» Maturity or term » Face value or par: Notional amount used to compute interest payments » Coupon rate: Determines the amount of each coupon payment, expressed as an » Priority in case
Trang 1z Introduction to bonds and bond markets
z Zero coupon bonds
» Bond Prices Over Time
» Yield Curve Revisited
» Interest rate sensitivity – Duration & Immunization
z Forward Rates
Trang 2Copyright © Michael R Roberts
What is a Bond and What are its Features?
z A bond is a security that obligates the issuer to make interest and principal
payments to the holder on specified dates.
» Maturity (or term)
» Face value (or par): Notional amount used to compute interest payments
» Coupon rate: Determines the amount of each coupon payment, expressed as an
» Priority in case of default
Coupon Rate Face Value Number of Coupon Payments per Year
Repayment Schemes
z Bonds with a balloon (or bullet) payment
» Pure discount or zero-coupon bonds
– Pay no coupons prior to maturity.
» Coupon bonds
– Pay a stated coupon at periodic intervals prior to maturity.
» Floating-rate bonds
– Pay a variable coupon, reset periodically to a reference rate
z Bonds without a balloon payment
» Perpetual bonds
– Pay a stated coupon at periodic intervals.
» Annuity or self-amortizing bonds
– Pay a regular fixed amount each payment period.
– Principal repaid over time rather than at maturity.
Trang 3Copyright © Michael R Roberts
Who Issues Bonds?
z US Government (Treasuries)
» T-bills: 4,13,16-week maturity, zero coupon bonds
» T-notes: 2,3,5,10 year, semi-annual coupon bonds
» T-bonds: 20 & 30-year, semi-annual coupon bonds
» TIPS: 5,10,20-year, semi-annual coupon bond, principal π-adjusted
» Strips: Wide-ranging maturity, zero-coupon bond, IB-structured
z Foreign Governments
z Municipalities
» Maturities from one month to 40 years, semiannual coupons
» Exempt from federal taxes (sometimes state and local as well).
» Generally two types: Revenue bonds vs General Obligation bonds
» Riskier than government bonds (e.g., Orange County)
Who Issues Bonds? (Cont.)
z Agencies:
» E.g Government National Mortgage Association (Ginnie Mae),
Student Loan Marketing Association (Sallie Mae)
» Most issues are mortgage-backed, pass-through securities.
» Typically 30-year, monthly paying annuities mirroring underlying
securities
» Prepayment risk.
z Corporations
» 4 types: notes, debentures, mortgage, asset-backed
» ~30 year maturity, semi-annual coupon set to price at par
» Additional features/provisions:
– Callable: right to retire all bonds on (or after) call date, for call price
– convertible bonds
– putable bonds
Trang 4Copyright © Michael R Roberts
Bond Ratings
Aaa AAA Highest quality Very small risk of default
Aa AA High quality Small risk of default
A A High-Medium quality Strong attributes, but potentially
B B Able to pay currently, but at risk of default in the future
Caa CCC Poor quality Clear danger of default
Ca CC High speculative quality May be in default
C C Lowest rated Poor prospects of repayment
The US Bond Market – Flows
Amount ($bil.) Source: Flow of Funds Data 2005-2007
132.3 104.4
94.5 Consumer Credit
1417.5
53.6 195 307.3
2005
1397.1
213.4 177.3 183.7
2006
1053.2
314.1 214.6 237.5
2007
Mortgages
Corporate Municipal U.S Gov.
Debt Instrument
Dollar volume of bonds traded daily is 10 times that of equity markets!
Outstanding investment-grade dollar denominated debt is about $8.3 trillion (e.g.,
treasuries, agencies, corporate and MBSs
Trang 5Copyright © Michael R Roberts
Zero Coupon Bonds (a.k.a Pure Discount Bonds)
z Notation Reminder:
» V n = B n = Market price of the bond in period n
» F = Face value
» R= Annual percentage rate
» m = compounding periods (annual Æ m = 1, semiannual Æ m = 2,…)
» i = Effective periodic interest rate; i=R/m
» T = Maturity (in years)
» N = Number of compounding periods; N = T*m
z Value a 5 year, U.S Treasury strip with face value of $1,000
The APR is 7.5% with quarterly compounding?
» Approach 1: Using R (APR) and i (effective periodic rate)
» Approach 2: Using r (EAR)
» Approach 3: Using r (periodic discount rate)
?
?
?
Trang 6Copyright © Michael R Roberts
Yield to Maturity
z The Yield to Maturity (YTM) is the one discount rate that
sets the present value of the promised bond payments equal to
the current market price of the bond
» Doesn’t this sound vaguely familiar…
z Example: Zero-Coupon Bond
» But this is just the IRR since
⎛ ⎞
Yields for Different Maturities
z Note: bonds of different maturities have different YTMs
Trang 7Copyright © Michael R Roberts
Spot Rates, Term Structure, Yield Curve
z A spot rate is the interest rate on a T-year loan that is to be made today
» r 1=5% indicates that the current rate for a one-year loan today is 5%.
» r 2=6% indicates that the current rate for a two-year loan today is 6%.
» Etc.
» Spot rate = YTM on default-free zero bonds.
z The term structure of interest rates is the series of spot rates r 1 , r 2 , r 3,…
relating interest rates to investment term
z The yield curve is just a plot of the term structure: interest rates against
investment term (or maturity)
» Zero-Coupon Yield Curve: built from zero-coupon bond yields (STRIPS)
» Coupon Yield Curve: built from coupon bond yields (Treasuries)
» Corporate Yield Curve: built from corporate bond yields of similar risk (i.e.,
credit rating)
Term Structure of Risk-Free U.S Interest
Rates, January 2004, 2005, and 2006
Trang 8Copyright © Michael R Roberts
Using the Yield Curve
z We should discount each cash flow by its appropriate discount
rate, governed by the timing of the cash flow
today (Use the term structure from January 2004)
z Generally speaking, we must use the appropriate discount rate
for each cash flow:
z All of our valuation formulas (e.g., perpetuity, annuity)
assume a flat term structure.
» I.e., there is only one discount rate for cash flows received at any point
C PV
r g
=
−
Trang 9Copyright © Michael R Roberts
Interest Rate Sensitivity Zero Coupon Bonds
z Why do zero-coupon bond prices change? Interest rates
change!
z The price of a zero-coupon bond maturing in one year from
today with face value $100 and an APR of 10% is:
bond, the interest rate increase to 15% What is the price of the
i
= +
Characterizing the Price Rate Sensitivity
of Zero Coupon Bonds
z Consider the following 1, 2 and 10-year zero-coupon bonds, all with
3 Longer term bonds are more sensitive to IR changes than short term bonds
4 The lower the IR, the more sensitive the price.
Trang 10Copyright © Michael R Roberts
Quantifying the Interest Rate Sensitivity
of Zero Coupon Bonds – DV01
z What’s the natural thing to do? Compute the derivative
» If we change the interest rate by a little (e.g., 0.0001 or 1 basis point) than
multiplying this number by the derivative should tell me how much the price
will change, all else equal (i.e., DV01 = Dollar Value of 1 Basis Point)
z Alternatively, we can just compute the prices at two different interest rates
and look at the difference: B 0 (i) – B 0 (i+0.0001)
2
2 0
i V
i V
z Consider an amortization bond maturing in two years with
semiannual payments of $1,000 Assume that the APR is 10%
with semiannual compounding
z How can we value this security?
1 Brute force discounting
2 Recognize the stream of cash flows as an annuity
Trang 11Copyright © Michael R Roberts
Replication
z Can we construct the same cash flows as our amortization
bond using other securities?
A First Look at Arbitrage
z What if the bond is selling for $3,500 in the market?
Trang 12Copyright © Michael R Roberts
Valuation of Straight Coupon Bond
Example
z What is the market price of a U.S Treasury bond that has a
coupon rate of 9%, a face value of $1,000 and matures
exactly 10 years from today if the interest rate is 10%
Present Value = Current Price = ?
Valuation of Straight Coupon Bond
General Formula
z What is the market price of a bond that has an annual coupon
C, face value F and matures exactly T years from today if the
required rate of return is R, with m-periodic compounding?
» Coupon payment is: c = C/m
» Effective periodic interest rate is: i = R/m
i
F i
i c
Zero Annuity
V
1 )
1 ( 1
0
Trang 13Copyright © Michael R Roberts
Relationship Between Coupon Bond Prices
and Interest Rates
z Bond prices are inversely related to interest rates (or yields).
z A bond sells at par only if its interest rate equals the coupon
rate
» Most bonds set the coupon rate at origination to sell at par
z A bond sells at a premium if its coupon rate is above the
Trang 14Copyright © Michael R Roberts
YTM and Bond
Price Fluctuations
Over Time
Yield to Maturity Coupon Bonds
z Recall: The Yield to Maturity is the one discount rate that sets the
present value of the promised bond payments equal to the current market
price of the bond
z Prices are usually given from trade prices
» need to infer interest rate that has been used
» This is not the annualized yield, which equals yield* = ( 1 + yield / m) m-1
z Typically must solve using a computer
» E.g., IRR function in excel or your calculator since:
m yield
F m
yield m
yield
c B
/ 1
/ 1
1 1
−
=
m yield
F m
yield m
yield
c B
/ 1
/ 1
1 1
−
=
Trang 15Copyright © Michael R Roberts
The Yield Curve Revisited
» Often referred to as “the yield curve”
» Same idea as the zero-coupon yield curve except we use the
yields from coupon paying bonds, as opposed to
zero-coupon bonds
– Treasury notes and bonds are semi-annual coupon paying bonds
» We often use On-the-Run Bonds to estimate the yields
– On-the-Run Bonds are the most recently issued bonds
Interest Rate Sensitivity
Duration
z The Duration of a security is the percent sensitivity of the
price to a small parallel shift in the level of interest rates
» A small uniform change dy across maturities might by 1 basis point.
» Duration gives the proportionate decline in value associated with a rise
in yield
» Negative sign is to cancel negative first derivative
z Alternatively, given a duration DB of a security with price B, a
uniform change in the level of interest rates brings about a
change in value of
1
B dB Duration D
B dy
= = −
B
Trang 16Copyright © Michael R Roberts
Duration of a Coupon Bond
which we can rearrange
1 1 Time in Years "Weight" on until n payment n payment
N
n n
z Compute the duration of a two-year, semi-annual, 10%
coupon, par bond, with face value of $100
Trang 17Copyright © Michael R Roberts
More on Duration
z Duration is a linear operator: D(B 1 + B 2 ) = D(B 1 ) + D(B 2 )
» The duration of a portfolio of securities is the value-weighted sum of
the individual security durations
» DVO1 is also a linear operator
z Duration is a local measure
» Based on slope of price-yield relation at a specific point
» Based on a bond of fixed maturity but maturity declines over time
z Bank of Philadelphia balance sheet (Figures in $billions, D=duration
assuming flat spot rate curve)
z Duration of liabilities =
z The problem:
» Increases in interest rates will decrease value of liabilities by more than assets
because of duration mismatch.
Liabilities & Shareholders Equity Assets
$25 Total Liabilities (D = ?)
25 Total Assets (D = 1)
$5 Shareholder Equity
$10 2-Year Notes (D = 1.77)
$10 Commercial Paper (D = 0.48)
?
Trang 18z We want our assets and liabilities to experience similar value
changes when interest rates change, so set these two
expressions to be equal and solve for D L (D A =1.0):
z What fraction of the bank’s liabilities should be in CP and
Notes in order to get a liability duration of 1.25
z How much money should the bank hold in CP and Notes in
order to get a liability duration of 1.25
z How should the bank alter their liabilities to achieve this
structure
?
?
?
Trang 19Copyright © Michael R Roberts
Forward Rates
z A forward rate is a rate agreed upon today, for a loan that is
to be made in the future (Not necessarily equal to the future
spot rate!)
» f2,1=7% indicates that we could contract today to borrow money at 7%
for one year, starting two years from today
z Example: Consider the following term structure
r1=5.00%, r2=5.75%, r3=6.00%
» Consider two investment strategies:
1 Invest $100 for three years Æ how much do we have?
2 Invest $100 for two years, and invest the proceeds at the one-year forward
rate, two periods hence Æ how much do we have?
» When are these two payoffs equal? (i.e what is the implied forward
rate?)
Forward Rates
z Strategy #1: Invest $100 for three years Æ how much do we
have
z Strategy #2: Invest $100 for two years and then reinvest the
proceeds for another year at the one year forward rate, two
periods hence Æ how much do we have
z When are these two payoffs equal? (i.e what is the implied
forward rate?)
?
?
?
Trang 20Copyright © Michael R Roberts
Arbitraging Forward Rates
Example
z What if the prevailing forward rate in the market is 7%, as
opposed to what calculated in the previous slide?
z Step 1: Is there a mispricing and, if so, what is mispriced
z Step 2: Is the forward loan cheap or expensive
z Step 3: Given your answer to Step 2, what is the first step in
taking advantage of the mispricing
Trang 21Copyright © Michael R Roberts
General Forward Rate Relation
z Forward rates are entirely determined by spot rates (and vice
versa) by no arbitrage considerations
z General Forward Rate Relation: (1+rn+t)n+t=(1+rn)n(1+fn,t)t
z Think of this picture for intuition:
(1+r1)
3
Summary
z Bonds can be valued by discounting their future cash flows
z Bond prices change inversely with yield
z Price response of bond to interest rates depends on term to
maturity
» Works well for zero-coupon bond, but not for coupon bonds
z Measure interest rate sensitivity using duration
z The term structure implies terms for future borrowing:
» Forward rates
» Compare with expected future spot rates