CEO since 1990: Dan Amos
To promote a new health insurance product in Japan, AFLAC dressed up its duck as the manekineko, a mythical Japanese cat thought to bring good luck.
That helped sales rise 10%, to $18.3 billion, and earnings to rise 19%, to $1.5 billion. But it didn't stop AFLAC stock from sliding to $10.83 in March 2009 from its 2008 high of $68.81. (It's now around $56).
After that downturn, CEO Dan Amos decided to skip his annual stress test.
NEXT: 21. Apple