Mechanically Extracted Company Signals and their Impact on Stock and Credit Markets

I analyze company news from Reuters with the 'General Inquirer' and relate measures of positive sentiment, negative sentiment and disagreement to abnormal stock returns, stock and option trading volume, the volatility spread and the CDS spread. I test hypotheses derived from market microstructure models. Consistent with these models, sentiment and disagreement are strongly related to trading volume. Moreover, sentiment and disagreement might be used to predict stock returns, trading volume and volatility. Trading strategies based on positive and negative sentiment are profitable if the transaction costs are moderate, indicating that stock markets are not fully efficient.Content Analysis, Company News, Market Microstructure

Portfolio Choice for HARA Investors: When Does 1/γ (not) Work?

In the continuous time-Merton-model the instantaneous stock proportions are inversely proportional to the investorâs local relative risk aversion γ. This paper analyses the conditions under which a HARA-investor can use this 1/γ-rule to approximate her optimal portfolio in a finite time setting without material effects on the certainty equivalent of the portfolio payoff. The approximation is of high quality if approximate arbitrage opportunities do not exist and if the investorâs relative risk aversion is higher than that used for deriving the approximation portfolio. Otherwise, the approximation quality may be bad.HARA-utility, portfolio choice, certainty equivalent, approximated choice

Does Portfolio Optimization Pay?

All HARA-utility investors with the same exponent invest in a single risky fund and the risk-free asset. In a continuous time-model stock proportions are proportional to the inverse local relative risk aversion of the investor (1/γ-rule). This paper analyses the conditions under which the optimal buy and holdportfolio of a HARA-investor can be approximated by the optimal portfolio of an investor with some low level of constant relative risk aversion using the 1/γ-rule. It turns out that the approximation works very well in markets without approximate arbitrage opportunities. In markets with high equity premiums this approximation may be of low quality.HARA-utility, portfolio choice, certainty equivalent, approximated choice

eXplainable AI for Quantum Machine Learning

Parametrized Quantum Circuits (PQCs) enable a novel method for machine learning (ML). However, from a computational point of view they present a challenge to existing eXplainable AI (xAI) methods. On the one hand, measurements on quantum circuits introduce probabilistic errors which impact the convergence of these methods. On the other hand, the phase space of a quantum circuit expands exponentially with the number of qubits, complicating efforts to execute xAI methods in polynomial time. In this paper we will discuss the performance of established xAI methods, such as Baseline SHAP and Integrated Gradients. Using the internal mechanics of PQCs we study ways to speed up their computation

Legitimacy intermediation in the multilevel European polity and its collapse in the euro crisis

This essay re-examines the dual – republican and liberal – foundations of democratic legitimacy in the Western traditions of normative political theory. Considered in isolation, the European Union conforms to liberal standards but cannot satisfy republican criteria. Given these conflicting standards, debates on the alleged European democratic deficit have remained inconclusive. Moreover, they have failed to pay sufficient attention to the multilevel character of the European polity and to the normative potential of legitimacy intermediation in its two-step compliance and legitimating relationships. I argue, however, that the capacity of democratic member states to legitimate the exercise of European governing functions is being destroyed in the present euro crisis, and I briefly discuss the implications of this new constellation.In der westlichen Tradition der normativen politischen Theorie beruht demokratische Legitimität auf der doppelten Grundlage republikanischer und liberaler Prinzipien. Für sich betrachtet entspricht die Europäische Union zwar liberalen Kriterien, aber eben nicht den republikanischen Anforderungen. Angesichts so unterschiedlicher Kriterien konnte es auch im Streit über das angebliche europäische Demokratiedefizit keine Einigung geben. Überdies ignorierte diese Diskussion den Mehrebenen-Charakter der europäischen Politik und das normative Potenzial der Legitimationsvermittlung zwischen Union und Bürgern durch die demokratisch verfassten Mitgliedstaaten. Die gegenwärtige Eurokrise allerdings zerstört die Fähigkeit demokratischer Mitgliedstaaten, die Ausübung europäischer Herrschaftsfunktionen zu legitimieren. Der Aufsatz erörtert die Implikationen dieser neuen Konstellation.1 Introduction 2 Legitimacy discourses The republican discourse The liberal discourse Differences 3 Constitutional democracies – and the European Union? 4 Legitimacy intermediation in the multilevel European polity 5 The end of legitimacy intermediation in the euro crisis Monetary Union and the failure of output legitimacy Rescuing the euro through supranational intervention 6 Legitimate supranational government? Input-oriented European legitimacy? 7 Reducing the burden on European legitimacy Reference

Exotic Option Pricing in Stochastic Volatility Levy Models and with Fractional Brownian Motion

The paper Exotic Option Pricing in Stochastic Volatility Levy Models and with Fractional Brownian Motion aims on extending the restrictive Black-Scholes model by allowing volatility to evolve randomly. These models are used to price exotic derivatives and certificates. The first stochastic volatility model is the Heston model. In order to capture jumps in volatility and stock evolution, Levy processes and Ornstein-Uhlenbeck processes are under discussion. Using the convenient features of Levy processes, a stochastic volatility stock evolution model, where volatility is driven by a Levy process and volatility evolution and stock evolution are linked, is introduced.This model is named after Barndorff-Nielsen and Shephard (BNS for short). However, the BNS model does not include the long memory behavior of volatility. This justifies a discussion about the fractional Brownian motion, the most important stochastic process to model long memory. Finally, the different models are calibrated by fitting prices of observed European options and compared when bonus certificates and express certificates are valued

Mechanically Extracted Company Signals and their Impact on Stock and Credit Markets

I analyze company news from Reuters with the 'General Inquirer' and relate measures of positive sentiment, negative sentiment and disagreement to abnormal stock returns, stock and option trading volume, the volatility spread and the CDS spread. I test hypotheses derived from market microstructure models. Consistent with these models, sentiment and disagreement are strongly related to trading volume. Moreover, sentiment and disagreement might be used to predict stock returns, trading volume and volatility. Trading strategies based on positive and negative sentiment are profitable if the transaction costs are moderate, indicating that stock markets are not fully efficient

Zum Lehrerbild Eugen Finks

Der Aufsatz befasst sich mit dem Lehrerbild Eugen Finks

Lehrer- und Lehrerinnenbildung in Baden im 19. Jahrhundert

Der Aufsatz befasst sich mit den Anfängen der Lehrerbildung in der Gründungszeit des Großherzogtums Baden