The great metropolis, by the author of 'Random recollections of the Lords and Commons'

David Ricardo's three golden rules

I may observe that he amassed his immense fortune by a scrupulous attention to what he called his own three golden rules, the observance of which he used to press on his private friends. Theses were, "Never refuse an option when you can get it", "Cut short your losses", "Let your profits run on".

Never refuse an option when you can get it

Cut short your losses

He meant that when a member had made a purchase of stock, and prices were falling, he ought to resell immediately.

Let your profits run on

He meant that when a member possessed stock, and prices were rising, he ought not to sell until prices had reached their highest, and were beginning again to fall.