Institutional investors and stock market efficiency: The case of the January anomaly

In this paper, we investigate the effect of institutional investors on the January stock market anomaly. The Polish and Hungarian pension system reforms and the associated increase in investment activities of pension funds are used as a unique institutional characteristic to provide evidence on the impact of individual versus institutional investors on the January effect. We find robust empirical results that the increase in institutional ownership has reduced the magnitude of an anomalous January effect induced by individual investors’ trading behavior.Institutional traders; Individual investors; January effect; Polish and Hungarian pension fund investors

Steht der deutsche Aktienmarkt unter politischem Einfluss?

Die vorliegende Arbeit untersucht den Zusammenhang zwischen politischen Zyklen und Aktienrenditen in Deutschland. Während sich die bis dato verfügbaren Studien über politisch bedingte Aktienmarktanomalien auf die USA konzentrieren, analysieren wir deren Existenz in deutschen Aktienrenditen. Im Gegensatz zu den empirischen Ergebnissen für die USA zeigen sich für Deutschland keine Anomalienmuster in Akteinrenditen, die sich auf rechte oder linke Bundesregierungen zurückführen lassen. In Übereinstimmungen mit den für die USA verfügbaren Evidenzen ist auch für Deutschland von einem politisch beeinflussten Wahlzyklus in Akteinrenditen auszugehen. Zudem widerlegen unsere empirischen Ergebnisse für Deutschland die Hypothese, dass sich der US-amerikanische Wahlzyklus auch auf den deutschen Aktienmarkt überträgt. --Kapitalmarkteffizienz,Kapitalmarktanomalien,politische Aktienmarktzyklen

Institutional investors and stock market efficiency: The case of the January anomaly

In this paper, we investigate the effect of institutional investors on the January stock market anomaly. The Polish and Hungarian pension system reforms and the associated increase in investment activities of pension funds are used as a unique institutional characteristic to provide evidence on the impact of individual versus institutional investors on the January effect. We find robust empirical results that the increase in institutional ownership has reduced the magnitude of an anomalous January effect induced by individual investors' trading behavior

Institutional investors and stock market efficiency: The case of the January anomaly

In this paper, we investigate the effect of institutional investors on the January stock market anomaly. The Polish and Hungarian pension system reforms and the associated increase in investment activities of pension funds are used as a unique institutional characteristic to provide evidence on the impact of individual versus institutional investors on the January effect. We find robust empirical results that the increase in institutional ownership has reduced the magnitude of an anomalous January effect induced by individual investors’ trading behavior

Steht der deutsche Aktienmarkt unter politischem Einfluss?

Die vorliegende Arbeit untersucht den Zusammenhang zwischen politischen Zyklen und Aktienrenditen in Deutschland. Während sich die bis dato verfügbaren Studien über politisch bedingte Aktienmarktanomalien auf die USA konzentrieren, analysieren wir deren Existenz in deutschen Aktienrenditen. Im Gegensatz zu den empirischen Ergebnissen für die USA zeigen sich für Deutschland keine Anomalienmuster in Akteinrenditen, die sich auf rechte oder linke Bundesregierungen zurückführen lassen. In Übereinstimmungen mit den für die USA verfügbaren Evidenzen ist auch für Deutschland von einem politisch beeinflussten Wahlzyklus in Akteinrenditen auszugehen. Zudem widerlegen unsere empirischen Ergebnisse für Deutschland die Hypothese, dass sich der US-amerikanische Wahlzyklus auch auf den deutschen Aktienmarkt überträgt

Data from: Less is more: selective advantages can explain the prevalent loss of biosynthetic genes in bacteria

Bacteria that have adapted to nutrient-rich, stable environments are typically characterized by reduced genomes. The loss of biosynthetic genes frequently renders these lineages auxotroph, hinging their survival on an environmental uptake of certain metabolites. The evolutionary forces that drive this genome degradation, however, remain elusive. Our analysis of 949 metabolic networks revealed auxotrophies are likely highly prevalent in both symbiotic and free-living bacteria. To unravel whether selective advantages can account for the rampant loss of anabolic genes, we systematically determined the fitness consequences that result from deleting conditionally essential biosynthetic genes from the genomes of Escherichia coli and Acinetobacter baylyi in the presence of the focal nutrient. Pairwise competition experiments with each of 20 mutants auxotrophic for different amino acids, vitamins, and nucleobases against the prototrophic wild type unveiled a pronounced, concentration-dependent growth advantage of around 13% for virtually all mutants tested. Individually deleting different genes from the same biosynthesis pathway entailed gene-specific fitness consequences and loss of the same biosynthetic genes from the genomes of E. coli and A. baylyi differentially affected the fitness of the resulting auxotrophic mutants. Taken together, our findings suggest adaptive benefits could drive the loss of conditionally essential biosynthetic genes

Pervasive Selection for Cooperative Cross-Feeding in Bacterial Communities

Bacterial communities are taxonomically highly diverse, yet the mechanisms that maintain this diversity remain poorly understood. We hypothesized that an obligate and mutual exchange of metabolites, as is very common among bacterial cells, could stabilize different genotypes within microbial communities. To test this, we developed a cellular automaton to model interactions among six empirically characterized genotypes that differ in their ability and propensity to produce amino acids. By systematically varying intrinsic (i.e. benefit-to-cost ratio) and extrinsic parameters (i.e. metabolite diffusion level, environmental amino acid availability), we show that obligate cross-feeding of essential metabolites is selected for under a broad range of conditions. In spatially structured environments, positive assortment among cross-feeders resulted in the formation of cooperative clusters, which limited exploitation by non-producing auxotrophs, yet allowed them to persist at the clusters’ periphery. Strikingly, cross-feeding helped to maintain genotypic diversity within populations, while amino acid supplementation to the environment decoupled obligate interactions and favored auxotrophic cells that saved amino acid production costs over metabolically autonomous prototrophs. Together, our results suggest that spatially structured environments and limited nutrient availabilities should facilitate the evolution of metabolic interactions, which can help to maintain genotypic diversity within natural microbial populations.ISSN:1553-734XISSN:1553-735

Selective_benefits_auxotrophy_raw_data

The file contains data containing fitness (Mathusian parameters) and productivity (Max optical density at 600nm) of different auxotrophic mutants of Escherichia coli and Acinetobacter baylyi when growing in minimal medium supplemented with either amino acids, vitamins or nucleobases

Activation of Hypoxia-Inducible Factor Signaling Modulates the RNA Protein Interactome in Caenorhabditis elegans

The cellular response to hypoxia is crucial to organismal survival, and hypoxia-inducible factors (HIF) are the key mediators of this response. HIF-signaling is central to many human diseases and mediates longevity in the nematode. Despite the rapidly increasing knowledge on RNA-binding proteins (RBPs), little is known about their contribution to hypoxia-induced cellular adaptation. We used RNA interactome capture (RIC) in wild-type Caenorhabditis elegans and vhl-1 loss-of-function mutants to fill this gap. This approach identifies more than 1,300 nematode RBPs, 270 of which can be considered novel RBPs. Interestingly, loss of vhl-1 modulates the RBPome. This difference is not primarily explained by protein abundance suggesting differential RNA-binding. Taken together, our study provides a global view on the nematode RBPome and proteome as well as their modulation by HIF-signaling. The resulting RBP atlas is also provided as an interactive online data mining tool (http://shiny.cecad.uni-koeln.de:3838/celegans_rbpome)