Can We Afford a Housing Boom?

12 September 2016

3 min read

Michael Canter, PhD| Director; Chief Investment Officer—Securitized Assets

The US housing market is healthy, but some market participants worry it may be starting to heat up too much. We think that’s a mistake—and an opportunity. That’s because mortgages today have little in common with the risky loans made before the housing crisis.

The confusion, in our view, stems from how people assess the credit quality of today’s loans. Before investors and analysts buy a residential mortgage-backed security (RMBS)—or assign a credit rating to one—they naturally want to know something about the quality of the underlying mortgage loans and the potential for defaults. The easiest way to do that is by reviewing average credit statistics.

For instance, there are FICO scores, which assess the overall credit strength of borrowers. Loan-to-value (LTV) ratios compare the size of the loan to the value of the property. And debt-to-income ratios indicate how much of a borrower’s monthly income goes to debt payments.

The Problem With Averages

Here’s the problem with focusing on the top-level averages: they can be misleading. These credit statistics (and a few others) can tell you a lot about the probability of default for an individual mortgage loan. But when those same statistics are averaged across thousands of loans in an RMBS, they become less meaningful.

The really meaningful aspect of loan analysis is how the different credit metrics relate and interact to define the riskiness of individual loans. For instance, do borrowers with low FICO scores also have high LTV ratios, meaning weak credit and high debt? Or do they have strong credit and more debt? And how are the different risk levels distributed throughout the RMBS?

Piling Risk On Top Of Risk

The practice of having multiple high-risk red flags in an individual loan is known as risk layering. Some risk layering is inevitable; borrowers rarely have perfect credit. But even a small increase in the number of negative credit metrics in a loan pool can substantially increase default probability.

In other words, risk layering—not average credit metrics—drives RMBS performance. The more risk layering there is, the higher the chances of default and the greater the potential loss.

Before the housing crisis hit, non-agency RMBS had a lot of risk layering. After all, subprime lenders routinely originated interest-only loans and lent money to borrowers without verifying their income or even requiring a down payment. This is a big reason why so many underlying loans defaulted when the housing bubble burst. We estimate that about half the losses experienced by precrisis RMBS were driven by risk layering.

Battle Of The RMBS Vintages

Many casual observers might look at surface-level metrics on the new risk-sharing transactions from government-sponsored enterprises Fannie Mae and Freddie Mac and assume that the underlying loans would default in large numbers if the US housing rebound were to reverse course. (Risk-sharing transactions are also known as Credit Risk Transfer securities [CRTs] and are issued under the names STACR by Freddie Mac and CAS by Fannie Mae.)

However, a closer look at the collateral suggests that isn’t necessarily true. Comparing precrisis RMBS to the new risk-sharing transactions (Display) shows that risk-sharing transactions have much less risk layering. We can see this by looking at the presence of various combinations of credit metrics that indicate riskier loans.

New Risk-Sharing Transactions: Less Risk Layering

Share of Mortgages in Risky Cohorts (Percent)

As of January 31, 2016
Weak Credit and High Debt Service cohort defined as borrowers with FICO score of less than 700 and debt-to-income (DTI) ratio greater than 45; Weak Credit and High Leverage cohort defined as borrowers with FICO score of less than 700 and current loan-to-value (CLTV) ratio greater than 80; High Leverage and High Debt Service cohort defined as CLTV greater than 80 and DTI ratio less than 45
Vintage statistics: 2006 data based on Freddie Mac 30-year purchase originations; 2016 data derived from STACR 2016-DNA1, a GSE credit risk transfer security
Source: Bank of America Merrill Lynch

For example, we isolated mortgage loans where the borrowers had both low FICO scores (weak credit) and high debt-to-income ratios. In the 2006 agency RMBS, 10.9% of underlying mortgage loans had that combination; for the 2016 risk-sharing transaction, only 0.7% did.

We saw the same disparity in other risky credit combinations: weak credit combined with high leverage (a high loan-to-value ratio) and high leverage combined with a high debt-to-income ratio. All of these risky cohorts were much smaller in the new risk-sharing transactions.

Today’s Mortgages Are Different

That’s because lending standards are now extremely tight: only high-quality borrowers are getting loans. Borrowers with lower-than-average FICO scores tend to have offsetting positives: maybe they’ve made a large down payment, or have a very low debt-to-income ratio or loan-to-value ratio. As a result, we think these transactions would come through another period of market stress or housing slowdown with few defaults.

Some investors, though, are acting as if it were still 2007. They’re treating the new breed of mortgage-backed securities from GSEs as if they had a lot of risk layering.

As a result, we think many risk-sharing transactions are cheap relative to the amount of credit risk being taken. If you have the patience and resources to dig deeper into the underlying loans, this presents great relative value.

As we’ve said before, we think the GSE credit risk-sharing transactions offer a great opportunity to get access to newly originated loans in the US mortgage market. This may be underappreciated now—but we doubt it will stay that way.

The views expressed herein do not constitute research, investment advice or trade recommendations and do not necessarily represent the views of all AB portfolio-management teams.

About the Authors

This is a marketing communication. This information is provided by AllianceBernstein (Luxembourg) S.à r.l. Société à responsabilité limitée, R.C.S. Luxembourg B 34 305, 2-4, rue Eugène Ruppert, L-2453 Luxembourg. Authorised in Luxembourg and regulated by the Commission de Surveillance du Secteur Financier (CSSF). It is provided for informational purposes only and does not constitute investment advice or an invitation to purchase any security or other investment. The views and opinions expressed are based on our internal forecasts and should not be relied upon as an indication of future market performance. The value of investments in any of the Funds can go down as well as up and investors may not get back the full amount invested. Past performance does not guarantee future results.

This information is directed at Professional Clients only and is not intended for public use.

Can We Afford a Housing Boom?

The Problem With Averages

Piling Risk On Top Of Risk

Battle Of The RMBS Vintages

Today’s Mortgages Are Different

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