Theories of the Yield Curve Copyright © 1996-2006 Investment Analytics
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The Yield Curve
What is the yield curve? How is the curve constructed? Why is the yield curve shaped the way it is? Why does its shape change? How can a trader profit from this?
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Yield Curve Theories
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The Yield Curve
Zero-Coupon Bonds, Face Value $1,000: Term Price Discount YTM 1 925.93 1/(1+y1) 8.000% 2 841.75 1/(1+y2)2 8.995% 9.660% 3 758.33 1/(1+y3)3 4 683.18 1/(1+y4)4 9.993% Spot Yield (Zero Coupon Yield)
y1 is called the one year spot rate y2 is called the two year spot rate
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Yield Curve Theories
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Spot Rate
Yield Curve Example
8%
1
4 Years to Maturity
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Yield Curve Theories
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Building a Yield Curve
In practice we have coupon bonds, not just zeros Term Price Discount YTM 8.000% 1 925.93 Z 1/(1+y1) 2 841.75 Z 1/(1+y2)2 8.995% 3 952.40 C Bond in year 3 is a coupon bond
Pays 8% coupon ($80 per year) How do we proceed?
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Yield Curve Theories
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Bootstrapping
Method: split into coupon and principal payments and treat each as a zero $80
$80
1
2
Then solve equation:
$1,080
3
952.40 = $80/(1+y1) + $80/(1+y2)2 + $1080/(1+y3)3 y1 & y2 are known y3 = 10.020%
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Yield Curve Theories
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Example: US Treasury Yield Curve YIELD vs. MATURITY 7.48%
15-May-17
7.47% 7.46% 15-Feb-16 15-May-16 15-Nov-15 15-Aug-15
7.45% 7.44% 7.43%
15-Nov-16
15-Feb-15
7.42% 7.41% 7.40% Dec-14
Jul-15
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Jan-16
Aug-16
Yield Curve Theories
Mar-17
Sep-17
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Yield Curve Analysis
Fairly normal yield curve
Yield on the 9 1/4 of Feb ‘16 looks to be a basis point too high 2.4bp pickup on the 8 /4% of May ‘17 indicates value in this sector
Clear relationship between yield and tenor What about relationship between yield and risk?
Use duration as a proxy for risk Plot yield vs. duration Makes relative values more distinct
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Yield Curve Theories
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Yield vs. Duration YIELD vs. DURATION 7.48% 7.47% 7.47% 7.46% 7.46% 7.45% 7.45% 7.44% 7.44% 7.43% 7.43% 7.42% 9.20
May 17
Feb 16
May 16 Nov 16
Nov 15 Aug 15 Feb 15
9.40
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9.60
9.80
10.00
Yield Curve Theories
10.20
10.40
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Yield Enhancement Swap
Because it has higher coupon, the 8 3/4 of May ’17 has lower duration than the 7 1/4 of May ’16 or the 7 1/2 or Nov ’16. By trading at slightly higher yield, the market would appear to be underpricing it slightly Bond Swap: Action Maturity Coupon Price YTM Duration Sell 15-Nov-16 7 1/2% 100 18/32 7.4467% 10.278 Buy 15-May-17 8 3/4% 11323/32 7.4706% 10.054
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Yield Curve Theories
Slide: 10
Limitations to Traditional Yield Curve Analysis
Yield curve:
A primitive expression of risk/return tradeoff
Drawbacks
Maturity is poor indicator of bond price volatility YTM is not a measure of potential return
For Buy and Hold investor, assumes coupons are reinvested at YTM For Active investor, assumes that if bond is sold prior to maturity, it is sold at same yield as on purchase date
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Yield Curve Theories
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Example: Euro Yield Curves Euro Yield Curves 5
4.5 France Germany 4
3.5
3 Source: Bloom berg 9/Apr/99
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30 Years
20 Years
15 Years
10 Years
9 Years
8 Years
7 Years
6 Years
5 Years
4 Years
3 Years
2 Years
1 Years
6 Months
3 Months
2.5
Yield Curve Theories
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Other Yield Curves
Swaps curve
Swap rate (coupon) by tenor Swap curve lies above treasury curve
Due to default risk Swap rates quoted as spread over same maturity treasury yield
Corporate bond yield curve
Trades at spread over treasury curve
Default risk
Many corporate bonds include option features
Callable, putable, convertible Calculate option-adjusted spread
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Yield Curve Theories
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LIBOR Spot Rates
Spots quoted as add-on interest Actual/360 daycount Example: 3 month deposit
Today is Jan 12 2001 Deposit matures April 12, 2001 Number of days: 91 Rate is r, P is principal
Value at maturity: P x (1 + r x 91 / 360)
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Yield Curve Theories
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Daycounts
How many days in a month and year
30/360 (Money Market)
Actual/360 (LIBOR)
in one month, get 1+(30/360)r in one month get 1 + (31/360)r if 31 days
Actual/365 (Treasury)
(or actual/actual: adjust for leap year)
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Yield Curve Theories
Slide: 15
Discount Factors and Compounding
Notation:
D = 1 / (1 + R) T/360 R = -1 + (1 / D)360/T
R is Semi-annually compounded (Treasury)
D = 1 / (1 + R x T / 360) R = (-1 + 1/D) * 360 / T
R is annually compounded (LIBOR):
T = Time (days), D = Discount Factor
R is simple:
R = % Interest rate,
D = 1 / (1 + R / 2) T/182.5 R = 2 * (-1 + 1 / D)182.5/T
R is continuously compounded:
D = e-RT/360 R = -Ln(D) x 360 / T
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Yield Curve Theories
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Yield Curve Theories
Expectations Theory Liquidity Preference Theory Risk Theory
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Yield Curve Theories
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Expectations Theory
Forward rate = Expected future spot rate FT = E(ST) Implications:
Bond yields relate to expected future spot rates
(1 + y2)2 = (1 + S1) (1 + f2) = (1 + S1) (1 + E[S2])
Upward sloping yield curve means investors anticipate higher interest rates
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Yield Curve Theories
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Liquidity Preference Theory
Investors require a liquidity premium to hold long term securities FT > E[ST] Liquidity Premium: LT = FT - E[ST] Example: S1 = E[S2] = 10%
Expectations Hypothesis
(1 + y2)2 = (1 + S1) (1 + E[S2]) => y2 = 10%
Liquidity Preference
F2 = 11% > E[S2] = 10% (L2 = 1%) (1 + y2)2 = (1 + S1) (1 + f2) => y2 = 10.5%
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Yield Curve Theories
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Constant Liquidity Premium Forward Rate 11% Yield Curve
Constant Liquidity Premium
10% Expected Spot Rate
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Yield Curve Theories
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Rising Liquidity Premium
Forward Rate 11% Yield Curve
Rising Liquidity Premium
10% Expected Spot Rate Copyright © 1996-2006 Investment Analytics
Yield Curve Theories
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Risk Measures
Price Risk:
Probability of Zero Loss (over 1 month):
Change in price for 1% change in yield (dollar duration or “PV of an 01”) Likelihood that price of an issues falls by no more than interest earned (over 1 month)
Required Holding Period:
Period require to hold a security so that the probability of zero loss exceeds a specified level
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Yield Curve Theories
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Risk and Yield
Price risk is proportional to duration
30 year bond has greater price risk than 2 year note
Higher yield means lower price risk
A par bond at 15% yield has a price risk just over half that of a par bond at 7% yield
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Yield Curve Theories
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Holding Period for 30Y Bond x Yield 4
Years
Volatility = 11%
7%
e Yi
ld
11%
ld e i Y
15
0 50%
Probability of Zero Loss
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Yield Curve Theories
ie %Y
ld
90% Slide: 24
Holding Period for 30Y Bond x Vol 3
Years
Yield= 11%
15
%
l Vo 11% 7
0 50%
ol V %
Probability of Zero Loss
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Yield Curve Theories
l Vo
90% Slide: 25
Holding Period for 2Y Note x Yield 60
Days
Volatility = 2.2%
7%
e Yi
ld
11
0 50%
ie Y %
ld
ield Y % 15
Probability of Zero Loss
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Yield Curve Theories
90% Slide: 26
Implications for Yield Curve Shape
2y Note much safer than 30y Bond
(holding period days rather than years)
As investor extends along yield curve, probability of losing money rises Hence must receive risk premium in higher yields CONCLUSION: Yield curve +ve slope
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Yield Curve Theories
Slide: 27
Yield Curve Shape & Yield Level
Curve has +ve slope at low yields Curve has -ve slope at high yields Why? As yields increase:
Probability of Zero Loss rises Risk of long-maturity issue relative to shortmaturity issue falls Investors buy the long end, yield curve flattens, then inverts
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Yield Curve Theories
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Shape of Yield Curve Changes with Yield Level Averages 6/1/79 - 3/9/99
16.00% 14.00% 12.00% > 14% 13-14% 8.00%
12-13%
6.00%
11-12% 10-11%
4.00%
9-10% 2.00%
8-9%
0.00% 2
7-8% 3
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5
7
10
Lo ng Bo nd Yi eld
Yield
10.00%
30
Yield Curve Theories
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Empirical Tests
Forward rates: biased or unbiased forecast of future spot rates? Spot vs Forward Rates 1971 - 1995 20% 18% Spot 3M 16%
Forw ard 3M
14% 12% 10% 8% 6% 4% 2%
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Yield Curve Theories
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3/12/71
0%
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Yield Curve Regression Model
Regression Model
St = a0 + bFt-3 + εt
Expectations theory: b = 1 Liquidity/risk theory: b < 1
St is spot rate at time t Ft is 3m forward rate εt is a white noise process: IID ~ No(0, σ2)
Forward typically exceeds future spots rates By an amount, which is the liquidity/risk premium
See lab exercise
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Yield Curve Theories
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Regression Analysis Regression Statistics Multiple R 89% R Square 79% Adjusted R Square 79% Standard Error 1.56% Observations 1294
Intercept Forward 3M
Coefficients Std. Error 0.0046 0.0012 0.9476 0.0138
t Stat 3.6847 68.7944
P-value Lower 95% Upper 95% 0.0002 0.0021 0.0070 0.0000 0.9206 0.9746
b < 1: indicates expectations theory does not hold (reject at the 5% confidence level) Copyright © 1996-2006 Investment Analytics
Yield Curve Theories
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Residual Plot
Evidence of violation of model assumptions
Residual variance is not constant
Need more sophisticated testing procedures Residual model, Plot 8% 6% 4%
Residuals
2% 0% 0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
20%
-2% -4% -6% -8% -10%
Forward 3M
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Yield Curve Theories
Slide: 33
Other Empirical Evidence
Fama (1976, 1984), Shiller (1979), Mankiw & Miron (1986)
Predictive power of forward rate is weak Varies dramatically over sub-periods Due to term premium (he conjectured)
Buser, Kayroli, Sanders (1996)
Variation is due to the term premium Model term premium using GARCH model Adjusted forward rate is good predictor of spot
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Yield Curve Theories
Slide: 34
Summary: Yield Curve Theories
Expectations Hypothesis FT = E(ST)
Liquidity Preference
Investors require a liquidity premium to hold long term securities Liquidity Premium: LT = FT - E[ST] Idea: why not try to capture LT ?
Risk Theory
Empirical evidence suggests otherwise
Probability of zero loss
Empirical evidence: favors liquidity/risk model
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Yield Curve Theories
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