Diversification increases systemic risk, contrary to belief.
problem Systemic risk due to diversification at banks.
method Examined diversification's impact on joint default probability and systemic risk using VaR.
result Diversification reduces individual and systemic risk, contrary to common belief.
Shaped by structural forces of change, banking in emerging markets has recently experienced a decline in its traditional activities, leading banks to diversify into new business strategies. This paper examines whether the observed shift into non-interest based activities improves financial performance. Using a sample o…
We test the hypothesis that interconnections across financial institutions can be explained by a diversification motive. This idea stems from the empirical evidence of the existence of long-term exposures that cannot be explained by a liquidity motive (maturity or currency mismatch). We model endogenous interconnection…
Model analyzes how heterogeneity in bank and asset distributions affects financial contagion.
problem Effect of power-law distributions on financial contagion stability.
method Modeling financial contagion in a bipartite network with heterogeneous degrees and balance-sheet sizes.
result Power-law degree distributions in banks decrease system stability, while in assets increase it.
Investigates diversification quotient based on VaR and ES for portfolio models.
problem Quantifying diversification of portfolios using VaR and ES.
method Introduced and analyzed DQ based on VaR and ES for elliptical and MRV distributions.
result Explicit formulas and portfolio optimization problems for VaR and ES DQ are derived.
This paper investigates two mechanisms of financial contagion that are, firstly, the correlated exposure of banks to the same source of risk, and secondly the direct exposure of banks in the interbank market. It will consider a random network of banks which are connected through the inter-bank market and will discuss t…
Study minimizes market inefficiency in systemic economies.
problem Minimizing deviations of market prices from fundamental values.
method Characterized market inefficiency and developed a matrix of holdings to minimize it.
result Portfolio holdings should deviate more from diversification if banks have similar systemic significance.
Many immunization strategies have been proposed to prevent infectious viruses from spreading through a network. In this study, we propose efficient immunization strategies to prevent a default contagion that might occur in a financial network. An essential difference from the previous studies on immunization strategy i…
Model measures diversification in Austrian interbank market, showing increased homogeneity.
problem Measuring diversification in Austrian interbank market.
method Dynamic network model with Markov property to capture time dependencies.
result Core banks tend to distribute market exposures more equally over time.
Excessive leverage, i.e. the abuse of debt financing, is considered one of the primary factors in the default of financial institutions. Systemic risk results from correlations between individual default probabilities that cannot be considered independent. Based on the structural framework by Merton (1974), we discuss …
This study presents an ANWSER model (asset network systemic risk model) to quantify the risk of financial contagion which manifests itself in a financial crisis. The transmission of financial distress is governed by a heterogeneous bank credit network and an investment portfolio of banks. Bankruptcy reproductive ratio …
We consider a model of contagion in financial networks recently introduced in the literature, and we characterize the effect of a few features empirically observed in real networks on the stability of the system. Notably, we consider the effect of heterogeneous degree distributions, heterogeneous balance sheet size and…
Most of the banks' operational risk internal models are based on loss pooling in risk and business line categories. The parameters and outputs of operational risk models are sensitive to the pooling of the data and the choice of the risk classification. In a simple model, we establish the link between the number of ris…
The interconnectedness of financial institutions affects instability and credit crises. To quantify systemic risk we introduce here the PD model, a dynamic model that combines credit risk techniques with a contagion mechanism on the network of exposures among banks. A potential loss distribution is obtained through a m…
We detect the backbone of the weighted bipartite network of the Japanese credit market relationships. The backbone is detected by adapting a general method used in the investigation of weighted networks. With this approach we detect a backbone that is statistically validated against a null hypothesis of uniform diversi…
Investigates how diversification preferences relate to risk attitudes.
problem Connecting diversification preferences to risk attitudes.
method Analyzes diversification preferences for various pairs of risks under different conditions.
result Diversification preferences for certain pairs of risks imply specific levels of risk aversion.
Study examines diversification of mid-mountain ski tourism.
problem Understanding transformations in ski mid-mountain territories.
method Applied regional diversification theory to French ski areas.
result Identified three steps in tourism diversification paths.
The study provides foundations for naive diversification, a preference for equal treatment of alternatives.
problem Understanding and mathematically grounding naive diversification preferences.
method Axiomatization of naive diversification as a preference for equality over inequality, and derivation of its relationship to classical diversification.
result Naive diversification is a preference for equality over inequality, and it is characterized by convex and permutation invariant preferences.
The paper proposes a new approach to portfolio selection that maximizes diversification and return.
problem Maximizing diversification and return in portfolio selection.
method A bi-objective model that maximizes a diversification measure and portfolio expected return.
result The return-diversification approach outperforms strategies based on diversification or classical risk-return approaches.
New method diversifies risk using complex numbers.
problem Minimizing portfolio risk under constraints.
method Complex valued principal component analysis in risk diversification.
result Outperforms conventional risk parity and diversification methods.
A new diversification measure DQ derived from risk measures addresses limitations of existing indices.
problem Limitations of existing diversification indices in capturing tail heaviness and common shocks.
method DQs are defined based on a parametric family of risk measures, satisfying six axioms of diversification.
result DQs can properly capture tail heaviness and common shocks, improving portfolio selection.
Paper introduces lexical ratio to measure portfolio diversification.
problem Traditional diversification metrics overlook non-numerical relationships.
method Uses textual data to capture diversification dimensions through entropy-based insights.
result Lexical ratio (LR) outperforms traditional metrics in optimizing portfolio returns.
Study on diversification of α-stable risks, revealing limits to diversification due to tail dependence.
problem Diversification of α-stable risks with tail dependence. method Analysis of aggregated Value-at-Risk under different tail dependence structures.
result Limits to diversification are violated, especially for low tail index values and positive dependence.
One of the findings of the recent literature is that the 2008 financial crisis caused reduction in international diversification benefits. To fully understand the possible potential from diversification, we build an empirical model which combines generalised autoregressive score copula functions with high frequency dat…
Coherent diversification of tech fields correlates with higher labor productivity.
problem Understanding how firms' technological diversification impacts productivity.
method Analyzed patent data of 70k firms over 2004-2013, defined coherent diversification as network of related tech fields.
result Firms with coherent diversification structure outperform those with scattered diversification in labor productivity.
Despite the availability of very detailed data on financial market, agent-based modeling is hindered by the lack of information about real trader behavior. This makes it impossible to validate agent-based models, which are thus reverse-engineering attempts. This work is a contribution to the building of a set of styliz…
Diversification improves profits for heavy-tailed investments.
problem Investment portfolios of Pareto-distributed returns.
method Stochastic dominance and majorization order.
result Diversification increases first-order stochastic dominance for heavy-tailed returns.
New framework optimizes portfolio diversification beyond mean-variance.
problem Optimizing portfolio diversification beyond classical methods.
method Introduces portfolio dimensionality, connects diversification to non-Gaussian returns, and develops global optimization algorithms.
result Maximizing portfolio dimensionality leads to highly non-trivial optimization problems with multiple local optima.
Diversification represents the idea of choosing variety over uniformity. Within the theory of choice, desirability of diversification is axiomatized as preference for a convex combination of choices that are equivalently ranked. This corresponds to the notion of risk aversion when one assumes the von-Neumann-Morgenster…
This paper improves the Diversification Quotient (DQ) for better risk management.
problem Improving portfolio diversification measurement.
method Empirical estimation of DQ using VaR and ES, with asymptotic properties verified.
result Empirical DQ estimators are more robust and have better asymptotic properties.
The paper explores tail diversification in financial markets using entropy and mutual information.
problem Tail diversification in financial time series.
method Statistical independence through differential entropy and mutual information, using moments as contrast functions.
result Tail covariance matrix is a key driver of tail diversification.
Investment diversification affects financial stability, depending on network connectivity.
problem Analyzing stability of financial networks with diversified portfolios.
method Random matrix dynamical model with portfolio rebalancing, considering heterogeneity and diversification effects.
result Stability/instability transition depends on the largest eigenvalue of the random matrix.
We present four methods of assessing the diversification potential within a stock market, two of these are based on principal component analysis. They were applied to the Australian stock exchange for the years 2000 to 2014 and all show a consistent picture. The potential for diversification declined almost monotonical…
Defines diversification as a binary relationship between financial portfolios.
problem Defines diversification in a new binary relationship for financial portfolios.
method Proposes a new definition of diversification based on convex linear combinations and second order stochastic dominance.
result The proposed definition coincides with second order stochastic dominance.
Investment diversification increased during the financial crisis, but similarity between funds remains a systemic risk.
problem Systemic risk in mutual fund investments during the financial crisis.
method Investigated the bipartite network of US mutual fund portfolios and their assets, analyzed their evolution during the crisis, and introduced a simplified model of financial shock propagation.
result Large overlap between mutual fund portfolios is more likely than expected, indicating strong correlations and systemic risk.
Analyzes re-ranking diversification algorithms based on function optimization.
problem Improving diversification in ranking systems.
method Examines re-ranking algorithms based on maximizing submodular/modular functions and their optimality in terms of total curvature.
result Adjusting hyperparameters can optimize relevance-diversity trade-offs.
Review of diversification models finds simple rules still best.
problem Testing new diversification models for out-of-sample performance.
method Tested sixteen strategies across six datasets.
result No new models consistently outperform simple diversification rules.
The paper addresses portfolio diversification under model uncertainty using robust dynamic mean-variance approach.
problem Model uncertainty in portfolio diversification and its effects on optimal strategies.
method Develops a continuous time framework for dynamic multi-asset mean-variance portfolio selection under model uncertainty, considering ambiguity aversion in expected return rates and correlation matrix.
result Proves a separation principle for robust control problem, reducing optimal dynamic strategy determination to minimal risk premium computation.
Oil is perceived as a good diversification tool for stock markets. To fully understand this potential, we propose a new empirical methodology that combines generalized autoregressive score copula functions with high frequency data and allows us to capture and forecast the conditional time-varying joint distribution of …
Diversification return is an incremental return earned by a rebalanced portfolio of assets. The diversification return of a rebalanced portfolio is often incorrectly ascribed to a reduction in variance. We argue that the underlying source of the diversification return is the rebalancing, which forces the investor to se…
Risk-only investment strategies have been growing in popularity as traditional in- vestment strategies have fallen short of return targets over the last decade. However, risk-based investors should be aware of four things. First, theoretical considerations and empirical studies show that apparently dictinct risk-based …
A new portfolio method using quantum mechanics improves risk diversification.
problem Improving risk-based portfolio construction methods for multi-asset portfolios.
method Schrödinger principal component analysis applied to extract common factors from asset fluctuations.
result The proposed method outperforms conventional risk parity and other risk diversification methods.
The study revisits portfolio diversification by relaxing assumptions for skewed, multi-regime, and leptokurtic asset returns.
problem Underestimation of risk in portfolio diversification due to assumptions that are inconsistent with real-world asset returns.
method Calibrated a Markov-modulated Levy process model to equity market data to demonstrate the merits of the approach.
result The calibrated models effectively match empirical moments and show the importance of relaxing assumptions in portfolio diversification.
Study on diversifying equity portfolios during financial crises and stability.
problem Determining the effectiveness of diversification strategies during financial crises and stability.
method Analysis of 20 years of US stock price data, including GFC and COVID-19 crashes, using eigenvalues, graph-theoretic diagnostics, and hierarchical clustering.
result During financial crises, diversification via sector-based portfolios is ineffective, while during stability, 30-40 stocks provide sufficient diversification.
Investing in cryptocurrencies can improve portfolio risk-return profile, especially with diversification strategies.
problem Investing in cryptocurrencies and evaluating their potential for portfolio allocation strategies.
method Investigated different types of investors, various portfolio construction rules, and incorporated liquidity constraints.
result Cryptocurrencies can improve the risk-return profile of portfolios, especially with diversification strategies.
Optimizes portfolios with utility theory, diversification, and leverage.
problem Finding optimal portfolio allocation strategies.
method Utility theory, exponential and logarithmic utilities, compound probability distributions, maximum expected utility, generalized mean-variance.
result Enhanced portfolio allocation strategies with natural explanations.
New methods show sparse portfolios offer no advantage over mean-variance in diversification.
problem Investment diversification and risk management with sparse portfolios.
method Developed and implemented a new estimation procedure for sparse second-order stochastic spanning using a greedy algorithm and Linear Programming.
result No benefit from expanding a sparse opportunity set beyond 45 assets; optimal sparse portfolio reduces tail risk.
Portfolio diversification and active risk management are essential parts of financial analysis which became even more crucial (and questioned) during and after the years of the Global Financial Crisis. We propose a novel approach to portfolio diversification using the information of searched items on Google Trends. The…