In this paper we consider general consumption, portfolio and retirement optimization
problems in which a working investor has liquidity constraints. Closed-form solutions are
obtained for the utility maximization problems and numerical procedures are given for
the general utility function under the liquidity constraints. The numerical results for a
special utility function, for example, the constant relative risk aversion(CRRA) utility
function, suggest that the restriction to borrow future income makes the investor retire
in a lower critical wealth level than in the case of no liquidity constraints.

