In the literature on optimal portfolio selection, closed-form solutions are rare, especially when the additional liquidity risk is taken into consideration. In this talk, a new closed-form solution for a revised Merton (1969) model, subject to a particular form of market illiquidity, is presented. Our success hinges on innovatively interpreting the so-called “wealth turnover” adopted by Guasoni & Weber (2019) under the framework of the Leland transaction cost model (1985). As a result, we have managed to preserve the tractability so that an exact closed-form solution can be found, which enables us to provide a better discussion on the impact of liquidity risk in portfolio optimization without making an assumption on the order of the liquidity parameter, at least mathematically. As a solution verification process, we have compared our results with those of the Merton (1969) and Guasoni & Weber (2019), respectively.