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Credit rating agencies and the subprime crisis

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Through Security (finance) and S&P Global Ratings

The pools of debt the agencies gave their highest ratings to included over three trillion dollars of loans to homebuyers with bad credit and undocumented incomes through 2007. Hundreds of billions of dollars' worth of these triple-A securities were downgraded to "junk" status by 2010, and the writedowns and losses came to over half a trillion dollars.

This led "to the collapse or disappearance" in 2008–09 of three major investment banks (Bear Stearns, Lehman Brothers, and Merrill Lynch), and the federal government's buying of $700 billion of bad debt from distressed financial institutions.

Impact on the crisis

Credit rating agencies came under scrutiny following the mortgage crisis for giving investment-grade, "money safe" ratings to securitized mortgages (in the form of securities known as mortgage-backed securities (MBS) and collateralized debt obligations (CDO)) based on "non-prime"—subprime or Alt-A—mortgages loans.

Demand for the securities was stimulated by the large global pool of fixed income investments which had doubled from $36 trillion in 2000 to $70 trillion by 2006—more than annual global spending—and the low interest rates from competing fixed income securities, made possible by the low interest rate policy of the U.S. Federal Reserve Bank for much of that period. These high ratings encouraged the flow of global investor funds into these securities funding the housing bubble in the US.

Ratings were/are vital to "private-label" asset-backed securities—such as subprime mortgage-backed securities (MBS), and collateralized debt obligations (CDO), "CDOs squared", and "synthetic CDOs"—whose "financial engineering" make them "harder to understand and to price than individual loans".

Earlier traditional and more simple "prime" mortgage securities were issued and guaranteed by Fannie Mae and Freddie Mac—"enterprises" sponsored by the Federal government. Their safety wasn't questioned by conservative money managers. Non-prime private label mortgage securities were neither made up of loans to borrowers with high credit ratings nor insured by a government enterprise, so issuers used an innovation in securities structure to get higher agency ratings. They pooled debt and then "sliced" the result into "tranches", each with a different priority in the debt repayment stream of income. The most "senior" tranches highest up in priority of revenue—which usually made up most of the pool of debt—received the triple A ratings. This made them eligible for purchase by the pension funds and money market funds restricted to top-rated debt, and for use by banks wanting to reduce costly capital requirements under Basel II.

The complexity of analyzing the debt pool mortgages and tranche priority, and the position of the Big Three credit rating agencies "between the issuers and the investors of securities", is what "transformed" the agencies into "key" players in the process, according to the Financial Crisis Inquiry Report. "Participants in the securitization industry realized that they needed to secure favorable credit ratings in order to sell structured products to investors. Investment banks therefore paid handsome fees to the rating agencies to obtain the desired ratings."

According to the CEO of a servicer of the securitization industry, Jim Callahan of PentAlpha, "The rating agencies were important tools to do that because you know the people that we were selling these bonds to had never really had any history in the mortgage business. ... They were looking for an independent party to develop an opinion,"

From 2000 to 2007, Moody's rated nearly 45,000 mortgage-related securities—more than half of those it rated—as triple-A. In contrast only six (private sector) companies in the United States were given that top rating.

By December 2008, there were over $11 trillion structured finance securities outstanding in the US bond market debt.

CDOs

Rating agencies were even more important in disposing of the MBS tranches that could not be rated triple A. Although these made up a minority of the value of the MBS tranches, unless buyers were found for them, it would not be profitable to make the security in the first place. And because traditional mortgage investors were risk-averse (often because of SEC regulations or restrictions in their charters), these less-safe tranches were the most difficult to sell.

To sell these "mezzanine" tranches, investment bankers pooled them to form another security—known as a collateralized debt obligation (CDO). Though the raw material of these "obligations" was made up of BBB, A−, etc. tranches, the CRAs rated 70% to 80% of the new CDO tranches triple A. The 20–30% remaining mezzanine tranches were usually bought up by other CDOs, to make so-called "CDO-Squared" securities which also produced tranches rated mostly triple A by rating agencies. This process was disparaged as a way of transforming "dross into gold" or "ratings laundering" by at least some business journalists.

Trust in rating agencies was particularly important for CDOs for another reason—their contents were subject to change, so CDO managers "didn't always have to disclose what the securities contained". This lack of transparency did not affect demand for the securities. Investors "weren't so much buying a security" as they "were buying a triple-A rating", according to business journalists Bethany McLean and Joe Nocera.

Still another structured product was the "synthetic CDO". Cheaper and easier to create than original "cash" CDOs, these securities did not provide funding for housing. Instead synthetic CDO-buying investors were in effect providing insurance (in the form of "credit default swaps") against mortgage default. Synthetics "referenced" cash CDOs, and rather than providing investors with interest and principal payments from MBS tranches, they paid insurance premium-like payments from credit default swap "insurance". If the referenced CDOs defaulted, investors lost their investment, which was paid out as insurance. Because synthetics referenced another (cash) CDO, more than one—in fact numerous—synthetics could be made to reference the same original. This multiplied the effect if a referenced security defaulted.

Here again the giving of triple-A ratings to "large chunks" of synthetics by the rating agencies was crucial to the securities' success. The buyer of synthetic tranches (who often went on to lose his investment) was seldom an analyst "who had investigated the mortgage-backed security", was aware of deteriorating mortgage underwriting standards, or that the payments they would receive were often coming from investors betting against mortgage-backed security solvency. Rather, "it was someone who was buying a rating and thought he couldn't lose money."

Downgrades and writedowns

By the end of 2009, over half of the collateralized debt obligations by value issued at the end of the housing bubble (from 2005–2007) that rating agencies gave their highest "triple-A" rating to, were "impaired"—that is either written-down to "junk" or suffered a "principal loss" (i.e. not only had they not paid interest but investors would not get back some of the principal they invested). The Financial Crisis Inquiry Commission estimates that by April 2010, of all mortgage-backed securities Moody's had rated triple-A in 2006, 73% were downgraded to junk.

Mortgage underwriting standards deteriorated to the point that between 2002 and 2007 an estimated $3.2 trillion in loans were made to homeowners with bad credit and undocumented incomes (e.g., subprime or Alt-A mortgages) and bundled into MBSs and collateralized debt obligations that received high ratings and therefore could be sold to global investors. Higher ratings were believed justified by various credit enhancements including over-collateralization (i.e., pledging collateral in excess of debt issued), credit default insurance, and equity investors willing to bear the first losses. But as of September 2008, bank writedowns and losses on these investments totaled $523 billion.

Rating agencies lowered the credit ratings on $1.9 trillion in mortgage backed securities from the third fiscal quarter (1 July—30 September) of 2007 to the second quarter (1 April–30 June) of 2008. One institution, Merrill Lynch, sold more than $30 billion of collateralized debt obligations for 22 cents on the dollar in late July 2008.

The net worth of financial institutions owning the newly downgraded securities declined, requiring the institutions to acquire additional capital, to maintain capital ratios, which in turn often lowered the net-worth value of the institutions above and beyond the low of value of the downgraded securities. Adding to the financial chain reaction were regulations—governmental or internal—requiring some institutional investors to carry only investment-grade (e.g., "BBB" and better) assets. A downgrade below that meant forced asset sales and further devaluation.

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