“…In the Miller and Orr's model, it is moreover highlighted that the cash balance follows a normal distribution, which may be a very ideal state. Since then, a few scholars, including Girgis (1968) [16], Eppen and Fama (1969) [12], Daellenbach (1971Daellenbach ( , 1974 [9] [10], Hausman and Sanchez-Bell (1975) [17], Milbourne (1983) [22], Vickson (1985) [29] and Smith (1989) [26], Baccarin (2002) [1] and Bensoussan, Chutani and Sethi(2009) [7], have tried to overcome the defects by using dynamic programming methods. See also Song, Ching, Siu and Yiu (2013) [27] for a recent discussion on the issue.…”