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A callable bond
(or redeemable bond) is a
bond whose
indenture includes one or more
call
provisions providing for the early retirement ("call" or
"redemption") of the bond. Call provisions
may provide for optional redemption,
extraordinary redemption or
sinking fund redemption. When included in
a bond's indenture, extraordinary and sinking fund redemption are "boiler
plate" provisions that usually afford the issuer little opportunity to
benefit at investors' expense. Form an investment standpoint, it is
optional redemption that is interesting or a cause for concern. This
article focuses exclusively on callable bonds with optional redemption
provisions.
Such callable bonds are especially popular in
the United States, where corporate bonds
and municipal bonds are often
callable. US Treasuries generally
are not callable. Most callable bonds are
coupon bonds.
Convertible bonds
are often callable. Zero-coupon bonds
sometimes are.
A call provision
need not be exercised to the bond holder's economic detriment. For example, an issuer might exercise a
call provision to retire a secured bond whose indenture places unwanted
restrictions on the sale of
collateral. This might be inconvenient for
investors, but it would do them little economic harm. Such redemptions are
rare. Generally, a bond is called when it is economically beneficial for
the issuer to do so—and economically detrimental to bond holders. The
typical scenario is that interest rates fall, so
the issuer calls the bonds and
issue new bonds at the lower interest rates. Such a transaction is called a
refunding. It benefits the issuer, but
investors are forced to surrender their high-coupon bonds and reinvest in
the lower interest rate environment.
In the secondary
market, callable bonds don't exhibit the same price sensitivities as
non-callable bonds. If interest rates drop, a non-callable bond's market
price will rise. This tendency is muted in a callable bond, since falling
interest rates make it likely that the bond will be called. Once the
first
call date has passed, the bond's
clean
price won't generally rise above the
call price. As is apparent
in Exhibit 1, callable bonds tend to have a shorter
duration and lower convexity
than do comparable non-callable bonds.
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The price behavior of a callable bond is
compared with that of a similar non-callable bond. As interest rates
drop, their prices diverge, reflecting the fact that the callable
bond is likely to be called. |
A callable bond
can be thought of a non-callable bond bundled with a
short
call option on
that non-callable bond:
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callable bond = non-callable bond – call option |
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The bond holder
is short the call option, and the issuer is
long
the call option. The option has economic value, so the issuer compensates
investors with a higher nominal yield than would
be payable on a comparable non-callable bond. That higher yield is like an
option premium the issuer
pays the bond holder for the call option.
The bundled short
call option makes callable bonds very difficult to analyze. The
yield on a
non-callable bond depends upon interest rates and the issuer's
credit
quality. The yield on a callable bond depends upon both of these and the
value of the embedded call option. This makes yields on callable and
non-callable
bonds not directly comparable. Also, yields on two callable bonds cannot be
directly compared either, since their call features may differ in terms of
call protection,
call schedules and the degree to which the call options
are in-the-money or
out-of-the-money. Further
complicating matters, the value of the call option depends on the
volatility of interest rates, which can
change unpredictably.
There is also the
question of what metric of
yield to consider when comparing bonds. Nominal yield
and current yield are problematic with any bond.
While yield to maturity is useful for comparing
non-callable bonds, it is somewhat meaningless for callable bonds—which
may be called long before they mature. Yield metrics designed specifically
for callable bonds—such as yield to first call or
yield to worst—offer an indicating of value that
is crude at best.
Sophisticated
analysis of callable bonds requires the use of
financial engineering techniques
that simultaneously value the credit risk,
interest rate risk and optionality of
a callable bond. Few investors have the resources to perform such
analyses, although bond dealers generally do.
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