The leadership transition Costco announced this week was hardly unexpected considering outgoing CEO Jim Sinegal is 75, but it does underscore what arguably has been one of the greatest distinctions between Costco and Sam's clubs for the past 25 years, namely the stability of senior leadership. Sinegal founded Costco along with company chairman Jeffrey Brotman in 1983 and the pair have been running the show ever since. Conversely, Sam's Club has been led by approximately 10 different senior executive during approximately the same time although they didn't always carry the title of CEO. Beginning with Ron Loveless, leadership transitioned for brief periods of time to Nick White, Al Johnson, Dean Sanders, Joe Hardin, Mark Hansen, Tom Grimm, Kevin Turner and Doug McMillon. Current president and CEO Brian Cornell joined Sam's Club about two and a half years ago after Doug McMillon was named president and CEO of Walmart's international division.