DUPONT, the third-biggest United States chemical company, says Executive Vice President Ellen Kullman is to take over as chief executive officer on January 1, replacing Charles Holliday Jr.

Holliday, 60, will continue as chairman until Kullman takes over that position as well, Wilmington, Delaware-based DuPont said yesterday in a statement.

Kullman, 52, joined the company in 1988 and has been an executive vice president since 2006. She will be named president on October 1, Bloomberg News said.

DuPont's shares have risen 10 percent in five years, trailing the 18 percent gain in the Standard & Poor's 500 Index. Profit more than tripled from 2003 to last year, when net income was US$2.99 billion.

"Now is the right time to make a seamless transition to new leadership," Holliday said.

Holliday, who has been with DuPont for 38 years and has been CEO since February 1998, said Kullman's transition to chairman will be "relatively brief," without giving a specific date.

DuPont shares fell US$2.65, or 5.5 percent, to US$45.39 in New York Stock Exchange composite trading. The shares have gained 2.9 percent this year.