However, as highlighted in Lemmon et al. (2008) traditional determinants of capital structure do not fully
account for the variations in leverage ratios. In this regard, Morellec (2010) casts doubt on the usefulness of the existing corporate financing decision model that has focused exclusively on demand side factors. At the same time, some recent studies provide evidence suggesting that the supply of capital is not frictionless (see for example, Sufi, 2009; Lemmon & Roberts, 2010; Choi et al., 2010). Hence, if the supply of capital is uncertain then firm financing and investment decisions will depend on both demand and supply factors. We therefore, address this problem by modelling the firm financing and investment decisions as a function of both demand and supply side frictions as follows: