ABSTRACT
The stability of the zero state of the stock price or the capital is useful from a financial point of view. If we know the conditions under which the stock price S(t) (or the capital) tends to zero (S(t)→ 0), when t→+∞, (these are stability conditions), then we shall also know the conditions under which the stock price (or the capital) tends to infinity (S(t)→ +∞), when t → +∞ (these are instability conditions). This is a desirable situation for an investor.
