Supplies Ken Chenault's start date. His tenure itself builds fine from the 2018-01-30 8-K (resigned, succeeded by Squeri), but that filing gives no start date, so without this he renders as "? -> 2018-02-01". The 2007-03-15 start came from a baseline extraction of the 2007 DEF 14A that produced the weak name "Mr. Chenault"; a rename_tenure override used to fix that name, but it silently did nothing whenever the baseline tenure was not built. Understates his real 2001 start; end 2018-02-01 is Squeri's confirmed start.
Ken Chenault stepped down as CEO of American Express Company, with Stephen Squeri succeeding him effective February 1, 2018.