Over-allotment options in IPOs on Germany's Neuer Markt - an empirical investigation
Stefanie A. Franzke
- Over-allotment arrangements are nowadays part of almost any initial public offering. The underwriting banks borrow stocks from the previous shareholders to issue more than the initially announced number of shares. This is combined with the option to cover this short position at the issue price. We present empirical evidence on the value of these arrangements to the underwriters of initial public offerings on the Neuer Markt. The over-allotment arrangement is regarded as a portfolio of a long call option and a short position in a forward contract on the stock, which is different from other approaches presented in the literature.
Given the economically substantial values for these option- like claims we try to identify benefits to previous shareholders or new investors when the company is using this instrument in the process of going public. Although we carefully control for potential endogeneity problems, we find virtually no evidence for a reduction in underpricing for firms using over-allotment arrangements. Furthermore, we do not find evidence for more pronounced price stabilization activities or better aftermarket performance for firms granting an over-allotment arrangement to the underwriting banks.
EFM Classification: 230, 410
Strongly interacting parton-hadron matter in- and out-off equilibrium
Elena L. Bratkovskaya
Volodymyr P. Konchakovski
- We study the equilibrium properties of strongly-interacting infinite parton-hadron matter, characterized by the transport coefficients such as shear and bulk viscosity and electric conductivity, and the non-equilibrium dynamics of heavy-ion collisions within the Parton-Hadron-String Dynamics (PHSD) transport approach, which incorporates explicit partonic degrees of freedom in terms of strongly interacting quasiparticles (quarks and gluons) in line with an equation of state from lattice QCD as well as the dynamical hadronization and hadronic collision dynamics in the final reaction phase. We discuss in particular the possible origin for the strong elliptic flow v2 of direct photons observed at RHIC energies.
A unified account of the properties of demonstrative pronouns in German
- The aim of this paper is to give a unified account of the way that German demonstrative pronouns (henceforth: D-pronouns) like der, die and das behave (a) in sentences where they receive a coreferential interpretation, and (b) in sentences where they receive a covarying interpretation because they are in some way dependent on a quantificational expression – either via direct binding or indirectly, because the value they receive varies with the value that is assigned to the variable bound by an indefinite determiner.
If vs. when, wenn vs. als: microvariation in the semantics of conditional and temporal complementizers in English and German
- In this paper, I compare the functions that the English complementizers if and when, on the one hand, and German wenn and als, on the other, have in episodic as well as in generic and adverbially quantified sentences. My claim is that all these complementizers take situation predicates as arguments, but differ with respect to the conditions they impose on these situation predicates.
Connexin 37 and Connexin 43 genotypes in correlation to cytokines in induced sputum and blood in cystic fibrosis (CF)
- Meeting abstract: Abstracts of the 50th Workshop for Pediatric Research
We have provided evidence in former studies that cytokines (IL-8, TNF alpha, LBP, TGFß) measured in blood correlate negatively with lung function in deltaF508 homozygous patients...
Avoiding the rating bounce: why rating agencies are slow to react to new information
- Rating agencies state that they take a rating action only when it is unlikely to be reversed shortly afterwards. Based on a formal representation of the rating process, I show that such a policy provides a good explanation for the puzzling empirical evidence: Rating changes occur relatively seldom, exhibit serial dependence, and lag changes in the issuers’ default risk. In terms of informational losses, avoiding rating reversals can be more harmful than monitoring credit quality only twice per year.
Evaluating credit risk models : a critique and a proposal
- Evaluating the quality of credit portfolio risk models is an important issue for both banks and regulators. Lopez and Saidenberg (2000) suggest cross-sectional resampling techniques in order to make efficient use of available data. We show that their proposal disregards cross-sectional dependence in resampled portfolios, which renders standard statistical inference invalid. We proceed by suggesting the Berkowitz (1999) procedure, which relies on standard likelihood ratio tests performed on transformed default data. We simulate the power of this approach in various settings including one in which the test is extended to incorporate cross-sectional information. To compare the predictive ability of alternative models, we propose to use either Bonferroni bounds or the likelihood-ratio of the two models. Monte Carlo simulations show that a default history of ten years can be sufficient to resolve uncertainties currently present in credit risk modeling.
Modeling the effects of neuronal morphology on dendritic chloride diffusion and GABAergic inhibition
- Poster presentation at the Twenty Third Annual Computational Neuroscience Meeting: CNS*2014 Québec City, Canada. 26-31 July 2014.
Gamma-aminobutyric acid receptors (GABAARs) are ligand-gated chloride (Cl−) channels which mediate the majority of inhibitory neurotransmission in the CNS. Spatiotemporal changes of intracellular Cl− concentration alter the concentration gradient for Cl− across the neuronal membrane and thus affect the current flow through GABAARs and the efficacy of GABAergic inhibition. However, the impact of complex neuronal morphology on Cl− diffusion and the redistribution of intracellular Cl− is not well understood. Recently, computational models for Cl− diffusion and GABAAR-mediated inhibition in realistic neuronal morphologies became available [1-3]. Here we have used computational models of morphologically complex dendrites to test the effects of spines on Cl− diffusion. In all dendritic morphologies tested, spines slowed down longitudinal Cl− diffusion along dendrites and decreased the amount and spatial spread of synaptically evoked Cl− changes. Spine densities of 2-10 spines/µm decreased the longitudinal diffusion coefficient of Cl− to 80-30% of its value in smooth dendrites, respectively. These results suggest that spines are able to limit short-term ionic plasticity  at dendritic GABAergic synapses.
The emergence of cohorts of co-active neurons in random recurrent networks provides a mechanism for orientation and direction selectivity
- Poster presentation at The Twenty Third Annual Computational Neuroscience Meeting: CNS*2014 Québec City, Canada. 26-31 July 2014: We study random strongly heterogeneous recurrent networks of firing rate neurons, introducing the notion of cohorts: groups of co-active neurons, who compete for firing with one another and whose presence depends sensitively on the structure of the input. The identities of neurons recruited to and dropped from an active cohort changes smoothly with varying input features. We search for network parameter regimes in which the activation of cohorts is robust yet easily switchable by the external input and which exhibit large repertoires of different cohorts. We apply these networks to model the emergence of orientation and direction selectivity in visual cortex. We feed these random networks with a set of harmonic inputs that vary across neurons only in their temporal phase, mimicking the feedforward drive due to a moving grating stimulus. The relationship between the phases that carries the information about the orientation of the stimulus determines which cohort of neurons is activated. As a result the individual neurons acquire non-monotonic orientation tuning curves which are characterized by high orientation and direction selectivity. This mechanism of emergence for direction selectivity differs from the classical motion detector scheme, which is based on the nonlinear summation of the time-shifted inputs. In our model these two mechanisms coexist in the same network, but can be distinguished by their different frequency and contrast dependences. In general, the mechanism we are studying here converts temporal phase sequence into population activity and could therefore be used to extract and represent also various other relevant stimulus features.
Topographic embedding of MOR18-2 in the mouse olfactory bulb
- Poster presentation at 1st International Workshop on Odor Spaces.
Mice are exceptional in their ability to capture their chemical environment, mapping the olfactory world into a basic sensory representation with over one thousand different types of chemical sensors, that is, olfactory sensory neurons (OSNs). OSNs of each type converge in the olfactory bulb onto exclusive distinct physiological areas called glomeruli. The glomeruli constitute the first relay station of olfactory stimulus representation in the mouse brain. Thus, the stimulus induced glomerular input pattern spatially embodies an important part of the sensory representation in the olfactory bulb. Still, topographic organization principles (chemotopy, tunotopy) are under debate. One reason might be that investigation are, due to experimental limitations, only performed on stimuli sets in the size of one hundred odors. But this represents only a tiny snapshot of the vast amount of molecules in the olfactory world and topographic relationships might be disguised in the incomplete representation of molecular receptive ranges (MRR). Therefore we investigated the problem with the MOR18-2 glomerulus as point of reference: First we determined it's MRR. Then, based on a measurement set covering this MRR, we elucidated the topographic embedding. It shows that MOR18-2 is embedded in a hierarchy of patchy tunotopic domains.