Even when a stock I own has fallen precipitously, my ownership of the underlying company doesn't need to change. The market’s assessment of the company’s prospects changed but it can change just as dramatically the next day, or week or year.

It is hard enough to predict a company’s future prospects; it is hopeless for me as a retail investor, to try to predict how the market will assess the company in the near-future. I’ve learned to not bother trying.