
Relationship Between Two Discrete Frequencies
- Suppose rate
is compounded
times per annum, Let the equivalent rate compounded
times per annum be
. The
rate means that an amount A compounds to:
at the end of one year.
The rate means that an amount A compounds to:
at the end of one year.
Rate compounded
times per year is therefore equivalent to rate
compounded
times per year when:
EXAMPLE –
Suppose the rate is 5% with semi-annual compounding, and the equivalent rate with quarterly compounding needs to be calculated. In this case
The equivalent rate with quarterly compounding is therefore __________________
Spot Rates
- The spot rate is the interest rate earned when cash is received at just one future time. It is also referred to as the zero-coupon interest rate, or just the “zero.”
Suppose USD 100 is invested today and is repaid with USD 120 in three years with no intermediate payments. The three-year spot rate is the rate that equates USD 120 in three years with USD 100 today. If the rate R is measured with annual compounding, then
With semi-annual compounding for example, the rate is given by:
When the discount factor d(t) is applied to this, it should bring it back to 100. Hence:
Par Rates
- The value of the coupon rate for which the value of the bond will be equal to its face value is referred to as the par rate.
- Let A(T) be the value of an instrument that pays USD 1 on every payment date (this is referred to as an annuity):
A(T) = d(0.5) + d(1.0) + d(1.5) + ⋯ + d(T)
It can be easily shown that for a semi-annual paying bond, the par rate is given by
- Suppose the spot interest rates, expressed with semi-annual compounding, for 0.5, 1.0, 1.5, and 2.0 years be 4%, 5%, 5.5%, and 6% (respectively).
The two-year par rate (%) is
Thus, a two-year bond paying a coupon semi-annually at a rate of __________________ per year is worth par.
Valuing Bond Using Par Rates
- The par rate in conjunction with the annuity factors A(T) to provide a way of valuing bonds with other coupons. Consider a bond with maturity T, coupon c, and a face value of 100. The value of the bond (V) is
It is known that:
Substituting for d(T)
In the earlier example, the par rate is _________________. When the coupon is ___________, this formula gives the value of the bond as:
Forward Rates
- Forward rates are the future spot rates implied by today’s spot rates. For example, suppose the offered one-year rate is 3% and the offered two-year rate is 4% (both with annual compounding). Suppose F is the forward rate for the second year. The forward rate is such that USD 100, if invested at 3% for the first year and at a rate of F for the second year, gives the same outcome as 4% for two years. This means that:
- When rates are expressed with semi-annual compounding (as is frequently the case in fixed-income markets), an extension of this analysis shows that the forward rate per six months for a six-month period starting at time T is
- where
are the spot rates for maturities T and T + 0.5 (respectively) with semi-annual compounding. Thus, the annualized forward rate expressed with semi-annual compounding is twice this.
- When rates are expressed with continuous compounding, the forward rate for the period between time
is
where
is the spot rate for maturity
is the spot rate for maturity
. This formula is approximately true when other compounding frequencies are used for the rates.
- When forward rates for successive periods are compounded, spot rates are obtained. For example, suppose all rates are expressed with semi-annual compounding, and that
are forward rates in n successive six-month periods. Then:
Thus, if a large financial institution can borrow or lend at spot rates, it can lock in the forward rate.
Properties Of Spot, Forward, And Par Rates
- Key properties of the rates discussed till now are as follows:
- If the term structure is flat (with all spot rates the same), all par rates and all forward rates equal the spot rate.
- If the term structure is upward-sloping, the par rate for a certain maturity is below the spot rate for that maturity.
- If the term structure is downward-sloping, the par rate for a certain maturity is above the spot rate for that maturity.
- If the term structure is upward-sloping, forward rates for a period starting at time T are greater than the spot rate for maturity T.
- If the term structure is downward-sloping, forward rates for a period starting at time T are less than the spot rate for maturity T.
- The situation for an upward-sloping term structure case is illustrated in this Table.
| Maturity (yrs) | Spot | 6-Month Fwd | Par |
|---|---|---|---|
| 0.5 | 2.01 | 4.04 | 2.01 |
| 1 | 3.02 | 4.86 | 3.01 |
| 1.5 | 3.63 | 5.27 | 3.62 |
| 2 | 4.04 | 5.83 | 4.01 |
| 2.5 | 4.40 | 5.94 | 4.36 |
| 3 | 4.65 | 6.24 | 4.60 |
| 3.5 | 4.88 | 6.36 | 4.82 |
| 4 | 5.06 | 6.54 | 4.99 |
| 4.5 | 5.23 | 6.67 | 5.14 |
| 5 | 5.37 | 5.28 |
- The situation for a downward-sloping term structure case is illustrated in this Table.
| Maturity (yrs) | Spot | 6-Month Fwd | Par |
|---|---|---|---|
| 0.5 | 5.06 | 4.24 | 5.06 |
| 1 | 4.65 | 3.73 | 4.66 |
| 1.5 | 4.35 | 3.73 | 4.36 |
| 2 | 4.19 | 3.17 | 4.21 |
| 2.5 | 3.99 | 3.07 | 4.01 |
| 3 | 3.84 | 3.12 | 3.86 |
| 3.5 | 3.73 | 3.08 | 3.76 |
| 4 | 3.65 | 3.10 | 3.68 |
| 4.5 | 3.59 | 3.08 | 3.62 |
| 5 | 3.54 | 3.57 |
Flattening And Steepening Term Structures
- A flattening term structure occurs
- When long- and short-maturity rates both move down, but long-maturity rates move down by more than short-maturity rates (known as a bull flattener); or
- When long- and short-maturity rates both move up, but short-maturity rates move up by more than long-maturity rates (known as a bear flattener).
- A steepening term structure occurs
- When long- and short-maturity rates both move down but short-maturity rates move down by more than long-maturity rates; or
- When long- and short-maturity rates both move up, but short-maturity rates move up by less than long-maturity rates.
- Note that a flattening term structure is not necessarily one that becomes flatter and a steepening term structure is not necessarily one that becomes steeper. If a term structure is already upward-sloping, then a steepening will cause it to be more upward-sloping and a flattening will cause it to be less upward-sloping. But if it is downward-sloping, the reverse is true. The steepening/flattening language refers to the relative rate movements and does not depend on the initial slope of the yield curve.
- Suppose a trader thinks the current upward-sloping term structure will steepen so that 20-year rates increase faster than ten-year rates. The trader can short 20-year bonds and buy ten-year bonds. If the trader is right, the 20-year bonds will decline in value relative to the ten-year bonds and the trader will make money. Similarly, a trader who thinks that the term structure will flatten should buy 20-year bonds and short ten-year bonds.
Frequently Asked Questions
What is the relationship between different compounding frequencies for interest rates ?
The relationship between different compounding frequencies can be calculated using specific formulas to determine equivalent interest rates.
What are spot rates ?
Spot rates are the interest rates earned on cash received at a single future time, often referred to as zero-coupon rates.
How do par rates differ from spot rates ?
Par rates are the coupon rates at which a bond's price equals its face value, whereas spot rates apply to cash received at a single future time.
How do you calculate a bond's value using par rates ?
Bond value can be calculated using par rates along with annuity factors to determine its present value.
What are forward rates ?
Forward rates are future interest rates implied by current spot rates, representing expected rates for future periods.
How do you determine the equivalent interest rate with different compounding frequencies ?
Equivalent rates can be determined by adjusting for different compounding periods using a specific formula.
What happens when the term structure is upward-sloping ?
In an upward-sloping term structure, forward rates are typically higher than the corresponding spot rates for future periods.
What is a flattening term structure ?
A flattening term structure occurs when long-term rates decrease more than short-term rates, reducing the slope of the yield curve.
What is a steepening term structure ?
A steepening term structure occurs when long-term rates increase more than short-term rates, increasing the slope of the yield curve.
How can traders profit from changes in the term structure ?
Traders can profit by taking positions that benefit from expected changes, such as steepening or flattening of the yield curve, by buying or shorting bonds of different maturities.
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