, comes after two years of pressure from activist investors who argued that shareholders of both companies would realize greater value if they were broken up.

The new company, DowDuPont, will be owned 50-50 by the current shareholders of both companies, they said Friday in a joint statement. Dow Chief Executive Officer Andrew Liveris, 61, will become executive chairman. DuPont CEO Ed Breen, 59, will be CEO of the new company.