Langfristige Stabilität und Wachstum in einem IS/LM-Modell mit Finanzierungsfunktion der Investitionen und Bilanzrestriktion der Unternehmen

Abstract

Long-term Stability and Growth in an IS/LM Model with Financing Function of the Investments and Balance-Sheet Restriction of Firms

This model describes for a closed economy, excluding the public sector, the stockflow dynamics resulting from investment financing via credit and the issue of shares. The development of the national product and yields on shares in successive periodic equilibria is examined. Christ’s concept of long-term equilibrium as a stationary state with stock changes from zero is taken as a basis and its stability is analysed. The development of the system terminates in this stationary state where the stabilizing effect of capital stock growth due to investments overcompensates for the destabilizing effects of money supply growth likewise induced by investments. And nothing is changed even when additional disequilibria are permitted on the goods market. The stationary state, however, is associated with a positive national product only in consequence of the asset-forming effect in the consumption function. This appears to be problematical. Long-term equilibrium is therefore defined on the other hand as evolutionary. By the introduction of technical progress that increase the marginal productivity of capital and the accelerator, the original model is expanded to a growth model. The equilibrium condition of neoclassical growth theory (K = constant) implies that all flow and stock magnitudes grow at the constant rate of technical progress; the yields on shares and the financing costs do not change in the growth process. The “monetary side” of the economy does not play a role for the – demonstrated – stable growth equilibrium, in contrast to the determination of the period equilibrium