Properties of Optimal Smooth Functions in Additive Models for Hedging Multivariate Derivatives

In this paper, we consider an optimal hedging problem for multivariate derivative based on the additive sum of smooth functions on individual assets that minimize the mean square error (or the variance with zero expected value) from the derivative payoff. By applying the necessary and sufficient condition with suitable discretization, we derive a set of linear equations to construct optimal smooth functions, where we show that the computations involving conditional expectations for the multivariate derivatives may be reduced to those of unconditional expectations, and thus, the total procedure can be executed efficiently. We investigate the theoretical properties for the optimal smooth functions and clarify the following three facts: (i) the value of each individual option takes an optimal trajectory to minimize the mean square hedging error under the risk neutral probability measure, (ii) optimal smooth functions for the put option may be constructed using those for the call option (and vice versa), and (iii) delta in the replicating portfolio may be computed efficiently. Numerical experiments are included to show the effectiveness of our proposed methodology.     

Empirical analysis of factors promoting the Japanese 3G mobile phone

This paper aims to specify factors promoting the 3G mobile in Japan. The factors are represented by value-added services such as FeliCa, which enables e-payment, data roaming services, and full music downloads. Panel data from the three main carriers, which occupy over 90% of the Japanese mobile market, is utilized. In order to control network effects as well as the endogeneity of variables, the Arellano–Bond dynamic panel estimation is adopted. As a result, the launch of the iPhone 3G, FeliCa, data roaming, full music downloads, and the flat rate are revealed to have affected the diffusion of the 3G mobile in Japan. The results, reflecting the importance of value-added services, can be applied not only to the next generation mobile development, but also to the promotion of 3G networks in other countries.     

Explaining Foreign Holdings of Asia's Debt Securities: The Feldstein–Horioka Paradox Revisited*

In this paper, we find that home bias is still present in all economies and regions, especially in the case of short‐term debt securities, but that there are substantial variations among economies and regions in the strength of home bias, with the eurozone economies, the USA and developing Asia showing relatively weak home bias and advanced Asia, especially Japan, showing relatively strong home bias. We then examine trends over time in foreign holdings of debt securities and find that capital has been flowing from the USA and the eurozone economies to both advanced Asia (especially Japan) and developing Asia, and that foreign holdings of debt securities have been increasing in advanced as well as developing Asia but for different reasons. The main reason in the case of advanced Asia (especially Japan) appears to be higher risk‐adjusted returns, whereas the main reason in the case of developing Asia appears to be the growth of debt securities markets combined with relatively weak home bias and (in the case of short‐term securities) lower exchange rate volatility. Finally, we find that since the global financial crisis, foreign holdings of debt securities have declined (i.e. that home bias has strengthened) in all economies and regions except developing Asia, where they have increased (except for a temporary decline in 2008) but where their share is still much lower than the optimal share warranted by the capital asset pricing market model.     

WHY DO CHILDREN TAKE CARE OF THEIR ELDERLY PARENTS? ARE THE JAPANESE ANY DIFFERENT?

We conduct a theoretical and empirical analysis of why children live with (or near) their parents and provide care and assistance to them using microdata from a Japanese household survey, the Osaka University Preference Parameter Study. We find that the Japanese are more likely to live with (or near) their elderly parents and/or to provide care and attention to them if they expect to receive a bequest from them, which constitutes strong support for the strategic bequest motive, but that their caregiving behavior is also heavily influenced by the strength of their altruism toward their parents and social norms.     

Do the Retired Elderly in Europe Decumulate Their Wealth? The Importance of Bequest Motives,Precautionary Saving,Public Pensions,and Homeownership

We use microdata on a large number of European countries from the Survey of Health, Ageing and Retirement in Europe (SHARE) to examine the wealth accumulation (saving) behavior of the retired elderly in Europe. We find that less than half of the retired elderly in Europe are decumulating their wealth and that the average wealth accumulation rate of the retired elderly in Europe is positive though relatively moderate (6.6 percent over a 3-year period). These findings suggest that the Wealth Decumulation Puzzle (the tendency of the retired elderly to not decumulate their wealth or to decumulate their wealth more slowly than expected) applies in the case of Europe. Moreover, our regression results suggest that bequest motives, generous public pension systems, and the reluctance of retired elderly homeowners to sell or borrow against their owner-occupied housing are the primary explanations for the existence of the Wealth Decumulation Puzzle in Europe.     

Model Predictive Control for Optimal Pairs Trading Portfolio with Gross Exposure and Transaction Cost Constraints

Model predictive control (MPC) is a flexible yet tractable technique in control engineering that recently has gained much attention in the area of finance, particularly for its application to portfolio optimization. In this paper, we extend the MPC with linear feedback setting in Yamada and Primbs (in: Proceedings of the IEEE conference on decision and control, pp 5705–5710, 2012) by incorporating the following two important and practical issues: The first issue is gross exposure (GE), which is the total value of long and short positions invested in risky assets (or stocks) as a proportion of the wealth possessed by a hedge fund. This quantity measures the leverage of a hedge fund, and the fund manager may limit the amount of leverage by imposing an upper bound, i.e., a GE constraint. The second issue is related to transaction costs, where the MPC algorithm may require frequent trades of many stocks leading to large transaction costs in practice. Here we assume that the transaction cost is proportional to the change in the amount of money (i.e., the change of absolute values of long or short positions) invested in each stock. We formulate the MPC strategy based on a conditional mean-variance problem which we show reduces to a convex quadratic problem, even with gross exposure and proportional transaction cost constraints. Based on numerical experiments using Japanese stock data, we demonstrate that the incorporation of the transaction cost constraint improves the empirical performance of the wealth in terms of Sharpe ratio, which may be improved further by adding the GE constraint.     

Two‐Aggregate Games: Demonstration Using a Production–Appropriation Model

We expand the scope of the two‐aggregate method by applying it to a situation in which many heterogeneous players are free to contribute to both aggregates. Such situations naturally arise in various resource allocation problems. Hence, our method is useful in many applications. A production–appropriation model is employed to illustrate how the problem of establishing the Nash equilibrium can be reduced from solving n>2 best‐response functions in n unknowns to solving two consistency conditions in two unknowns. We then conduct a comparative static exercise that the conventional approach could not handle easily, if at all, to demonstrate the power of our method.     

The determinants and long-term projections of saving rates in Developing Asia

In this paper, we present data on trends over time in domestic saving rates in twelve economies in Developing Asia during the 1966–2007 period and analyze the determinants of these trends. We find that domestic saving rates in Developing Asia have, in general, been high and rising but that there have been substantial differences from economy to economy, that the main determinants of these trends appear to have been the age structure of the population (especially the aged dependency ratio), income levels, and the level of financial sector development, and that the impacts of income levels and the level of financial sector development have been nonlinear (convex and concave, respectively). We then project future trends in domestic saving rates in Developing Asia for the 2011–2030 period based on our estimation results and find that the domestic saving rate in Developing Asia as a whole will remain roughly constant during the next two decades despite rapid population aging in some economies in Developing Asia because population aging will occur much later in other economies and because the negative impact of population aging on the domestic saving rate will be largely offset by the positive impact of higher income levels.