Young investors are at the peak of their human capital which is defined as the present value of all expected future income derived from their labor. Human capital is illiquid because at the beginning of their careers young investors cannot cash in their future earnings or pension accounts which they have not earned yet. A person’s human capital is highest when they have finished their training or education for their career and it steadily trends downward from there. Social Security and pension payments are derived from labor thus they are considered part of human capital so at retirement if a person receives social security or a pension from a company their human capital at retirement would not be zero. | 
