CFA L2 Fixed Income Flashcards
Spot rate/Spot price
The price quoted for immediate settlement on an interest rate, commodity, security, or a currency. It is the YTM on zero-coupon bonds.
Calculation for zero-coupon: Pt = 1 ÷ (1 + S_T)^T
Calculation for coupon bond: Vt = PMT ÷ (1 + S_T)^T
- Ex: $100 bond set to mature in 1 year. No coupons or any other payments during that period. The spot rate is the PV of this bond.
- Pt = price of $1 par zero-coupon bond
- S_T= Spot rate at time T
Spot curve
Yield curve for spot rates. The spot rate is on the y-axis and maturity is on the x-axis.
Forward rate
An annualized interest rate for a financial transaction that is agreed upon today, but starts at another time (j), and has a maturity of k.
Calculation: F(j,k) = 1 ÷ [ 1 + f(j,k) ]^k
- f(j,k) = the forward RATE applicable on a k-year loan starting in j years.
- the forward PRICE of a $1 par zero-coupon bond maturing at time j+k delivered at time j.
Forward rate example:
The rate for a 5 year loan is 6% and the rate for a 2 year loan is 4%. What is the forward rate for a 3 year loan beginning 2 years from now?
J = 2
K = 3
f(2,3) = [ (1.06)^5 ÷ (1.04)^2 ]^(1/3) - 1 = 7.35%
OR
[ (6% * 5) - (4% * 2) ÷ 3 ] = 7.33% → this is an approximation
Yield-to-maturity (YTM)
The total return anticipated on a bond if the bond is held until it matures.
- For a zero-coupon bond, the spot rate = YTM. For a coupon bond, the two ARE NOT equal.
Spot rate example:
Compute the price and YTM of a 3 year 4% annual pay, $1,000 par bond given the following spot rate curves: S1 = 5%, S2=6%, and S3 = 7%.
[ 40 ÷ (1 + .05)^1 ] + [ 40 ÷ (1 + .06)^2 ] + [ (1000 + 40) ÷ (1 + .07)^3 ] = $922.64
YTM can be found by using a calculator:
N = 3 ; I/Y = x ; PV = 922.64 ; PMT = 40 ; FV = $1,000
When will the return on a bond equal a bond’s yield?
When the bond is HTM, when all payments (coupons and principal) are made in full and on time, and all coupons are reinvested at the original YTM.
- If the yield curve is not flat, the coupon payments will not be reinvested at the YTM and the expected return will differ from the yield.
Forward pricing model
Values forward contracts based on arbitrage-free pricing. This model equates buying a long-maturity zero-coupon bond to entering into a forward contract to buy a zero-coupon bond that matures at the same time
Formula: F(j,k) = P(j+k) ÷ Pj
Forward pricing example:
Calculate the forward price two years from now for a $1 par, zero-coupon, three-year bond given the following spot rates:
The two-year spot rate, S2 = 4%.
The five-year spot rate, S5 = 6%.
P(j) = P(2) = [ 1 ÷ (1 + .04)^2 ] = 0.9246
P(j+k) = P(2+3) = P(5) = [ 1 ÷ (1 + .06)^5 ] = 0.7473
F(j,k) = 0.7473 ÷ 0.9246 = 0.8082
…
So, $0.8082 is the price agreed to today, to pay in two years, for a three-year bond that will pay $1 at maturity.
The forward rate model
The forward rate model tells us that the forward rate should make investors indifferent between buying a long-maturity zero-coupon bond versus buying a shorter-maturity zero-coupon bond and reinvesting the principal.
Formula: [ 1 + S(j+k) ]^(j+k) = (1 + S_j)^j * [ 1 + f(j,k) ]^k
OR
[ 1 + f(j,k) ]^k = [1 + S(j+k) ]^(j+k) ÷ (1 + Sj)^j
This equation suggests that the forward rate f(2,3) should make investors indifferent between buying a five-year zero-coupon bond versus buying a two-year zero-coupon bond and at maturity reinvesting the principal for three additional years.
Par rate
The YTM of a bond trading at par
Bootstrapping
A process that calculates spot rates from the par rate curve. Bootstrapping involves using the output of one step as an input to the next step.
Bootstrapping example:
Given:
Maturity 1 = 1% par rate
Maturity 2 = 1.25% par rate
Maturity 3 = 1.50% par rate
Compute the 2 year spot rate
100 = (1.25 ÷ 1.01) + ((100 + 1.25) ÷ (1 + r2)^2)
100 = 1.2376 + (101.25 ÷ (1 + r2)^2)
98.7624 = 101.25 ÷ (1 + r2)^2
(1 + r2)^2 = 1.025187723
1 + r2 = 1.012515542
r2 = 0.012515542
This shows how zero coupon rates can be derived from the par curve
True or false: If the spot rate curve is flat, the forward rate curve is flat and lies equally with it. If the spot rate curve is upward sloping, the forward rate curve is also upward sloping and lies above it. And if the spot rate curve is inverted, the forward rate curve is inverted and lies below it?
True
True or false: The spot rate for a long-maturity security will equal the geometric mean of the one period spot rate and a series of one-year forward rates?
True
- Active bond portfolio managers will try to outperform the market by predicting how the future spot rates will differ from those predicted by the current forward curve.
- If the future spot rates are below the current forward rates, the portfolio manager wil see a greater return than the one-year Rf.
Forward price evolution
If the future spot rates evolve as the forward curve predicted, the forward price will remain unchanged. Therefore, a change in the forward price indicates that the future spot rate(s) did not conform to the forward curve. When spot rates turn out to be lower than implied by the forward curve, the forward price will increase and vice versa.
Maturity matching
A bond investment strategy that’s purchasing bonds that have a maturity equal to the investor’s investment horizon.
Riding the yield curve/rolling down the yield curve
A bond investment strategy. When a yield curve is upward sloping, investors seeking superior returns may pursue this strategy. This strategy involves an investor purchasing bonds w/ longer maturities than their investment horizons. In an upward-sloping yield curve, shorter maturity bonds have lower yields than longer maturity bonds. As the bond approaches maturity (rolls down the yield curve), it is valued using successively lower yields and, therefore, at successively higher prices.
If the yield curve remains unchanged over the investment horizon, riding the yield curve strategy will produce higher returns than a simple maturity matching strategy, increasing the total return of a bond portfolio. The greater the difference between the forward rate and the spot rate, and the longer the maturity of the bond, the higher the total return.
This strategy increases IRR
Holding period return formula
(Closing value ÷ Beginning value) - 1
Holding period return example:
Given benchmark spot rates:
Maturity 1 = 3% spot rate
Maturity 2 = 4% spot rate
Maturity 3 = 5% spot rate
Expected spot rates:
Year 1 = 5.01%
Year 2 = 6.01%
Calculate the one-year holding period return of a 1-year zero coupon bond, 2-year zero coupon bond, and a 3-year zero coupon bond.
(1): ($1 ÷ 1.03) = 0.9709
Holding period return = ($1 ÷ 0.9709) -1 = 3%
(2): ($1 ÷ (1.04)^2) = 0.924556213
($1 ÷ 1.0501) = 0.9523
Holding period return = 0.9523 ÷ 0.924556213 = 3%
(3) = ($1 ÷ (1.05)^3) = 0.8638375985
($1 ÷ 1.0601^2) = 0.8898285399
Holding period return = 0.8898285399 ÷ 0.8638375985 = 3%
Interest rate swap
A forward contract where one party makes payments based on a fixed rate while the counterparty makes payments based on a floating rate. The fixed rate in an interest rate swap is called the swap rate.
Swap rate curve
A curve that plots how different swap rates are at different maturities.
- DOES NOT indicate credit risk.
- Can be used to indicate premium for time value of money.
Why do market participants use the swap rate curve?
- Swap rates reflect the credit risk of commercial banks rather than the credit risk of governments.
- The swap market is not regulated by any government, which makes swap rates in different countries more comparable.
- The swap curve typically has yield quotes at many maturities, while the U.S. government bond yield curve has only a small number of maturities.
- Swap rate curves are not affected by technical market factors that affect the yields on government bonds.
Swap spread
The amount the fixed-rate side of an interest rate swap exceeds the yield of a government bond w/ the same maturity.
Formula: Swap fixed rate - treasury yield
- Swap spreads are almost always positive, reflecting the lower credit risk of governments compared to the credit risk of surveyed banks that determines the swap rate.
Spot rate curve example:
Given:
Maturity 1 = 3% spot rate
Maturity 2 = 4% spot rate
Maturity 3 = 5% spot rate
Compute the swap fixed rate for years 1, 2, and 3.
(1) [ SFR1 ÷ (1 + S1) ] + [ 1 ÷ (1 + S1) ] = 1
[ SFR1 ÷ (1.03) ] + [1 ÷ 1.03 ] = 1
[ SFR1 ÷ (1.03) ] = 0.9709
SFR1 = 3%
(2) [ SFR2 ÷ (1 + S1) ] + [ SFR2 ÷ (1 + S2)^2 ] + [ 1 ÷ (1 + S2)^2 ] = 1
[ SFR2 ÷ (1.03) ] + [SFR2 ÷ (1.04)^2 ] + [1 ÷ (1.04)^2 ] = 1
True or false: Retail banks are more likely to use the swap rate curve as a benchmark than the government spot curve?
False, retail banks are likely to use as the government spot rate as a benchmark. However, wholesale banks are likely to use the swap rate curve as a benchmark.
Interpolated spread (I-spread)
A type of short-term interest rate spread. The amount by which the yield on the risky bond exceeds the swap rate for the same maturity. If a swap rate isn’t available for a specific maturity, the missing swap rate can be estimated from the swap rate curve using linear interpolation.
Formula: Yield on the risky bond - swap rate
- While a bond’s yield reflects time value as well as compensation for credit and liquidity risk, I-spread only reflects compensation for credit and liquidity risks. The higher the I-spread, the higher the compensation for liquidity and credit risk.
Interpolated rate calculation
rate for lower bound + [ ((# of years for interpolated rate − # of years for lower bound) * [ higher bound rate − lower bound rate)) ÷ (# of years for upper bound − # of years for lower bound) ]
I-Spread example:
a 6% bond is current yielding 2.5% and matures in 1.6 years. Given the swap curve:
tenor-0.5 = 1%
tenor-1 = 1.25%
tenor-1.5 = 1.35%
tenor-2 = 1.50%
Compute the I-spread
Interpolated rate = 0.0135 + [ ((1.6 - 1.5)(.015 - .0135)) ÷ (2 - 1.5) ] = 1.38%
I-spread = 2.5% - 1.38% = 0.97%
Z-spread/Zero volatility spread
The spread that, when added to each spot rate on the default-free spot curve, makes the present value of a bond’s cash flows equal to the bond’s market price. Therefore, the Z-spread is a spread over the entire spot rate curve.
Formula: Market price of risky bond = (CF1 ÷ (1 + r1 + z)) + (CF1 ÷ (1 + r2 + z)^2) …
Z-spread MUST be used for bonds WITHOUT embedded options.
- Zero-volatility spread is a commonly used measure of relative value for MBS and ABS. However, it only considers one path of interest rates, while OAS considers every spot rate along every interest rate path.
TED spread
A short-term interest rate spread. The amount by which the 3-month MRR exceeds the interest rate on short-term U.S. government debt (3-month T-bill) of the same maturity. The TED spread is seen as an indication of the credit and liquidity risk in the banking sector. A rising TED spread indicates that market participants believe banks are increasingly likely to default on loans and that risk-free T-bills are becoming more valuable in comparison. The TED spread captures the risk in the banking system more accurately than the 10-year swap spread.
MRR OIS Spread
The amount by which the MRR rate (which includes some credit risk) exceeds the OIS rate (which includes only minimal credit risk) and also indicates the level of credit and liquidity risk in the banking system.
OIS stands for overnight indexed swap and represents interest rate on unsecured overnight lending between banks. The OIS rate roughly reflects the federal funds rate and includes minimal counterparty credit risk.
True or false: The swap spread of a default free bond should provide an indication of the bond’s illiquidity—or, alternatively, that the bond is mispriced?
True
Theories that explain why a yield curve takes a particular shape:
- Unbiased expectations theory
- Local expectations theory
- Liquidity preference theory
- Segmented markets theory
- Preferred Habitat Theory
Unbiased expectations theory/pure expectations theory
This theory states that investors’ expectations determine the shape of the interest rate term structure and that forward rates are solely a function of expected future spot rates and that every maturity strategy has the same expected return over a given investment horizon. The underlying principle behind this theory is risk neutrality: Investors DON’T DEMAND A RISK PREMIUM for maturity strategies that differ from their investment horizon.
Long-term interest rates = the mean of future expected short-term rates
- If the yield curve is upward sloping, the short-term rates are expected to rise.
Local Expectations Theory
Similar to the unbiased expectations theory but only holds the risk-neutrality assumption for short periods. OVER LONG PERIODS OF TIME, RISK PREMIUMS SHOULD EXIST. Over short periods, every bond should earn the Rf.
- This theory doesn’t hold because the short-holding-period returns of long-maturity bonds can be shown to be higher than short-holding-period returns on short-maturity bonds due to liquidity premiums and hedging concerns.
Liquidity preference theory
This theory states that forward rates reflect investors’ expectations of future spot rates, plus a liquidity premium to compensate investors for exposure to interest rate risk. The liquidity premium is positively related to maturity (ex: a 25-year bond should have a larger liquidity premium than a five-year bond).
- States that the forward rate is biased because it includes a liquidity premium.
- Under this theory, the yield curve may take any shape. Even after adding the premium to a steep downward sloping yield curve the result will still be downward sloping.
- An upward slowing yield curve may be due to future expectations if rising rates or the liquidity premium- we don’t know.
Segmented markets theory
This theory states that yields are not determined by liquidity premiums and expected spot rates, but rather, the shape of the yield curve is determined by the preferences of borrowers and lenders, which drives supply/demand for loans of different maturities. The theory suggests that the yield at each maturity is determined independently of the yields at other maturities.
- The segmented markets theory proposes that market participants have strong preferences for specific maturities.
- Under segmented markets theory, investors in one maturity segment of the market will not move into any other maturity segments.
Preferred Habitat Theory
This theory states that forward rates represent expected future spot rates plus a premium, but it does not support the view that this premium is directly related to maturity. Borrowers require cost savings (lower yields) and lenders require a yield premium (higher yields) to move out of their preferred habitats (preferred maturities).
- The preferred habitat theory proposes that market participants have strong preferences for specific maturities, however risk premiums can incentivize investors to change maturities to take advantage of certain opportunities.
- Unlike the liquidity preference theory, under the preferred habitat theory a 10-year bond might have a higher or lower risk premium than the 25-year bond.
Yield curve risk
Risk to the value of a bond portfolio due to unexpected shifts (parallel vs non-parallel) in the yield curve.
Parallel shifts vs nonparallel shifts
Parallel shifts = changes in the yield curve where the yield of every maturity goes up or down by the same proportion.
Nonparallel shift (steepness change) = Long-term interest rates increase while short-term rates decrease or vice versa.
Nonparallel shift (curvature change) = Increasing curvature means short- and long-term interest rates increase while intermediate rates do not change.
How to measure sensitivity to yield curve risk?
There are three main approaches:
1. Effective duration
2. Key rate duration
3. A three-factor model that decomposes changes in the yield curve into changes in level, steepness, and curvature. This is a regression model. The three factors will be estimated using past data.
- Changes in the shape of yield curve is explained by (in order of importance): level, steepness and curvature.
Effective duration
Effective duration is used mostly for bonds w/ embedded options and measures the price sensitivity to a 1% change in rates. Measures price sensitivity to small PARALLEL shifts in the yield curve. This measure of duration takes into account the fact that expected CFs will fluctuate as rates change and is, therefore, a measure of risk.
Calculation: ED = ((BV _ -△Y) - (BV _ △Y)) ÷ (2 * BV0 * △Y)
Does not work w/ non-parallel shifts in the yield curve.
- Parallel shifts explain more than 75% of the variation in bond portfolio returns.
- The larger the coupon, the lower the duration.
Shaping risk
Changes in portfolio value due to changes in the shape of the benchmark yield curve.
- Effective rate DOES NOT measure shaping risk.
Key rate duration
Measures the sensitivity of the value of a security or bond portfolio to changes in the yield at a particular maturity only. It’s the approximate % change in the value of a bond portfolio in response to a 100 basis point change in the corresponding par rate (YTM of a bond that trades at par), holding all other par rates constant.
- More precise than effective duration.
- Can be used for non-parallel shifts.
- Captures shaping risk.
3 factor model
The 3rd approach is to measure yield curve risk is to run a regression w/ 3 independent variables: level ΔXL (a parallel increase/decrease in int. rates), steepness ΔXS, and curvature ΔXC.
True or false: Effective duration = the sum of the key rate durations?
True
True or false: Empirical data shows that long-term rates are more volatile than short-term rates?
False
- Volatility at the long-maturity end is thought to be associated with uncertainty regarding the real economy and inflation, while volatility at the short-maturity end reflects risks regarding monetary policy.
- Two-thirds of the variation in short and intermediate-term yields is explained by monetary policy, and the remaining is explained by the other factors. In contrast, inflation explains two-thirds of the variation in long-term yields, with the remaining mostly explained by monetary policy.
True or false: Embedded options make bonds less sensitive to interest rate fluctuations?
False, more sensitive
Bond risk premium/term premium/duration premium
The excess return over the one-year Rf earned by investors for investing in long-term government bonds.
Formula: Er - Rf
- Er = expected return on a long-term government bond.
Bearish flattening vs bullish steepening
Bearish flattening hapens when central banks raise the short-term rates. Oppositely, bullish steepening happens when central banks lower the short-term rates.
Factors besides monetary policy and inflation that affect bond prices?
- Fiscal policy: Expansionary policy increases yields and vice versa.
- Maturity structure: The government’s choice of maturity when issuing new securities affects the supply (and yield) of bonds in those maturity segments. An increase in offerings in a specific segment of the market increases the supply and increases the yield in that segment (the market segmentation theory).
- Investor demand: Domestic and foreign investor demand and preferences for specific maturity segments affect the yield in that segment. The more demand, the lower the yield.
Bullet portfolio vs barbell portfolio
Bullet portfolio: A bond portfolio concentrated in a single maturity.
Barbell portfolio: A portfolio with short and long maturities.
Bond duration
Measures how long it takes, in years, for an investor to be repaid a bond’s price by the bond’s total CFs.
- PMs will increase duration in anticipation of a fall in rates, and decrease duration in anticipation of a rise in rates.
- PMs will rotate out of bullet structuring and into barbell structuring in expecation of a bullish flattening of the yield curve.
- If PMs expect a curvature change, for example, where 10 year yields increase while other yields remain the same, PMs will use a bullet strategy.
What are the two types of arbitrage?
- Value additivity: When the value of the whole differs from the sum of the values of parts
- Dominance: When one asset trades at a lower price than another asset with identical characteristics
Arbitrage-free valuation
Values securities such that no market participant can earn an arbitrage profit in a trade involving that security. Arbitrage-free valuation of a fixed-rate, option-free bond entails discounting each of the bond’s future CFs using the corresponding spot rate (how we normally value a bond).
- Arbitrage-free valuation gives us the price of a bond where we cannot carry out a value additivity strategy or dominance strategy.
Stripping/reconstitution
A five-year, 5% Treasury bond should be worth the same as a portfolio of its coupon and principal strips. If the portfolio of strips is trading for less than an intact bond, one can purchase the strips, combine them (reconstituting), and sell them as a bond. Similarly, if the bond is worth less than its component parts, one could purchase the bond, break it into a portfolio of strips (stripping), and sell those components.
Arbitrage example:
Security A - current price = $99 ; payoff in one year = $100
Security B- current price = $990 ; payoff in one year = $1,010
Security C- current price = $100 ; payoff in one year = $102
Security D- current price = $100 ; payoff in one year = $103
Securities A and B are identical in every respect other than as noted. Similarly, securities C and D are identical in every other respect. Find the arbitrage opportunities.
(1) Short 10 units of secrity A ($990 inflow) and long 1 unit of security B. This leads to 0 outflow currently. Then, in one year, there will be a $1,000 outflow from security A but a $1,010 inflow from security B, so there will be a $10 profit.
(2) Short 1 unit of Security C and long 1 unit of security D. This lead to 0 outflow currently. Then, in one year, there will be a $102 outflow from security C but a $103 inflow from security D.
Binomial interest rate tree
A model to value a bond that allows both rates and the underlying cash flows to vary. This model assumes that interest rates have an equal probability of taking one of two possible values in the next period. This model is a lognormal random walk w/ two properties: higher volatility at higher rates and non-negative interest rates.
Binomial interest rate trees begin w/ a root (i0), which is the current 1-period spot rate. Then, it moves to two nodes: An upper node (1,U) and a lower node (1,L). Then, each of those nodes will have two nodes of their own and so on. To value each node: take the corresponding node * e^(2σ)
- If the binomial lattice is correctly calibrated, it should give the same value for an option-free bond as using the par curve used to calibrate the tree.
Backward induction
The process of valuing a bond using a binomial interest rate tree. For a bond that has N compounding periods, the current value of the bond is determined by computing the bond’s possible values at Period N and working backwards to Node 0. The value of a bond at a given node in a binomial tree is the average of the present values of the two possible values from the next period.
Backwards induction example:
A $100 par 7% annual coupon bond has two years to maturity. The discount rate for i1U is 7.1826%, the rate for i1L is 5.3210%, and the rate for i0 is 4.5749%. Fill in the tree and calculate the value of the bond today.
i1U = (($100 + $7) ÷ (1.07826)) = $99.83
i1L = (($100 + 7) ÷ (1.053210)) = $101.59
i0 = [ (($99.83 + $101.59) ÷ 2) + $7 ] ÷ 1.045749 = $103
3 rules of building binomial interest rate trees:
- The interest rate tree should generate arbitrage-free values for the benchmark security (the value of bonds produced by the interest rate tree must be equal to their market price).
- Adjacent forward rates must be two standard deviations apart.
- The middle forward rate in a period is approximately equal to the implied (from the benchmark spot rate curve) one-period forward rate for that period.
Example: Calibrating a binomial interest rate tree to match a specific term structure.
Firm A generates a binomial interest rate tree consistent with a set data and an assumed volatility of 20%. The data is as follows:
Maturity 1 - par rate = 3% - spot rate = 3%
Maturity 2 - par rate = 4% - spot rate = 4.020%
Maturity 3 - par rate = 5% - spot rate = 5.069%
Given that the forward rates at i0 = 3% and i1U = 5.7883%, calculate:
(1): The forward rate at i1L
(1): i1L = i1U * e^(-2σ) = .057883 * e^(-2 * 0.20) = 0.0388 = 3.88%
(2): We must use bootstrapping:
Pathwise valuation
Discounting a bond’s CFs for each likely interest rate path and calculating the average of these values across all the paths. It is an alternative method to the backward induction approach.
Number of paths = 2^(n-1)
Pathwise valuation example:
Firm A wants to value a 3-year 3% annual-pay bond that is option-free and $100 par. The forward rates are as follows:
i0 = 3%
i1U = 5.7883%
i1L = 3.8800%
i2UU = 10.7383%
i2UL/i2LU = 7.1981%
i2LL = 4.8250%
Compute the value at i0 using pathwise valuation
There are 4 paths:
Path 1: [ (3 ÷ (1.03)) + (3 ÷ (1.03 * 1.057883)) + (103 ÷ (1.03 * 1.057883 * 1.107383)) ] = $91.03
Path 2: [ (3 ÷ (1.03)) + (3 ÷ (1.03 * 1.057883)) + (103 ÷ (1.03 * 1.057883 * 1.071981)) ] = $93.85
Path 3: [ (3 ÷ (1.03)) + (3 ÷ (1.03 * 1.0388)) + (103 ÷ (1.03 * 1.0388 * 1.071981)) = $95.52
Path 4: [ (3 ÷ (1.03)) + (3 ÷ (1.03 * 1.0388)) + (103 ÷ (1.03 * 1.0388 * 1.048250)) = $97.53
($91.04 + $93.85 + $95.52 + $97.53) ÷ 4 = $94.49
True or false: Prepayment risk is affected not only by the level of interest rate at a particular point in time, but also by the path rates took to get there?
True
True or false: An important assumption of the binomial valuation process is that the value of the CFs at a given point in time is dependent on the path that interest rates followed up to that point?
False, the important assumption is it’s indepedent.
- Because of this assumption, we cannot use a binomial model to value MBSs where prepayment risk lurks.
Monte Carlo forward-rate simulation
This method randomly generates a large # of interest rate paths, using a model that incorporates a volatility assumption and an assumed probability distribution. Similar to pathwise valuation, the value of the bond is the average of the diffferent values from the various paths. The simulated paths should be calibrated so benchmark interest rate paths value benchmark securities at their market price (i.e., arbitrage-free valuation). This calibration process results in a drift adjusted model.
W/ this method, the underlying CFs can be path DEPENDENT.
Term structure
The relationship between credit spreads and maturity
- The credit spread is inversely related to the recovery rate and positively related to the probability of default.
Term structure models
Models that analyze the statistical properties of interest rate movements. The two major types of term structure models are:
1. Equilibrium term structure models
2. Arbitrage-free models
Equilibrium term structure models
Models that attempt to model the term structure using fundamental economic variables that are thought to determine interest rates. Two main types are:
1. Cox-Ingersoll-Ross model
2. Vasicek Model
Cox-Ingersoll-Ross (CIR) Model
Assumes the economy has a natural long-run interest rate (b) that the short-term rate (r) converges to at a speed of (a). Interest rate volatility varies with r and is not constant. Produces nonnegative rates only.
Formula: drt = (a(b - r) * dt) + (σ * (√rdz))
- drt = change in the short-term interest rate
- a = speed of mean reversion.
- b= long-run value of short-term interest rate
- r = the short-term interest rate
- dt = a small increase in time
- σ = volatility
- dz = a small random walk movement
Vasicek Model
This model suggests that interest rates are mean reverting to some long-run value.
Formula: drt = a(b - r) * dt + (σ * dz)
- b = mean reverting level
- r = int. rate
- a = speed- how fast rates are reverting to mean level. Between 0 and 1.
- d = ∆ (dt is ∆ in time, dr is ∆ in rates, and dz is ∆ in noise. z is from a standard normal dist.)
- σ = assumed level of volatility
- The difference between this and the CIR model is that volatility in this model does not increase as the level of interest rates increases
- The main disadvantage of the Vasicek model is that the model does not force interest rates to be nonnegative
Arbitrage-free models
These models assume markets price bonds correctly.
Ho-Lee model
An arbitrage-free model that is calibrated by using market prices to find the θ that generates the current term structure. This model assumes that changes in the yield curve are consistent with a no-arbitrage condition. The model assumes constant volatility and a constant drift. This model is derived from the concepts of the Black-Scholes model. The interest rates generated from this model can be used to determine the prices of zero-coupon bonds and the spot curve.
Formula: drt = (θt * dt) + (σ * dzt)
- θt = a time-dependent drift term
- This model can have negative rates
Kalotay-Williams-Fabozzi (KWF) Model
An arbitrage-free model that assumes no volatility and no drift and also does not assume mean reversion. However, the KWF model assumes that the short-term rate is lognormally distributed.
Formula: (d * ln(rt)) = (θt * dt) + (σ * dzt)
Gauss+ Model
A multifactor model that incorporates short, medium, and long-term rates, where the long-term rate is designed to be mean reverting and depends on macroeconomic variables. Medium-term rates revert to the long-term rate, while the short-term rate depends on the central bank’s the short-term rate, and does not have a random component.
True or false: Increasing the # of paths used in the pathwise valuation model increases the statistical accuracy of the estimated value and produces a value closer to the true fundamental value of the security?
False, the larger the # of paths, the more accurate the value in a statistical sense. However, whether the value is closer to the true fundamental value depends on the accuracy of the model inputs.
True or false: One of the drawbacks of the Vasicek and CIR models is that the model prices generated by these models generally do not coincide with observed market prices?
True
Advantages of embedded options for issuers:
- Manage IRR
- Ability to issue bonds at an attractive coupon rate
Protection period for callable bonds
A period during which the bond cannot be called
European-style vs American-style vs Bermudan-style
European-style: When the option can only be exercised on a single day immediately after the protection period.
American-style: When the option can be exercised at any time after the protection period.
Bermudan-style: When the option can be exercised at fixed dates after the protection period.
Extendible bond
A bond that allows the investor to extend the maturity of the bond. An extendible bond can be evaluated as a putable bond with longer maturity
Estate put
A bond which includes a provision that allows the heirs of an investor to put the bond back to the issuer upon the death of the investor. The value of this contingent put option is inversely related to the investor’s life expectancy; the shorter the life expectancy, the higher the value.
Sinking fund provision
A bond that requires the issuer to set aside funds periodically to to retire the bond. This provision reduces the credit risk of the bond.
- These bonds typically have several other issuer options embedded (ex: call options).