This paper demonstrates that the level of autocorrelation in the market index returns of the Brussels Stock Exchange depends on the number of securities which make up the index as well as their price adjustment delay. It also shows that the value of the systematic risk depends on both the choice of an index and the length of the differencing interval used to calculate the returns. Furthermore it highlights the fact that autocorrelation coefficients and systematic risk coefficients also exhibit seasonal fluctuations.

The observed fact that firms invest even if capacities are not fully employed does not fit into most standard formalizations of optimal firm behaviour. In this paper, the q investment approach is adapted to an imperfect competitive economy where the representative firm is assumed to face demand uncertainty. Nominal rigidities and short-run factor complementarity are imposed as sufficient conditions to allow for the coexistence of investment and excess capacity. Since capacities are underemployed, marginal q is shown to diverge from average q. Finally, excess capacity subsists at steady state being more than a short-run phenomena.

Cette contribution a pour objet d’élaborer un modèle mettant en relation la variable q de Tobin corrigée pour la fiscalité avec le taux d’accumulation du capital dans le but d’évaluer l’effet de l’incitation fiscale sur l’investissement privé en Suisse. L’estimation du modèle sur la base des données portant sur la période d’après-guerre révèle le rô1e mineur joué par la fiscalité dans le processus d’investissement en Suisse. Par ailleurs, d’après les rèsultats de la simulation du modèle sous divers scénarios de réforme fiscale, les instruments fiscaux employés en Suisse, à savoir la manipulation du taux d’imposition des bénéfices et des taux de dépréciation fiscalement admis paraissent relativement inefficaces. Par contre, un instrument direct comme le crédit d’impôt, jamais encore utilisé, témoigne d’une assez grande efficacité.

Cet article présente une estimation économétrique de 1961 à 1986 des probabilités que l’industrie française se soit trouvée respectivement en régime keynesien et en régime de profit. Un modèle de demande de capital en déséquilibre a été testé par les moindres carrés non linéaires, en supposant que les probabilités d’apparition des régimes suivaient une loi logistique. La contrainte keynesienne de demande est mesurée par les anticipations de demande tirées des enquêtes de conjoncture. De 1975 à 1982, l’investissement industriel aurait été limité principalement par l’insuffisance des profits. De 1983 à 1986, en moyenne, l’équilibre des contraintes de demande et de profit serait rétabli.

The focus of this article is the comparison of the relative influence of different determinants of investment (demand, the relative price of capital and labour, and profit) for five large European countries and the United States. The investment equations are derived from production functions, either putty-putty or putty-clay, in the context of a disequilibrium model. The comparison of annual and quarterly estimates (after aggregation in a equivalent annual model) improves the evaluation of the precision of the parameter estimates.

In all these countries, in accordance with the accelerator effect, demand is the dominant influence in the short term, fading away in the medium term. In contrast, profit is not a predominant influence except in the medium term. Its role thus seems to result from the effect of expectations on investment profitability rather than from short run self-financing constraints. With respect to factor substitution, the analysis confirms that this is only weakly linked to changes in the relative price of capital and labour.

In this paper we estimate an investment demand function derived from a standard adjustment costs framework. We also suppose that the speed of adjustment depends on the capacity of the firms to finance their investment projects with their own generated resources. The model is estimated for a sample of 140 firms and 4 years (1978-81).

Using the consistent within-groups estimator, the main results are : 1) expected output appears as the most important determinant of investment ; 2) profits affect investment in the long-run only through the adjustment cost channel ; 3) relative factor prices are not significant, reflecting a very slow substitution between labour and capital in spanish industry.

This paper is devoted to the analysis of the investment behavior of the firm in the context of a quantity rationing (or disequilibrium) model with monopolistic competition on the goods market. Investment is entirely profit-driven as in the q-theory of investment. The profit variable is however decomposed into three components: the markup rate on variable costs, the capacity utilization rate and the discrepancy between the optimal and the actual-labor ratios. The model has the same long run implication as an accelerator model if and only if the optimal capacity utilization rate is constant in the long run. The suggested quantity rationing model is estimated on French data, over the period 1956-1985. The emphasis is on the investment equation. The parameter estimates are shown to have remained fairly stable over time.