When To Sell Shares Or A General Rule for Everything You Undertake

This quote from an American business tycoon ...

Fortunes have been made by those selling too early.

... is very similar to this quote from the Tao Te Ching

Better stop short than fill to the brim.
Oversharpen the blade, and the edge will soon blunt.

Retire when the work is done.
This is the way of heaven.