June 22 (UPI) -- Fred Smith, the founder of shipping giant Federal Express, has died at the age of 80, the company announced Saturday. His cause of death was not revealed.

Smith, a U.S. Marine Corps veteran, founded the company in 1973 with just limited staff and 14 small Dassault Falcon 20 jets.

He led the company until stepping down in 2022, after growing it to a global behemoth with over 500,000 employees globally and a fleet of about 700 aircraft and hundreds of thousands of vehicles.

"It is with profound sadness and a heavy heart that I share that Frederick W. Smith, our founder and executive chairman, died earlier today," FedEx chief executive Raj Subramaniam said in a statement Saturday.

Beyond his leadership of the company, Smith has been heralded for his pioneering of the "hub-and-spoke" delivery system that revolutionized the field of logistics.