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Collateralized debt obligations are
securitized interests in pools
of—generally non-mortgage—assets. Assets—called
collateral—usually comprise loans
or debt instruments. A CDO may be called a
collateralized loan obligation
(CLO) or collateralized bond
obligation (CBO) if it holds only loans or
bonds, respectively.
Investors bear the credit risk of the collateral. Multiple
tranches
of securities are issued by the CDO, offering investors various maturity
and credit risk characteristics. Tranches are categorized as senior,
mezzanine, and subordinated/equity, according to their degree of credit
risk. If there are defaults or the CDO's collateral otherwise
underperforms, scheduled payments to senior tranches take precedence over
those of mezzanine tranches, and scheduled payments to mezzanine tranches
take precedence over those to subordinated/equity tranches. Senior and
mezzanine tranches are typically
rated, with the former receiving ratings of A to AAA and the latter
receiving ratings of B to BBB. The ratings reflect both the
credit quality of underlying
collateral as well as how much protection a given tranch is afforded by
tranches that are subordinate to it.
A CDO has a sponsoring organization, which establishes a
special
purpose vehicle to hold collateral and issue securities. Sponsors
can include banks, other financial institutions or investment managers, as
described below. Expenses associated with running the special purpose
vehicle are subtracted from cash flows to investors. Often, the sponsoring
organization retains the most subordinate equity tranch of a CDO.
For someone who is new to CDOs, the instruments can seem
difficult to understand. This is because there are actually a variety of
different instruments that are all lumped together under the moniker "CDO."
Some of the different structures are detailed below.
One important distinction is that between
static and managed
deals. With the former, collateral is fixed through the life of the CDO.
Investors can assess the various tranches of the CDO with full knowledge
of what the collateral will be. The primary risk they face is credit risk.
With a managed CDO, a portfolio manager is appointed to actively manage
the collateral of the CDO. The life of a managed deal can be divided into
three phases:
Ramp-up lasts about a year, during which
the portfolio manager initially invests the proceeds from sales of the
CDO's securities.
The reinvestment or revolver period lasts
five or more years. The manager actively manages the CDO's collateral,
reinvesting cash flows as well as buying and selling assets.
In the final period, collateral matures or
is sold. Investors are paid off. At the time they purchase the CDO's securities, investors
in a managed deal do not know what specific assets the CDO will invest in,
and those assets will change over time. All investors know is the identity
of the portfolio manger and the investment guidelines that he will work
under. Accordingly, investors in managed CDOs face both credit risk as
well as the risk of poor management. Investors have the added burden of
paying portfolio management fees. Today, most CDOs are managed deals. In
many cases, the portfolio manager is the sponsor.
CDOs can be structured as cash-flow
or market-value deals. The former is
analogous to a
CMO.
Cash flows from collateral are used to pay
principal and interest to investors.
If such cash flows prove inadequate, principal and interest is paid to tranches according to seniority. At any point in time, all immediate
obligations to a given tranch are met before any payments are made to less
senior tranches.
With a market value deal, principal and interest payments
to investors come from both collateral cash flows as well as sales of
collateral. Payments to tranches are not contingent on the adequacy of the
collateral's cash flows, but rather the adequacy of its
market value.
Should the market value of collateral drop below a certain level, payments
are suspended to the equity tranch. If it falls even further, more senior
tranches are impacted. An advantage of a market value CDO is the added
flexibility they afford the portfolio manager. She is not constrained by a
need to match the cash flows of collateral to those of the various
tranches.
Another distinction is that between
balance-sheet CDOs and
arbitrage CDOs. These names correspond to
respective motivations of the sponsoring organization. With a balance
sheet deal, the sponsoring organization is a bank or other institution
that holds—or anticipates acquiring—loans or debt that it wants to remove
from its balance sheet. Similar to a traditional
ABS, the CDO is a
vehicle for it to do so. Arbitrage deals are motivated by the
opportunity to add value by repackaging
collateral into tranches. This is the same motivation for most
CMOs. In
finance, the law of one price suggests that the securities of a CDO should
have the same market value as its underlying collateral. In practice, this
is often not the case. Accordingly, a CDO can represent a theoretical
arbitrage.
Much of the "arbitrage" in a CDO arises from a persistent
market imperfection related to the somewhat arbitrary distinction between
investment grade and
junk debt. Many institutional investors
face limits on their ability to hold below-investment-grade debt. This can
take the form of regulations,
capital requirements, and investment
restrictions imposed by management. Insurance companies, pension plans,
banks and mutual funds can all face some sorts of limitations. As a
result, junk often trades at spreads to investment grade debt that are
wider than might be explained purely by credit considerations. With a CDO,
a portfolio of below-investment-grade debt can be repackaged into
tranches, some of which receive investment grade—and even AAA—ratings.
CDOs are mostly about repackaging and transferring credit
risk. While it is possible to issue a CDO backed entirely by high-quality
bonds, the structure is more relevant for collateral comprised partially
or entirely of marginal obligations.
This leads us to another important distinction: that
between cash and
synthetic CDOs. So far, we have been discussing cash CDOs. These
expose investors to credit risk by actually holding collateral that is
subject to default. By comparison, a synthetic deal holds high quality or cash collateral
that has little or no default risk. It exposes investors to credit risk by
adding credit default swaps
(CDSs) to the collateral. Synthetic CDOs can be static or managed.
They can be balance-sheet or arbitrage deals.
Arbitrage synthetic deals are motivated by regulatory or
practical considerations that might make a bank want to retain ownership
of debt while achieving capital relief through CDSs. In this case, the
sponsoring bank has a portfolio of obligations, called the reference
portfolio. It retains that portfolio, but offloads its credit risk by
transacting CDSs with the CDO.
For arbitrage synthetic deals, two advantages are
an
abbreviated ramp-up period (for managed deals), and
the possibility
that selling protection through CDSs can be less expensive than directly
buying the underlying bonds. This is often true at the lower end of
the credit spectrum.
The biggest advantage to (balance sheet or arbitrage)
synthetic CDOs often is the fact that they don't have to be fully funded.
For a cash CDO to have credit exposure to
USD 100MM
of bonds, it must attract USD 100MM in investments so it can buy those
bonds. With a synthetic deal, credit exposure to USD 1000MM in obligations
might be supported by just USD 150MM in high-quality collateral. In such a
partially-funded deal, the entire USD 1000MM reference portfolio is
tranched, but only the lower-rated tranches are funded. In this example,
the most senior USD 850MM tranch would be called a super senior tranch. It
might be retained by the sponsor or sold off as a CDS. The funded piece
might comprise USD 100MM of investment grade tranches and USD 50MM of
mezzanine and unrated tranches.
In arbitrage deals, partial funding offers higher capital
relief than does full funding under the
Basel capital requirements.
For synthetic deals, it is generally less expensive to sell the super
senior tranch as a CDS than it would be to fund that tranch.
Analyzing CDOs is difficult. Not only is there an entire
portfolio of credits to analyze, in managed deals, an investor won't know
what collateral will be purchased. On top of this is the added complexity
of the tranching, which must also be analyzed. Sophisticated
portfolio credit risk
models should be used. Needless to say, there is
much potential for manipulation or abuse by sponsors. CDOs are appealing
to investors because of the attractive
yields they offer, but this market,
more than most, is one of caveat emptor.
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