Wednesday, April 28, 2010

Credit Ratings vs. Credit Default Swaps

As an alternative to relying overly on ratings produced by credit rating agencies, several ratings reform proposals offer the usage of bond or credit default swap (CDS) prices or spreads as a more plausible option. Some of these proposals are positively suggestive of the fact that market prices are both more accurate and more predictive than credit ratings.

I’m not convinced.

Firstly, with ratings being so deeply embedded throughout our financial structure, the ratings of the assets themselves become an integral component of the market-implied risk assessment. For example, even when analyzing securitized products Vink and Fabozzi (2009) show credit ratings to be a major factor accounting for the movement of primary market spreads. Thus, for any proposal to be convincing it would have to test the accuracy and reliability of CDS spreads on unrated bonds or companies. Alternatively, a study would need to compare the performance of traded securities whose ratings are not publicly known (also known as shadow ratings) to the performance of those shadow ratings.

Secondly, bond yields (or spreads-to-swaps) and credit default swap premiums are largely incomparable to credit ratings for many reasons. These differences will have to be tackled in a separate piece, but at the very least there’s that non-insignificant concept of liquidity. Both CDS premiums and bond yields include the various risks – not just credit risks – that come with investing in, or buying protection on, a security. Credit ratings speak solely to long-term credit risks.

One may argue that the ratings were far less accurate than CDS spreads during the crisis, and that this (i.e., during a market dislocation) is the only time we depend on accurate default projections and we should therefore abolish rating agencies in general. While I don’t wish to complain of these proposals, I fear that they complain unfairly of the rating agencies.

Yes the CDS spreads may better reflect default probability during a crisis. By definition they’re more adaptive to changing market conditions, versus the ratings which are long-term predictors. But would you want ratings to change in as volatile a fashion as CDS spreads? Would you want ratings to depend on headline news, or on audited (or lightly audited) financial data? Also, one shouldn’t forget that CDS spreads on CDOs and RMBS tranches were just as poor reflections of market-perceived asset quality before the crisis. The crisis could only occur, in part, because the banks were able to buy protection so cheaply from the monolines, by way of being long the CDS -- the infamous negative basis trades.

But even if these proposals made sense and even if their hypotheses were correct, they would be missing at least one crucial point: we need ratings. Meaningful ratings are essential – certainly now. Let me explain why, albeit by way of a long-winded explanation.

For financial reform to be successful it needs ultimately to deal with the flaws in our banks’ risk management procedures – and to deal with them in an environment in which the very serious practice of risk mitigation is left by senior management to risk managers, just as the serious business of growing revenues while attending to shareholder pressure is left by risk managers to upper management.

That these two functions are more adversarial than independent in nature is a concept not to be lost on us. Overly cautious risk management might hinder the implementation of growth opportunities, or the extent thereof. At times, indeed, they may be thought by the skeptic to be mutually exclusive.

Indeed the overpowering pressures that come with business initiatives can influence even the most judicious risk manager’s ability to perform her function in an objective manner, even though her function ought to be both separate from and independent of the business strategies. (See for example “Lehman’s Worst Offense: Risk Management.”)

With both traders and management being compensated for revenue generation, and with prudent risk managers acting only as a hindrance to the initiation and exploitation of growth opportunities, there remains little incentive for senior managers to maintain a healthy risk management environment. Instead of cultivating an environment in which risk managers are educated in monitoring the real risks (which requires expensive resources including personnel, data and systems) they are seen rather as a burden and a cost center, and are therefore starved of the resources necessary to question traders, trades, and trading strategies.

In sum, we remain in the infancy of creating a functioning risk control practice in place at our major banks. We are yet to promote adequate business-peer challenge processes and our price verification processes remain immature. Credit ratings, if created and applied properly, can provide a healthy starting point for internal skepticism; they can provide the independent credit risk assessment that supplements an analysis performed by the front-office or by the back-office.


CDS spreads are untested as a predictor of long-term default probability on unrated securities. Perhaps the reliability of CDS spreads depends on the underlying referenced entity being rated. There’s no doubt that CDS spreads are useful indicators – but I seriously doubt that they’re anywhere near as useful as ratings in predicting long-term default probabilities or losses.

I remain convinced there's an important place in our market for one or more independent agencies to provide their objective opinions in the form of a rating. For ratings reform to be successful, however, requires that the necessary measures be put in place to ensure that rating analysts are unfettered by market share concerns, and are incentivized only by ratings quality and accuracy. If we can achieve these objectives, ratings will return to providing a meaningful utility.

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