Closed book opened

Thanks to Tetrapilotomos since yesterday the mechanisms of bourse respectively stock exchange to me no longer are a riddle wrapped up in enigmata:

You buy one hen, one cock,
and sooner or later you have 100 hens.

Then there comes a torrential flood,
and all your hens get drowned.

When in this moment you sigh:
'Ah, if only I had bought ducks', - that's stock exchange.