I find that the standard class of a#ne models produces poor forecasts of future changes in Treasury yields. Better forecasts are generated by assuming that yields follow random walks. The failure of these models is driven by one of their key features: The compensation that investors receive for facing risk is a multiple of the variance of the risk. This means that risk compensation cannot vary independently of interest rate volatility. I also describe and empirically estimate a class of models that is broader than the standard a#ne class. These "essentially a#ne" models retain the tractability of the usual models, but allow the compensation for interest rate risk to vary independently of interest rate volatility. This additional flexibility proves useful in forming accurate forecasts of future yields. Address correspondence to the University of California, Haas School of Business, 545 Student Services Building #1900, Berkeley, CA 94720. Phone: 510-642-1435. Email address: du#ee@haas.b...

Understanding volatility in emerging capital markets is important for determining the cost of capital and for evaluating direct investment and asset allocation decisions. We provide an approach that allows the relative importance of world and local information to change through time in both the expected returns and conditional variance processes. Our time-series and cross-sectional models analyze the reasons that volatility is different across emerging markets, particularly with respect to the timing of capital market reforms. We find that capital market liberalizations often increase the correlation between local market returns and the world market but do not drive up local market volatility.

Editor: John Shawe-Taylor We study the problem of learning many related tasks simultaneously using kernel methods and regularization. The standard single-task kernel methods, such as support vector machines and regularization networks, are extended to the case of multi-task learning. Our analysis shows that the problem of estimating many task functions with regularization can be cast as a single task learning problem if a family of multi-task kernel functions we define is used. These kernels model relations among the tasks and are derived from a novel form of regularizers. Specific kernels that can be used for multi-task learning are provided and experimentally tested on two real data sets. In agreement with past empirical work on multi-task learning, the experiments show that learning multiple related tasks simultaneously using the proposed approach can significantly outperform standard single-task learning particularly when there are many related tasks but few data per task.

CAPRi Working Papers contain preliminary material and research results, and are circulated prior to a full peer review in order to stimulate discussion and critical comment. It is expected that most Working Papers will eventually be published in some other form, and that their content may also be revised. CAPRi WORKING PAPER NO. 17

The views expressed are those of the authors and do not necessarily reflect those of the Bank of England. We thank Angus Guyatt for outstanding research support. We thank Reza Bahar, Patricia Jackson and other Bank of England colleagues for valuable comments and Angus Guyatt and Steve Grice for research assistance. Copies of working papers may be obtained from Publications Group, Bank of England,

In this paper we show how to formulate and solve robust portfolio selection problems. The objective of these robust formulations is to systematically combat the sensitivity of the optimal portfolio to statistical and modeling errors in the estimates of the relevant market parameters. We introduce "uncertainty structures" for the market parameters and show that the robust portfolio selection problems corresponding to these uncertainty structures can be reformulated as second-order cone programs and, therefore, the computational effort required to solve them is comparable to that required for solving convex quadratic programs. Moreover, we show that these uncertainty structures correspond to confidence regions associated with the statistical procedures used to estimate the market parameters. We demonstrate a simple recipe for efficiently computing robust portfolios given raw market data and a desired level of confidence.

411 144 ecb d All rights reserved. Photocopying for educational and non-commercial purposes permitted provided that the source is acknowledged. ISSN 1607-1484Table of contents Abstract 5 1 Introduction: general aspects of the reference value for monetary growth in the context of the ECB’s monetary policy strategy 7 2 A first look at the data 10 2.1 The concept of M3 income velocity and its behaviour in the euro area 10 2.2 Data and aggregation issues 12

This paper provides a practical simulation-based Bayesian and non-Bayesian analysis of correlated binary data using the multivariate probit model. The posterior distribution is simulated by Markov chain Monte Carlo methods and maximum likelihood estimates are obtained by a Monte Carlo version of the EM algorithm. A practical approach for the computation of Bayes factors from the simulation output is also developed. The methods are applied to a dataset with a bivariate binary response, to a four-year longitudinal dataset from the Six Cities study of the health effects of air pollution and to a sevenvariate binary response dataset on the labour supply of married women from the Panel Survey of Income Dynamics.

This paper investigates whether management ownership structures and large non-management blockholders are related to firm value across a sample of 1433 firms from 18 emerging markets. When a management group’s control rights exceed its cash flow rights, I find that firm values are lower. I also find that large non-management control rights blockholdings are positively related to firm value. Both of these effects are significantly more pronounced in countries with low shareholder protection. One interpretation of these results is that external shareholder protection mechanisms play a role in restraining managerial agency costs and that large non-management blockholders can act as a partial substitute for missing institutional governance mechanisms.

We explore the effect of computerization on productivity and output growth using data from 527 large US firms over 1987-1994. We find that computerization makes a contribution to measured productivity and output growth in the short term (using one year differences) that is consistent with normal returns to computer investments. However, the productivity and output contributions associated with computerization are up to five times greater over long periods (using five to seven year differences). The results suggest that the observed contribution of computerization is accompanied by relatively large and time-consuming investments in complementary inputs, such as organizational capital, that may be omitted in conventional calculations of productivity. The large long-run contribution of computers and their associated complements that we uncover may partially explain the subsequent investment surge in computers in the late 1990s.