DuPont merged with Dow Chemical in 2017 to form DowDuPont.
The companies announced their merger of equals in December 2015, and the transaction closed on August 31, 2017. The combined company was named DowDuPont and was intended to be separated into three independent businesses.
Those businesses became Dow, DuPont, and Corteva. Dow focused on materials science, DuPont on specialty products, and Corteva on agriculture. The separations were completed in stages during 2019.
The arrangement is easy to confuse with a permanent combination under the DowDuPont name. DowDuPont was a temporary corporate structure rather than the final identity of the entire enterprise. DuPont and Dow also have long histories that predate this transaction by many decades.