Opportunity cost and opportunity gain

Opportunity cost and opportunity gain – A phenomenon arising out of comparison between returns on alternative investment opportunities available to an investor.

For example an investor gets return of 13% p.a. in bank deposits, while he can get 18% in shares, the opportunity cost of investing in bank deposits vis-à-vis the investment in shares is 18% - 13% = 5%. As against this, the investment in shares fetches an opportunity gain of 5% p.a. Thus opportunity cost and gain are relative terms and absolutely dynamic, as the returns even in the case of same investment vary from time to time.
Opportunity cost or gain is a dynamic concept and not static one. Further it is a product of time and holds good only for a short period. It is always determined for a pair of alternative investment opportunities.