MEMPHIS, Tenn. — Theodore L. Weise, chief executive of Federal Express Corp., is planning to retire after 28 years with the world's leading overnight package delivery service.

Weise, 55, will be succeeded by David J. Bronczek, 45, a FedEx executive vice president with 23 years at the company. Weise denied his decision to step aside was prompted by a disappointing earnings report last month.

FDX, a $17 billion transportation company, is the parent of FedEx and several other subsidiaries, including RPS Inc., Viking Freight Inc., Roberts Express Inc. and FDX Logistics Inc.

"Ted has been at my side since the very beginning, consistently providing invaluable counsel and strong leadership in numerous capacities,'' said Frederick W. Smith, chief executive of FDX Corp. and founder of Federal Express.

Paul Schlesinger, a market analyst with Donaldson Lufkin & Jenrette of New York, said the change in FedEx management should not greatly alter the company's operations.

"It would appear to me that one old hand retires and another old hand takes his place,'' Schlesinger said. "There shouldn't be a material difference in direction.''

Weise went to work for FedEx in 1972 when the company still was being formed and was creating its system for time-specific, cross-country package deliveries. It now delivers some 3 million packages to 210 countries each business day.

Weise said he knew when he became CEO last year that he would hold the job for only a couple of years. The retirement has nothing to do with the company's disappointing first quarter, he said.

"Time has just come,'' Weise said.

FDX reported lower-than-expected earnings of 52 cents a share last month and warned of possible weakness in the current quarter, sending shares of FDX tumbling 12.4 percent. FDX later announced it would buy back 15 million shares of its stock to show confidence in the company.

After retirement, Weise will continue as a consultant on air operations for the company.

"Few men or women have enjoyed the privilege, as I have, of joining a struggling startup and helping it become one of the premier companies in the world,'' Weise said.

Bronczek is currently chief operating officer for FedEx.

"Dave Bronczek brings considerable international experience, strong business acumen and creative strategic thinking to the CEO position,'' Smith said.

The retirement plans were announced after the close of trading on the New York Stock Exchange, where FDX gained 43 3/4 cents to $42.75 a share.