HEDGING AND PORTFOLIO OPTIMIZATION UNDER TRANSACTION COSTS: A MARTINGALE APPROACH12

We derive a formula for the minimal initial wealth needed to hedge an arbitrary contingent claim in a continuous-time model with proportional transaction costs; the expression obtained can be interpreted as the supremum of expected discounted values of the claim, over all (pairs of) probability measures under which the “wealth process” is a supermartingale. Next, we prove the existence of an optimal solution to the portfolio optimization problem of maximizing utility from terminal wealth in the same model, we also characterize this solution via a transformation to a hedging problem: the optimal portfolio is the one that hedges the inverse of marginal utility evaluated at the shadow state-price density solving the corresponding dual problem, if such exists. We can then use the optimal shadow state-price density for pricing contingent claims in this market. the mathematical tools are those of continuous-time martingales, convex analysis, functional analysis, and duality theory.     

The role of political tactics on the organizational context–career success relationship

Drawing from the norm of reciprocity, signal theory, and psychological contracts, we argue that the use of different types of political tactics, based on their social desirability, can be reciprocal behavioral reactions to contextual cues (i.e. perceptions of organizational support and politics) that can predict career success. Using a sample of 117 middle managers, our findings suggest that the use of sanctioned political tactics partially mediates the relationship between perceptions of organizational support and career success, while non-sanctioned political tactics suppress the relationship between perceptions of organizational politics and career success.     

Predicting European Union Recessions in the Euro Era: The Yield Curve as a Forecasting Tool of Economic Activity

Several studies have established the predictive power of the yield curve for the U.S. and various European countries. In this paper we use data from the European Union (EU15), from 1994:Q1 to 2008:Q3. We use the European Central Bank’s euro area yield spreads to predict European real GDP deviations from the long-run trend. We also augment the models tested with non monetary policy variables: the unemployment and a composite European stock price index. The methodology employed is a probit model of the inverse cumulative distribution function of the standard distribution using several formal forecasting and goodness of fit evaluation tests. The results show that the yield curve augmented with the composite stock index has significant forecasting power in terms of the EU15 real output.     

The numéraire portfolio in semimartingale financial models

We study the existence of the numéraire portfolio under predictable convex constraints in a general semimartingale model of a financial market. The numéraire portfolio generates a wealth process, with respect to which the relative wealth processes of all other portfolios are supermartingales. Necessary and sufficient conditions for the existence of the numéraire portfolio are obtained in terms of the triplet of predictable characteristics of the asset price process. This characterization is then used to obtain further necessary and sufficient conditions, in terms of a no-free-lunch-type notion. In particular, the full strength of the “No Free Lunch with Vanishing Risk” (NFLVR) condition is not needed, only the weaker “No Unbounded Profit with Bounded Risk” (NUPBR) condition that involves the boundedness in probability of the terminal values of wealth processes. We show that this notion is the minimal a-priori assumption required in order to proceed with utility optimization. The fact that it is expressed entirely in terms of predictable characteristics makes it easy to check, something that the stronger NFLVR condition lacks.      

Transition to IFRS and compliance with mandatory disclosure requirements: What is the signal?

The present study examines 153 Greek listed companies' compliance with all IFRS mandatory disclosure requirements during 2005 and complements and extends prior literature in the following way. The unique setting i.e., measuring compliance with IFRS mandatory disclosure requirements during the first year of IFRS implementation, allows for examination of the possibility that the changes in the 2004 shareholders' equity and net income, as a result of the adoption of IFRS, constitute explanatory factors for compliance. Thus, this study hypothesises that, in addition to the financial measures and other corporate characteristics that prior literature identifies as proxies for explaining compliance, a significant change in fundamental financial measures, because of the change in the accounting regime, may also explain compliance based on the premises of the relevant disclosure theories. The findings confirm these hypotheses. This study also makes a methodological contribution on measuring compliance with all IFRS mandatory disclosure requirements by using two different disclosure index methods and pointing out the different conclusions may be drawn as a result.     

Access to private equity and real firm activity: Evidence from PIPEs

We study how access to private equity financing affects real firm activities using a broad panel of publicly traded U.S. firms that raise external equity through private placements (PIPEs) between 1995 and 2008. The public firms relying on PIPEs are generally small, high-tech firms that cannot finance investment internally and likely face severe external financing constraints; PIPEs are by far the most important source of finance for these firms. We show that firms use PIPE inflows to maintain extremely high R&D investment ratios and to build substantial cash reserves. We also use GMM techniques that control for firm-specific effects and the endogeneity of the decision to raise private equity and find that PIPE funding has a substantial impact on corporate investment in cash reserves and R&D, and a smaller but significant impact on investment in non-cash working capital, but little impact on fixed investment or acquisitions. Our estimates indicate that R&D investment initially increases by $0.20–$0.25 for each dollar of private equity flowing into the firm, and that PIPE funds initially invested in cash ultimately go to R&D. These findings offer direct evidence that access to private equity finance has an important effect on the key input that drives innovation at the firm- and economy-wide levels.