When the asset market is incomplete, equilibrium allocations are not invariant to changes in the financial policies of firms: in the presence of secondary assets, such as options, whose payoffs depend nonlinearly on the price of equity, the range of attainable reallocations of revenue varies as a firm alters its position in the asset market. Corporate financial policy is thus relevant. When assets are nominal, monetary policy implemented through open market operations is also effective.
Detemple, J., Gottardi, P., & Polemarchakis, HM. (1995). The Relevance of Financial Policy. European Economic Review, 39(6), 1133-1154. https://doi.org/10.1016/0014-2921(94)00106-A (Original work published 1995)