The wealth effects of portfolio rebalancing in emerging equity markets

This paper analyzes the wealth effects of alternative portfolio rebalancing strategies for equity investments in nine emerging markets for the period from 1976 to 1998. The choice of rebalancing intervals has a large effect on wealth accumulation and the geometric mean return. The difference between no rebalancing and semi-annual rebalancing is 5.87 percentage points per year. Surprisingly, semi-annual rebalancing, which was optimal for this data set, was also 2.62 percentage points per year better than monthly rebalancing. Positive first- and second-degree autocorrelation among the monthly returns appears to account for the decrease in returns for rebalancing more frequently than semi-annually.     

Risk-weighted capital requirements and portfolio rebalancing

We use a 2013 Norwegian policy reform to study how banks react to higher capital requirements and how these adjustments transmit to the real economy. Using bank balance sheet data, we document that banks raise capital ratios by reducing risk-weighted assets. Most of the reduction in risk-weighted assets is accounted for by a reduction in average risk weights. Consistent with this reduction in risk, we document a substantial decline in credit supply to the corporate sector relative to the household sector. We also show that banks react to higher requirements by increasing interest rates, consistent with the reduction in corporate credit growth being supply driven. Using administrative loan level tax data, we document a reduction in lending on the firm level. This is robust to controlling for firm fixed effects, thereby accounting for potential firm-bank matching. Finally, we find that the reduction in bank lending has a negative impact on firm employment growth and that this effect is driven by small firms.     

Analytical solutions of optimal portfolio rebalancing

We study optimal portfolio rebalancing in a mean-variance type framework and present new analytical results for the general case of multiple risky assets. We first derive the equation of the no-trade region, and then provide analytical solutions and conditions for the optimal portfolio under several simplifying yet important models of asset covariance matrix: uncorrelated returns, same non-zero pairwise correlation, and a one-factor model. In some cases, the analytical conditions involve one or two parameters whose values are determined by combinatorial, rather than numerical, algorithms. Our results provide useful and interesting insights on portfolio rebalancing, and sharpen our understanding of the optimal portfolio.     

Monetary policy and portfolio rebalancing: Evidence from European equity mutual funds

In this study, we provide empirical evidence on the portfolio rebalancing of European equity mutual funds following both conventional (CMP) and unconventional monetary policies (UMP). We use 1772 equity mutual funds’ portfolio holdings over the period 2002Q4–2016Q4. This level of granularity allows us to characterise the funds’ asset allocation in different portfolio dimensions: the size, style, currency, and domicile of the stocks, and managers’ preferred investment strategies. Using a panel fixed effect estimator, our results support the existence of portfolio rebalancing across equity categories following UMP. European equity mutual funds’ assets are, on average, reallocated towards mid-cap, and core stocks and developing economies, and shifted away from small-cap and value stocks and home as well as developed countries. Furthermore, mutual funds seem to concentrate on their preferred and historical investment strategies. These two results suggest that managers are more willing to invest in safer and familiar stocks following UMP announcements thereby decreasing the risk of asymmetry of information. We finally show that the funds size, returns volatility and expense ratio affect the strength of the rebalancing.     

Conditional performance, portfolio rebalancing, and momentum of small-cap mutual funds

To assess the performance of small-cap stocks net of transaction costs, we analyze 165 actively managed small-cap oriented portfolios. Our analysis addresses three areas of interest: (i) performance net of transaction costs, (ii) the magnitude of trading costs incurred when rebalancing an actively managed portfolio, and (iii) the potential for momentum strategy profits when investing in small-cap stocks.Using conditional estimation, we find that small-cap funds have earned a significantly positive abnormal return of about 2% per year in the period January 1986 to December 2000. We also estimate the cost of January rebalancing to be 0.4% of portfolio value, a value that is significant for over 20% of the portfolios under study.Finally, after trading frictions are taken into account, we find evidence that small-cap portfolios exhibit significant return patterns, similar in nature to momentum patterns initially documented in a frictionless setting by [J. Finance 48 (1993) 65; J. Finance 56 (2001) 699]. Our findings support recent behavioral models, which attempt to explain these patterns. Consistent with the findings of Jegadeesh and Titman, we find that past “winners” continue to outperform in the next 12 months, followed by a performance reversal.     

International equity portfolio allocations and transaction costs

In spite of the critical role of transaction cost, there are not many papers that explicitly examine its influence on international equity portfolio allocation decisions. Using bilateral cross-country equity portfolio investment data and three direct measures of transaction costs for 36 countries, we provide evidence that markets where transaction costs are lower attract greater equity portfolio investments. The results imply that future research on international equity portfolio diversification cannot afford to ignore the role of transaction costs, and policy makers, especially in emerging markets, will have to reduce transaction costs to attract higher levels of foreign equity portfolio investments.     

The dual optimizer for the growth-optimal portfolio under transaction costs

We consider the maximization of the long-term growth rate in the Black–Scholes model under proportional transaction costs as in Taksar et al. (Math. Oper. Res. 13:277–294, 1988). Similarly as in Kallsen and Muhle-Karbe (Ann. Appl. Probab. 20:1341–1358, 2010) for optimal consumption over an infinite horizon, we tackle this problem by determining a shadow price, which is the solution of the dual problem. It can be calculated explicitly up to determining the root of a deterministic function. This in turn allows one to explicitly compute fractional Taylor expansions, both for the no-trade region of the optimal strategy and for the optimal growth rate.     

Foreign reserve and money dynamics with asset portfolio adjustment: international evidence

In this paper we argue that more complete modeling of foreign exchange intervention and sterilization dynamics is necessary when there are adjustment costs to changing private portfolios and/or the central bank attempts to balance longer-run monetary control against short-term exchange rate objectives. We show that measured correlations between domestic credit and foreign asset changes, often interpreted as ‘sterilization coefficients’, may be misleading because they vary with the pattern of disturbances as well as private agent and central bank behavior. We assess the empirical significance of this issue by estimating vector error correction models of the domestic and foreign asset components of the monetary base for Japan and Germany. In both countries, we find that that the impact of foreign exchange intervention on domestic credit falls markedly after several months, implying that the degree of sterilization decreases over time. However, the monetary base remained largely insulated as foreign asset positions were subsequently ‘unwound.’     

Aggregation of exponential smoothing processes with an application to portfolio risk evaluation

In this paper we propose a unified framework to analyse contemporaneous and temporal aggregation of a widely employed class of integrated moving average (IMA) models. We obtain a closed-form representation for the parameters of the contemporaneously and temporally aggregated process as a function of the parameters of the original one. These results are useful due to the close analogy between the integrated GARCH (1, 1) model for conditional volatility and the IMA (1, 1) model for squared returns, which share the same autocorrelation function. In this framework, we present an application dealing with Value-at-Risk (VaR) prediction at different sampling frequencies for an equally weighted portfolio composed of multiple indices. We apply the aggregation results by inferring the aggregate parameter in the portfolio volatility equation from the estimated vector IMA (1, 1) model of squared returns. Empirical results show that VaR predictions delivered using this suggested approach are at least as accurate as those obtained by applying standard univariate methodologies, such as RiskMetrics.     

Lumpiness,capital adjustment costs and investment dynamics

Aggregate investment in the US economy displays a hump-shaped pattern in response to shocks, and the autocorrelation of aggregate investment growth is positive for the first few quarters, turning negative for the later quarters. This paper shows that this feature of the data is the natural outcome of a two-sector consumption/investment model designed and calibrated to reproduce plant-level evidence on capital accumulation.     

Financial contagion in the laboratory: The cross-market rebalancing channel

We present the results of the first experimental study of financial markets contagion. We develop a model of financial contagion amenable to be tested in the laboratory. In the model, contagion happens because of cross-market rebalancing, a channel for transmission of shocks across markets first studied by Kodres and Pritsker (2002). Theory predicts that, because of portfolio rebalancing, a negative shock in one market transmits itself to the others, as investors adjust their portfolio allocations. The theory is supported by the experimental results. The price observed in the laboratory is close to that predicted by theory, and strong contagion effects are observed. The results are robust across different market structures. Moreover, as theory predicts, lower asymmetric information in a (“developed”) financial market increases the contagion effects in (“emerging”) markets.     

The introduction of the Euro and its effects on portfolio decisions

Examining investment behavior related to the Euro introduction, we address the relevance of different investment determinants. With the advent of the currency union two potential sources of portfolio reallocation can be distinguished: First, the diminishment of exchange rate risk and transaction costs within the EMU. Second, the increase of correlation of EMU returns so that diversification benefits decreased. We test for structural breaks in the holdings of German investors and estimate a market model to account for the two effects. A significant decrease in national and an increase in EMU and rest-of-the-world investments can be observed. Comparing the observed holdings with benchmark portfolios, we find that investment home bias has diminished since the Euro introduction.     

Worst case portfolio vectors and diversification effects

We consider the problem of identifying the worst case dependence structure of a portfolio X ₁,…,X _n of d-dimensional risks, which yields the largest risk of the joint portfolio. Based on a recent characterization result of law invariant convex risk measures, the worst case portfolio structure is identified as a μ-comonotone risk vector for some worst case scenario measure μ. It turns out that typically there will be a diversification effect even in worst case situations. The only exceptions arise when risks are measured by translated max correlation risk measures. We determine the worst case portfolio structure and the worst case diversification effect in several classes of examples as, e.g. in elliptical, Euclidean spherical, and Archimedean type distribution classes.     

Direct and spillover portfolio effects of COVID-19

This paper investigates the direct and spillover portfolio effects from the global outbreak of COVID-19. We find that an increase of the newly added cases of one specific country causes investors to significantly decrease their portfolio allocations in the outbreak countries (direct effect). Simultaneously, investors also decrease their allocations to other countries (spillover effect). In addition, we provide evidence and documentation that the transmission mechanism underlying foreign exposures matter to the above-mentioned portfolio effect. Moreover, we provide evidence for phase heterogeneity. The first wave of the COVID-19 pandemic has significant direct and spillover portfolio effects, but the impacts are weakened in second wave of the pandemic. The capital reallocation effect occurs only when the disease becomes global. Finally, our heterogeneities analysis shows that both local and spillover effects are mitigated when the economies are more developed and democratic and when the country has better health care facilities.     

International portfolio diversification and multilateral effects of correlations

Not only are investors biased toward home assets, but when they do invest abroad, they appear to favor countries with returns more correlated with home assets. Often attributed to a preference for familiarity, this ‘correlation puzzle’ further reduces effective diversification. We use a multi-country general equilibrium model of portfolio choice to study how bilateral equity holdings are affected by return correlations among alternative destination and source countries. From the theoretical model, we develop an empirical approach to estimate a gravity equation for equity holdings that incorporates the overall covariance structure in a theoretically rigorous yet tractable manner. Estimation using this approach resolves the correlation puzzle, and finds that international investors do seek the diversification benefits of low cross-country correlations, as theory would predict.     

International portfolio diversification: Currency,industry and country effects revisited

We examine the relative importance of country, industry, world market and currency risk factors for international stock returns. Our approach focuses on testing the mean-variance efficiency of the various factor portfolios. An unconditional analysis does not show significant differences between country, industry and world portfolios, nor any role for currency risk factors. However, when we allow expected returns, volatilities and correlations to vary over time, we find that equity returns are mainly driven by global industry and currency risk factors. We propose a novel test to evaluate the relative benefits of alternative investment strategies and find that including currencies is critical to take full advantage of the diversification benefits afforded by international markets.     

Shadow prices,fractional Brownian motion,and portfolio optimisation under transaction costs

The present paper accomplishes a major step towards a reconciliation of two conflicting approaches in mathematical finance: on the one hand, the mainstream approach based on the notion of no arbitrage (Black, Merton & Scholes), and on the other hand, the consideration of non-semimartingale price processes, the archetype of which being fractional Brownian motion (Mandelbrot). Imposing (arbitrarily small) proportional transaction costs and considering logarithmic utility optimisers, we are able to show the existence of a semimartingale, frictionless shadow price process for an exponential fractional Brownian financial market.     

The impacts of index rebalancing and their implications: Some new evidence from Japan

This study investigates the Nikkei 225 rebalancing. Unlike those for changes in the S&P 500, the price effects are permanent for both additions and deletions despite significant price reversals around both the announcement and effective days. The permanent price effects are shown to be consistent with the imperfect substitute hypothesis. Furthermore, the ‘arbitrage game’, as documented for the S&P additions, is played with both the Nikkei 225 additions and deletions. Lastly, consistent with its higher popularity, the Nikkei 225 changes induce more pronounced price and volume effects, more arbitrage trading, but less long-term volume effects than the Nikkei 500 reshuffles.