15,777 research outputs found
Sector concentration in loan portfolios and economic capital
The purpose of this paper is to measure the potential impact of business-sector concentration on economic capital for loan portfolios and to explore a tractable model for its measurement. The empirical part evaluates the increase in economic capital in a multi-factor asset value model for portfolios with increasing sector concentration. The sector composition is based on credit information from the German central credit register. Finding that business sector concentration can substantially increase economic capital, the theoretical part of the paper explores whether this risk can be measured by a tractable model that avoids Monte Carlo simulations. We analyze a simplified version of the analytic value-at-risk approximation developed by Pykhtin (2004), which only requires risk parameters on a sector level. Sensitivity analyses with various input parameters show that the analytic approximation formulae perform well in approximating economic capital for portfolios which are homogeneous on a sector level in terms of PD and exposure size. Furthermore, we explore the robustness of our results for portfolios which are heterogeneous in terms of these two characteristics. We find that low granularity ceteris paribus causes the analytic approximation formulae to underestimate economic capital, whereas heterogeneity in individual PDs causes overestimation. Indicative results imply that in typical credit portfolios, PD heterogeneity will at least compensate for the granularity effect. This suggests that the analytic approximations estimate economic capital reasonably well and/or err on the conservative side. --sector concentration risk,economic capital
Sector Concentration in Loan Portfolios and Economic Capital
The purpose of this paper is to measure the potential impact of business-sector concentration on economic capital for loan portfolios and to explore a tractable model for its measurement. The empirical part evaluates the increase in economic capital in a multi-factor asset value model for portfolios with increasing sector concentration. The sector composition is based on credit information from the German central credit register. Finding that business sector concentration can substantially increase economic capital, the theoretical part of the paper explores whether this risk can be measured by a tractable model that avoids Monte Carlo simulations. We analyze a simplified version of the analytic value-at-risk approximation developed by Pykhtin (2004), which only requires risk parameters on a sector level. Sensitivity analyses with various input parameters show that the analytic approximation formulae perform well in approximating economic capital for portfolios which are homogeneous on a sector level in terms of PD and exposure size. Furthermore, we explore the robustness of our results for portfolios which are heterogeneous in terms of these two characteristics. We find that low granularity ceteris paribus causes the analytic approximation formulae to underestimate economic capital, whereas heterogeneity in individual PDs causes overestimation. Indicative results imply that in typical credit portfolios, PD heterogeneity will at least compensate for the granularity effect. This suggests that the analytic approximations estimate economic capital reasonably well and/or err on the conservative side.sector concentration risk, economic capital
Concentration risk under Pillar 2: When are credit portfolios infinitely fine grained?
The ongoing debate concerning credit concentration risk is mainly driven by the requirements on credit risk management due to Pillar 2 of Basel II since risks (e.g. concentration risk) that are not fully captured by Pillar 1 should be adequately considered in the banks' risk management. This instruction is indeed relevant since quantifying credit portfolio risk in Pillar 1 is based on an Asymptotic Single Risk Factor (ASRF) framework in which concentration risk is not covered. Against the background of the ASRF model, we determine the number of credits up to which concentration risk leads to a significant estimation error so that the assumption of an infinitely fine grained portfolio is inadequate. We conclude that the critical portfolio size varies from 22 up to 35,986 debtors, dependent on assets correlation and probability of default. Using a modified valuation function (granularity adjustment) it is possible to reduce the critical number of credits by averaged 83.04 %. --Basel II,Pillar 2,Concentration Risk,Granularity Adjustment
Correlation, CDOs of ABS and the subprime crisis.
systemic risks; high correlation regimes; subprime crisis;
Forecasting of financial data: a novel fuzzy logic neural network based on error-correction concept and statistics
First, this paper investigates the effect of good and bad news on volatility in the BUX return time series using asymmetric ARCH models. Then, the accuracy of forecasting models based on statistical (stochastic), machine learning methods, and soft/granular RBF network is investigated. To forecast the high-frequency financial data, we apply statistical ARMA and asymmetric GARCH-class models. A novel RBF network architecture is proposed based on incorporation of an error-correction mechanism, which improves forecasting ability of feed-forward neural networks. These proposed modelling approaches and SVM models are applied to predict the high-frequency time series of the BUX stock index. We found that it is possible to enhance forecast accuracy and achieve significant risk reduction in managerial decision making by applying intelligent forecasting models based on latest information technologies. On the other hand, we showed that statistical GARCH-class models can identify the presence of leverage effects, and react to the good and bad news.Web of Science421049
Should the advanced measurement approach be replaced with the standardized measurement approach for operational risk?
Recently, Basel Committee for Banking Supervision proposed to replace all
approaches, including Advanced Measurement Approach (AMA), for operational risk
capital with a simple formula referred to as the Standardised Measurement
Approach (SMA). This paper discusses and studies the weaknesses and pitfalls of
SMA such as instability, risk insensitivity, super-additivity and the implicit
relationship between SMA capital model and systemic risk in the banking sector.
We also discuss the issues with closely related operational risk
Capital-at-Risk (OpCar) Basel Committee proposed model which is the precursor
to the SMA. In conclusion, we advocate to maintain the AMA internal model
framework and suggest as an alternative a number of standardization
recommendations that could be considered to unify internal modelling of
operational risk. The findings and views presented in this paper have been
discussed with and supported by many OpRisk practitioners and academics in
Australia, Europe, UK and USA, and recently at OpRisk Europe 2016 conference in
London
Exploratory analysis of high-resolution power interruption data reveals spatial and temporal heterogeneity in electric grid reliability
Modern grid monitoring equipment enables utilities to collect detailed
records of power interruptions. These data are aggregated to compute publicly
reported metrics describing high-level characteristics of grid performance. The
current work explores the depth of insights that can be gained from public
data, and the implications of losing visibility into heterogeneity in grid
performance through aggregation. We present an exploratory analysis examining
three years of high-resolution power interruption data collected by archiving
information posted in real-time on the public-facing website of a utility in
the Western United States. We report on the size, frequency and duration of
individual power interruptions, and on spatio-temporal variability in aggregate
reliability metrics. Our results show that metrics of grid performance can vary
spatially and temporally by orders of magnitude, revealing heterogeneity that
is not evidenced in publicly reported metrics. We show that limited access to
granular information presents a substantive barrier to conducting detailed
policy analysis, and discuss how more widespread data access could help to
answer questions that remain unanswered in the literature to date. Given open
questions about whether grid performance is adequate to support societal needs,
we recommend establishing pathways to make high-resolution power interruption
data available to support policy research.Comment: Journal submission (in review), 22 pages, 8 figures, 1 tabl
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