Sovereign Debt Portfolios Research Articles

DOMESTIC ORIGINAL SIN OF SOVEREIGN DEBT IN TÜRKİYE

The study analyzes the original sin of sovereign debt in Türkiye with a focus on domestic original sin. Eichengreen and Hausmann (1999) define original sin as the inability of a country to borrow in its own currency in the international market, while the issuance of foreign currency debt in the domestic market is defined as domestic original sin (Eichengreen, Hausmann, and Panizza, 2003). In this context, the structure of the debt portfolio was evaluated based on the indicators developed by Eichengreen, et al. (2003) and its simplified version widely used in the literature. Based on the analysis of the sovereign debt portfolio, it has been concluded that although the debt stock to GDP ratio is relatively low in Türkiye, the domestic original sin has reached historically high levels and currency mismatch is significant.

Hidden Debt

We study the role of transparency in debt and default dynamics in a quantitative sovereign default model augmented with asymmetric information. We assume that the sovereign debt portfolio is not transparent and part of the debt is not observable to lenders. The quantitative model is calibrated to the Bolivian economy and matches its long-term and business cycle properties. The quantitative results show that when the government moves to a transparent reporting regime, bond prices improve and the sovereign debt portfolio shifts toward noncontingent debt with an increase in overall debt level. However, higher debt increases default frequency and reduces welfare.

Sovereign Debt Portfolios, Bond Risks, and the Credibility of Monetary Policy

ABSTRACTWe document that governments whose local currency debt provides them with greater hedging benefits actually borrow more in foreign currency. We introduce two features into a government's debt portfolio choice problem to explain this finding: risk‐averse lenders and lack of monetary policy commitment. A government without commitment chooses excessively countercyclical inflation ex post, which leads risk‐averse lenders to require a risk premium ex ante. This makes local currency debt too expensive from the government's perspective and thereby discourages the government from borrowing in its own currency.

Unconventional Monetary Policy Shocks in the Euro Area and the Sovereign-Bank Nexus

We explore the effects of the ECB’s unconventional monetary policy on the banks’ sovereign debt portfolios. In particular, using panel vector autoregressive (VAR) models we analyze whether banks increased their domestic government bond holdings in response to non-standard monetary policy shocks, thereby possibly promoting the sovereign-bank nexus, i.e. the exposure of banks to the debt issued by the national government. Our results suggest that euro area crisis countries’ banks enlarged their exposure to domestic sovereign debt after innovations related to unconventional monetary policy. Moreover, the restructuring of sovereign debt portfolios was characterized by a home bias.

Unconventional Monetary Policy Shocks in the Euro Area and the Sovereign-Bank Nexus

We explore the effects of the ECB’s unconventional monetary policy on the banks’ sovereign debt portfolios. In particular, using panel vector autoregressive (VAR) models we analyze whether banks increased their domestic government bond holdings in response to non-standard monetary policy shocks, thereby possibly promoting the sovereign-bank nexus, i.e. the exposure of banks to the debt issued by the national government. Our results suggest that euro area crisis countries’ banks enlarged their exposure to domestic sovereign debt after innovations related to unconventional monetary policy. Moreover, the restructuring of sovereign debt portfolios was characterized by a home bias.

Sovereign Debt Portfolios, Bond Risks, and the Credibility of Monetary Policy

Nominal debt provides consumption-smoothing benefits if it can be inflated away during recessions. However, we document empirically that countries with more countercyclical inflation, where nominal debt provides better consumption-smoothing, issue more foreign-currency debt. We propose that monetary policy credibility explains the currency composition of sovereign debt and nominal bond risks in the presence of risk-averse investors. In our model, low credibility governments inflate during recessions, generating excessively countercyclical inflation in addition to the standard inflationary bias. With countercyclical inflation, investors require risk premia on nominal debt, making nominal debt issuance costly for low credibility governments. We provide empirical support for this mechanism, showing that countries with higher nominal bond-stock betas have significantly larger nominal bond risk premia and borrow less in local currency.

What Drives Sovereign Debt Portfolios of Banks in a Crisis Context?

We study determinants of sovereign portfolios of Spanish banks over a long time-span, starting in 2008. Our findings challenge the view that banks engaged in moral hazard strategies to exploit the regulatory treatment of sovereign exposures. In particular, we show that being a weakly capitalized bank is not related to higher holdings of domestic sovereign debt. While a strong link is present between central bank liquidity support and sovereign holdings, opportunistic strategies or reach-for-yield behavior appear to be limited to the non-domestic sovereign portfolio of well-capitalized banks, which might have taken advantage of their higher risk-bearing capacity to gain exposure (via central bank liquidity) to the set of riskier sovereign bonds. Furthermore, we document that financial fragmentation in EMU markets has played a key role in reshaping sovereign portfolios of banks. Overall, our results have important implications for the ongoing discussion on the optimal design of the risk-weighted capital framework of banks.

What Drives Sovereign Debt Portfolios of Banks in a Crisis Context?

We study determinants of sovereign portfolios of Spanish banks over a long time-span, starting in 2008. Our findings challenge the view that banks engaged in moral hazard strategies to exploit the regulatory treatment of sovereign exposures. In particular, we show that being a weakly capitalized bank is not related to higher holdings of domestic sovereign debt. While a strong link is present between central bank liquidity support and sovereign holdings, opportunistic strategies or reach-for-yield behavior appear to be limited to the non-domestic sovereign portfolio of well-capitalized banks, which might have taken advantage of their higher risk-bearing capacity to gain exposure (via central bank liquidity) to the set of riskier sovereign bonds. Furthermore, we document that financial fragmentation in EMU markets has played a key role in reshaping sovereign portfolios of banks. Overall, our results have important implications for the ongoing discussion on the optimal design of the risk-weighted capital framework of banks.

A Primer on Managing Sovereign Debt-Portfolio Risks

This paper provides an overview of sovereign debt portfolio risks and discusses various liability management operations (LMOs) and instruments used by public debt managers to mitigate these risks. Debt management strategies analyzed in the context of helping reach debt portfolio targets and attain desired portfolio structures. Also, the paper outlines how LMOs could be integrated into a debt management strategy and serve as policy tools to reduce potential debt portfolio vulnerabilities. Further, the paper presents operational issues faced by debt managers, including the need to develop a risk management framework, interactions of debt management with fiscal policy, monetary policy, and financial stability, as well as efficient government bond markets.

A Primer on Managing Sovereign Debt-Portfolio Risks

This paper provides an overview of sovereign debt portfolio risks and discusses various liability management operations (LMOs) and instruments used by public debt managers to mitigate these risks. Debt management strategies analyzed in the context of helping reach debt portfolio targets and attain desired portfolio structures. Also, the paper outlines how LMOs could be integrated into a debt management strategy and serve as policy tools to reduce potential debt portfolio vulnerabilities. Further, the paper presents operational issues faced by debt managers, including the need to develop a risk management framework, interactions of debt management with fiscal policy, monetary policy, and financial stability, as well as efficient government bond markets.

Interest rate, liquidity, and sovereign risk: derivative-based VaR

PurposeThe purpose of this paper is to study connections between interest rate risk and credit risk and investigate the inter-risk diversification benefit due to the joint consideration of these risks in the banking book containing sovereign debt.Design/methodology/approachThe paper develops the historical derivative-based value at risk (VaR) for assessing the downside risk of a sovereign debt portfolio through the integrated treatment of interest rate and credit risks. The credit default swaps spreads and the fixed-leg rates of interest rate swap are used as proxies for credit risk and interest rate risk, respectively.FindingsThe proposed methodology is applied to the decade-long history of emerging markets sovereign debt. The empirical analysis demonstrates that the diversified VaR benefits from imperfect correlation between the risk factors. Sovereign risks of non-core emu states and oil producing countries are discussed through the prism of VaR metrics.Practical implicationsThe proposed approach offers a clue for improving risk management in regards to banking books containing government bonds. It could be applied to access the riskiness of investment portfolios containing the wider spectrum of assets beyond the sovereign debt. The approach represents a useful tool for investigating interest rate and credit risk interrelation.Originality/valueThe proposed enhancement of the traditional historical VaR is twofold: usage of derivative instruments’ quotes and simultaneous consideration of the interest rate and credit risk factors to construct the hypothetical liquidity-free bond yield, which allows to distil liquidity premium.

Sovereign Debt Portfolios, Bond Risks, and the Credibility of Monetary Policy

Nominal debt provides consumption-smoothing benefits if it can be inflated away during recessions. However, we document empirically that countries with more countercyclical inflation, where nominal debt provides better consumption-smoothing, issue more foreign-currency debt. We propose that monetary policy credibility explains the currency composition of sovereign debt and nominal bond risks in the presence of risk-averse investors. In our model, low credibility governments inflate during recessions, generating excessively countercyclical inflation in addition to the standard inflationary bias. With countercyclical inflation, investors require risk premia on nominal debt, making nominal debt issuance costly for low credibility governments. We provide empirical support for this mechanism, showing that countries with higher nominal bond-stock betas have significantly larger nominal bond risk premia and borrow less in local currency.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Home Bias in Bank Sovereign Bond Purchases and the Bank-Sovereign Nexus

We study whether a pre-existing link between bank and sovereign credit risk biased euro area banks?' sovereign debt portfolio choices during 2011Q4 and 2012Q1 JEL Classification: G01, G11, G21, H6

Value-at-Risk for fixed-income portfolios: a Kalman filtering approach

We propose a way of measuring the risk of a sovereign debt portfolio by using a simple two-factor short rate model. The model is calibrated from data and then the changes in the bond prices are simulated by using a Kalman filter. The bond prices being simulated remain arbitrage-free, in contrast with principal component analysis-based strategies for simulation and risk measurement of debt portfolios. In liquid sovereign debt markets, a risk measurement methodology which allows the future bond price scenarios to be arbitrage-free may be seen as a potentially more realistic way of measuring the debt portfolio risk due to interest rate fluctuations. We demonstrate the performance of this methodology with calibration and backtesting, both on simulated data as well as on a real portfolio of US government bonds.

A hierarchical copula-based world-wide valuation of sovereign risk

We propose a new model for the aggregation of risks that is very flexible and useful in high dimensional problems. We propose a copula-based model that is both hierarchical and hybrid (HYC for short), because: (i) the dependence structure is modeled as a hierarchical copula, (ii) it unifies the idea of the clusterized homogeneous copula-based approach (CHC for short) and its limiting version (LHC for short) proposed in Bernardi and Romagnoli (2012, 2013). Based on this, we compute the loss function of a world-wide sovereign debt portfolio which accounts for a systemic dependence of all countries, in line with a global valuation of financial risks. Our approach enables us to take into account the non-exchangeable behavior of a sovereign debts’ portfolio clustered into several classes with homogeneous risk and to recover a possible risks’ hierarchy. A comparison between the HYC loss surface and those computed through a pure limiting approach, which is commonly used in high dimensional problems, is presented and the impact of the concentration and the granularity errors is appreciated. Finally the impact of an enlargement of the dependence structure is discussed, in the contest of a geographical area sub-portfolios analysis now relevant to determine the risk contributions of subgroups under the presence of a wider dependence structure. This argument is presented in relation to the evaluation of the insurance premium and the collateral related to the designed project of an euro-insurance-bond.

Systemic risk, sovereign yields and bank exposures in the euro crisis

Since 2008, eurozone sovereign yields have diverged sharply, and so have the corresponding credit default swap (CDS) premia. At the same time, banks' sovereign debt portfolios have featured an increasing home bias. In this paper, we investigate the relationship between these two facts, and its rationale. First, we inquire to what extent the dynamics of sovereign yield differentials relative to the swap rate and CDS premia reflect changes in perceived sovereign solvency risk or rather different responses to systemic risk due to the possible collapse of the euro. We do so by decomposing yield differentials and CDS spreads in a country-specific and a common risk component via a dynamic factor model. We then investigate how the home bias of banks' sovereign portfolios responds to yield differentials and to their two components, by estimating a vector error-correction model on 2007–13 monthly data. We find that in most countries of the eurozone, and especially in its periphery, banks' sovereign exposures respond positively to increases in yields. When bank exposures are related to the country and common risk components of yields, it turns out that (1) in the periphery, banks increase their domestic exposure in response to increases in country risk, while in core countries they do not; (2) in most eurozone countries banks respond to an increase in the common risk factor by raising their domestic exposures. Finding (1) suggests distorted incentives in periphery banks' response to changes in their own sovereign's risk. Finding (2) indicates that, when systemic risk increases, all banks tend to increase the home bias of their portfolios, making the eurozone sovereign market more segmented. — Niccolo Battistini, Marco Pagano and Saverio Simonelli

Sovereign debt portfolios: risks and liability management operations

This paper addresses issues relating to (1) sovereign debt portfolio risks stemming from high sovereign debt levels and unbalanced debt portfolio structures, and (2) liability management operations intended to meet specified debt management objectives, including mitigation of these risks. Further, it outlines some common operations used by public debt managers such as debt swaps and debt buybacks, and explains the rationale and benefits from their undertakings.

The Cost Effectiveness of the UK's Sovereign Debt Portfolio*

AbstractThis paper provides a recursive empirical analysis of the scope for cost minimization in public debt management when the debt manager faces a given short‐term interest rate dictated by monetary policy as well as risk and market impact constraints. It simulates the ‘real‐time’ interest costs of alternative portfolios for UK government debt between April 1985 and March 2000. These portfolios are constructed using forecasts of return spreads based on a recursive modelling procedure. While we find statistically significant evidence of predictability, the interest cost savings are quite small when portfolio shares are constrained to lie within historical bounds.