Did investors outsource their risk analysis to rating agencies? Evidence from ABS-CDOs

Based on a sample of 3254 floating rate tranches from 617 ABS-CDOs (collateralized debt obligations backed by asset-backed securities), this paper tests the “rating overdependence” hypothesis – i.e., that ratings of structured products are a sufficient statistic (in terms of predicting future credit performance) for yield spreads at origination. The paper’s findings are fourfold. First, yield spreads at issuance predict future performance of ABS-CDO tranches even after controlling for the information contained in ratings. Second, the ability of yield spreads to predict future performance, however, is driven exclusively by ratings below AAA (and, to a lesser extent, also by the lowest priority AAA tranches), whereas spreads of super senior AAA tranches show no information content. Third, the predictive ability of yield spreads is lower for tranches from later vintages and for tranches from deals with more complex collateral pools. Fourth, the conditional correlation between ratings and spreads, in turn, is increasing in time and higher for tranches from complex deals. In sum, the evidence indicates that investors in (especially AAA) tranches from later and more complex deals have avoided performing costly due diligence on the securities they bought.     

Tranching and Rating

In this paper we analyse the source and magnitude of marketing gains from selling structured debt securities at yields that reflect only their credit ratings, or specifically at yields on equivalently rated corporate bonds. We distinguish between credit ratings that are based on probabilities of default and ratings that are based on expected default losses. We show that subdividing a bond issued against given collateral into subordinated tranches can yield significant profits under the hypothesised pricing system. Increasing the systematic risk or reducing the total risk of the bond collateral increases the profits further. The marketing gain is generally increasing in the number of tranches and decreasing in the rating of the lowest rated tranche.     

Disagreement and asset prices

How do differences of opinion affect asset prices? Do investors earn a risk premium when disagreement arises in the market? Despite their fundamental importance, these questions are among the most controversial issues in finance. In this paper, we use a novel data set that allows us to directly measure the level of disagreement among Wall Street mortgage dealers about prepayment speeds. We examine how disagreement evolves over time and study its effects on expected returns, return volatility, and trading volume in the mortgage-backed security market. We find that increased disagreement is associated with higher expected returns, higher return volatility, and larger trading volume. These results imply that there is a positive risk premium for disagreement in asset prices. We also show that volatility in and of itself does not lead to higher trading volume. Instead, only when disagreement arises in the market is higher uncertainty associated with more trading. Finally, we are able to distinguish empirically between two competing hypotheses regarding how information in markets gets incorporated into asset prices. We find that sophisticated investors appear to update their beliefs through a rational expectations mechanism when disagreement arises.     

The alchemy of CDO credit ratings

Collateralized loan obligations (CLOs) were one of the largest and fastest growing segments of the structured finance market, fueling the 2003-2007 boom in syndicated loans and leveraged buyouts. The credit crisis brought CLO issuance to a halt, and as a result the leveraged loan market dried up. Similar to other structured finance products, investors in CLOs rely heavily on credit rating provided by the rating agencies, yet little is known about CLO rating practices. This paper attempts to fill the gap. Using novel hand-collected data on 3912 tranches of collateralized loan obligations we document the rating practices of CLOs and analyze their structures.     

An analytical approach for systematic risk sensitivity of structured finance products

The global financial crisis has shown that many financial institutions dealing with credit derivatives were exposed to severe unexpected losses. This indicates that systematic influences are decisively underestimated particularly with regard to structured products like securitized tranches of collateralized debt obligations. Our analytical study addresses these systematic effects: We provide a simple model which allows a closed-form comparison of both bonds and tranches with respect to their systematic risk. We demonstrate that the exposure to systematic risk of tranches may be many times higher than the exposure of bonds, even if both products share the same rating grade, e.g., an ‘AAA’ rating, measured by either default probability or expected loss. Particularly in economic downturns, default rates of tranches may be multiples of those of bonds. Our results help understand high default rates of tranches during the financial crisis and show that classical ratings are insufficient metrics for measuring risks of structured products.     

Disagreement,tastes, and asset prices

Standard asset pricing models assume that: (i) there is complete agreement among investors about probability distributions of future payoffs on assets; and (ii) investors choose asset holdings based solely on anticipated payoffs; that is, investment assets are not also consumption goods. Both assumptions are unrealistic. We provide a simple framework for studying how disagreement and tastes for assets as consumption goods can affect asset prices.     

CDOs and the financial crisis: Credit ratings and fair premia

We study risk and return characteristics of CDOs using the market standard models. We find that fair spreads on CDO tranches are much higher than fair spreads on similarly-rated corporate bonds. Our results imply that credit ratings are not sufficient for pricing, which is surprising given their central role in structured finance markets. This illustrates limitations of the rating methodologies that are solely based on real-world default probabilities or expected losses and do not capture risk premia. We also demonstrate that CDO tranches have large exposure to systematic risk and thus their ratings and prices are likely to decline substantially when credit conditions deteriorate.     

Commitment, banks and markets

We examine how banks and financial markets interact with one another to provide liquidity to investors. The critical assumption is that financial markets are characterized by limited enforcement of contracts, and in the event of default only a fraction of borrowers’ assets can be seized. Limited enforcement reduces the fraction of assets that can be used as collateral and thus individuals subject to liquidity shocks face borrowing constraints. We show how banks endogenously overcome these borrowing constraints by pooling resources across several depositors, and increase the liquidity provided by financial markets.     

The price of sin: The effects of social norms on markets

We provide evidence for the effects of social norms on markets by studying “sin” stocks—publicly traded companies involved in producing alcohol, tobacco, and gaming. We hypothesize that there is a societal norm against funding operations that promote vice and that some investors, particularly institutions subject to norms, pay a financial cost in abstaining from these stocks. Consistent with this hypothesis, we find that sin stocks are less held by norm-constrained institutions such as pension plans as compared to mutual or hedge funds that are natural arbitrageurs, and they receive less coverage from analysts than do stocks of otherwise comparable characteristics. Sin stocks also have higher expected returns than otherwise comparable stocks, consistent with them being neglected by norm-constrained investors and facing greater litigation risk heightened by social norms. Evidence from corporate financing decisions and the performance of sin stocks outside the US also suggest that norms affect stock prices and returns.     

Disagreement and the Cost of Capital

We assess how forms of disagreement among investors affect a firm's cost of capital. Firms experience a lower cost of capital if investors perceive that other investors are ignoring relevant disclosures (perceived errors of omission), but a higher cost of capital if investors perceive that others are responding to irrelevant disclosures (perceived errors of commission). The impact of these two sources of disagreement on the cost of capital is determined by the distribution of opinion and the nature of disclosure. For example, even though aggregated disclosures reveal less to investors, aggregated disclosures may decrease the cost of capital by eliminating disagreement associated with perceived errors of commission. These and additional results arise because the cost of capital is driven not only by investors’ uncertainty about the firm's future earnings performance, but also by investors’ uncertainty about the evolution of beliefs, which partly determines the path of prices.     

The market for new issues of municipal bonds: The roles of transparency and limited access to retail investors

I examine how transparency and interdealer trading affects prices investors pay in municipal bond offerings. Real-time trade reporting for municipal bonds started January 31, 2005. The dispersion of purchase prices fell sharply at that time. There was little impact on average markups for most trades, but they increased for purchases of more than $100,000. Bonds often pass through a series of dealers before being placed with a buy-and-hold investor. As the interdealer trades progress, trade sizes decline and trade prices rise. Markups on investor purchases increase with the amount of interdealer trading before the trade.     

Collateral pricing

We examine how collateral affects the cost of debt capital. Using a novel data set of secured debt issued by U.S. airlines, we construct industry-specific measures of collateral redeployability. We show that debt tranches that are secured by more redeployable collateral exhibit lower credit spreads, higher credit ratings, and higher loan-to-value ratios—an effect which our estimates show to be economically sizeable. Our results suggest that the ability to pledge collateral, and in particular redeployable collateral, lowers the cost of external financing and increases debt capacity.     

Are All Ratings Created Equal? The Impact of Issuer Size on the Pricing of Mortgage‐Backed Securities

Initial yields on both AAA‐rated and non‐AAA rated mortgage‐backed security (MBS) tranches sold by large issuers are higher than yields on similar tranches sold by small issuers during the market boom years of 2004 to 2006. Moreover, the prices of MBS sold by large issuers drop more than those sold by small issuers, and the differences are concentrated among tranches issued during 2004 to 2006. These results suggest that investors price the risk that large issuers received more inflated ratings than small issuers, especially during boom periods.     

The price of skill: Performance evaluation by households

Skilled investors make money off uninformed investors. By acting as intermediaries, they provide a hedge to the uninformed investors themselves. I present a model in which households have imperfect information about expected returns. Non-traded income shocks lead them to rebalance, sometimes at the wrong time. Active funds hedge this risk by trading on superior information. In equilibrium, they pay off when non-traded income disappoints, earning a premium that makes them appear to underperform index funds after fees. Empirical results using aggregate fund flows support the model. A corresponding asset pricing test can account for the apparent underperformance of active funds.     

Active loan trading

Using a novel dataset of leveraged loan trades executed by managers of collateralized loan obligations (CLOs), we document the importance of “active loan trades” – trades executed at a manager’s discretion. More active trading increases the returns to CLO equity investors, lowers collateral portfolio default rates, and increases the manager’s chances of closing a new deal. Examining the observed loan trades, we find that more active CLOs trade at better prices than less active CLOs, selling leveraged loans earlier and before they get downgraded. Our findings suggest that more active CLOs are better at anticipating deteriorations in loan credit quality.     

Non-rating revenue and conflicts of interest

Rating agencies produce ratings used by investors, but obtain most of their revenue from issuers, leading to a conflict of interest. We employ a unique data set on the use of non-rating services, and the associated payments, in India, to test if this conflict affects ratings quality. Agencies rate issuers that pay them for non-rating services higher (than agencies not hired for such services). Such issuers also have higher default rates. Both effects are increasing in the amount paid. These results suggest that issuers which hire agencies for non-rating services receive higher ratings despite having higher default risk.     

Valuation of collateralized debt obligations with hierarchical Archimedean copulae

Modelling portfolio credit risk is one of the crucial challenges faced by financial services industry in the last few years. We propose the valuation model of collateralized debt obligations (CDO) based on hierarchical Archimedean copulae (HAC) with up to three parameters, with default intensities calibrated to market data and with random loss given defaults that are correlated with default times. The methods presented are used to reproduce the spreads of the iTraxx Europe tranches. Our approach describes the market prices better than the standard pricing procedure based on the Gaussian distribution. We also obtain a flat correlation smile across tranches thereby solving the implied correlation puzzle.     

Incentives to innovate and financial crises

In this paper I develop a model of a competitive financial system with unrestricted but costly entry and an endogenously determined number of competing financial institutions (“banks” for short). Banks can make standard loans on which plentiful historical data are available and unanimous agreement exists on default probabilities. Or banks can innovate and make new loans on which limited historical data are available, leading to possible disagreement over default probabilities. In equilibrium, banks make zero profits on standard loans and positive profits on innovative loans, which engenders innovation incentives for banks. But innovation brings with it the risk that investors could disagree with the bank that the loan is worthy of continued funding and hence could withdraw funding at an interim stage, precipitating a financial crisis. The degree of innovation in the financial system is determined by this trade-off. Welfare implications of financial innovation and mechanisms to reduce the probability of crises are discussed.     

Hedging structured credit products during the credit crisis: A horse race of 10 models

Pricing and hedging structured credit products poses major challenges to financial institutions. This paper puts several valuation approaches through a crucial test: How did these models perform in one of the worst periods of economic history, September 2008, when Lehman Brothers went under? Did they produce reasonable hedging strategies? We study several bottom-up and top-down credit portfolio models and compute the resulting delta hedging strategies using either index contracts or a portfolio of single-name CDS contracts as hedging instruments. We compute the profit-and-loss profiles and assess the performances of these hedging strategies. Among all 10 pricing models that we consider the Student-t copula model performs best. The dynamical generalized-Poisson loss model is the best top-down model, but this model class has in general problems to hedge equity tranches. Our major finding is however that single-name and index CDS contracts are not appropriate instruments to hedge CDO tranches.     

Securitization of Longevity Risk Using Percentile Tranching

Securitizations that transfer risk to the financial markets are a potential solution to longevity risk in the annuity business. The classical Lee–Carter model is applied to generate the future stochastic survival distribution. A method to design inverse survivor bonds using percentile tranches and to calculate the security prices is presented. The percentile tranche method is a simple and practical way for the issuer to design and price the security. This method can serve to identify the risk–yield relationship, which can provide investors with clear insight regarding the appropriate choice of tranches.