Home Depot's

(HD) - Get Report

co-founder and co-chairman, Arthur Blank, said Wednesday that he will retire after his term ends in May.

Bernie Marcus, also a co-founder and co-chairman, is expected to continue as the chairman of the board.

Blank said his decision was primarily based on the positive transition of Robert Nardelli into the chief executive role. Blank said he will continue to be available to the Nardelli, the board and the senior management team whenever needed. Blank was named chief executive in May 1997.

Nardelli left

General Electric

(GE) - Get Report

in December

to become CEO of home improvement products retailer Home Depot. Blank plans to focus his time on expanding the work of the Arthur M. Blank Family Foundation, while increasing his involvement in the business and nonprofit communities in Atlanta, where Home Depot is based.

Shares of Home Depot fell $2.07, or 4.7%, to $42.02 in recent

New York Stock Exchange

trading.